"For many years previous to this period (1829), ingenious mechanics had been engaged in attempting to solve the problem of the best and most economical boiler for the production of high-pressure steam. Various improvements had been suggested and made in the Trevithick boiler, as it was called, from the supposition that Mr. Trevithick was its inventor. But Mr. Oliver Evans, of Pennsylvania, many years before employed the same kind of boiler, and as he did not claim the invention, the probability is that it was in use before his time. The boiler in question was provided with an internal flue, through which the heated air and flames passed, after traversing the length of the under side of the boiler, before entering the chimney."This was the form of boiler adopted by Mr. Stephenson in his Killingworth engine, to which he added the steam-blast with such effect. We cannot do better than here quote the wordsof Mr. Robert Stephenson on the construction of the 'Rocket' engine:—'After the opening of the Stockton and Darlington, and before that of the Liverpool and Manchester Railway, my father directed his attention to various methods of increasing the evaporative power of the boiler of the locomotive engine. Amongst other attempts, he introduced tubes (as had before been done in other engines)—small tubes containing water, by which the heating surface was materially increased. Two engines with such tubes were constructed for the St. Etienne Railway, in France, which was in progress of construction in the year 1828; but the expedient was not successful; the tubes became furred with deposit, and burned out."'Other engines, with boilers of a variety of construction, were made, all having in view the increase of the heating surface, as it then became obvious to my father that the speed of the engine could not be increased without increasing the evaporative power of the boiler. Increase of surface was in some cases obtained by inserting two tubes, each containing a separate fire, into the boiler; in other cases the same result was obtained by returning the same tube through the boiler; but it was not until he was engaged in making some experiments, during the progress of the Liverpool and Manchester Railway, in conjunction with Mr. Henry Booth, the well-known secretary of the company, that any decided movement in this direction was effected, and that the present multitubular boiler assumed a practicable shape. It was in conjunction with Mr. Booth that my father constructed the 'Rocket' engine."'In this instance, as in every other important step in science or art, various claimants have arisen for the merit of having suggested the multitubular boiler as a means of obtaining the necessary heating surface. Whatever may be the value of their respective claims, the public, useful, and extensive application of the invention must certainly date from the experiments made at Rainhill. M. Seguin, for whom engines had been made by my father some few years previously, states that he patented a similar multitubular boiler in France several years before. A still prior claim is made by Mr. Stevens, of New York, who was all but a rival to Mr. Fulton in the introduction of steamboats on the American rivers. It is stated that as early as 1807 he used the multitubular boiler."'These claimants may all be entitled to great and independent merit; but certain it is, that the perfect establishment of the success of the multitubular boiler is more immediately due to the suggestion of Mr. Henry Booth, and to my father's practical knowledge in carrying it out.'"We may here briefly state that the boiler of the 'Rocket' was cylindrical, with flat ends, 6 feet in length, and 3 feet 4 inches in diameter. The upper half of the boiler was used as a reservoir for the steam, the lower half being filled with water. Through the lower part twenty-five copper tubes of 3 inches diameter extended, which were open to the fire-box at one end and to the chimney at the other. The fire-box, or furnace, 2 feet wide and 3 feet high, was attached immediately behind the boiler, and was also surrounded with water."
"For many years previous to this period (1829), ingenious mechanics had been engaged in attempting to solve the problem of the best and most economical boiler for the production of high-pressure steam. Various improvements had been suggested and made in the Trevithick boiler, as it was called, from the supposition that Mr. Trevithick was its inventor. But Mr. Oliver Evans, of Pennsylvania, many years before employed the same kind of boiler, and as he did not claim the invention, the probability is that it was in use before his time. The boiler in question was provided with an internal flue, through which the heated air and flames passed, after traversing the length of the under side of the boiler, before entering the chimney.
"This was the form of boiler adopted by Mr. Stephenson in his Killingworth engine, to which he added the steam-blast with such effect. We cannot do better than here quote the wordsof Mr. Robert Stephenson on the construction of the 'Rocket' engine:—'After the opening of the Stockton and Darlington, and before that of the Liverpool and Manchester Railway, my father directed his attention to various methods of increasing the evaporative power of the boiler of the locomotive engine. Amongst other attempts, he introduced tubes (as had before been done in other engines)—small tubes containing water, by which the heating surface was materially increased. Two engines with such tubes were constructed for the St. Etienne Railway, in France, which was in progress of construction in the year 1828; but the expedient was not successful; the tubes became furred with deposit, and burned out.
"'Other engines, with boilers of a variety of construction, were made, all having in view the increase of the heating surface, as it then became obvious to my father that the speed of the engine could not be increased without increasing the evaporative power of the boiler. Increase of surface was in some cases obtained by inserting two tubes, each containing a separate fire, into the boiler; in other cases the same result was obtained by returning the same tube through the boiler; but it was not until he was engaged in making some experiments, during the progress of the Liverpool and Manchester Railway, in conjunction with Mr. Henry Booth, the well-known secretary of the company, that any decided movement in this direction was effected, and that the present multitubular boiler assumed a practicable shape. It was in conjunction with Mr. Booth that my father constructed the 'Rocket' engine.
"'In this instance, as in every other important step in science or art, various claimants have arisen for the merit of having suggested the multitubular boiler as a means of obtaining the necessary heating surface. Whatever may be the value of their respective claims, the public, useful, and extensive application of the invention must certainly date from the experiments made at Rainhill. M. Seguin, for whom engines had been made by my father some few years previously, states that he patented a similar multitubular boiler in France several years before. A still prior claim is made by Mr. Stevens, of New York, who was all but a rival to Mr. Fulton in the introduction of steamboats on the American rivers. It is stated that as early as 1807 he used the multitubular boiler.
"'These claimants may all be entitled to great and independent merit; but certain it is, that the perfect establishment of the success of the multitubular boiler is more immediately due to the suggestion of Mr. Henry Booth, and to my father's practical knowledge in carrying it out.'
"We may here briefly state that the boiler of the 'Rocket' was cylindrical, with flat ends, 6 feet in length, and 3 feet 4 inches in diameter. The upper half of the boiler was used as a reservoir for the steam, the lower half being filled with water. Through the lower part twenty-five copper tubes of 3 inches diameter extended, which were open to the fire-box at one end and to the chimney at the other. The fire-box, or furnace, 2 feet wide and 3 feet high, was attached immediately behind the boiler, and was also surrounded with water."
Stephenson knew of Trevithick's patent of 1802,[185]in which a three-tubed boiler is shown; and it was after that time that Oliver Evans and Fulton tried their experiments, and also the numerous engines with single or return double tube, at work in the principal towns of England prior to 1804,[186]and near his residence in childhood and in manhood.[187]
George Stephenson's Killingworth boiler, "to which he added the steam-blast with such effect," was a copy of Trevithick's boiler and blast, working since 1804 in Newcastle-on-Tyne, and was precisely the boiler described by Stephenson; "in other cases the same result was obtained by returning the same tube through the boiler." This is an admission from Stephenson that Trevithick's patent boiler was the best in use up to about 1828.
A further proof of the indirect public gain from the use of Trevithick's return-tube boiler over a period of thirty years is their having supplied high-pressure expansive steam in the first experiments made with such steam by the Admiralty, at whose request Mr. Rennie and others examined the duty of the Cornish high-pressure expansive engine, and Captain King, R.N., in charge of the Admiralty Department at Falmouth in 1830, gave an order to Harvey and Co. to construct high-pressure steam-boilers for the Government vessel 'Echo'; in 1831 the machinery was put on board the 'Echo' in the Government Dockyard at Plymouth, and included three of Trevithick's return-tube boilers, made of wrought iron, each 5 feet 6 inches in diameter and 24 feet long, with internal return fire-tube 2 feet 2 inches in diameter. The fire-place end of the boiler was 6 feet 9 inches deep by 5 feet 6 inches wide, to give room for the fire-place and ash-pit. The steam pressure was 20 lbs. on the inch above the atmosphere, worked by double-beat valves, 6 inches in diameter, with expansive gear.
This new machinery was fixed under the superintendence of the writer, after which the Government engineers took charge of the vessel, and the writer who had, as the mechanic in charge, worked like a slave, though receiving but 1s.6d.a day and expenses, was not invited to take any part in the experimental trials, nor ever heard of the result except in the ordinary rumours of Admiralty bungling on board the 'Echo.'
Those boilers were similar to the Trevithick boiler that had served the locomotive in Newcastle and elsewhere from 1801 to 1828, the first steamboat experiments in England, in Scotland, and in America, and the numerous high-pressure engines then at work.
Bottle-neck Boiler.Bottle-neck Boiler.
Bottle-neck Boiler.
The enlarging the fire-place end of boilers or fire-tubes has led to many forms. Trevithick's model of 1796[188]had an oval tube giving a greater spread of fire-bars; the same is seen in the 1808 steamboat;[189]the Dolcoath boilers of 1811[190]show the oval and also the bottle-neck fire-tube; the Welsh locomotive of 1804[191]had the fire-tube contracted at its bend or return portion; the Tredegar puddling-mill fire-tube of 1801[192]tapered gradually from the fire-bridge to the chimney end; in the London locomotive of 1808[193]the fire-tube took the bottle-neck shape close to the fire-bridge. The accompanying sketch shows the bottle-neck contraction, only on the top and sides of the fire-tube was to give breadth to the fire-barsd, and thickness to the fire at bridgec, after which the flue portion of the fire-tube was contracted: this boiler was for many years a favourite in Cornwall. The bottle-neck contraction of the 'Echo' boiler was similar to the above, except that the enlargement of the fire-place was downwards instead of upwards, and the fire-tube, instead of going through the end of the boiler, returned to near the enlarged fire-place, when it passed out through the side of the boiler to the chimney, just as in the Tredegar puddling-mill boiler; all those variations were with the object of increasing the fire-grate, and at the same time keeping down the gross size and weight of boiler and its water.
In 1805, Lord Melville failed to keep his appointment with Trevithick, on his proposal to construct a high-pressure steamboat.[194]Rennie, a pupil and friend of Watt, and familiar with Trevithick's high-pressure steam-dredgers on the Thames, was employed by Lord Melville and the Admiralty on the Plymouth Breakwater, where in 1813 Trevithick proposed the use of his high-pressure steam locomotive and boring engine.[195]In 1820 Rennie wrote to Watt, that the Admiralty had at last decided upon having a steamer; at that time fifteen years had passed since Trevithick's offer to propel the Admiralty by steam-puffers, and ten years more were to pass before they could make up their minds to venture on high-pressure steam from his boilers. The Steam Users' Association are equally hesitating, judging from words just spoken by an engineer, the son of an engineer:—
"Sir William Fairbairn said he had come to the conclusion, after many years' experience, that it was in their power to economize the present expenditure of fuel by a system which might not be altogether in accordance with the views of the members of the association or the public at large, and that was to increase the pressure of steam. He would have great pleasure in stating a few facts which might some day tend to bring about a change, if not a new era, in the use of steam. From the result of a series of experimental researches in which he had been engaged for several years on the density, force, and temperature of steam, he had become convinced that in case we were ever to attain a large economy of fuel in the use of steam, it must be at greatly-increased pressure, and at a rate of expansion greatly enlarged from what it was at present. Already steam users had effected a saving of one-half the coal consumed by raising the pressure from 7 lbs. and 10 lbs.—thepressure at which engines were worked forty years ago—to 50 lbs., or in some cases as high as 70 lbs. on the square inch."[196]
"Sir William Fairbairn said he had come to the conclusion, after many years' experience, that it was in their power to economize the present expenditure of fuel by a system which might not be altogether in accordance with the views of the members of the association or the public at large, and that was to increase the pressure of steam. He would have great pleasure in stating a few facts which might some day tend to bring about a change, if not a new era, in the use of steam. From the result of a series of experimental researches in which he had been engaged for several years on the density, force, and temperature of steam, he had become convinced that in case we were ever to attain a large economy of fuel in the use of steam, it must be at greatly-increased pressure, and at a rate of expansion greatly enlarged from what it was at present. Already steam users had effected a saving of one-half the coal consumed by raising the pressure from 7 lbs. and 10 lbs.—thepressure at which engines were worked forty years ago—to 50 lbs., or in some cases as high as 70 lbs. on the square inch."[196]
Dear me! would have been Trevithick's exclamation had he read this; did I devote my whole life to the making known the advantages of high-pressure steam, and did I, seventy years ago,[197]really work expansive steam of 145 lbs. on the inch in the presence of many of the leading engineers of the day! Of course this short extract of a speech made by a member of a practical society, may not be taken as conveying fully the speaker's views, but it illustrates the immense difficulty Trevithick encountered in making his numerous plans acceptable to the public.
Another modern statement bearing on inventions originating with Trevithick, but wearing new garbs with new names, shows the same tendency to ignore old friends, or, to say the least of it, to pass them by:—
"The trial of No. 36 steam-pinnace was made at Portsmouth yesterday. Her peculiarity consists in the arrangement of her propelling machinery, in the adaptation of the outside surface condenser, and a vertical boiler, both patented by Mr. Alexander Crichton. The condenser is simply a copper pipe passing out from the boat on one quarter at the garboard strake, and along the side of the keel, returning along the keel on the opposite side, and re-entering the boat on that quarter. The boiler is designed for boats fitted with condensing engines, and which, therefore, are without the acceleration of draught given by the exhausted steam being discharged into the funnel. It is of the vertical kind, and stands on a shallow square tank, whichforms the hot well. The tubes are horizontal over the fire, the water circulating through them. The condensed steam is pumped into the well at a temperature of 100°, and being there subjected to the heat radiating from the furnace, is pumped back into the boilers at nearly boiling point. It is estimated that, under these conditions, the pinnace would run for nearly 48 hours without having to 'blow off' or carry a supply of fresh water, the waste water being made good by sea water."[198]
"The trial of No. 36 steam-pinnace was made at Portsmouth yesterday. Her peculiarity consists in the arrangement of her propelling machinery, in the adaptation of the outside surface condenser, and a vertical boiler, both patented by Mr. Alexander Crichton. The condenser is simply a copper pipe passing out from the boat on one quarter at the garboard strake, and along the side of the keel, returning along the keel on the opposite side, and re-entering the boat on that quarter. The boiler is designed for boats fitted with condensing engines, and which, therefore, are without the acceleration of draught given by the exhausted steam being discharged into the funnel. It is of the vertical kind, and stands on a shallow square tank, whichforms the hot well. The tubes are horizontal over the fire, the water circulating through them. The condensed steam is pumped into the well at a temperature of 100°, and being there subjected to the heat radiating from the furnace, is pumped back into the boilers at nearly boiling point. It is estimated that, under these conditions, the pinnace would run for nearly 48 hours without having to 'blow off' or carry a supply of fresh water, the waste water being made good by sea water."[198]
The peculiarity of this steam-pinnace of 1871, on which a patent was granted, is stated to be a metal surface condenser exposed to the cold water at the bottom of the boat, returning the condensed steam at about boiling temperature to the boiler, and a vertical boiler with horizontal tubes through which the water circulates, both of which in principle, if not in detail, are seen in the surface condenser of Trevithick's iron-bottom ship of 1809, and his vertical boiler of 1816,[199]and further illustrated in the inventions spoken of in this and the following chapter; and yet on so all-important a subject, dealt with in various ways by Trevithick from 1804 to 1832, his plans are reproduced as discoveries in 1871.
About 1828, Mr. Rennie, Mr. Henwood, and others, reported on the advantages of high-pressure expansive steam in Wheal Towan engine,[200]on the north cliffs of Cornwall, near Wheal Seal-hole Mine on St. Agnes Head, where in 1797 Trevithick had worked his first high-pressure steam-puffer engine in competition with the Watt low-pressure steam-vacuum engine. Captain Andrew Vivian was then his companion, and the Cow and Calf, two rocks of unequal size, a mile from the land, were from that time called Captain Dick andCaptain Andrew, or the Man and his Man, and there they still remain in the Atlantic waves, fit emblems of their namesakes and their still living inventions. The stir made by those expansive trials led to the experiment in the 'Echo,' of which Mr. Henwood[201]thus speaks:—
"Captain William King, R.N., Superintendent of the Packet Station at Falmouth, attempted to impress on Viscount Melville, then First Lord of the Admiralty, the advantage of using high-pressure steam expansively in the Royal Navy, to whom Lord Melville replied that he had been taught by his friend, the late Mr. Rennie, that the danger attending such a course was very great, and that it would be difficult, if not impossible, to persuade him to the contrary."
"Captain William King, R.N., Superintendent of the Packet Station at Falmouth, attempted to impress on Viscount Melville, then First Lord of the Admiralty, the advantage of using high-pressure steam expansively in the Royal Navy, to whom Lord Melville replied that he had been taught by his friend, the late Mr. Rennie, that the danger attending such a course was very great, and that it would be difficult, if not impossible, to persuade him to the contrary."
Captain Dick and Captain Andrew, or the Man and his Man.[W. J. Welch.]
Captain Dick and Captain Andrew, or the Man and his Man.[W. J. Welch.]
Twenty-five years of precept and example caused the Admiralty to follow suit, and to request Mr. Ward, a Cornish engineer, to construct boilers and expansive valves for the Government steamboat 'Echo.' The writer was entrusted with fixing the machinery in thevessel at the Plymouth Dockyard, and before starting with it from Harvey and Co.'s foundry, waited on Captain King, R.N., at Falmouth, for his instructions, in happy ignorance of the fear of the Lords of the Admiralty to tread on Cornish high-pressure. After eying the applicant as captains in Her Majesty's service are apt to do when dealing with boys in the civil service, he vouchsafed to say, "Mind, young man, what you are about, for if there is a blow up, by —— you'll swing at the yard-arm."
HEATING APPARATUS—MARINE STEAM-ENGINES—REFORM COLUMN.
"Lauderdale House, Highgate,"March 1st, 1830.""Mr. Gilbert,"Sir,—I have to apologize for my neglect in not calling on you, but ill-health prevented it. I left home on the 11th February, arrived in town on the 14th, and remained there until the 24th, when I was compelled to leave for this place, having a free good air. I am now taking, twice a day, the flowers of zinc, from which I hope to be soon right again. I am much better, but afraid to enter the city. I hope to be able to call on you before the end of this week, being very anxious to see you, having a great deal to communicate respecting the experiments I have been making, which will bear out to the full our expectations."Your hot-house apparatus has been finished nearly three months, all but two or three days' work to fit the parts together; I expect that before this they are in Penzance, waiting a ship for London. While making a sketch of your work for the founder, a thought struck me that rooms might be better heated by hot water than by either steam or fire, and I send to you my thoughts on it, with a sketch for your consideration. I find that steam-pipes applied to heat cotton factories, with 1 surface foot of steam-pipe, heat 200 cubic feet of space to 60 degrees. I also found in Germany, where all the rooms are heated by cast-iron pipes about the heat of steam, that 1 foot of external flue heated 160 cubic feet of space to 70 degrees."I find also that about 200 surface feet of steam-engine cylinder-case will condense about as much steam as will produce 15 gallons of water per hour, and will consume about 4 bushels in twenty-four hours to keep the temperature of212 degrees. One bushel of coal will raise the temperature of 3600 lbs. of water from 40 to 212 degrees."A boiler, as the drawing, will contain 1200 lbs. of water, and consume one-third of a bushel of coal to raise the water from 40 to 212 degrees. It has 40 surface feet of hot sides giving out its heat. The 12-inch fire-tube in the boiler would raise the temperature to 212 degrees in about forty minutes. By these proofs it appears that 50 feet of surface steam sides will require 1 bushel of coal every twenty-four hours to keep up the boiling heat; therefore this boiler, having 40 surface feet, would give out the heat from one-third of a bushel of coal in twelve hours."Now suppose this charge of heat required to be thrown off in either more or less than twelve hours, the circular curtain would adjust the heat and time for extracting it.Hot-water Room-warmerHot-water Room-warmer."By the foregoing this coal and surface sides would heat to 60 degrees for twelve hours a space of 6800 cubic feet, equal to a room of 25 feet square and 11 feet high. If this boiler was placed in a room with a chimney, its water could be heated by having a small shifting wrought-iron chimney-tube of 4 inches diameter and 2 or 3 feet long attached to the end of the boiler while it was getting up steam, after which it might be removed, and the doors at both ends of the boiler closed; and as the boiler contains and retains its heat for twelve hours, more or less, it might be run on its wheels to any fire-place or chimney to get charged with heat, and then run into any room, where there was no chimney, or into bed-rooms, offices, or public buildings; it would be free from risk, not having either steam or loose fire. The circular curtain, being fast to a woodtable, would by being drawn up or down adjust the required heat and hide the boiler, and would be warm and comfortable to sit at. I think this plan would save three-quarters of the coal at present consumed; the expense of the boiler will not exceed 5l. When you have taken it into consideration, please to write me your opinion."I remain, Sir,"Your very humble servant,"R. Trevithick."P.S.—Boiler, 3 feet diameter, 3 feet long; fire-tube, 12 inches diameter, placed in the boiler, the same as my old boilers, made of iron plates 1/8th of an inch thick, weighing about 2 cwt."I had a summons to attend at Guildhall last Saturday on the coal trade, and was requested to attend a committee at Westminster for the same purpose, in consequence of my applying small engines to discharge ships."I attended, but with difficulty, from my ill-health."
"Lauderdale House, Highgate,"March 1st, 1830.
""Mr. Gilbert,
"Sir,—I have to apologize for my neglect in not calling on you, but ill-health prevented it. I left home on the 11th February, arrived in town on the 14th, and remained there until the 24th, when I was compelled to leave for this place, having a free good air. I am now taking, twice a day, the flowers of zinc, from which I hope to be soon right again. I am much better, but afraid to enter the city. I hope to be able to call on you before the end of this week, being very anxious to see you, having a great deal to communicate respecting the experiments I have been making, which will bear out to the full our expectations.
"Your hot-house apparatus has been finished nearly three months, all but two or three days' work to fit the parts together; I expect that before this they are in Penzance, waiting a ship for London. While making a sketch of your work for the founder, a thought struck me that rooms might be better heated by hot water than by either steam or fire, and I send to you my thoughts on it, with a sketch for your consideration. I find that steam-pipes applied to heat cotton factories, with 1 surface foot of steam-pipe, heat 200 cubic feet of space to 60 degrees. I also found in Germany, where all the rooms are heated by cast-iron pipes about the heat of steam, that 1 foot of external flue heated 160 cubic feet of space to 70 degrees.
"I find also that about 200 surface feet of steam-engine cylinder-case will condense about as much steam as will produce 15 gallons of water per hour, and will consume about 4 bushels in twenty-four hours to keep the temperature of212 degrees. One bushel of coal will raise the temperature of 3600 lbs. of water from 40 to 212 degrees.
"A boiler, as the drawing, will contain 1200 lbs. of water, and consume one-third of a bushel of coal to raise the water from 40 to 212 degrees. It has 40 surface feet of hot sides giving out its heat. The 12-inch fire-tube in the boiler would raise the temperature to 212 degrees in about forty minutes. By these proofs it appears that 50 feet of surface steam sides will require 1 bushel of coal every twenty-four hours to keep up the boiling heat; therefore this boiler, having 40 surface feet, would give out the heat from one-third of a bushel of coal in twelve hours.
"Now suppose this charge of heat required to be thrown off in either more or less than twelve hours, the circular curtain would adjust the heat and time for extracting it.
Hot-water Room-warmerHot-water Room-warmer.
Hot-water Room-warmer.
"By the foregoing this coal and surface sides would heat to 60 degrees for twelve hours a space of 6800 cubic feet, equal to a room of 25 feet square and 11 feet high. If this boiler was placed in a room with a chimney, its water could be heated by having a small shifting wrought-iron chimney-tube of 4 inches diameter and 2 or 3 feet long attached to the end of the boiler while it was getting up steam, after which it might be removed, and the doors at both ends of the boiler closed; and as the boiler contains and retains its heat for twelve hours, more or less, it might be run on its wheels to any fire-place or chimney to get charged with heat, and then run into any room, where there was no chimney, or into bed-rooms, offices, or public buildings; it would be free from risk, not having either steam or loose fire. The circular curtain, being fast to a woodtable, would by being drawn up or down adjust the required heat and hide the boiler, and would be warm and comfortable to sit at. I think this plan would save three-quarters of the coal at present consumed; the expense of the boiler will not exceed 5l. When you have taken it into consideration, please to write me your opinion.
"I remain, Sir,"Your very humble servant,"R. Trevithick.
"P.S.—Boiler, 3 feet diameter, 3 feet long; fire-tube, 12 inches diameter, placed in the boiler, the same as my old boilers, made of iron plates 1/8th of an inch thick, weighing about 2 cwt.
"I had a summons to attend at Guildhall last Saturday on the coal trade, and was requested to attend a committee at Westminster for the same purpose, in consequence of my applying small engines to discharge ships.
"I attended, but with difficulty, from my ill-health."
Trevithick was not above scheming for his friend's hot-house, warming it by a boiler on wheels, in form like his high-pressure steam-boiler. Rooms had before been heated by steam or hot air in pipes; but he thought a more simple and economical plan was to heat a certain quantity of water to boiling heat at any convenient place having a chimney, or in the open air, and then wheel the apparatus into the room to be warmed. If the room had a chimney, the fire could be kept up, or the temporary iron connecting chimney be removed and the apparatus wheeled into the middle of the room and used as a table.
The scheme promised to be successful, for in a letter nine months after the former he wrote that he had taken a patent for France, where it had made a great bustle among the scientific class, for coal in Paris was 3s.a hundredweight; some hot-water room-heaterswere the following day to be forwarded from London to Paris; while the numerous orders were more than he could execute. One in use at the 'George and Vulture' Tavern, of a Gothic shape, handsomely ornamented with brass, about two-thirds the size of the one in Mr. Gilbert's hot-house, burns 7 lbs. of coal a day, keeping the room at 65 degrees of heat during fifteen hours. The rage amongst the ladies was to have them handsomely ornamented.
Believing that they would be remunerative, he applied for the following English patent in February, 1831.
PLATE 16PLATE 16.HEATING APPARATUS.London: E & F.N. Spon, 48. Charing Gross. Kell Bros. Lith. London.
PLATE 16.HEATING APPARATUS.
London: E & F.N. Spon, 48. Charing Gross. Kell Bros. Lith. London.
Apparatus for Heating Apartments. 21st February, 1831."Now know ye, that in compliance with the said proviso, I, the said Richard Trevithick, do hereby declare that the nature of my said invention of a method or apparatus for heating apartments, and the manner in which the same is to be carried into effect, is shown by the following drawings and description, where Fig. 1, Plate XVI., represents a longitudinal vertical section through the middle of a metallic vessel capable of containing a considerable quantity of water, with a fire-place in the inside, surrounded with water in all parts except at the doorway and at an opening where the smoke may pass off into a common chimney. Fig. 2, a vertical section near the fire-door, at right angles to the section shown at Fig. 1; with the sections are also shown wheels and handles, which lie out of the planes of the sections. The letters of reference indicate the same parts in both figures,a, the vessel;b, the space for containing the water;c, the fire-place;d, the fire-bars, or grating;e, the ash-pit;f, an inner door, to prevent the air from entering over the fire, yet allow it to pass into the ash-pit, and thence up to the fire through the grating;g, an outer door, to be shut when the fire is to be extinguished;h, a chimney or flue, to convey the smoke into a common chimney: this flue may be removed when the water boils, and then the opening of the flue may be shut, to keep in the heat, either by a door or by a plug fitting the opening;k, the cover of the vessel, having a rim all round, within which iron cement is to be driven to make the vessel steam-tight;l, a hole in the middle of the cover, into which a plug is dropped having a fluted stem and a flat head ground steam-tight upon the cover; this plug or valve is for the purpose of allowing the escape of steam if it should be raised above boiling point, and the valve is taken out when it may be necessary to pour water into the vessel;m, four wheels, on which the vessel may be easily removed from one room to another;n, two handles, to facilitate the removal. To use this apparatus for the warming of an apartment, the vessel is nearly filled with water, and placed so near to a chimney in another room, if more convenient, that the flue-piecehmay convey away the smoke; a fire is then lighted upon the gratingd, and continued till the water boils, when the flue-piece is taken away, and the flue opening stopped with the plug or door, and also the outer fire-door closed. In this state the apparatus is drawn into the apartment to be warmed, where it will continue for many hours to give off a most agreeable heat without any of that offensive odour usually experienced from stoves heated by an enclosed fire. Figs. 3, 4, 5, and 6 represent another form of my apparatus for heating churches or other large buildings. Fig. 3, a vertical section, from A to B, of Figs. 5 and 6, with a representation of the flue and its flanch, which lie beyond that section and the fire doorway and its flanch, which lie nearer, and also the four wheels, two of which are on each side of the section. Fig. 5, a horizontal section, from E to F, of Figs. 3 and 4. Fig. 6, a horizontal section, from G to H, of Figs. 3 and 4, with a view of the four handles situated at a higher level than the section, and of the fire-bars at a lower level; the same letters of reference signify the same parts in all the four figures,a, the outer case of the water-vessel;b, the cover;c, the space for water;d, the fire-place and flue;e, the fire-bars, made in two pieces, to be introduced through the fire doorway;f, the ash-pit;g, the fire-door;h, pipes open at top and bottom, cemented into holes in the bottom, and in the cover of the water-vessel; these pipes are to admit a current of air up through them, in order the more speedily to carry the heat into the building;k, the aperture in the cover, to supply the vessel with water, and the plug to keep in the steam;l, four wheels, on which the whole is moved, each wheel revolving in a recess cast in the bottom of the outer case, as represented by dotted lines in Figs. 3 and 4;m, four handles;n, the flanches of the fire doorway and of the flue, represented in Fig. 4 by dotted lines. A pipe to communicate with a chimney while the water is being heated must be made to suit locality, and therefore cannot require any description. This apparatus can be heated in a vestry room, and the fire-door and flue closed and then wheeled into the church, where it will soon diffuse a most comfortable warmth; or the heat may be kept up while standing in its place by having a constant communication with a chimney, and thus diffuse a much more salubrious heat than can be obtained by metallic or earthen stoves heated immediately by the fire."
Apparatus for Heating Apartments. 21st February, 1831.
"Now know ye, that in compliance with the said proviso, I, the said Richard Trevithick, do hereby declare that the nature of my said invention of a method or apparatus for heating apartments, and the manner in which the same is to be carried into effect, is shown by the following drawings and description, where Fig. 1, Plate XVI., represents a longitudinal vertical section through the middle of a metallic vessel capable of containing a considerable quantity of water, with a fire-place in the inside, surrounded with water in all parts except at the doorway and at an opening where the smoke may pass off into a common chimney. Fig. 2, a vertical section near the fire-door, at right angles to the section shown at Fig. 1; with the sections are also shown wheels and handles, which lie out of the planes of the sections. The letters of reference indicate the same parts in both figures,a, the vessel;b, the space for containing the water;c, the fire-place;d, the fire-bars, or grating;e, the ash-pit;f, an inner door, to prevent the air from entering over the fire, yet allow it to pass into the ash-pit, and thence up to the fire through the grating;g, an outer door, to be shut when the fire is to be extinguished;h, a chimney or flue, to convey the smoke into a common chimney: this flue may be removed when the water boils, and then the opening of the flue may be shut, to keep in the heat, either by a door or by a plug fitting the opening;k, the cover of the vessel, having a rim all round, within which iron cement is to be driven to make the vessel steam-tight;l, a hole in the middle of the cover, into which a plug is dropped having a fluted stem and a flat head ground steam-tight upon the cover; this plug or valve is for the purpose of allowing the escape of steam if it should be raised above boiling point, and the valve is taken out when it may be necessary to pour water into the vessel;m, four wheels, on which the vessel may be easily removed from one room to another;n, two handles, to facilitate the removal. To use this apparatus for the warming of an apartment, the vessel is nearly filled with water, and placed so near to a chimney in another room, if more convenient, that the flue-piecehmay convey away the smoke; a fire is then lighted upon the gratingd, and continued till the water boils, when the flue-piece is taken away, and the flue opening stopped with the plug or door, and also the outer fire-door closed. In this state the apparatus is drawn into the apartment to be warmed, where it will continue for many hours to give off a most agreeable heat without any of that offensive odour usually experienced from stoves heated by an enclosed fire. Figs. 3, 4, 5, and 6 represent another form of my apparatus for heating churches or other large buildings. Fig. 3, a vertical section, from A to B, of Figs. 5 and 6, with a representation of the flue and its flanch, which lie beyond that section and the fire doorway and its flanch, which lie nearer, and also the four wheels, two of which are on each side of the section. Fig. 5, a horizontal section, from E to F, of Figs. 3 and 4. Fig. 6, a horizontal section, from G to H, of Figs. 3 and 4, with a view of the four handles situated at a higher level than the section, and of the fire-bars at a lower level; the same letters of reference signify the same parts in all the four figures,a, the outer case of the water-vessel;b, the cover;c, the space for water;d, the fire-place and flue;e, the fire-bars, made in two pieces, to be introduced through the fire doorway;f, the ash-pit;g, the fire-door;h, pipes open at top and bottom, cemented into holes in the bottom, and in the cover of the water-vessel; these pipes are to admit a current of air up through them, in order the more speedily to carry the heat into the building;k, the aperture in the cover, to supply the vessel with water, and the plug to keep in the steam;l, four wheels, on which the whole is moved, each wheel revolving in a recess cast in the bottom of the outer case, as represented by dotted lines in Figs. 3 and 4;m, four handles;n, the flanches of the fire doorway and of the flue, represented in Fig. 4 by dotted lines. A pipe to communicate with a chimney while the water is being heated must be made to suit locality, and therefore cannot require any description. This apparatus can be heated in a vestry room, and the fire-door and flue closed and then wheeled into the church, where it will soon diffuse a most comfortable warmth; or the heat may be kept up while standing in its place by having a constant communication with a chimney, and thus diffuse a much more salubrious heat than can be obtained by metallic or earthen stoves heated immediately by the fire."
It is doubtful if the profits he received from the heating apparatus covered the cost of the patent. The first stove was not unlike his first locomotive boiler. The more highly-finished stove resembled the marine tubular boiler, also of former years, in the further application of which we now follow him.
"Hayle,January 24th, 1829.""Mr. Gilbert,"Sir,—Since I have been down I have made a small portable engine, and set it to work on board a coal-ship for discharging the cargo; it is very manageable, and discharges 100 tons with 1 bushel of coal, without any person to attend it, there being a string that the man in the hold draws when the coal-basket is hooked, which is again drawn by the man who lands the basket on the deck; the string turns and re-turns the engine. It is near a ton weight, but as I find it double the power required, I am now making a smaller one, 3½ feet high and 3½ feet diameter, about 12 cwt."I intend this engine to warp the ship, pump it, cook the victuals, take in and out the cargo, and do all the hard work. The captains are very anxious to get them on board every ship. I think that an engine of 39 cwt. would propel their ships four miles an hour over and above the other work of the ship, and would neither be so heavy or take so much room as their present cooking house and furnace. I think that two iron paddles, one on each side of the rudder, under the stern, would do this very well; they would be in dead water, and out of the swell of the sea, and by being deep in the water would have a good resistance. Two paddles, each about 4 feet deep and 3 feet wide, would do this, without their rising out of the water; therefore their stroke would be nearly horizontal. The return stroke would be in the water. Thus, let the paddle stand perpendicular in the water, two-fifths of its width on one side, and three-fifths on the other side, the centre, which would turn its edge to the water on its back stroke, and its flat to the water on the forward stroke; it would be light, and out of the way of anything. I have a patent now going through the office for all this, which will also cover the new principle of returning the heat back again, as already described to you. The engine for drawing in Holland will be ready about the end of February, and by that time I shall have a complete portable engine ready for London for discharging, when I shall be in town.Boat and PropellerBoat and Propeller."I remain, Sir,"Your humble servant,"Rd. Trevithick."P.S.—Wheal Towan engine is working with three boilers, all of the same size, and the strong steam from the boilers to the cylinder-case; the boilers are so low as to admit the condensed water to run back from the case again into the boiler. They find that this water is sufficient to feed one of these boilers without any other feed-water; therefore one-third of the steam generated must be condensed by the cold sides of the cylinder-case, and this agrees with the experiments I sent to you from Binner Downs. Wheal Towan engine has an 80-inch cylinder,and requires 72 bushels of coal in twenty-four hours; therefore the cylinder-case must in condensing high-pressure steam use 24 bushels of coal in twenty-four hours. Boulton and Watt's case for a 63-inch cylinder, working with low-pressure steam, condensed only 4½ bushels of coal in equal time, the proportions of surface being as 190 to 240 in Wheal Towan. Nearly five times the quantity was condensed of high steam than of low steam, proving that there is a theory yet unaccounted for."
"Hayle,January 24th, 1829.
""Mr. Gilbert,
"Sir,—Since I have been down I have made a small portable engine, and set it to work on board a coal-ship for discharging the cargo; it is very manageable, and discharges 100 tons with 1 bushel of coal, without any person to attend it, there being a string that the man in the hold draws when the coal-basket is hooked, which is again drawn by the man who lands the basket on the deck; the string turns and re-turns the engine. It is near a ton weight, but as I find it double the power required, I am now making a smaller one, 3½ feet high and 3½ feet diameter, about 12 cwt.
"I intend this engine to warp the ship, pump it, cook the victuals, take in and out the cargo, and do all the hard work. The captains are very anxious to get them on board every ship. I think that an engine of 39 cwt. would propel their ships four miles an hour over and above the other work of the ship, and would neither be so heavy or take so much room as their present cooking house and furnace. I think that two iron paddles, one on each side of the rudder, under the stern, would do this very well; they would be in dead water, and out of the swell of the sea, and by being deep in the water would have a good resistance. Two paddles, each about 4 feet deep and 3 feet wide, would do this, without their rising out of the water; therefore their stroke would be nearly horizontal. The return stroke would be in the water. Thus, let the paddle stand perpendicular in the water, two-fifths of its width on one side, and three-fifths on the other side, the centre, which would turn its edge to the water on its back stroke, and its flat to the water on the forward stroke; it would be light, and out of the way of anything. I have a patent now going through the office for all this, which will also cover the new principle of returning the heat back again, as already described to you. The engine for drawing in Holland will be ready about the end of February, and by that time I shall have a complete portable engine ready for London for discharging, when I shall be in town.
Boat and PropellerBoat and Propeller.
Boat and Propeller.
"I remain, Sir,"Your humble servant,"Rd. Trevithick.
"P.S.—Wheal Towan engine is working with three boilers, all of the same size, and the strong steam from the boilers to the cylinder-case; the boilers are so low as to admit the condensed water to run back from the case again into the boiler. They find that this water is sufficient to feed one of these boilers without any other feed-water; therefore one-third of the steam generated must be condensed by the cold sides of the cylinder-case, and this agrees with the experiments I sent to you from Binner Downs. Wheal Towan engine has an 80-inch cylinder,and requires 72 bushels of coal in twenty-four hours; therefore the cylinder-case must in condensing high-pressure steam use 24 bushels of coal in twenty-four hours. Boulton and Watt's case for a 63-inch cylinder, working with low-pressure steam, condensed only 4½ bushels of coal in equal time, the proportions of surface being as 190 to 240 in Wheal Towan. Nearly five times the quantity was condensed of high steam than of low steam, proving that there is a theory yet unaccounted for."
Trevithick's portable high-pressure steam-puffer engine, when it discharged the first cargo of coal from a vessel at Hayle, was worked by the writer; it stood on the wharf near the ship, and on a signal from the hold, steam was turned on, raising rapidly the basket of coal the required height. In trying how quickly the work could be done the hook missed the basket-rope, and caught the man under the chin, swinging him high in the air, much to the engineman's discomfiture. Fortunately the suspended man had the good sense to lay hold of the rope above his head, and so supporting his weight, no great harm was done.
The object and the means were the revival of the nautical labourer of twenty years before.[202]The boiler was a wrought-iron barrel on its end, on small wheels, with internal fire-tube, in shape like the boiler of the recoil engine of 1815;[203]but less high in proportion to its diameter. The cylinder was let down into the top of the boiler, and like Newcomen's atmospheric engine had no cylinder cover. The piston-rod was a rack giving motion to a small pinion fixed on a shaft on the top of the boiler, and to a large grooved wheel, around which was wound the whip-rope from the vessel's hold; a brake-lever enabled the engineman either to stop orto reduce the speed. Four months prior to the date of this letter he had sent a written offer to the Common Council of the city of London, offering to provide engines to discharge all coal-ships for the saving he would effect in six months, or he would supply an engine and boxes complete for 100 guineas. He at the same time suggested that in place of the baskets holding 1 bushel, iron boxes on wheels, holding 4 bushels, with a spring steelyard attached, should be used with his steam-engine, giving the exact weight without delay. He seems to have forgotten his nautical labourer patented twenty years before;[204]but yet reproduced something very similar.
Every trading vessel was recommended to carry at least a 12-cwt. high-pressure steam-puffer engine, suitable for warping, pumping, and discharging cargo; but a 30-cwt. engine, not occupying more room than a caboose, would in addition cook for the crew, and propel the vessel at three or four miles an hour.
Two iron paddles, like the duck's feet described to his Binner Downs friends many years before,[205]were to be fixed on an iron shaft across the stern of the vessel, receiving from the engine a motion like a pendulum. Each duck's foot was an iron plate 4 feet deep and 3 feet wide, turning partly round on its iron leg, to which it was attached as a vane, about 1 foot of its width on one side of its leg, and 2 feet on the other side; when the leg and foot were drawn toward the vessel, the foot, turning on its leg as a centre, exposed its edge only to the water; on the reverse movement, the longer side like a vane turned round until its flat was opposed to the water, in which position it was keptby a catch until the return movement, so that when it propelled, its whole surface pressed against the water, and when moving in a contrary sense, only its edge offered resistance to the water.
The writer has no record of the practical application of the duck's foot as a steamboat propeller; but the portable puffer-engine now pulls on board the fisherman's heavy nets, and the magnificent steamer 'Adriatic' hoists her sails on iron yards and masts by six of those steam helps.[206]
Twenty years before he had solicited the Navy Board to try his iron ships propelled by high-pressure steam-engines, and had shown their applicability as steam-dredgers; and again, shortly after his return from America, he pressed on their attention the same subject under new forms, followed by communications with their engineer, Mr. Rennie, and a proposal to place an engine in a boat at his own cost.
The writer has attempted in this and the preceding chapter to classify Trevithick's schemes, crowded together in those last years of his life, but the subjects so run into one another that the acts of twenty years before must be borne in mind to enable the more modern plans to be understood.
The letter introducing the surface condenser, in 1828, at the commencement of the former chapter, was in a month followed by that recommending a particular kind of paddle to be used as auxiliary steam-power, and after six months of experiments, by the patent of 1831, and the following correspondence:—
"Hayle,December 30th, 1828.""Mr. Gilbert,"Sir,—Yesterday I saw Mr. George Rennie, and he requested me to write to the Admiralty, a copy of which I sendboth to you and to him, for your inspection. Mr. Rennie said there was a great deal contained in what I had stated to him, and that he would with pleasure forward my views, as far as he could with consistency."I remain, Sir,"Your very humble servant,"Richard. Trevithick.
"Hayle,December 30th, 1828.
""Mr. Gilbert,
"Sir,—Yesterday I saw Mr. George Rennie, and he requested me to write to the Admiralty, a copy of which I sendboth to you and to him, for your inspection. Mr. Rennie said there was a great deal contained in what I had stated to him, and that he would with pleasure forward my views, as far as he could with consistency.
"I remain, Sir,"Your very humble servant,"Richard. Trevithick.
"To the Right Honourable the Lords Commissioners of the Admiralty, &c., &c., &c."My Lords,"About one year since I had the honour of attending your honourable Board, with proposed plans for the improvement of steam navigation; and as you expressed a wish to see it accomplished, I immediately made an engine of considerable power, for the express purpose of proving by practice what I then advanced in theory. The result has fully answered my expectations; therefore I now make the following propositions to your honourable Board, that this entirely new principle and new mode may be fully demonstrated, on a sufficient scale for the use of the public."I humbly request that your Lordships will grant me the loan of a vessel of about two or three hundred tons burthen, in which I will fix, at my own expense and risk, an engine of suitable power to propel the same at the speed required. No alteration in the vessel will be necessary, and the whole apparatus required to receive its propelling force from the water can be removed and again replaced with the same facility as the sails, thus leaving the ship without any apparatus beyond its sides when propelled by wind alone, and when propelled by steam alone the apparatus outside the ship will receive scarcely any shock from the sea."This new invention entirely removes the great objection of feeding the boiler with salt and foul water, and not one-sixth part of the room for fuel, or of weight of machinery now used, will be required; it is also much more simple and safe, not only for navigation, but for all other purposes where locomotive power is required, and will supersede all animal power, as theobjections of weight, room, and difficulty of getting and of carrying water in locomotive engines is entirely removed. It will therefore prove an investigation of greater utility to the public than anything yet introduced."I have to beg the great favour of your Lordships appointing not only scientific but practical engineers to inspect my plans, that you may be perfectly satisfied of their utility, not only in theory, but also as to the practicability of carrying the same into full effect."
"To the Right Honourable the Lords Commissioners of the Admiralty, &c., &c., &c.
"My Lords,
"About one year since I had the honour of attending your honourable Board, with proposed plans for the improvement of steam navigation; and as you expressed a wish to see it accomplished, I immediately made an engine of considerable power, for the express purpose of proving by practice what I then advanced in theory. The result has fully answered my expectations; therefore I now make the following propositions to your honourable Board, that this entirely new principle and new mode may be fully demonstrated, on a sufficient scale for the use of the public.
"I humbly request that your Lordships will grant me the loan of a vessel of about two or three hundred tons burthen, in which I will fix, at my own expense and risk, an engine of suitable power to propel the same at the speed required. No alteration in the vessel will be necessary, and the whole apparatus required to receive its propelling force from the water can be removed and again replaced with the same facility as the sails, thus leaving the ship without any apparatus beyond its sides when propelled by wind alone, and when propelled by steam alone the apparatus outside the ship will receive scarcely any shock from the sea.
"This new invention entirely removes the great objection of feeding the boiler with salt and foul water, and not one-sixth part of the room for fuel, or of weight of machinery now used, will be required; it is also much more simple and safe, not only for navigation, but for all other purposes where locomotive power is required, and will supersede all animal power, as theobjections of weight, room, and difficulty of getting and of carrying water in locomotive engines is entirely removed. It will therefore prove an investigation of greater utility to the public than anything yet introduced.
"I have to beg the great favour of your Lordships appointing not only scientific but practical engineers to inspect my plans, that you may be perfectly satisfied of their utility, not only in theory, but also as to the practicability of carrying the same into full effect."
The petition in June, 1830, for the loan of a Government hulk, hung fire up to January 1832, when an attempt was made to move the Lords Commissioners of the Admiralty by the force of numbers.
"We, whose names are hereunto subscribed, have known Mr. Richard Trevithick, of Hale, in the county of Cornwall, for a period of years, and during which time his conduct has merited our unqualified approbation. As an engineer of experience and eminence few, if any, can surpass him, and his present improvement of the steam-engine seems to outvie all others. We therefore, in justice to his talent, strongly recommend to the Lords Commissioners of the Admiralty that he may be permitted, at his own costs and charges, to fit and make trial of his engine in one of His Majesty's vessels."Dated in London this 27th day of January, 1832."
"We, whose names are hereunto subscribed, have known Mr. Richard Trevithick, of Hale, in the county of Cornwall, for a period of years, and during which time his conduct has merited our unqualified approbation. As an engineer of experience and eminence few, if any, can surpass him, and his present improvement of the steam-engine seems to outvie all others. We therefore, in justice to his talent, strongly recommend to the Lords Commissioners of the Admiralty that he may be permitted, at his own costs and charges, to fit and make trial of his engine in one of His Majesty's vessels.
"Dated in London this 27th day of January, 1832."
This was sent to Mr. Davies Gilbert, who on the same date suggested the following:—
"Recommendation of Mr. Rd. Trevithick, January 27, 1832."We have not any doubt or hesitation in recommending Mr. Richard Trevithick as a man of extraordinary powers of mind, and of fertility of invention."Cornwall owes to him much of the improvements that have been made on Mr. Watt's engine—improvements that have reduced the consumption of coal to a third; nor have his exertions been confined to steam-engines alone. He now proposes to make the same water act over and over again byalternate expansion and contraction, which plan, if it succeeds, will be found of immense importance to vessels and locomotive engines."Understanding that Mr. Trevithick is desirous of making the experiment at his own expense, we clearly recommend that facilities may be afforded him."[207]
"Recommendation of Mr. Rd. Trevithick, January 27, 1832.
"We have not any doubt or hesitation in recommending Mr. Richard Trevithick as a man of extraordinary powers of mind, and of fertility of invention.
"Cornwall owes to him much of the improvements that have been made on Mr. Watt's engine—improvements that have reduced the consumption of coal to a third; nor have his exertions been confined to steam-engines alone. He now proposes to make the same water act over and over again byalternate expansion and contraction, which plan, if it succeeds, will be found of immense importance to vessels and locomotive engines.
"Understanding that Mr. Trevithick is desirous of making the experiment at his own expense, we clearly recommend that facilities may be afforded him."[207]
This paltry question with the Admiralty indirectly produced more trustworthy evidence of the great importance of Trevithick's inventions than all that has been written of him under the professional terms Engineers, and Engineering.
The names are not given of those who believed that he had, as an established fact, reduced the consumption of coal in the Watt engine to one-third; they were not Cornishmen, or they would not have misspelt the word Hayle, but they understood the great value of using the same fresh water over and over again in marine steam-engines.
Mr. Mills, who had taken an active part in the screw-propeller experiments in 1815, was again interested in the proposed trial in a Government ship, and wrote, "I have just left Captain Johnstone; he has communicated with Faucett and Co., Barnes and Miller, and with the firm of Maudslay. He has had his mind disturbed again by Maudslay about the greater quantity of water required to condense steam at higher temperatures; I repeated the same as yourself, about the cylinder full of steam, atmosphere strong; however, he appears quite different to what he was on Friday." Such a clique of professional friends would sink a stronger man than Trevithick. A year or two from that time the writer designed a high-pressure steam-engine suitable for a steamboat, and on presenting it tothe eminent marine-engine builders whom he served, was told that the lightness of the engine would cause less profit to the makers. Their bills were based on the pounds weight delivered, and new designs necessitated new patterns and new troubles. It was unreasonable to expect those makers of marine steam-engines to report that Trevithick knew better than they did. They knew of his screw-propeller experiments fifteen years before, but they in no way benefited him, and the Admiralty Captain was either a tool in their hands, or powerless without them.
The primary object, when the loan of the ship was asked, was the using for marine purposes a high-pressure steam tubular boiler, combined with tubular condenser, supplying or returning its water as feed, thereby avoiding the use of salt water in the boiler; and this steam-engine, as shown in his patent of 1831, was to be applied either to his screw, or his duck's foot, or other propeller; but during the year or two of suspense, other schemes for propelling ships had occupied his thoughts, resulting in the patent of 1832.
Steam-Engines, 1832."Now know ye, that in compliance with the said proviso, I, the said Richard Trevithick, do hereby declare the nature of my said invention, as regards the improvement or improvements on the steam-engine, to consist in interposing between the boiler and the working cylinder, in a situation to be strongly heated, a long pipe formed of a compact series of curved or bent pipes, which I denominate the dry pipes, or steam-expanding apparatus, through which dry pipes I cause the steam, after it has been generated in the boiler in contact and consequently saturated with water, to pass with very great velocity, in order that it may imbibe a copious supply of additional heat without any addition of water, and by this additional heat to be expandedinto a greater bulk of steam, of about the same expansive force that it had acquired in the boiler, by which means I obtain a greater volume of steam for use in the working cylinder than the boiler alone would supply; and in order still further to augment this volume of steam, I place the working cylinder within a case constituting a part of the flue or chimney, that the cylinder may be kept considerably hotter than the steam employed in it by absorbing a great portion of the heat remaining in the flue after having heated the boiler and the dry pipes, which heat would otherwise pass away out of the top of the chimney and be wasted, but by this arrangement is converted into a useful power by further expanding the steam in the cylinder."And I do further declare, that in carrying this part of my said improvement into effect, I do not find it necessary to confine myself to any particular form of boiler, or arrangement of pipes, in which the steam is to be heated; but by preference, as being very compact in form, and economical of fuel in using, I make my boiler of a number of upright pipes, standing upon and communicating with a tubular ring placed around and a little below the fire-grate; these pipes all surround the fire-place, except two or three, the lower ends of which are elevated above the fire-door, but connected at the bottom by a branch pipe united to one of the adjoining upright pipes, thereby leaving an opening or place of access to the fire. These pipes all extend upwards to the height of several feet, according to the quantity of steam required to be raised, combined with local convenience, for it is obvious that the power of this boiler to raise steam may be increased either by increase of the length of the pipes, of their diameters, or of their numbers. And I do lay upon the upper ends of the pipes hereinbefore described and connect with them a tubular ring similar to that upon which the pipes stand, the two rings and the upright pipes forming together a vessel in which water has free communication by means of the bottom ring to stand at the same level in all the pipes, and the steam has free communication to pass from all the pipes into the upper ring; and I do, for the sake of obtaining great heat, place my system of dry pipes over thefire, and within the circular row of upright pipes of the boiler hereinbefore described; and I form my dry pipes in pairs, each pair constituting the figure that is well understood by the term inverted syphon; and I unite several of these syphons together by short bent pipes at the top, so as to constitute one long zigzag pipe, through which the steam must successively pass down and up the alternate legs of each syphon with great velocity, necessary for the rapid absorption of heat in its passage from the boiler to the working cylinder of the engine, the working cock, valves, or slide of which being united by a pipe of communication with that leg which is last in the succession of syphons; and I unite the first in succession of these inverted syphons with the upper tubular ring of the boiler by means of a bent pipe, in which a throttle-valve or cock is placed in order to limit the supply of steam, that it may have space in the dry pipes and working cylinder to expand in proportion as it receives additional heat; and I fix a safety-valve in communication with the boiler, and another in communication with the dry pipes; and I place around outside the boiler, at a small distance from the upright pipes, two cylindrical casings, one within the other, and fill up the space between the two casings with sand, ashes, or other material which conducts heat but slowly; and I close up the upper end of the casings over the boiler and the dry pipes with a covering in the form of a dome, and out of this enclosure I make the flue to pass to and around the working cylinder of the engine, whence the flue carries the smoke and little remaining heat away in any convenient manner; and I make my boiler-pipes, rings, and casings by preference of iron or copper, and my dry pipes of copper or other strong metal not liable to rapid oxidation by heat when in contact with steam; and I supply my boiler with water by means of a forcing pump, so adjusted as to keep the water of the proper height."And I do hereby further declare, that the nature of my said invention, as regards the improvements in the application of steam-power to navigation, consists in the drawing of water into a receptacle placed near within the stern of the navigable vessel, which water is drawn in through an orifice in the stern with amoderate degree of velocity in the direction of the course of the vessel, and ejected with great force and speed in a direction opposite to the course of the vessel through the same orifice, reduced to about a quarter of the area by means of a valve opening as the water enters, and partially shutting as the water is ejected; and thus I propel the vessel with great force, derived from the recoil of the water set into rapid motion in a direction opposite to the course of the vessel, the rapidity of the jet of water to be at least equal to double the required speed of the vessel to be navigated."And I further declare, that by preference I effect the purpose of receiving and of ejecting the water, and of deriving a motive force from its recoil, by means of a large vertical cylinder of cast iron or other metal, closed at both ends, in which a piston is forced up and down by a piston-rod sliding through a stuffing box in the lid, which piston-rod receives its motive force from a steam-engine; and I fix a tube into the after side of this cylinder, near the bottom, in communication with the space below the piston, which tube leads through the stern of the vessel, as low down as practicable, and opens on one side of the rudder; and I fix another tube into the after side of this cylinder, near the top, in communication with the space above the piston, which tube also leads through the stern of the vessel, as low down as practicable, but opens out on the other side of the rudder; and I place in the mouth of each of these tubes a valve opening inwards, to allow the water free entrance, equal to the bore of the tube, and partially shutting when the water is ejected, so as to reduce the opening through the stern to about one-fourth of the area of the tube."And I do hereby further declare, that the nature of my said invention, as regards the improvement in the application of steam-power to locomotion, consists in the application of such a boiler, together with the expanding apparatus as aforesaid, to locomotive engines, whereby a diminished weight of boiler and quantity of water and fuel is obtained; and in farther compliance with the said proviso, I, the said Richard Trevithick, do hereby describe the manner in which my said invention is to be performed, by the following description of its various parts indetail, reference being had to the drawing annexed, and to the figures and letters marked thereon, that is to say:—"Description of the Drawing.[Plate XVII.]PLATE 17PLATE 17.TREVITHICK'S PATENT BOILER AND ENGINE, 1832.London: E. & F.N. Spon. 48, Charing Cross. Kell Lith. London."Figure 1 represents a series of vertical sections through the various essential parts of the boiler, the dry pipes, the steam-pipe, the working cylinder, the propelling cylinder, and the flue, together with sections and views of other minor parts, serving to show the connections of the essential ones. The places at which these sections are taken are shown in Figure 2 by the dotted line from A to B, from B to C, from C to D, and from E to F. Figure 2 represents a plan of Figure 1, with the top coverings of the boiler and working cylinder removed. Figure 3 shows the manner of uniting the shorter upright pipes over the fire doorway with one of the adjoining ones, so as to give free circulation of the water in all the pipes. Figure 4 represents three pairs of syphons, which in their places stand in a circular form, but in this Figure are shown as spread out into a plane, in order the better to explain their structure and joinings. Similar small letters and numbers of reference are used to denote similar parts in all the Figures;a, the upright boiler-pipes, the upright and lower ends of which are contracted to leave room for bolt-heads and nuts, without throwing the pipes too far asunder;b, the tubular ring having a flanch projecting inwards and outwards at the upper side, perforated with apertures upon which the upright pipes are bolted, and another flanch at the bottom, projecting inwards, to bolt the ring down to the foundation plate;c, the foundation plate;d, the fire-grate;e, the fire doorway;f, the upper tubular ring, having a flanch at the bottom projecting inwards and outwards, and perforated with apertures corresponding with the tops of the upright pipes upon which the tubular ring lies, and to all which it is bolted;g, the level of the water in the boiler-pipes;h, the dry pipes formed like inverted syphons, so as to require no joining at the lower part near the fire; one leg of each of the two syphons shown in Figure 1 is in section, and broken near the bottom; an outside view of the other leg appears partly behind the section;k, the short bent pipes, each bolted to twosyphons, to unite them into one continuous pipe;l, the bent pipe uniting the upper tubular ring with the first in succession of the syphons; the proper situation for this pipe is that shown in Figure 2, but for the sake of clearness and simplicity in the drawing, it is shown in Figure 1 as if on the left-hand pipe and syphon;m, the throttle-cock on the bent pipel;n, the safety-valve lever, and weight on the same;p, the pipe of communication from the last in the succession of syphons to the working cylinder of the engine;r, the throttle-cock in the pipep;s, a four-way cock, worked by the hand-gear, to direct the steam alternately under and over the piston;t, the safety-valve in communication with the dry pipes;u, the two cylindrical casings surrounding the boiler-pipes, the space between the two being filled up with a slow conducting medium;v, the domical covering over the cylindrical enclosure;w, the flue leading out of the enclosure into the casing of the working cylinder;x, the casing of the working cylinder forming a continuation of the flue;y, the further continuation of the flue to the chimney;z, the waste-steam pipe leading into the chimney; 1, the steam-pipes leading from the working cock into the top and bottom of the working cylinder; 2, the working cylinder; 3, the piston with metallic packing; 4, the piston-rod passing down through a stuffing box at the bottom of the working cylinder, and also continuing downwards, to form the rod of the propelling piston; 5, the propelling cylinder; 6, the water or propelling piston; 7, the upper aperture leading to one of the tubes opening through the stern of the navigable vessel; 8, the lower aperture leading to the other tube, opening also through the stern of the navigable vessel; these apertures are made as wide as the cylinder will allow, in order that they may have but little depth, and not occasion an inconvenient length of the propelling cylinder; 9, a frame supporting the steam-cylinder upon the propelling cylinder; 10, the feed-pump for supplying the boiler with water; 11, an arm fastened on the piston-rod to work the feed-pump and hand-gear; 12, the hand-gear."Now, whereas I claim as my invention, firstly, the interposing between the boiler and the working cylinder of the steam-engine a long many-curved heated pipe, through whichthe steam is forced to pass with great rapidity without being permitted to come in direct contact with water, by which arrangement the steam is made to absorb additional heat, and at the same time allowed to expand itself into a greater volume."Secondly, placing the working cylinder of the engine within such part of the flue or chimney as shall ensure the cylinder to be kept hotter than the steam used in it, by which means the expanding of the steam is still further promoted."Thirdly, propelling a navigable vessel by the force of the recoil produced from water received with a moderate degree of velocity, into a receptacle near within the stern, in the direction of the course of the vessel, and ejected with great velocity in a direction opposite to that course, the velocity of the jet being at least double the required speed of the vessel to be propelled, provided always that the same be effected in manner hereinbefore described."Fourthly, applying a boiler combined with a steam expanding apparatus, as before described, instead of a boiler alone, to a locomotive engine, whereby the power of the steam is applied after the steam has undergone the expanding process, and whereby a diminution is effected in the weight of the boiler, and in the weight and consumption of water and of fuel."
Steam-Engines, 1832.
"Now know ye, that in compliance with the said proviso, I, the said Richard Trevithick, do hereby declare the nature of my said invention, as regards the improvement or improvements on the steam-engine, to consist in interposing between the boiler and the working cylinder, in a situation to be strongly heated, a long pipe formed of a compact series of curved or bent pipes, which I denominate the dry pipes, or steam-expanding apparatus, through which dry pipes I cause the steam, after it has been generated in the boiler in contact and consequently saturated with water, to pass with very great velocity, in order that it may imbibe a copious supply of additional heat without any addition of water, and by this additional heat to be expandedinto a greater bulk of steam, of about the same expansive force that it had acquired in the boiler, by which means I obtain a greater volume of steam for use in the working cylinder than the boiler alone would supply; and in order still further to augment this volume of steam, I place the working cylinder within a case constituting a part of the flue or chimney, that the cylinder may be kept considerably hotter than the steam employed in it by absorbing a great portion of the heat remaining in the flue after having heated the boiler and the dry pipes, which heat would otherwise pass away out of the top of the chimney and be wasted, but by this arrangement is converted into a useful power by further expanding the steam in the cylinder.
"And I do further declare, that in carrying this part of my said improvement into effect, I do not find it necessary to confine myself to any particular form of boiler, or arrangement of pipes, in which the steam is to be heated; but by preference, as being very compact in form, and economical of fuel in using, I make my boiler of a number of upright pipes, standing upon and communicating with a tubular ring placed around and a little below the fire-grate; these pipes all surround the fire-place, except two or three, the lower ends of which are elevated above the fire-door, but connected at the bottom by a branch pipe united to one of the adjoining upright pipes, thereby leaving an opening or place of access to the fire. These pipes all extend upwards to the height of several feet, according to the quantity of steam required to be raised, combined with local convenience, for it is obvious that the power of this boiler to raise steam may be increased either by increase of the length of the pipes, of their diameters, or of their numbers. And I do lay upon the upper ends of the pipes hereinbefore described and connect with them a tubular ring similar to that upon which the pipes stand, the two rings and the upright pipes forming together a vessel in which water has free communication by means of the bottom ring to stand at the same level in all the pipes, and the steam has free communication to pass from all the pipes into the upper ring; and I do, for the sake of obtaining great heat, place my system of dry pipes over thefire, and within the circular row of upright pipes of the boiler hereinbefore described; and I form my dry pipes in pairs, each pair constituting the figure that is well understood by the term inverted syphon; and I unite several of these syphons together by short bent pipes at the top, so as to constitute one long zigzag pipe, through which the steam must successively pass down and up the alternate legs of each syphon with great velocity, necessary for the rapid absorption of heat in its passage from the boiler to the working cylinder of the engine, the working cock, valves, or slide of which being united by a pipe of communication with that leg which is last in the succession of syphons; and I unite the first in succession of these inverted syphons with the upper tubular ring of the boiler by means of a bent pipe, in which a throttle-valve or cock is placed in order to limit the supply of steam, that it may have space in the dry pipes and working cylinder to expand in proportion as it receives additional heat; and I fix a safety-valve in communication with the boiler, and another in communication with the dry pipes; and I place around outside the boiler, at a small distance from the upright pipes, two cylindrical casings, one within the other, and fill up the space between the two casings with sand, ashes, or other material which conducts heat but slowly; and I close up the upper end of the casings over the boiler and the dry pipes with a covering in the form of a dome, and out of this enclosure I make the flue to pass to and around the working cylinder of the engine, whence the flue carries the smoke and little remaining heat away in any convenient manner; and I make my boiler-pipes, rings, and casings by preference of iron or copper, and my dry pipes of copper or other strong metal not liable to rapid oxidation by heat when in contact with steam; and I supply my boiler with water by means of a forcing pump, so adjusted as to keep the water of the proper height.
"And I do hereby further declare, that the nature of my said invention, as regards the improvements in the application of steam-power to navigation, consists in the drawing of water into a receptacle placed near within the stern of the navigable vessel, which water is drawn in through an orifice in the stern with amoderate degree of velocity in the direction of the course of the vessel, and ejected with great force and speed in a direction opposite to the course of the vessel through the same orifice, reduced to about a quarter of the area by means of a valve opening as the water enters, and partially shutting as the water is ejected; and thus I propel the vessel with great force, derived from the recoil of the water set into rapid motion in a direction opposite to the course of the vessel, the rapidity of the jet of water to be at least equal to double the required speed of the vessel to be navigated.
"And I further declare, that by preference I effect the purpose of receiving and of ejecting the water, and of deriving a motive force from its recoil, by means of a large vertical cylinder of cast iron or other metal, closed at both ends, in which a piston is forced up and down by a piston-rod sliding through a stuffing box in the lid, which piston-rod receives its motive force from a steam-engine; and I fix a tube into the after side of this cylinder, near the bottom, in communication with the space below the piston, which tube leads through the stern of the vessel, as low down as practicable, and opens on one side of the rudder; and I fix another tube into the after side of this cylinder, near the top, in communication with the space above the piston, which tube also leads through the stern of the vessel, as low down as practicable, but opens out on the other side of the rudder; and I place in the mouth of each of these tubes a valve opening inwards, to allow the water free entrance, equal to the bore of the tube, and partially shutting when the water is ejected, so as to reduce the opening through the stern to about one-fourth of the area of the tube.
"And I do hereby further declare, that the nature of my said invention, as regards the improvement in the application of steam-power to locomotion, consists in the application of such a boiler, together with the expanding apparatus as aforesaid, to locomotive engines, whereby a diminished weight of boiler and quantity of water and fuel is obtained; and in farther compliance with the said proviso, I, the said Richard Trevithick, do hereby describe the manner in which my said invention is to be performed, by the following description of its various parts indetail, reference being had to the drawing annexed, and to the figures and letters marked thereon, that is to say:—
"Description of the Drawing.[Plate XVII.]
PLATE 17PLATE 17.TREVITHICK'S PATENT BOILER AND ENGINE, 1832.London: E. & F.N. Spon. 48, Charing Cross. Kell Lith. London.
PLATE 17.TREVITHICK'S PATENT BOILER AND ENGINE, 1832.
London: E. & F.N. Spon. 48, Charing Cross. Kell Lith. London.
"Figure 1 represents a series of vertical sections through the various essential parts of the boiler, the dry pipes, the steam-pipe, the working cylinder, the propelling cylinder, and the flue, together with sections and views of other minor parts, serving to show the connections of the essential ones. The places at which these sections are taken are shown in Figure 2 by the dotted line from A to B, from B to C, from C to D, and from E to F. Figure 2 represents a plan of Figure 1, with the top coverings of the boiler and working cylinder removed. Figure 3 shows the manner of uniting the shorter upright pipes over the fire doorway with one of the adjoining ones, so as to give free circulation of the water in all the pipes. Figure 4 represents three pairs of syphons, which in their places stand in a circular form, but in this Figure are shown as spread out into a plane, in order the better to explain their structure and joinings. Similar small letters and numbers of reference are used to denote similar parts in all the Figures;a, the upright boiler-pipes, the upright and lower ends of which are contracted to leave room for bolt-heads and nuts, without throwing the pipes too far asunder;b, the tubular ring having a flanch projecting inwards and outwards at the upper side, perforated with apertures upon which the upright pipes are bolted, and another flanch at the bottom, projecting inwards, to bolt the ring down to the foundation plate;c, the foundation plate;d, the fire-grate;e, the fire doorway;f, the upper tubular ring, having a flanch at the bottom projecting inwards and outwards, and perforated with apertures corresponding with the tops of the upright pipes upon which the tubular ring lies, and to all which it is bolted;g, the level of the water in the boiler-pipes;h, the dry pipes formed like inverted syphons, so as to require no joining at the lower part near the fire; one leg of each of the two syphons shown in Figure 1 is in section, and broken near the bottom; an outside view of the other leg appears partly behind the section;k, the short bent pipes, each bolted to twosyphons, to unite them into one continuous pipe;l, the bent pipe uniting the upper tubular ring with the first in succession of the syphons; the proper situation for this pipe is that shown in Figure 2, but for the sake of clearness and simplicity in the drawing, it is shown in Figure 1 as if on the left-hand pipe and syphon;m, the throttle-cock on the bent pipel;n, the safety-valve lever, and weight on the same;p, the pipe of communication from the last in the succession of syphons to the working cylinder of the engine;r, the throttle-cock in the pipep;s, a four-way cock, worked by the hand-gear, to direct the steam alternately under and over the piston;t, the safety-valve in communication with the dry pipes;u, the two cylindrical casings surrounding the boiler-pipes, the space between the two being filled up with a slow conducting medium;v, the domical covering over the cylindrical enclosure;w, the flue leading out of the enclosure into the casing of the working cylinder;x, the casing of the working cylinder forming a continuation of the flue;y, the further continuation of the flue to the chimney;z, the waste-steam pipe leading into the chimney; 1, the steam-pipes leading from the working cock into the top and bottom of the working cylinder; 2, the working cylinder; 3, the piston with metallic packing; 4, the piston-rod passing down through a stuffing box at the bottom of the working cylinder, and also continuing downwards, to form the rod of the propelling piston; 5, the propelling cylinder; 6, the water or propelling piston; 7, the upper aperture leading to one of the tubes opening through the stern of the navigable vessel; 8, the lower aperture leading to the other tube, opening also through the stern of the navigable vessel; these apertures are made as wide as the cylinder will allow, in order that they may have but little depth, and not occasion an inconvenient length of the propelling cylinder; 9, a frame supporting the steam-cylinder upon the propelling cylinder; 10, the feed-pump for supplying the boiler with water; 11, an arm fastened on the piston-rod to work the feed-pump and hand-gear; 12, the hand-gear.
"Now, whereas I claim as my invention, firstly, the interposing between the boiler and the working cylinder of the steam-engine a long many-curved heated pipe, through whichthe steam is forced to pass with great rapidity without being permitted to come in direct contact with water, by which arrangement the steam is made to absorb additional heat, and at the same time allowed to expand itself into a greater volume.
"Secondly, placing the working cylinder of the engine within such part of the flue or chimney as shall ensure the cylinder to be kept hotter than the steam used in it, by which means the expanding of the steam is still further promoted.
"Thirdly, propelling a navigable vessel by the force of the recoil produced from water received with a moderate degree of velocity, into a receptacle near within the stern, in the direction of the course of the vessel, and ejected with great velocity in a direction opposite to that course, the velocity of the jet being at least double the required speed of the vessel to be propelled, provided always that the same be effected in manner hereinbefore described.
"Fourthly, applying a boiler combined with a steam expanding apparatus, as before described, instead of a boiler alone, to a locomotive engine, whereby the power of the steam is applied after the steam has undergone the expanding process, and whereby a diminution is effected in the weight of the boiler, and in the weight and consumption of water and of fuel."
The two great objects in this 1832 patent were superheating steam in tubular boilers, and propelling ships by forcing a stream of water from the stern at a speed of at least double that of the vessel. Similar ideas may be traced in his patent of 1815, where a tubular boiler gave superheated steam, and in 1809 his patent for propelling steamboats "consists of a tube of considerable length disposed horizontally in the water, and the stroke of rowing is made by means of a piston with valves."
An engine of 100-horse power was ordered in Shropshire to be placed on board the Government ship to test the value of those patents of 1831 and 1832. Oneconsequence was that a gentleman who had helped this scheme with his money wrote:—