There is a curious suggestiveness about this finding of aluminum at our very door, so to speak, some scores of centuries after the relatively rare and inaccessible metals had been known and utilized by man. But there is another yet more striking instance of an abundant element which man needed, but knew not how to obtain until the science of our own day solved the problem of making it available. This is the case of the nitrogen of the air. As every one knows, this gas forms more than three-fourths of the bulk of the atmosphere. But, unlike the other chief constituent, oxygen, it is not directly available for the use of plants and animals. Yet nitrogen is an absolutely essential constituent of the tissues of every living organism, vegetable and animal. Any living thing from which it is withheld must die of starvation, though every other constituent of food be supplied without stint; and the fact that the starving organism is bathed perpetually in an inexhaustible sea of atmosphere chiefly composed of nitrogen would not abate by one jot the certainty of its doom.
To be made available as food for plants (and thus indirectly as food for animals) nitrogen must be combined with some other element, to form a soluble salt.But unfortunately the atoms of nitrogen are very little prone to enter into such combinations; under all ordinary conditions they prefer a celibate existence. In every thunder-storm, however, a certain quantity of nitrogen is, through the agency of lightning, made to combine with the hydrogen of dissociated water-vapor, to form ammonia; and this ammonia, washed to the earth dissolved in rain drops, will in due course combine with constituents of the soil and become available as plant food. Once made captive in this manner, the nitrogen atom may pass through many changes and vicissitudes before it is again freed and returned to the atmosphere. It may, for example, pass from the tissues of a plant to the tissues of a herbivorous animal and thence to help make up the substance of a carnivorous animal. As animal excreta or as residue of decaying flesh it may return to the soil, to form the chief constituent of a guano bed, or of a nitrate bed,—in which latter case it has combined with lime or sodium to form a rocky stratum of the earth's crust that may not be disturbed for untold ages.
A moment's reflection on the conditions that govern vegetable and animal life in a state of nature will make it clear that a soil once supplied with soluble nitrates is likely to be replenished almost perpetually through the decay of vegetation. But it is equally clear that when the same soil is tilled by man, the balance of nature is likely to be at once disturbed. Every pound of grain or of meat shipped to a distant market removes a portion of nitrogen; and unless the deficit is artificially supplied, the soil becomes presently impoverished.
But an artificial supply of nitrogen is not easily secured—though something like twenty-five million tons of pure nitrogen are weighing down impartially upon every square mile of the earth's surface. In the midst of this tantalizing sea of plenty, the farmer has been obliged to take his choice between seeing his land become yearly more and more sterile and sending to far-off nitrate beds for material to take the place of that removed by his successive crops. The most important of the nitrate beds are situated in Chili, and have been in operation since the year 1830. The draft upon these beds has increased enormously in recent years, with the increasing needs of the world's population. In the year 1870, for example, only 150,000 tons of nitrate were shipped from the Chili beds; but in 1890 the annual output had grown to 800,000 tons; and it now exceeds a million and a half. Conservative estimates predict that at the present rate of increased output the entire supply will be exhausted in less than twenty years. And for some years back scientists and economists have been asking themselves, What then?
But now electro-chemistry has found an answer—even while the alarmists were predicting dire disaster. Means have been found to extract the nitrogen from the atmosphere, in a form available as plant food, and at a cost that enables the new synthetic product to compete in the market with the Chili nitrate. So all danger of a nitrogen famine is now at an end,—and applied science has placed to its credit another triumph, second to none, perhaps, among all its conquests. The authorof this truly remarkable feat is a Swedish scientist, Christian Birkeland by name, Professor of Physics in the University of Christiania. His experiments were begun only about the year 1903, and the practical machinery for commercializing the results—in which enterprise Professor Birkeland has had the co-operation of a practical engineer, Mr. S. Eyde—is still in a sense in the experimental stage,—albeit a large factory was put in successful operation in 1905 at Notodden, Norway.
Professor Birkeland has thus accomplished what many investigators in various parts of the world have been striving after for years. The significance of his accomplishment consists in the fact that he has demonstrated the possibility of making nitrogen combine with oxygen in large quantities and at a relatively low expense. The mere fact of the combination, as a laboratory possibility, had been demonstrated in an elder generation by Cavendish, and more recently by such workers as Sir William Crookes, and Lord Rayleigh in England and Professors W. Mutjmaan and H. Hofer in Germany. Moreover, the experiments of Messrs. Bradley and Lovejoy, conducted on a commercial scale at Niagara Falls, had seemed to give promise of a complete solution of the problem; had, indeed, produced a nitrogen compound from the air in commercial quantity, but not, unfortunately, at a cost that made competition with the Chili nitrate possible. Equally unsuccessful in solving this important part of the problem had been the experiments, conducted on a large scale, of Professors Kowalski and Moscicki, at Freiburg.
All these experimenters had adopted the same agent as the means of, so to say, forcing the transformation—namely, electricity. The American investigators employed a current of ten thousand volts; the German workers carried the current to fifty thousand volts. The flame of the electric arc thus produced ignited the nitrogen with which it came in contact readily enough; but the difficulty was that it came in contact with so little. Despite ingenious arrangements of multiple poles, the burning-surface of the multiple arc remained so small in proportion to the expenditure of energy that the cost of the operation far exceeded the commercial value of the product. Such, at least, must be the inference from the fact that the establishments in question did not attain commercial success.
The peculiarity of Professor Birkeland's method is based upon the curious fact that when the electric arc is made to pass through a magnetic field, its line of flame spreads out into a large disk—"like a flaming sun." The sheet of flame thus produced represents no greater expenditure of energy than the lightning flash of light that the same current would produce outside the magnetic field; but it obviously adds enormously to the arc-light surface that comes in contact with the air, and hence in like proportion to the amount of nitrogen that will be ignited. In point of fact, this burning of nitrogen takes place so rapidly in laboratory experiments as to vitiate the air of the room very quickly. In the commercial operation, with powerful electro-magnets and a current of five thousand volts, operating, of course, in closed chambers, the ratiobetween energy expended and result achieved is highly satisfactory from a business standpoint, and will doubtless become still more so as the apparatus is further perfected.
To the casual reader, unaccustomed to chemical methods, there may seem a puzzle in the explanation just outlined. He may be disposed to say, "You speak of the nitrogen as being ignited and burned; but if it is burned and thus consumed, how can it be of service?" Such a thought is natural enough to one who thinks of burning as applied to ordinary fuel, which seems to disappear when it is burned. But, of course, even the tyro in chemistry knows that the fuel has not really disappeared except in a very crude visual sense; it has merely changed its form. In the main its solid substance has become gaseous, but every atom of it is still just as real, if not quite so tangible, as before; and the chemist could, under proper conditions, collect and weigh and measure the transformed gases, and even retransform them into solids.
In the case of the atmospheric nitrogen, as in the case of ordinary fuel, a burning "consists essentially in the union of nitrogen atoms with atoms of oxygen." The province of the electric current is to produce the high temperature at which alone such union will take place. The portion of nitrogen that has been thus "burned" is still gaseous, but is no longer in the state of pure nitrogen; its atoms are united with oxygen atoms to form nitrous oxide gas. This gas, mixed with the atmosphere in which it has been generated, may now be passed through a reservoir of water, and thenew gas combines with a portion of water to form nitric acid, each molecule of which is a compound of one atom of hydrogen, one atom of nitrogen, and three atoms of oxygen; and nitric acid, as everyone knows, is a very active substance, as marked in its eagerness to unite with other substances as pure nitrogen is in its aloofness.
In the commercial nitrogen-plant at Notodden, the transformed nitrogen compound is brought into contact with a solution of milk of lime, with the resulting formation of nitrate of lime (calcium nitrate), a substance identical in composition—except that it is of greater purity—with the product of the nitrate beds of Chili. Stored in closed cans as a milky fluid, the transformed atmosphere is now ready for the market. A certain amount of it will be used in other manufactories for the production of various nitrogenous chemicals; but the bulk of it will be shipped to agricultural districts to be spread over the soil as fertilizer, and in due course to be absorbed into the tissues of plants to form the food of animals and man.
Just at the time when the Scandinavian experimenters were solving the problem of securing nitrogen from the air, other experimenters in Italy, operating along totally different lines, reached the same important result. The process employed by these investigators is known as the Frank and Caro process, and it bids fair to rival the Norwegian method as a commercial enterprise.The process is described as follows by an engineering correspondent of the LondonTimesin the Engineering Supplement of that periodical for January 22, 1908:
"This process is based upon the absorption of nitrogen by calcium carbide, when this gas, in the pure form, is passed over the carbide heated to a temperature of 1,100 degrees centigrade in retorts of special form and design. The calcium carbide required as raw material for the cyanamide manufacture is produced in the usual manner by heating lime and coke to a temperature of 2,500 degrees centigrade in electric furnaces of the resistance type.
"The European patent rights of the Frank and Caro process have been purchased by the Societa Generale per la Cianamide of Rome, and the various subsidiary companies promoting the manufacture in Italy, France, Switzerland, Norway, and elsewhere, are working under arrangement with the parent company as regards sharing of profits.
"The first large installation of a plant for carrying out this process was erected at Piano d'Orta, in Central Italy, and was put into operation in December, 1905. The power for this factory is developed by an independent company, and is obtained by taking water from the river Pescara and leading it to a point above the generating station at Tramonti. A head of 90 feet, equivalent to 8,400 horse-power, is here made available for the industries of the district. The power of the cyanamide factory is transmitted a distance of 6-1/4 miles at 6,000 volts. An aluminum and chemical works are also dependent upon the same power station.
"The Piano d'Orta works contains six furnaces for the manufacture of cyanamide, each furnace containing five retorts for absorption of the nitrogen by the carbide. A retort is capable of working off three charges of 100 kilograms (220 pounds) of carbide per day of 24 hours, the weight of the charge increasing to 125 kilograms by the nitrogen absorbed. The present carbide consumption of the Piano d'Orta factory is, therefore, at the rate of about 3,000 tons per annum, and the output of calcium cyanamide is about 3,750 tons per annum. The company controlling the manufacture at Piano d'Orta is named theSocieta Italiana per la Fabbricazione di Prodotti Azotati. Extensions of the factory at this place to a capacity of 10,000 tons per annum are already in progress. Another company is also planning the erection of similar works at Fiume and at Sebenico, on the eastern borders of the Adriatic Sea. The additional electric power required will be obtained by carrying out the second portion of the power development scheme on the river Pescara. A fall of 235 feet, equivalent to 22,000 horse-power, is available at the new power station, which is being erected at Piano d'Orta."
After stating that companies to operate the Frank and Caro process have been organized in France, in Switzerland, in Germany, in England, and in America,—the last-named plant being at Muscle Shoals, Tennessee River, in Northern Alabama—the writer continues:
"These facts prove that the manufacture of the new nitrogenous manure will soon be carried on in all themore important countries on both sides of the Atlantic. If the financial results come up to the promoter's expectations the industry in five years' time will have become one of considerable magnitude.
"A modification of the original process of some importance has been suggested by Polzeniusz. This chemist has found that the addition of fluorspar (CaF2) to the carbide reduces the temperature required for the absorption process by 400 degrees centigrade, while it also produces a less deliquescent finished material.
"As regards cost of manufacture, no very reliable figures are yet available, but the companies promoting the new manufacture are regulating their sale prices by those of the two rival artificial manures—ammonium sulphate and nitrate of soda. Calcium cyanamide is now being sold in Germany at 1s. to 1s. 6d. (25 to 37 cents) per unit of combined nitrogen cheaper than ammonium sulphate, and 3s. to 3s. 6d. (75 to 87 cents) per unit cheaper than nitrate of soda. Whether the manufacture will prove remunerative at this price of about £10 10s. ($102.50) per ton remains to be seen. It is evident that, as the raw material of the cyanamide manufacture (calcium carbide) costs at least £8 ($40) per ton to produce under the most favorable conditions, the margin of profit will not be large, and that very efficient management will be required to earn fair dividends on the capital sunk in the new industry.
"It must be noted, however, that the processes are new and are doubtless capable of improvement as experience is gained in working them; while, on theother hand, the competition of the two rival artificial manures is likely to diminish as the years pass on.
"The new industry is, therefore, likely to be a permanent addition to the list of electro-metallurgical processes. But for the present its success can only be expected in centres of very cheap water-power, as, for instance, in those localities where the electric horse-power year can be generated and transmitted to the cyanamide works at an inclusive cost of £2 ($10) or under."
It will be observed that the active instrumentality by which the industrial feats thus far outlined have been accomplished, is that weird conveyer of energy known as electricity. In the case of the aluminum manufacture, electricity operated according to the strange process of electrolysis, in virtue of which certain atoms of matter move to one pole of a battery while other atoms move to the opposite pole, thus effecting a separation—the result being, in the case in question, the deposit of pure aluminum at the negative pole. In the case of the nitrogen factories, however, the manner of operation of the electric current is quite different. Electricity, as such, is not really concerned in the matter; the efficiency of the current depends solely upon the production of heat. For example, any other agency that brought the atmosphere to a corresponding temperature would be equally efficacious in igniting the nitrogen. But in actual practice, for this particularpurpose, no other known means of producing high temperatures could at all compete with the electric arc.
There are numerous other operations involving the employment of high temperatures in which electricity is equally preeminent. It is feasible with the electric arc to attain a temperature of about 3,600 degrees centigrade—and even this might be exceeded were it not that carbon, of which the electrodes are composed, volatilizes at that temperature. Meantime, the highest attainable temperature with ordinary fuels in the blast furnace is only about 1,800 degrees; and the oxy-hydrogen flame is only about two hundred degrees higher. A mixture of oxygen and acetylene, however, burns at a temperature almost equaling that of the electric arc; and this flame, manipulated with the aid of a blowpipe, offers a useful means of applying a high temperature locally, for such processes as the welding of metals. The very highest temperatures yet reached in laboratory or workshop, however, are due to the use of explosive mixtures. Thus a mixture of the metal aluminum granulated, and oxide of iron, when ignited by a fulminating powder, readjusts its atoms to form oxide of aluminum and pure iron, and does this with such fervor that a temperature of about three thousand degrees is reached, the resulting iron being not merely melted but brought almost to the boiling point. Practical advantage is taken of this reaction for the repair of broken implements of iron or steel, the making of continuous rails for trolleys, and the like.
This reaction of aluminum and iron does not, to be sure, give a higher temperature than the electric arc; but this culminating feat has been achieved, in laboratory experiments, through the explosion of cordite in closed steel chambers; the experimenters being the Englishmen Sir Andrew Noble and Sir F. Abel. It is difficult to estimate accurately the degree of heat and pressure attained in these experiments; but it is believed that the temperature approximated 5,000 degrees centigrade, while the pressure represented the almost inconceivable push of ninety tons to the square inch.
It may be of interest to explain that cordite is a form of smokeless powder composed of gun cotton, nitroglycerine, and mineral jelly. No doubt the extreme heat produced by its explosion is associated with the suddenness of the reaction; corresponding to the efficiency as a propellant that has led to the adoption of this powder for use in the small arms of the British Army. No commercial use has yet been made of cordite as a mere producer of heat; but there is an interesting suggestion of possible future uses in the fact that crystals of diamond have been found in the residue of the explosion chamber—microscopic in size, to be sure, but veritable diamonds in miniature. Sir William Crookes has suggested that, could the reaction be prolonged sufficiently, "there is little doubt that the artificial formation of diamonds would soon pass from the microscopic stage to a scale more likely to satisfy the requirements of science, if not those of personal adornment."
In attempting to suggest the importance of science in its relation to modern industries, I have thought it better to cite three or four illustrative cases in some detail rather than to attempt a comprehensive summary of the almost numberless lines of commercial activity that have a similar origin and dependence.
To attempt a full list of these would be virtually to give a catalogue of mechanical industries. It may be well, however, to point out a few familiar instances, in order to emphasize the economic importance of the subject; and to suggest a few of the lines along which present-day investigators are seeking further conquests.
Very briefly, then, consider how the application of scientific knowledge has changed the aspect of the productive industries. Thanks to science, farming is no longer a haphazard trade. The up-to-date farmer knows the chemical constitution of the soil; understands what constituents are needed by particular crops and what fertilizing methods to employ to keep his land from deteriorating. He knows how to select good seed according to the teaching of heredity; how to combat fungoid and insect pests by chemical means; how to meet the encroachments of the army of weeds. In the orchard, he can tell by the appearance of leaf and bark whether the soil needs more of nitrogen, of potash, or of humus; he uses sprays as a surgeon usesantiseptics; he introduces friendly insects to prey on insect pests; he irrigates or surface-tills or grows cover crops in accordance with a good understanding of the laws of capillarity as applied to water in the earth's crust. In barnyard and dairy he applies a knowledge of the chemistry of foods in his treatment of flock and herd; he ventilates his stables that the stock may have an adequate supply of oxygen; he milks his cows with a mechanical apparatus, extracts the cream with a centrifugal "separator," and churns by steam or by electric power.
In the affairs of manufacturer and transporter of commodities, methods are no less revolutionary. Steam power and electric dynamo everywhere hold sway; trolley and electric light and telephone have found their way to the most distant hamlet; electricians and experimental chemists are searching for new methods in the factories; artificial stone is competing with the product of the quarries; artificial dyes have sounded the doom of the madder and indigo industries.
And yet it requires no great gift of prophecy to see that what has been accomplished is only an earnest of what is to come in the not distant future. In every direction eager experimenters are on the track of new discoveries. Any day a chance observation may open new and important fields of exploration, just as Hall's observation about the power of cryolite to absorb aluminum pointed the way to the new aluminum industry; and as Birkeland's chance observation of the electric arc in a magnetic field unlocked the secret of the unresponsive nitrogen. It will probably notbe long, for example, before a way will be found to produce electric light without heat—in imitation of the wonderful lamp of the glow-worm.
Then in due course we must learn to use fuel without the appalling waste that at present seems unavoidable. A modern steam-engine makes available only five to ten per cent. of the energy that the burning fuel gives out as heat—the rest is dissipated without serving man the slightest useful purpose. Moreover, the new studies in radio-activity have taught us that every molecule of matter locks up among its whirling atoms and corpuscles a store of energy compared with which the energy of heat is but a bagatelle. It is estimated that a little pea-sized fragment of radium has energy enough in store—could we but learn to use it—to drive the largest steamship across the ocean—taking the place of hundreds of tons of coal as now employed. The mechanics of the future must learn how to unlock this treasury of the molecule; how to get at these atomic and corpuscular forces, the very existence of which was unknown to science until yesterday. The generation that has learned that secret will look back upon the fuel problems of our day somewhat as we regard the flint and steel and the open fire of the barbarian.
If problems of energy offer such alluring possibilities as this, problems of matter are even more inspiring. The new synthetic chemistry sets no bounds to its ambitions. It has succeeded in manufacturing madder, indigo, and a multitude of minor compounds. It hopes some day to manufacture rubber, starch,sugar—even albumen itself, the very basis of life. Rubber is a relatively simple compound of hydrogen and carbon; starch and sugar are composed of hydrogen, carbon, and oxygen; albumen has the same constituents, plus nitrogen. The raw materials for building up these substances lie everywhere about us in abundance. A lump of coal, a glass of water, and a whiff of atmosphere contain all the nutritive elements, could we properly mix them, of a loaf of bread or a beefsteak. And science will never rest content until it has learned how to make the combination. It is a long road to travel, even from the relatively advanced standpoint of to-day; but sooner or later science will surely travel it.
And then—who can imagine, who dare predict, the social and economic revolution that must follow? Our social and business life to-day differs more widely from that of our grandfathers than theirs differed from the life of the Egyptian and Babylonian of three thousand years ago; but this gap is as ditch to cañon compared with the gap that separates us from the life of that generation of our descendants which shall have learned the secret of making food-stuffs from inorganic matter in the laboratory and factory. It is a long road to travel, I repeat; but modern science travels swiftly and with many short-cuts, and it may reach this goal more quickly than any conservative dreamer of to-day would dare to predict.
All speed to the ambitious voyager!
REFERENCE LIST AND NOTES
CHAPTER IMAN AND NATUREFor a general discussion of primitive conditions of labor and prehistoric man's civilization, it will be of interest in connection with this chapter to consult volume I., chapter I., which deals with prehistoric science. The appendix notes on that chapter (vol. I., pp. 302, 303) refer to some books which may be consulted for fuller information along the same lines.CHAPTER IIHOW WORK IS DONE(p. 31). For study of Archimedes, giving a detailed account of his discoveries, see vol. I., p. 196seq.It will be of interest also to review, in connection with this chapter, the story of the growth of knowledge of mechanics in the time of Galileo, Descartes, and Newton as told in the chapters entitled "Galileo and the New Physics," vol. II. (p. 93seq.), and "The Success of Galileo in Physical Science," vol. II., p. 204seq.CHAPTER IIITHE ANIMAL MACHINEFor further insight into the activities of the animal machine, the reader may refer to various chapters on the progress of physiology and anatomy in earlier volumes. The following references will guide to the accounts of the successive advances from the earliest time:Vol. I., pp. 194, 195 describe briefly the earlier anatomical studiesof the Alexandrian physicians, Herophilus and Erasistratus; and pp. 282, 283, outline the studies of the famous physician, Galen.Vol. II., "From Paracelsus to Harvey," in particular, p. 163seq.; and chapters IV. (p. 173seq.) and V. (p. 202seq.) dealing with the progress of anatomy and physiology in the eighteenth and nineteenth centuries respectively. The chapter on "Experimental Psychology" (p. 245seq.) may also be consulted.Vol. V., chapter V., dealing with the Marine Biological Laboratory at Naples (p. 113seq.) and chapter VI., "Ernst Haeckel and the New Zoology" (p. 144seq.) present other aspects of physiological problems.CHAPTER IVTHE WORK OF AIR AND WATEROnpage 63reference is made to the work of the old Greeks, Archimedes and Ctesibius. An account of Archimedes' discovery of the laws of buoyancy of solids and liquids will be found in vol. I., p. 208.(p. 64). The machines of Ctesibius and Hero. See vol. I., p. 242seq., for a full account of these mechanisms.(p. 65). Toricelli, the pupil of Galileo, and his discovery of atmospheric pressure. For a fuller account of his discovery and what came of it see vol. II., p. 120seq.(p. 66). Boyle's experiments on atmospheric pressure. See vol. II., p. 204seq.(p. 66). Mariotte and Von Guericke. See vol. II., p. 210seq.(p. 71). Roman mills. A scholarly discussion of the subject of Roman mills, based on a comprehensive study of the references in classical literature, is given in Beckmann'sHistory of Inventions, London, 1846.(p. 73). Recent advances in water wheels. As stated in the text, the quotation is from an article onMotive Power Appliances, by Mr. Edward H. Sanborn, in theTwelfth Census Reportof the United States.CHAPTER VCAPTIVE MOLECULES; THE STORY OF THE STEAM-ENGINE(p. 82). The experiments of Hero of Alexandria. For a full account of the experiments see vol. I., pp. 249, 250.(p. 84). The Marquis of Worcester's steam engine. The original account appeared, as stated, in the Marquis of Worcester'sCentury of Inventions, published in 1663.(p. 92). Newcomen's engine. As stated in the text, the account of Newcomen's engine is quoted from the report of the Department of Science and Arts of the South Kensington Museum, now officially known as the Victoria and Albert Museum.(pp. 107-109). James Watt. The characterization of Watt here given is taken from an article in an early edition of the Edinburgh Encyclopædia published about the year 1815.CHAPTER VITHE MASTER WORKER(p. 112). High-pressure steam. The work referred to is Leupold'sTheatrum Machinarum, 1725.(p. 122). Rotary Engines. The quotation is from the report of the Victoria and Albert Museum above cited.(pp. 127, 128). Turbine engines. The quotation is from an anonymous article in the LondonTimes, August 14, 1907.(pp. 129, 130). Turbine engines. The quotation is from an article onMotive Power Appliancesin theTwelfth Census Reportof the United States, vol. X., part IV., by Mr. Edward H. Sanborn.CHAPTER VIIGAS AND OIL ENGINES(pp. 135, 136, 137). Gas engines. Quoted from the report of the Victoria and Albert Museum above cited.(pp. 141-144). Gas engines and steam engines in the United States. Quoted from the report of the Special Agents of theTwelfth Censusof the United States, 1902.(pp. 146, 147). The Svea heater. From an article by Mr. G. Emil Hesse inThe American Inventorfor April 15, 1905.CHAPTER VIIITHE SMALLEST WORKERSIn connection with this chapter the reader will do well to review various earlier portions of the work outlining the generalhistory of the growth of knowledge of electricity and magnetism. For example:Vol. II., p. 111seq., for an account of William Gilbert's study of magnetism; pp. 213, 215 describing first electrical machine; and chapter XIV., "The Progress of Electricity from Gilbert and Von Guericke to Franklin," p. 259seq.Vol. III., chapter VII., "The Modern Development of Electricity and Magnetism," p. 229seq.Vol. V., p. 92seq., the section on Prof. J. J. Thompson and the nature of electricity.Other chapters that may be advantageously reviewed in connection with the present one are the following:Vol. III., chapter VI., "Modern Theories of Heat and Light," p. 206seq.; chapter VIII., "The Conservation of Energy," p. 253seq.; and chapter IX., "The Ether and Ponderable Matter," p. 283seq.CHAPTER IXMAN'S NEWEST CO-LABORER: THE DYNAMOThe references just given for chapter VIII. apply equally here.The experiments of Oersted and Faraday are detailed in vol. III., p. 236seq.CHAPTER XNIAGARA IN HARNESSSame references as for chapters VIII. and IX.CHAPTER XITHE BANISHMENT OF NIGHT(p. 221). Davy and the electric light. The quotation here given is reproduced from vol. III., pp. 234, 235. The very great importance and general interest of the subject seem to justify the repetition, descriptive of this first electric light. Davy's original paper was given at the Royal Institution in 1810.(p. 237). "Peter Cooper Hewitt—Inventor," by Ray Stannard Baker, inMcClure's Magazine, June, 1903, p. 172.In connection with the problem of color of the light emitted byMr. Hewitt's mercury-vapor tube, the chapter on "Newton and the Composition of Light" (vol. II., p. 225seq.) may be consulted. Also "Modern Theories of Heat and Light," vol. III., p. 206seq.CHAPTER XIITHE MINERAL DEPTHSThe chapter on "The Origin and Development of Modern Geology," vol. III., p. 116seq., may be read in connection with the allied subjects here treated.In preparing the section on the use of electricity in mining, the article by Thomas Commerford Martin, entitledElectricity in Mining, in the United StatesCensus Reportof 1905, has been freely drawn upon. The quotations on pp.262,266,268, and270are from that source.CHAPTER XIIITHE AGE OF STEELSee note under chapter XII.CHAPTER XIVSOME RECENT TRIUMPHS OF APPLIED SCIENCEIn connection with various portions of this chapter the reader will find much that is of interest in the story of chemical development in general as detailed in volume III., pp. 3-72 inclusive.Also various chapters on electricity as outlined under chapter VII. above.(p. 310). Nitrogen from the air. The quotation is from theEngineering Supplementof the LondonTimes, January 22, 1908.
CHAPTER I
MAN AND NATURE
For a general discussion of primitive conditions of labor and prehistoric man's civilization, it will be of interest in connection with this chapter to consult volume I., chapter I., which deals with prehistoric science. The appendix notes on that chapter (vol. I., pp. 302, 303) refer to some books which may be consulted for fuller information along the same lines.
CHAPTER II
HOW WORK IS DONE
(p. 31). For study of Archimedes, giving a detailed account of his discoveries, see vol. I., p. 196seq.It will be of interest also to review, in connection with this chapter, the story of the growth of knowledge of mechanics in the time of Galileo, Descartes, and Newton as told in the chapters entitled "Galileo and the New Physics," vol. II. (p. 93seq.), and "The Success of Galileo in Physical Science," vol. II., p. 204seq.
CHAPTER III
THE ANIMAL MACHINE
For further insight into the activities of the animal machine, the reader may refer to various chapters on the progress of physiology and anatomy in earlier volumes. The following references will guide to the accounts of the successive advances from the earliest time:
Vol. I., pp. 194, 195 describe briefly the earlier anatomical studiesof the Alexandrian physicians, Herophilus and Erasistratus; and pp. 282, 283, outline the studies of the famous physician, Galen.
Vol. II., "From Paracelsus to Harvey," in particular, p. 163seq.; and chapters IV. (p. 173seq.) and V. (p. 202seq.) dealing with the progress of anatomy and physiology in the eighteenth and nineteenth centuries respectively. The chapter on "Experimental Psychology" (p. 245seq.) may also be consulted.
Vol. V., chapter V., dealing with the Marine Biological Laboratory at Naples (p. 113seq.) and chapter VI., "Ernst Haeckel and the New Zoology" (p. 144seq.) present other aspects of physiological problems.
CHAPTER IV
THE WORK OF AIR AND WATER
Onpage 63reference is made to the work of the old Greeks, Archimedes and Ctesibius. An account of Archimedes' discovery of the laws of buoyancy of solids and liquids will be found in vol. I., p. 208.
(p. 64). The machines of Ctesibius and Hero. See vol. I., p. 242seq., for a full account of these mechanisms.
(p. 65). Toricelli, the pupil of Galileo, and his discovery of atmospheric pressure. For a fuller account of his discovery and what came of it see vol. II., p. 120seq.
(p. 66). Boyle's experiments on atmospheric pressure. See vol. II., p. 204seq.
(p. 66). Mariotte and Von Guericke. See vol. II., p. 210seq.
(p. 71). Roman mills. A scholarly discussion of the subject of Roman mills, based on a comprehensive study of the references in classical literature, is given in Beckmann'sHistory of Inventions, London, 1846.
(p. 73). Recent advances in water wheels. As stated in the text, the quotation is from an article onMotive Power Appliances, by Mr. Edward H. Sanborn, in theTwelfth Census Reportof the United States.
CHAPTER V
CAPTIVE MOLECULES; THE STORY OF THE STEAM-ENGINE
(p. 82). The experiments of Hero of Alexandria. For a full account of the experiments see vol. I., pp. 249, 250.
(p. 84). The Marquis of Worcester's steam engine. The original account appeared, as stated, in the Marquis of Worcester'sCentury of Inventions, published in 1663.
(p. 92). Newcomen's engine. As stated in the text, the account of Newcomen's engine is quoted from the report of the Department of Science and Arts of the South Kensington Museum, now officially known as the Victoria and Albert Museum.
(pp. 107-109). James Watt. The characterization of Watt here given is taken from an article in an early edition of the Edinburgh Encyclopædia published about the year 1815.
CHAPTER VI
THE MASTER WORKER
(p. 112). High-pressure steam. The work referred to is Leupold'sTheatrum Machinarum, 1725.
(p. 122). Rotary Engines. The quotation is from the report of the Victoria and Albert Museum above cited.
(pp. 127, 128). Turbine engines. The quotation is from an anonymous article in the LondonTimes, August 14, 1907.
(pp. 129, 130). Turbine engines. The quotation is from an article onMotive Power Appliancesin theTwelfth Census Reportof the United States, vol. X., part IV., by Mr. Edward H. Sanborn.
CHAPTER VII
GAS AND OIL ENGINES
(pp. 135, 136, 137). Gas engines. Quoted from the report of the Victoria and Albert Museum above cited.
(pp. 141-144). Gas engines and steam engines in the United States. Quoted from the report of the Special Agents of theTwelfth Censusof the United States, 1902.
(pp. 146, 147). The Svea heater. From an article by Mr. G. Emil Hesse inThe American Inventorfor April 15, 1905.
CHAPTER VIII
THE SMALLEST WORKERS
In connection with this chapter the reader will do well to review various earlier portions of the work outlining the generalhistory of the growth of knowledge of electricity and magnetism. For example:
Vol. II., p. 111seq., for an account of William Gilbert's study of magnetism; pp. 213, 215 describing first electrical machine; and chapter XIV., "The Progress of Electricity from Gilbert and Von Guericke to Franklin," p. 259seq.
Vol. III., chapter VII., "The Modern Development of Electricity and Magnetism," p. 229seq.
Vol. V., p. 92seq., the section on Prof. J. J. Thompson and the nature of electricity.
Other chapters that may be advantageously reviewed in connection with the present one are the following:
Vol. III., chapter VI., "Modern Theories of Heat and Light," p. 206seq.; chapter VIII., "The Conservation of Energy," p. 253seq.; and chapter IX., "The Ether and Ponderable Matter," p. 283seq.
CHAPTER IX
MAN'S NEWEST CO-LABORER: THE DYNAMO
The references just given for chapter VIII. apply equally here.
The experiments of Oersted and Faraday are detailed in vol. III., p. 236seq.
CHAPTER X
NIAGARA IN HARNESS
Same references as for chapters VIII. and IX.
CHAPTER XI
THE BANISHMENT OF NIGHT
(p. 221). Davy and the electric light. The quotation here given is reproduced from vol. III., pp. 234, 235. The very great importance and general interest of the subject seem to justify the repetition, descriptive of this first electric light. Davy's original paper was given at the Royal Institution in 1810.
(p. 237). "Peter Cooper Hewitt—Inventor," by Ray Stannard Baker, inMcClure's Magazine, June, 1903, p. 172.
In connection with the problem of color of the light emitted byMr. Hewitt's mercury-vapor tube, the chapter on "Newton and the Composition of Light" (vol. II., p. 225seq.) may be consulted. Also "Modern Theories of Heat and Light," vol. III., p. 206seq.
CHAPTER XII
THE MINERAL DEPTHS
The chapter on "The Origin and Development of Modern Geology," vol. III., p. 116seq., may be read in connection with the allied subjects here treated.
In preparing the section on the use of electricity in mining, the article by Thomas Commerford Martin, entitledElectricity in Mining, in the United StatesCensus Reportof 1905, has been freely drawn upon. The quotations on pp.262,266,268, and270are from that source.
CHAPTER XIII
THE AGE OF STEEL
See note under chapter XII.
CHAPTER XIV
SOME RECENT TRIUMPHS OF APPLIED SCIENCE
In connection with various portions of this chapter the reader will find much that is of interest in the story of chemical development in general as detailed in volume III., pp. 3-72 inclusive.
Also various chapters on electricity as outlined under chapter VII. above.
(p. 310). Nitrogen from the air. The quotation is from theEngineering Supplementof the LondonTimes, January 22, 1908.
TRANSCRIBER'S NOTESObvious typographical and punctuation errors have been corrected after careful comparison with other occurrences within the text and consultation of external sources.Except for those changes noted below, inconsistent or archaic spelling of a word or word-pair within the text has been retained. For example: horseshoe horse-shoe; superheated super-heated; intrusted; incased.In html browsers, the changes below are identified in the text with adotted blue underline, and a mouse-hover popup.piii.'Friction, p. 35' changed to 'Friction, p. 39'.piii.'muscular action, p. 45' changed to '... action, p. 49'.piv.'Ctesibus' changed to 'Ctesibius'.piv.'wind-mill' changed to 'windmill'.p93.'was done is' changed to 'was done in'.p115(Illustration caption). 'Trevethick' changed to 'Trevithick'.p122.'drlving' changed to 'driving'.p181(Illustration caption). 'pull pieces' left unchanged (probablymeant to be 'pole pieces').p191.'Horsehoe' changed to 'Horseshoe'.p264.'Liége' changed to 'Liège'.p298.'repellant' changed to 'repellent'.
TRANSCRIBER'S NOTES
Obvious typographical and punctuation errors have been corrected after careful comparison with other occurrences within the text and consultation of external sources.
Except for those changes noted below, inconsistent or archaic spelling of a word or word-pair within the text has been retained. For example: horseshoe horse-shoe; superheated super-heated; intrusted; incased.
In html browsers, the changes below are identified in the text with adotted blue underline, and a mouse-hover popup.
piii.'Friction, p. 35' changed to 'Friction, p. 39'.piii.'muscular action, p. 45' changed to '... action, p. 49'.piv.'Ctesibus' changed to 'Ctesibius'.piv.'wind-mill' changed to 'windmill'.p93.'was done is' changed to 'was done in'.p115(Illustration caption). 'Trevethick' changed to 'Trevithick'.p122.'drlving' changed to 'driving'.p181(Illustration caption). 'pull pieces' left unchanged (probablymeant to be 'pole pieces').p191.'Horsehoe' changed to 'Horseshoe'.p264.'Liége' changed to 'Liège'.p298.'repellant' changed to 'repellent'.