COOPER.
1. The cooper manufactures casks, tubs, pails, and various other articles for domestic use, as well as vessels for containing all kinds of liquids and merchandise of a dry nature. He also applies hoops to boxes which are to be transported, with their valuable contents, to a distance from the cities.
2. The productions of this art being of prime necessity, the trade must have been exercised at a very early period. Roman writers on rural economy speak of the existence of its productions more than two thousand years ago; nevertheless they are still unknown in some countries, and there the inhabitants keep or carry liquids in skins daubed over with pitch.
3. Bottles of this kind were used, more or less, in all parts of the Roman empire, in the days of our Savior; and to such he alluded, when speaking of puttingnew wine into old bottles. Earthen vessels of various dimensions, were also in extensive use at the same time. The custom of keeping wine in such vessels, is still common in the southern parts of Europe. Pliny accords to the Piedmontese the merit of introducing casks. In his time, they were daubed with pitch.
4. Cedar and oak are the woods chiefly employed as materials in this business; and the persons who carry it on, as well as journeymen, confine their attention to the production of wares from one or the other of these woods; hence the division of the workmen intocedar coopersandoak coopers.
5. It is not always the case, however, that every cooper executes all kinds of work belonging to either one of these divisions of the trade; but this is not because there is any peculiar difficulty attending any part of the business, but because some particular kind of coopering is required in preference to others; for example, in some places, flour barrels are the casks most needed; in others, those for sugar, tobacco, pearlash, or some kind of spirits.
6. In illustrating the general operations of this business, we will describe the process of making a tub. The timber is first cut to the proper length with the kind of saw used in the cities for cutting fire-wood. It is next split into pieces with afrow, the curvature of which corresponds, at least with some degree of exactness, to that of the proposed vessel. The several pieces are then shaved on the edges with a straightdrawing-knife, on the inside with one of a concave form, and on the outside with one of corresponding convexity.
7. After this, they are jointed on a long plane, which is placed with its face upwards, in an inclined position. The workman is guided in giving the proper angle to the surface cut with the plane, by a woodengauge of peculiar form. The staves, having been thus prepared, are set up in atruss-hoop; and after this has been driven down, one or two others which are to remain are put on. The outside is then made smooth with aconvexdrawing-knife, and the inside with a smoothing-plane, the edge of which is circular, to correspond with the form of the surface. The inside of small wooden vessels is generally made smooth with a crooked drawing-knife.
8. The staves are now sawn off to a uniform length at the bottom, and a groove is cut for the insertion of the bottom. The latter operation is performed by means of a cutting instrument fixed in a kind of gauge. The several pieces to compose the bottom are brought to the proper form and smoothness with a straight drawing-knife; and, having been slightly fastened together by wooden pins, the whole, as one piece, is inserted in its proper place by driving it down from the top on the inside. The whole process is finished by driving on the hoops, and making the holes in the handles.
9. The cedar employed in this business is a considerable tree, which grows in various parts of the world, but especially in the United States, where it occupies large tracts calledcedarorcypress swamps. The wood is soft, smooth, and of an aromatic smell. It is likewise much used for shingles. The Dismal Swamp, lying in Virginia and North Carolina, contains an abundance of this kind of timber.
10. The operations in oak vary from those in cedar so far as to conform to the nature of the material, and the form of the vessels manufactured. In bringing the staves to the proper form, the workman is guided altogether by the eye; and, if they must be bent, they require to be heated. The fire for this purpose is made of shavings and chips in a small furnace of sheet iron, called acrusset. The hoops, both for cedarand oak wares, are made of thin strips of iron, or of small oak, hickory, ash, or cedar saplings. Within a few years, several machines have been invented, for getting out staves, and for bringing them to the proper form, as well as for performing several other parts of the cooper's operations.
11. The coopers in England derive a great deal of their employment from the West India trade. Barrels, puncheons, and hogsheads, are carried out of the country filled with dry goods, and are returned filled with rum and sugar. In the United States, much work of this kind is done for the same market; but then the staves and heads are only fitted and marked here, to be afterwards put together in the West Indies.
WHEELWRIGHT.
1. The artisan who makes the wood-work of common wheel carriages, or the wheels of coaches, is denominated a wheelwright; but, under this head, we propose to include whatever we may say on constructing and finishing wheel carriages in general.
2. It must be evident, even to a superficial observer, that this business, in its different branches, occupies a large space in our domestic industry, since almost every farmer in the country owns a vehicle of some sort, and since the streets of our busy cities and towns exhibit, during a great part of the day, scenes of bustle occasioned, in a great measure, by the passing and repassing of carriages of different kinds.
3. The principal kinds of wheel carriages made in this country, are the cart, the wagon, the gig, andthe coach; and of each of these there are various sorts, differing in strength and mode of construction, to suit the particular purposes to which they are to be applied. The business of making these vehicles is divided into a number of branches; but, as the manufacture of the coach embraces a greater variety of operations than any other species of carriage, we have selected it as affording the best means of explaining the operations of the whole business.
4. In large establishments for making coaches and other vehicles of the best workmanship, the operators confine their attention to the execution of particular parts of the work; for example, one man makes the wheels, another the carriage and body, another fashions and applies the iron, another does the painting and polishing, and another the trimming. In smaller establishments, a greater proportion of the work is executed by one person.
5. The wheels of the coach, as well as those of every other vehicle in which they are used, are composed of ahub, and severalspokes, andfelloes. The hubs are commonly made of a kind of tough wood, calledgum, which is reduced to the desired form in the lathe. The hole through the centre is made with a common auger, and enlarged with one tapering towards the point, and having through its whole length two cutting edges. The mortices for the spokes are made with a chisel driven with a mallet.
6. The spokes are made of white oak, and the felloes, of ash or hickory; and both are brought to the required form and smoothness with the saw, axe, drawing-knife, spoke-shave, chisel, and sand-paper. The constituent parts of thecarriage, orrunning gears, are theaxles,perch, andspring-beds, orbolsters, to which are added thetongue, orpole, and some other parts connected with it.
7. The joints in this part of the vehicle are madeperfectly tight by the application of putty; whereas, in the body, glue is used for this purpose. The latter substance will not answer in the former case, since it cannot bear exposure to water. The wood generally employed for the carriage part, as well as for the frame of the body, is ash; and the several parts are sawn from planks of suitable thickness. In this part of the work, the operator is guided by patterns made of thin pine boards. The panels of the body are made of thin boards of poplar or bass-wood. The manner in which the several parts are dressed and put together is too obvious to need description.
8. The wheels and the carriage, after having received one coat of paint, are sent to the blacksmith to be ironed. The hub is bound, at each end with hoops of iron, commonly plated with brass or silver, and the outside rim or felloes are bound with an irontire, and fastened with strong nails or spikes. The tires are made red-hot before they are applied, that they may be made to fit in every part with accuracy.
9. Bands, bolts, or strips of iron, are applied to those parts of the wood-work which may be exposed to friction, or which require additional strength. The axles are also made of wrought iron, either by the blacksmith who executes the other iron work, or by persons who manufacture them by the quantity for sale. The same remark is applicable to thethorough-boxes, which are inserted into the hub to prevent injury by friction, and to cause the wheel to revolve with freedom and accuracy.
10. The painting, varnishing, and polishing, of the body of the coach, when done in the best manner, comprise a tedious process. It is first covered with a coat of paint; the grain of the wood is then filled up with putty, and the surface is again covered with paint. Five coats offilling, composed of ochre, japan varnish, and spirits of turpentine, are next successivelyapplied. After the surface has been rubbed with a solid piece of pumice-stone, it is again painted, and rubbed with sand-paper. Several coats of paint are next laid on, and the work is finished by the application of a few coats of copal-varnish, and by the use of pumice-stone. The painting and varnishing of the wheels and carriage part, is far less expensive and tedious.
11. The nature of the trimmings, and the manner in which they are put together and applied, need not be described, since a few moments' inspection of a finished vehicle of this kind, will give any one a clear conception of the whole of this branch of the business. So far as trimming the inside, and the manufacture of cushions are concerned, the operations are similar to those of the upholsterer.
12. Wheel carriages may be classed among the primitive inventions, although the first authentic notice we have of their use, we find in the scripture history of Joseph, the son of Jacob, in which it is related, that this great and good man "was made to ride in the second chariot" of the king's, and that he sent wagons from Egypt to convey thither his father and family from the land of Canaan.
13. Covered wagons were used in the days of Moses; and the wandering Scythians, in the time of the Romans, had them covered with leather. The seat for the driver is said to have been invented by Oxylus, an Ætolian, who took possession of the kingdom of Elis, about 1100 years before Christ. Many of the nations of antiquity used chariots in the field of battle, and the axles were sometimes armed with scythes or some other sharp cutting instruments. Two persons commonly occupied one vehicle, one of whom drove the horses, and the other fought the enemy. The inhabitants of the promised land fought in chariots, even before the settlement of the people of Israelin that country; and the Greeks likewise employed them, for warlike purposes, at the siege of Troy.
14. The carriages used by the Romans were of various kinds, some of which were carried on the shoulders of men, and others, having two or four wheels, were drawn by horses, asses, mules, or oxen. Nevertheless, neither they, nor any other nation of antiquity, ever suspended the body of any carriage on leathers, or supported it on springs; and the use of almost every species of vehicle for the conveyance of persons, was banished by the policy of the barbarous nations that afterwards became masters of civilized Europe, the feudal lords conceiving it important, that their military vassals should serve them on horseback.
15. Even as late as the sixteenth century, ministers rode to court, and magistrates of imperial cities to council, on the back of this animal; and, in the same manner, kings and lords made their public entry on the most solemn occasions. In accounts of papal ceremonies which occurred during several centuries, we find no mention of a state-coach; but, instead of it, state-horses or state-mules. The horse for his holiness was required to be a gentle and tractable nag, of a gray color; and a stool with three steps was necessary to aid him in mounting. The emperor or kings, if present, held his stirrup, and led his beast. Bishops also made their public entrance on horses or asses richly decorated.
16. Covered carriages, however, were known in the principal states of Europe in the fifteenth and sixteenth centuries; but they were at first used only by women of rank, since the men thought it disgraceful to ride in them. At this period, when the electors of the German empire did not choose to be present at the meetings of the states, they excused themselves to the emperor by stating that their health would notpermit them to ride on horseback, and it was not becoming for them to ride like women.
17. But, for a long time, the use of carriages was forbidden even to women; and, as late as the year 1545, the wife of a certain duke obtained from him, with great difficulty, the privilege of using a covered carriage in a journey to the baths. The permission was granted on the condition that her attendants should not enjoy the same favor. Nevertheless, it is certain that emperors, kings, and princes, began to employ covered carriages on journeys, in the fifteenth century; and a few instances occur of their use in public solemnities. Ambassadors appeared, for the first time, in coaches, at a public solemnity, in 1613, at Erfurth.
18. In the history of France, we find many proofs, that, in the fourteenth, fifteenth, and sixteenth centuries, the French monarchs commonly rode on horses, the servants of the court on mules, and the princesses, together with the principal ladies, sometimes at least, on asses. Carriages of some sort, however, appear to have been used at a very early period there. An ordinance of Philip the Fair, issued in 1294, forbids their use by the wives of citizens.
19. In the year 1550, three coaches were introduced into Paris; one of which belonged to the queen, another to Diana de Poictiers, and the third to Raimond de Laval, a cavalier of the court of Francis I., who was so large that no horse could carry him. It is not certain, however, that the body of these vehicles were suspended on leather straps. The inventor of this material improvement cannot be ascertained, nor is it positively determined, that it had been made, until about the middle of the seventeenth century.
20. Coaches were introduced into Spain and Portugal, in the year 1546, and into Sweden near theclose of the same century. In the capital of Russia, there were elegant coaches as early as the beginning of the seventeenth century. In Switzerland, they were rare, as late as 1650. Carriages began to be used at Naples in the thirteenth century; from this place they spread all over Italy; and here, also, glass panels originated.
21. Carriages of some sort were used in England at a very early period, and those first employed by the ladies, were calledwhirlicoats. According to some authors, coaches were introduced in the year 1555; but, according to others, not until twenty-five years after this period. Before the latter date, Queen Elizabeth, on public occasions, rode on the same horse with her chamberlain, seated behind him on a pillion; although, in the early part of her reign, she owned a chariot.
22. In 1601, men were forbidden the use of the coach by act of Parliament, the legislators supposing such indulgence to be too effeminate; but this law seems to have been little regarded, as this vehicle was in common use, about the year 1605. Twenty years after this time, hackney coaches began to ply in London; but these were prohibited, in 1635, on the alleged ground that the support of so many horses increased the expense of keeping those belonging to the king. Two years after this, however, fifty coaches were licensed, and, in 1770, there were one thousand.
23. The stage-coach was first employed in France, and was introduced into England, near the middle of the eighteenth century, by Jethro Tull, the celebrated agriculturist. They were not employed, in any country, in the transportation of the mail, until the year 1784. Before this time, it was carried chiefly on horseback.
24. In the United States, the manufacture of carriages of every kind has greatly increased within a fewyears, and those lately made exhibit many improvements on those of former periods. The places which seem to be most distinguished for the manufacture of good carriages, in this country, are Philadelphia, Newark, and Troy.
POTTER.
1. The artisan called the potter converts plastic materials into hard and brittle vessels of various kinds, denominated, in general terms,earthen ware.
2. Alumine is the basis of all clays, and is the only earth that possesses the degree of plasticity which renders the operations of the potter practicable. It is, however, never found or used in a pure state, but in combination with other substances, particularly with silex, lime, magnesia, and the oxyde of iron.
3. In the manufacture of vessels from argillaceous compounds, the different degrees of beauty and costliness depend upon the quality of the raw materials, and the labor and skill expended in the operation. The various productions of the pottery may be classed under the following denominations—common earthenware, white earthen ware, stone ware, and porcelain; but of each of these there are many varieties.
4.Common earthen ware.—This ware is made of a kind of clay very generally diffused over the earth, and which is essentially the same with that employed in making bricks. The potters are often supplied with this material by the brickmakers, who select for them that which is too tenacious, orfat, for their own purpose. All common clays contain more or less of the oxyde of iron, which causes the wares made of them to turn red in burning.
5. In preparing the clay for use, the potter adds to it, when necessary, a portion of fine loam, in order to lessen its tenacity, and to prevent the vessels to be made of it from cracking, while undergoing the fire. When the materials have been mixed, and partially incorporated with water, the mass is thrown into a tub, fixed in the ground about one-half of its depth. In the centre of this tub, is placed a shaft, in a perpendicular position, from which radiate, in a horizontal direction, a number of knives or cutters.
6. This machine is put in motion by horse-power, and by it the clay is repeatedly cut, and properly kneaded. The workman then cuts it into thin slices with a small wire, and, having rejected all matters not fit for his purpose, he further kneads it with his hands, and forms it into lumps, corresponding in amount of matter with the different vessels which he proposes to make.
7. For the best kinds of this ware, the same species of clay is used; but then it is differently prepared. It is first dissolved in water; and, when the coarser particles have settled to the bottom of the vessel, the fluid suspending the rest is drawn off, and made to pass through a sieve into a reservoir. After the particles of the material have precipitated, the water is drawn off, and the residuum is thrown upona large flat pan or reservoir made of bricks, where the mass is freed from its superfluous moisture by evaporation in the air, or by means of artificial heat applied beneath. It is then laid by in a damp place, for future use.
8. Before the clay, thus purified from extraneous and coarser particles, is formed into vessels, it is beaten with a stout piece of wood, until the mass has become of an equal consistence throughout, and then repeatedly cut into two pieces with a wire, and slapped together to expel the air. The former of these operations is calledwedging, and the latter,slapping.
9.White and cream-colored waresare made of clays which contain so little oxyde of iron, that it does not turn red in burning, but, on the contrary, improves in whiteness in the furnace. There are several species of white clay, found in many different localities, most of which, however, are known under the denomination ofpipe-clay; or they are distinguished by the names of the places where they are obtained.
10. In preparing these clays for use, they are reduced to a minute division by machinery, and afterwards dissolved in water, and otherwise treated in a manner similar to that used for the better kinds of common wares, as described in the seventh and eighth paragraphs. For the purpose of diminishing the shrinkage in the fire, and with the view of increasing the whiteness of the ware, pulverized flint-stone is added to the clay, in the proportion of about one part of the former to five of the latter.
11. In reducing the silex to the requisite fineness, it is first brought to a red heat; and, while in this state, it is thrown into cold water, to diminish the cohesion of its parts. It is then pounded by machinery, levigated with water in a mill, sifted, mashed, andotherwise treated like the clay. The materials are mixed while in a state of thin pulp.
12. The several operations performed by the potter, in converting the clay thus prepared into different kinds of vessels, and in completing the whole process of the manufacture of earthen ware, may be included under the following divisions, viz., throwing, turning, pressing, burning, painting and printing, and glazing. They are not, however, all used in producing and finishing vessels of every shape and quality.
13.Throwing.—This operation is performed on a potter's wheel, which consists of a round table, and some simple means to put it in motion. The clay having been placed on the centre of this machine, the workman communicates to the latter a rotary motion with his foot, and gives the proposed form to the material with his hands, which have been previously wet with water, to prevent them from sticking. This method is used for all vessels and parts of vessels of a circular form; and, in many cases, no other operation is necessary to give them the requisite finish, so far as their conformation is concerned.
14.Turning.—The vessels are cut from the thrower's wheel with a small wire; and when, by the evaporation of moisture, they have become firm enough to endure the operation, they are turned on a lathe. The objects of this operation are to communicate to them a more exact shape, and to render them more uniform in thickness. The potter's wheel, with the addition of some contrivance to hold the pieces in a proper position, is frequently used for turning. The coarser kinds of common wares are never turned.
15.Pressing.—Vessels, or parts of vessels, which are of an irregular shape, and which cannot be formed on the wheel, are usually made by a process calledpressing. This kind of work is executed in moulds made of plaster of Paris, and these are formed onmodels of clay or wood, which have been made in the exact shape of the proposed vessel. Sometimes individual specimens of the wares of one country or pottery are used as models in another; in such cases, the expense of the moulds is considerably diminished.
16. The moulds frequently consist of several parts, which fit accurately together; for example, the mould for a pitcher is composed of two pieces for the sides, and one for the bottom. In forming a pitcher in such a mould, the material, which has been spread out to a proper and uniform thickness, is laid upon the inside of each portion of it, and the superfluous clay is trimmed off with a knife. The mould is then closed, and thin strips of clay are laid over the seams; the removal of the several pieces of the mould, completes the operation.
17. Handles, spouts, figures in relief, and other additions of this nature, are separately made in moulds, and stuck on the vessel with the same kind of materials, sometimes mingled with a small proportion of plaster of Paris. These appendages are added after the vessels have become partially solid in the air.
18.Burning.—All vessels, even after they have been dried in the atmosphere, are in a very frangible state; and, to render them sufficiently firm for use, they are submitted to the process of burning in a kiln. To preserve the ware from injury while enduring the fire, the several pieces are enclosed in cylindrical boxes calledsaggers, which are made of baked clay. These boxes are placed one above another around the sides of the kiln, which is of a circular form, and gradually tapering to the top.
19. In burning the coarser wares, every piece is not thus inclosed; but, between every two saggers, a naked piece is placed. A moderate fire is first raised,which is gradually increased, until the contents of the kiln are brought to a red heat. The burning occupies between twenty-four and forty-eight hours. All wares, except the coarsest kinds, are twice, and sometimes thrice, burned; and, after having been once submitted to the process, they are said to be in a state ofbiscuit.
20.Painting and printing.—When the vessels are to be ornamented with colors, it is necessary, in most cases, that this part of the work be done after the first burning. In China, and at the porcelain manufactory in Philadelphia, the drawings are executed by hand with a pencil. The same method is used in Europe in elaborate pieces of workmanship. But, in the common figured wares, where but one color is used, the designs are first engraved on metallic plates, and impressions are taken from them on thin paper, by means of a copperplate printing-press.
21. In transferring to vessels designs thus produced, the paper, while in a damp state, is applied closely to the surface of the biscuit, and rubbed on with a piece of flannel. The porosity of the earthen material causes the immediate absorption of the coloring matter, which, in all cases, is some metallic oxyde. For a blue color, the oxyde of cobalt is used; and for a black, those of manganese and iron. The paper is washed from the ware with a sponge.
22.Glazing.—To prevent the penetration of fluids, and to improve the appearance of the ware, a superficial vitreous coating is necessary. This can be produced by the aid of various substances; but, in a majority of cases, red lead is the basis of the mixture employed for this purpose. Equal parts of ground flints and red lead are used for the common cream-colored wares. These materials are mixed with, and suspended in, water, and each piece is dipped in the liquid. The moisture is soon absorbed by the clay,leaving the glazing particles on the surface, which, in the burning that follows, is converted into a uniform and durable vitreous coating.
23.Stone ware.—The materials of this ware, as well as the mode of preparing them, differ but little from those of the common and better kinds of earthen wares. The clays, however, which contain but little or no oxyde of iron are chosen, since this substance would cause the ware to melt and warp, before a sufficient degree of heat could be applied to give it the requisite hardness.
24. The glazing is formed by a vitrification of the surface of the vessels, caused by the action of common salt thrown into the kiln, when it has been raised to its greatest heat. This glazing is more perfect than that on ordinary earthen wares, being insoluble by most chemical agents. It is hardly necessary to remark that this method of glazing precludes the use of saggers.
25.Porcelain.—This ware exceeds every other kind in the delicacy of its texture, and is peculiarly distinguished by a beautiful semi-transparency, which is conspicuous when held against the light. In China, it is made chiefly of two kinds of earth; one of which is denominatedpetuntze, and the otherkaolin; but both are varieties of feldspar, found in the mountains, in different localities. They are brought to the manufactories from a distance in the form of bricks; the materials, as taken from the mines, having been reduced to an impalpable powder in mortars, either by the labor of men or by water-power.
26. These materials are combined in different proportions in the manufacture, according to the quality of the proposed ware. In the best kind, equal quantities are used; but for those of inferior quality, a greater proportion of petuntze is employed. The translucency so much admired in porcelain, ortseki,as the Chinese call it, is owing to the petuntze, which, in burning, partially melts, and envelops the infusible kaolin.
27. It is not known who was the inventor of porcelain, as the Chinese annals are silent with regard to this point; nor do we know more of the date at which the manufacture was commenced. It is certain, however, that it must have been before the fifth century of the Christian era. Since this ware has been known to Europeans, it has been manufactured chiefly, and in the greatest perfection, in the large and populous village of King-te-ching.
28. Porcelain was first brought to Europe from Japan and China, and for a long time its materials and mode of manufacture remained a secret, in spite of the efforts of the Jesuit missionaries, who resided in those countries. At length, in 1712, Father Entrecolles sent home to France, specimens of petuntze and kaolin, together with a summary description of the process of the manufacture.
29. Shortly after this important event had transpired, it was discovered that materials nearly of the same kind existed in abundance in various parts of Europe. The manufacture of porcelain was, therefore, soon commenced in several places; and it has since been successfully carried on.
30. The porcelain wares of Europe are superior to those of the Chinese, in the variety and elegance of their forms, as well as in the beauty of the designs executed upon them; but, as some of the processes successfully practised in China, remain still to be learned by the Europeans, the Oriental porcelain has not yet been equalled in the hardness, strength, and durability of its body, and in the permanency of its glaze. The manufacturers of Saxony are said to have been the most successful in their imitations in these respects.
31. The porcelain earths are found in various partsof the United States, but particularly at Wilmington, in the state of Delaware. Nevertheless, there is now but one porcelain manufactory in our country, and this is yet in its infancy. The establishment is located in Philadelphia, and it has been lately incorporated, with the privilege of one hundred thousand dollars capital.
32. The principle of induration by heat, is the same in the manufacture of earthen wares as in making bricks; and, as the latter can be more easily dispensed with than the former in a primitive state of society, it is but reasonable to suppose that earthen ware was first invented; but the art of making bricks must have been practised before the deluge, or the posterity of Noah would not have attempted so soon as about one hundred years after that catastrophe, to build a city and a tower of these materials. It is, therefore, evident, that this art was of antediluvian origin; and it was probably one of the earliest brought to any degree of perfection.
33. The art of the potter was practised more or less by every nation of antiquity, and the degree of perfection to which it was carried in every country corresponded with the state of the arts generally. The Greeks were consequently very celebrated for their earthen wares. The Etruscans have also been particularly noted for their manufacture of the elegant vases which have been dug, in modern times, from the depositories of the dead, in Lower Italy.
34. Until the commencement of the manufacture of porcelain in Europe, this art continued in a very rude condition, although practised to a considerable extent in many places. It was much improved in England about the year 1720, by the addition of flints to the usual material; and, between thirty and forty years after this, it was brought to great perfection, in all its branches, chiefly through the scientific exertions of the celebrated potter, Josiah Wedgewood.
GLASS BLOWER.
1. Glass is a substance produced from a combination of silicious earths with alkalies, and, in many cases, with metallic oxydes. The basis of every species of glass is silex, which is found in a state nearly pure in the sands of many situations. It is also found in the common flints and quartz pebbles.
2. When quartz pebbles or flints are employed, they must be first reduced to powder. This is done by grinding them in a mill, after they have been partially reduced, by heating them in the fire, and plunging them into cold water. Sand has the advantage of being already in a state of division sufficiently minute for the purpose. To prepare it for application, it only requires to be washed and sifted, in order to free it from the argillaceous and other substances unfit foruse. A great proportion of the sand employed in the manufacture of the better kinds of glass in the United States, is taken from the banks of the Delaware River.
3. The alkaline substances used are potash and soda. For the finer kinds of glass, pearlash, or soda procured by decomposing sea-salt, is used; but, for the inferior sorts, impure alkalies, such as barilla, Scotch and Irish kelp, and even wood-ashes, as well as the refuse of the soap-boiler's kettle, are made to answer the purpose. Lime, borax, and common salt, are also frequently used as a flux in aid of some of the other substances just mentioned.
4. Of the metallic oxydes which make a part of the materials of some glass, the deutoxyde of lead, or, as it is usually denominated, red lead, is the most common. This substance is employed in making flint glass, which is rendered by it more fusible, heavy and tough, and more easy to be ground or cut, while, at the same time, it increases its brilliancy and refractive power.
5. Black oxyde of manganese is also used in small quantities, with the view of rendering the glass more colorless and transparent. Common nitre produces the same effect. White arsenic is also added to the materials of this kind of glass, to promote its clearness; but, if too much is used, it communicates a milky whiteness. The use of this substance in drinking vessels is not free from danger, when the glass contains so much alkali as to render any part of it soluble in acids.
6. The furnace in which the materials are melted is a large conical stack, such as is represented at the head of this article. In some cases, it is surrounded by a large chimney, which extends above the roof of the building. In the sides are several apertures, near which are placed the crucibles, or melting-pots, containing the materials. The fuel is applied in an arch,which is considerably lower than the surface of the ground on which the operators stand, while at work.
7. The melting-pots are made chiefly of the most refractory clays and sand. Much of the clay used for this purpose, in many of the glass-houses in the United States, is imported from Germany. The materials, having been sifted, and mixed with a suitable quantity of water, the homogeneous mass is formed into crucibles, by spreading it on the inside of vessels which are much in the shape of a common wash-tub. After the clay has become sufficiently solid to sustain itself, the hoops are removed from the vessel, and the several staves taken apart.
8. The crucibles are suffered to dry in the atmosphere for two or three months, after which they are applied to use as they may be needed. Before they are placed in the main furnace, they are gradually raised to an intense heat in one of smaller dimensions, built for this express purpose. The fuel employed in fusing themetalis chiefly pine wood, which, in all cases, is previously dried in a large oven. Four of the five furnaces near Philadelphia, which belonged to Doctor Dyott, were heated with rosin.
9. The materials having been mixed, in the proposed proportions, which are determined by weight, they are thrown into the melting-pots, and, by a gradually increasing heat, reduced to a paste, suitable for application by the blower. This part of the process is commonly performed at night, while the blowers are absent from the works.
10. The applications of glass are so exceedingly extensive, that it is inconvenient, if not impossible, to manufacture every species of it at one glass-house or at one establishment. Some, therefore, confine their attention to the production of window glass, and such articles of hollow ware as may be made, with profit, from the same kind of paste. Others makevials and other species of ware, employed by the druggist, apothecary, and chemist. And again, the efforts, at some factories, are confined entirely to the manufacture of flint glass, or to that of plate glass for mirrors.
11. The principal operations connected with the manufacture of different species of glass, after the paste has been prepared, may be included under the following heads; viz., blowing, casting, moulding, pressing and grinding; although all these are never performed in one and the same establishment.
12.Blowing.—The operation of blowing is nearly or quite the same in the production of every species of glass ware, in which it is employed. The manipulations, however, connected with making different articles, are considerably varied, to suit their particular conformation. This circumstance renders it impossible for us to give more than a general outline of the process of this manufacture.
13. In the formation of window glass, the workman gathers upon the end of an iron tube a sufficient amount of the metal, which he brings to a cylindrical form by rolling it upon a cast iron or stone table. He then blows through the tube with considerable force, and thus expands the glass to the form of an inflated bladder. The inflation is assisted by the heat, which causes the air and moisture of the breath to expand with great power.
14. Whenever the glass has become too stiff, by cooling, for inflation, it is again softened by holding it in the blaze of the fuel, and the blowing is repeated, until the globe has been expanded to the requisite thinness. Another workman next receives it at the other end, upon an iron rod, called apunt, orpunting iron, when the blowing iron is detached. It is now opened, and spread into a smooth sheet, by the centrifugal force acquired by the rapid whirl given to it, in the manner exhibited in the preceding cut. The sheetthus produced is of a uniform thickness, except at the centre, where the iron rod had been attached.
15. An inferior kind of window glass, the materials of which are sand, kelp, and soap-boilers' waste, is made by blowing themetalinto cones, about a foot in diameter at their base; and these, while hot, are touched on one side with a cold iron dipped in water. This produces a crack, which runs through the whole length of the cone. The glass then expands into a sheet somewhat resembling a fan. This is supposed to be the oldest method of manufacturing window or plate glass.
16. The window glass produced in the manner first described, is calledcrown glass; and the other,broad glass. But by neither of these methods can the largest panes be produced. The blowing for these differs from the methods just described, in that the material is blown into an irregular cylinder, open at its further end. When a sufficient number of these cylinders have accumulated, the end to which the blowing iron had been attached, iscapped offby drawing round it a circle of melted glass, and the cylinder is divided longitudinally by touching it through its whole length with a hot iron. The cylinders, in this state, are put into the annealing oven, where, by aid of a heat which raises the glass to redness, it is expanded into sheets. These sheets are then broken into panes of several sizes by the aid of a diamond and a straight edge, as in the case of glass blown by other methods.
17.Casting.—Plate glass formed by the method last mentioned, is denominatedcylinder glass; and it is used not only for windows, but also for mirrors not exceeding four feet in length. Plates of greater dimensions are produced by a process calledcasting. The casting is performed by pouring the material, in a high state of fusion, upon a table of polished copper of large size, and having a rim elevated above its generalsurface, as high as the proposed plate is to be thick. To spread the glass perfectly, and to render the two surfaces parallel, a heavy roller of polished copper, resting upon the rim at the edges, is passed over it.
18. Plates thus cast are always dull and uneven. To render them good reflectors, it is necessary to grind and polish them. The plate to be polished is first cemented with plaster of Paris to a table of wood or stone. A quantity of wet sand, emery, or pulverized flints, is spread upon it, and another glass plate, similarly cemented to a wooden or stone surface, is placed upon it. The two plates are then rubbed together, until their surfaces have become plane and smooth. The last polish is given by colcothar and putty. Both sides are polished in the same manner.
19.Moulding.—Ornamental forms and letters are produced on the external surface of vessels, by means of metallic moulds; and the process by which this kind of work is performed is called moulding. In the execution, the workman gathers upon the end of his iron tube, a proper amount of the material, which he extends, and brings to a cylindrical form, by rolling it upon his table. He then expands it a little by a slight blast, and afterwards lets it down into the mould, which is immediately filled by blowing still stronger through the tube.
20. The vessel is then taken from the mould, and disengaged from the tube. The same tube, or a punting iron having been attached to the bottom, the other end is softened in the fire, and brought to the proposed form with appropriate tools, while the iron is rolled up and down upon the long arms of the glass-blower's chair. The ornamental moulds are made of cast iron, brass, or copper, and are composed of two parts, which open and shut upon hinges. The moulds for plain vials, castor oil bottles, small demijohns, &c., aremade of the kind of clay used for the crucibles. These consist merely of a mass of the clay, with a cylindrical hole in it of proper diameter and depth.
21.Pressing.—This process is applied in the production of vessels or articles which are very thick, and which are not contracted at the top. The operation is performed in iron moulds, which consist of two parts, and which have upon their internal surfaces the figures to be impressed upon the glass. The material, while in an elastic condition, is put into the lower part of the mould; and the other part, called thefollower, is immediately brought upon it with considerable force.
22. Every species of glass, before it can be used with safety, must beannealed, to diminish its brittleness. The annealing consists merely in letting down the temperature by degrees. Small boys, therefore, convey the articles, whatever they may be, as fast as they are made, to a moderately heated oven, which, when filled, is suffered to cool by degrees.
23.Cutting.—The name ofcut glassis given to the kind which is ground and polished in figures, appearing as if cut with a sharp instrument. This operation is confined chiefly to flint glass, which, being more tough and soft than the other kinds, is more easily wrought. In addition to this, it is considerably more brilliant, producing specimens of greater lustre.
24. An establishment for grinding glass contains a great number of wheels of cast iron, stone, and wood, of different sizes; and the process consists entirely in holding the glass against these, while they are revolving with rapidity. When a considerable portion of the material is to be removed, the grinding is commonly commenced on the iron wheel, on which is constantly pouring water and sharp sand, from a vessel above, which, from its shape, is called ahopper.
25. The period of the invention of glass is quite unknown; but the following is the usual story of itsorigin. Some merchants, driven by a storm upon the coasts of Phœnicia, near the River Belus, kindled a fire on the sand to cook their victuals, using as fuel some weeds which grew near. The ashes produced by the incineration of these plants, coming in contact with the sand, united with its particles, and, by the influence of the heat, produced glass.
26. This production was accidentally picked up by a Tyrian merchant, who, from its beauty and probable utility, was led to investigate the causes of its formation, and who, after many attempts, succeeded in the manufacture of glass. The legend probably originated in the fact, that glass was very anciently made at Tyre; and that the sand on the seashore in the immediate neighbourhood of the Belus, was well adapted to glass-making.
27. It is certainly probable, that an accidental vitrification might have given rise to the discovery; but the circumstance would have been more likely to take place in some operation requiring greater heat than that necessary for dressing food in the open air. The invention of glass must have been effected as early as fifteen hundred years before our era. It was manufactured very anciently in Egypt; but whether that country or Phœnicia is entitled to the preference, as regards priority in the practice of this art, cannot be determined.
28. Glass was made in considerable perfection at Alexandria, and was thence supplied to the Romans as late as the first quarter of the second century. Before this time, however, Rome had her glass manufactories, to which a particular street was assigned. The attention of the workmen was directed chiefly to the production of bottles and ornamental vases, specimens of which still remain, as monuments of their extraordinary skill.
29. In modern times, the manufacture of glass wasconfined principally to Italy and Germany. Venice became particularly celebrated for the beauty of the material, and the skill of its workmen; and as early as the thirteenth century, it supplied the greatest part of the glass used in Europe. The artists of Bohemia, also, came to be held in considerable reputation.
30. The art was first practised in England, in the year 1557, when a manufactory was erected at Crutched Friars, in the city of London, and shortly afterwards, another at the Savoy, in the Strand. In these establishments, however, were made little else than common window glass, and coarse bottles, all the finer articles being still imported from Venice. In 1673, the celebrated Duke of Buckingham brought workmen from Italy, and established a manufactory for casting plate glass for mirrors and coach windows. The art, in all its branches, is now extensively practised in great perfection, not only in Great Britain, but in many of the other kingdoms of Europe.
31. Before the commencement of the late war with England, very little, if any, glass was manufactured in the United States, except the most common window glass, and the most ordinary kinds of hollow ware. Apothecaries' vials and bottles, as well as every other variety of the better kinds of glass wares, had been imported from Europe, and chiefly from England.
32. Our necessities, created by the event just mentioned, produced several manufactories, which, however, did not soon become flourishing, owing, at first, to inexperience, and, after the peace, to excessive importations. But adequate protection having been extended to this branch of our national industry, by the tariff of 1828, it is now in a highly prosperous condition—so much so, that importations of glass ware have nearly ceased.