Читать книгу: «Inventions in the Century», страница 27

CHAPTER XXX.
ILLUMINATING GAS

"How wonderful that sunbeams absorbed by vegetation in the primordial ages of the earth and buried in its depths as vegetable fossils through immeasurable eras of time, until system upon system of slowly formed rocks have been piled above, should come forth at last, at the disenchanting touch of science, and turn the light of civilised man into day." —Prof. E. L. Youmans.

"The invention of artificial light has extended the available term of human life, by giving the night to man's use; it has, by the social intercourse it encourages, polished his manners and refined his tastes, and perhaps as much as anything else, has aided his intellectual progress." —Draper.

If one desires to know what the condition of cities, towns and peoples was before the nineteenth century had lightened and enlightened them, let him step into some poor country town in some out-of-the-way region (and such may yet be found) at night, pick his way along rough pavements, and no pavements, by the light of a smoky lamp placed here and there at corners, and of weeping lamps and limp candles in the windows of shops and houses, and meet people armed with tin lanterns throwing a dubious light across the pathways. Let him be prepared to be assailed by the odours of undrained gutters, ditches, and roads called streets, and escape, if he can, stumbling and falling into them. Let him take care also that he avoid in the darkness the drippings from the overhanging eaves or windows, and falling upon the slippery steps of the dim doorway he may be about to enter. Within, let him overlook, if he can, in the hospitable reception, the dim and smoky atmosphere, and observe that the brightest and best as well as the most cheerful illuminant flashes from the wide open fireplace. Occasionally a glowing grate might be met. The eighteenth century did have its glowing grates, and its still more glowing furnaces of coal in which the ore was melted and by the light of which the castings were made.

It is very strange that year after year for successive generations men saw the hard black coal break under the influence of heat and burst into flames which lit up every corner, without learning, beyond sundry accidents and experiments, that this gast, or geest, or spirit, or vapour, or gas, as it was variously called, could be led away from its source, ignited at a distance, and made to give light and heat at other places than just where it was generated.

Thus Dr. Clayton, Dean of Kildare, Ireland, in 1688 distilled gas from coal and lit and burned it, and told his learned friend, the Hon. Robert Boyle, about it, who announced it with interest to the Royal Society, and again it finds mention in the Philosophical Transactions fifty years later. Then, in 1726, Dr. Hales told how many cubic inches of gas a certain number of grains of coal would produce. Then Bishop Watson in 1750 passed some gas through water and carried it in pipes from one place to another; and then Lord Dundonald in 1786 built some ovens, distilled coal and tar, burned the gas, and got a patent. In the same year, Dr. Rickel of Würzburg lighted his laboratory with gas made by the dry distillation of bones; but all these were experiments. Finally, William Murdock, the owner of large workshops at Redruth, in Cornwall, a practical man and mechanic, and a keen observer, using soft coal to a large extent in his shops, tried with success in 1792 to collect the escaping gas and with it lit up the shops. Whether he continued steadily to so use the gas or only at intervals, at any rate it seems to have been experimental and failed to attract attention. It appears that he repeated the experiment at the celebrated steam engine works of Boulton and Watt at Soho, near Birmingham, in 1798, and again illuminated the works in 1802, on occasion of a peace jubilee.

In the meantime, in 1801, Le Bon, a Frenchman at Paris, had succeeded in making illuminating gas from wood, lit his house therewith, and proposed to light the whole city of Paris.

Thus it may be said that illuminating gas and the new century were born together – the former preceding the latter a little and lighting the way.

Then in 1803 the English periodicals began to take the matter up and discuss the whole subject. One magazine objected to its use in houses on the ground that the curtains and furniture would be ruined by the saturation produced by the oxygen and hydrogen, and that the curtains would have to be wrung out the next morning after the illumination. There doubtless was good cause for objection to the smoky, unpleasant smelling light then produced.

In America in 1806 David Melville of Newport, Rhode Island, lighted with gas his own house and the street in front of it. In 1813 he took out a patent and lighted several factories. In 1817 his process was applied to Beaver Tail Lighthouse on the Atlantic coast – the first use of illuminating gas in lighthouses. Coal oil and electricity have since been found better illuminants for this purpose.

Murdoch, Winser, Clegg and others continued to illuminate the public works and buildings of England. Westminster Bridge and the Houses of Parliament were lighted in 1813, and the streets of London in 1815. Paris was lighted in 1820, and the largest American cities from 1816 to 1825. But it required the work of the chemists as well as the mechanics to produce the best gas. The rod of Science had touched the rock again and from the earth had sprung another servant with power to serve mankind, and waited the skilled brain and hand to direct its course.

Produced almost entirely from bituminous coal, it was found to be composed chiefly of carbon, oxygen and hydrogen; but various other gases were mixed therewith. To determine the proper proportions of these gases, to know which should be increased or wholly or partly eliminated, required the careful labours of patient chemists. They taught also how the gas should be distilled, condensed, cleaned, scrubbed, confined in retorts, and its flow measured and controlled.

Fortunately the latter part of the eighteenth century and the early part of the nineteenth had produced chemists whose investigations and discoveries paved the way for success in this revolution in the world of light. Priestley had discovered oxygen. Dalton had divided matter into atoms, and shown that in its every form, whether solid, liquid, or gaseous, these atoms had their own independent, characteristic, unalterable weight, and that gases diffused themselves in certain proportions.

Berthollet, Graham, and a host of others in England, France, and Germany, advanced the art. The highest skilled mechanics, like Clegg of England, supplied the apparatus. He it was who invented a gas purifier, liquid gas meter, and other useful contrivances.

As the character of the gas as an illuminator depends on the quantity of hydro-carbon, or olefiant elements it contains, great efforts were made to invent processes and means of carbureting it.

The manufacture of gas was revolutionised by the invention of water gas. The main principle of this process is the mixture of hydrogen with the vapour of some hydro-carbon: Hydrogen burns with very little light and the purpose of the hydro-carbon is to increase the brilliancy of the flame. The hydrogen gas is so obtained by the decomposition of water, effected by passing steam through highly heated coals.

Patents began to be taken out in this line in England in 1823-24; by Donovan in 1830; Geo. Lowe in 1832, and White in 1847. But in England water gas could not compete with coal gas in cheapness. On the contrary, in America, especially after the petroleum wells were opened up, and nature supplied the hydro-carbon in roaring wells and fountains, water gas came to the front.

The leading invention there in this line was that of T. S. C. Lowe of Morristown, Pennsylvania, in 1873. In Lowe's process anthracite coal might be used, which was raised in a suitable retort to a great heat, then superheated steam admitted over this hot bed and decomposed into hydrogen and carbonic oxide; then a small stream of naphtha or crude petroleum was thrown upon the surface of the burning coal, and from these decompositions and mixtures a rich olefiant product and other light-giving gases were produced.

The Franklin Institute of Philadelphia in 1886 awarded Lowe, or his representatives, a grand medal of honour, his being the invention exhibited that year which in their opinion contributed most to the welfare of mankind.

A number of inventors have followed in the direction set by Lowe. The largest part of gas manufacture, which has become so extensive, embodies the basic idea of the Lowe process.

The competition set up by the electricians, especially in the production of the beautiful incandescent light for indoor illumination, has spurred inventors of gas processes to renewed efforts – much to the benefit of that great multitude who sit in darkness until corporations furnish them with light.

It was found by Siemens, the great German inventor of modern gas regenerative furnace systems, that the quality of the gas was much improved, and a greater intensity of light obtained, by heating the gases and air before combustion – a plan particularly adapted in lighting large spaces.

To describe in detail the large number of inventions relating to the manufacture of gas would require a huge volume – the generators, carburetors, retorts, mixers, purifiers, metres, scrubbers, holders, condensers, governors, indicators, registers, chargers, pressure regulators, etc., etc.

It was a great convenience outside of towns and cities, where gas mains could not be laid, to have domestic plants and portable gas apparatus, worked on the same principles, but in miniature form, adapted to a single house, but the exercise of great ingenuity was required to render such adaptation successful.

In the use of liquid illuminants, which need a wick to feed them, the Argand burner– that arrangement of concentric tubes between which the wick is confined – although invented by Argand in 1784, yet has occupied a vast field of usefulness in connection with the lamps of the nineteenth century.

A dangerous but very extensively used illuminating liquid before coal oil was discovered was camphene, distilled from turpentine. It gave a good light but was not a safe domestic companion.

Great attention has recently been paid to the production of acetylene gas, produced by the reaction between calcium carbide and water. The making of the calcium carbide by the decomposition of mixed pulverised lime and coal by the use of a powerful electric battery, is a preliminary step in the production of this gas, and was a subsequent discovery.

The electric light, acetylene, magnesium, and other modern sources of light, although they may be more brilliant and intense than coal gas, cannot compete in cheapness of production with the latter. Thus far illuminating coal gas is still the queen of artificial lights.

After gas was fairly started in lighting streets and buildings its adaptation to lamps followed; and among the most noted of gas lamps is that of Von Welsbach, who combined a bunsen gas flame and a glass chimney with a "mantle" located therein. This mantle is a gauze-like structure made of refractory quartz, or of certain oxides, which when heated by the gas flame produce an incandescent glow of intense brilliancy, with a reduced consumption of gas.

CHAPTER XXXI.
BRICK, POTTERY, GLASS, PLASTICS

When the nineteenth century dawned, men were making brick in the same way for the most part that they were fifty centuries before. It is recorded in the eleventh chapter of Genesis that when "the whole earth was of one language and one speech, it came to pass as they journeyed from the east that they found a plain in the land of Shinar; and they dwelt there, and they said to one another, Go to, let us make brick and burn them thoroughly, And they had brick for stone, and slime had they for mortar." Then commenced the building of Babel. Who taught the trade to the brick-makers of Shinar?

The journey from the east continued, and with it went brick making to Greece and Rome, across the continent of Europe, across the English channel, until the brick work of Cæsar, stamped by the trade mark of his legions, was found on the banks of the Thames, and through the fields of Caerleon and York.

Alfred the Great encouraged the trade, and the manufacture flourished finely under Henry VIII., Elizabeth and Charles I.

As to Pottery: – Could we only know who among the peoples of the earth first discovered, used, or invented fire, we might know who were the first makers of baked earthenware. Doubtless the art of pottery arose before men learned to bake the plastic clay, in that groping time when men, kneading the soft clay with their fingers, or imprinting their footsteps in the yielding surface and learning that the sun's heat stiffened and dried those forms into durability, applied the discovery to the making of crude vessels, as children unto this day make dishes from the tenacious mud. But the artificial burning of the vessels was no doubt a later imitation of Nature.

Alongside the rudest and earliest chipped stone implements have been found the hollow clay dish for holding fire, or food, or water. "As the fragment of a speech or song, a waking or a sleeping vision, the dream of a vanished hand, a draught of water from a familiar spring, the almost perished fragrance of a pressed flower call back the singer, the loved and lost, the loved and won, the home of childhood, or the parting hour, so in the same manner there linger in this crowning decade of the crowning century bits of ancient ingenuity which recall to a whole people the fragrance and beauty of its past." Prof. O. T. Mason. The same gifted writer, adds: "Who has not read, with almost breaking heart, the story of Palissy, the Huguenot potter? But what have our witnesses to say of that long line of humble creatures that conjured out of prophetic clay, without wheels or furnace, forms and decorations of imperishable beauty, which are now being copied in glorified material in the best factories of the world? In ceramic as well as textile art the first inventors were women. They quarried the clay, manipulated it, constructed and decorated the ware, burned it in a rude furnace and wore it out in a hundred uses."

From the early dawn of human history to its present noonday civilisation the progress of man may be traced in his pottery. Before printing was an art, he inscribed on it his literature. Poets and painters have adorned it; and in its manufacture have been embodied through all ages the choicest discoveries of the chemist, the inventor and the mechanic.

It would be pleasant to trace the history of pottery from at least the time of Homer, who draws a metaphor from the potter seated before his wheel and twirling it with both hands, as he shapes the plastic clay upon it; to dwell upon the clay tablets and many-coloured vases, covered with Egyptian scenes and history; to re-excite wonder over the arts of China, in her porcelain, the production of its delicacy and bright colours wrapped in such mystery, and stagnant for so many ages, but revived and rejuvenated in Japan; to recall to mind the styles and composition of the Phœnician vases with mythological legends burned immortally therein; the splendid work of the Greek potteries; to lift the Samian enwreathed bowl, "filled with Samian wine"; to look upon the Roman pottery, statues and statuettes of Rome's earlier and better days; the celebrated Faience (enamelled pottery) at its home in Faenza, Italy, and from the hands of its master, Luca della Robia; to trace the history of the rare Italian majolica; to tread with light steps the bright tiles of the Saracens; to rehearse the story of Bernard Palissy, the father of the beautiful French enamelled ware; to bring to view the splendid old ware of Nuremberg, the raised white figures on the deep blue plaques of Florence, the honest Delft ware of Holland; and finally to relate the revolution in the production of pottery throughout all Europe caused by the discoveries and inventions of Wedgwood of England in the eighteenth century. All this would be interesting, but we must hasten on to the equally splendid and more practical works of the busy nineteenth century, in which many toilsome methods of the past have been superseded by labour-saving contrivances.

The application of machinery to the manufacture of brick began to receive attention during the latter part of the eighteenth century, after Watt had harnessed steam, and a few patents were issued in England and America at that time for such machinery of that character, but little was practically done.

The operations in brickmaking, to the accomplishment of which by machines the inventors of the nineteenth century have devoted great talent, relate:

First, to the preparation of the clay. – In ancient Egypt, in places where water abounded, it appears that the clay was lifted from the bottoms of ponds and lakes on the end of poles, was formed into bricks, then sun-dried, modernly called adobes. The clay for making these required a stiffening material. For this straw was used, mixed with the clay; and stubble was also used in the different courses. Hence the old metaphor of worthlessness of "bricks without straw," but of course in burning, and in modern processes of pressing unburnt bricks, straw is no longer used. Sand should abound in the clay in a certain proportion, or be mixed therewith, otherwise the clay, whether burned or unburned, will crumble. Stones, gravel and sticks must be removed, otherwise the contraction of the clay and expansion of the stones on burning, produce a weak and crumbling structure.

Brick clay generally is coloured by the oxide of iron, and in proportion as this abounds the burned brick is of a lighter or a deeper red. It may be desired to add colouring matter or mix different forms of clay, or add sand or other ingredients. Clay treated by hand was for ages kneaded as dough is kneaded, by the hand or feet, and the clay was often long subjected, sometimes for years, to exposure to the air, frost and sun to disintegrate and ripen it. As the clay must be first disintegrated, ground or pulverised, as grain is first ground to flour to make and mould the bread, so the use of a grinding mill was long ago suggested. The first machine used to do all this work goes by the humble name of pug mill.

Many ages ago the Chilians of South America hung two ponderous solid wood or stone wheels on an axis turned by a vertical shaft and operated by animal power; the wheels were made to run round on a deep basin in which ores, or stones, or grain were placed to be crushed. This Chilian mill, in principle, was adopted a century or so ago in Europe to the grinding of clay. The pug mill has assumed many different forms in this age; and separate preliminary mills, consisting of rollers of different forms for grinding, alone are often used before the mixing operation. In one modern form the pug mill consists of an inverted conical-shaped cylinder provided with a set of interior revolving blades arranged horizontally, and below this a spiral arrangement of blades on a vertical axis, by which the clay is thoroughly cut up and crushed against the surrounding walls of the mill, in the meantime softened with water or steam if desired, and mixed with sand if necessary, and when thus ground and tempered is finally pressed down through the lower opening of the cylinder and directly into suitable brick moulds beneath.

Second. – The next operation is for moulding and pressing the brick. To take the place of that ancient and still used mode of filling a mould of a certain size by the hands with a lump of soft clay, scraping off the surplus, and then dumping the mould upon a drying floor, a great variety of machines have been invented.

In some the pug mill is arranged horizontally to feed out the clay in the form of a long horizontal slab, which is cut up into proper lengths to form the bricks. Some machines are in the form of a large horizontal revolving wheel, having the moulds arranged in its top face, each mould charged with clay as the wheel presents it under the discharging spout of the grinding mill, and then the clay is pressed by pistons or plungers worked by a rocking beam, and adapted to descend and fit into the mould at stated intervals; or the moulds, carried in a circular direction, may have movable bottom plates, which may be pressed upwards successively by pistons attached to them and raised by inclines on which they travel, forcing the clay against a large circular top plate, and in the last part of the movement carrying the pressed brick through an aperture to the top of the plate, where it is met by and carried away on an endless apron.

In some machines two great wheels mesh together, one carrying the moulds in its face, and the other the presser plate plungers, working in the former, the bricks being finally forced out on to a moving belt by the action of cam followers, or by other means.

In others the moulds are passed, each beneath a gravity-descending or cam-forced plunger, the clay being thus stamped by impact into form; or in other forms the clay in the moulds may be subjected to successive pressure from the cam-operated pistons arranged horizontally and on a line with the discharging belt.

Third, the drying and burning of the brick. – The old methods were painfully slow and tedious. A long time was occupied in seasoning the clay, and then after the bricks were moulded, another long time was necessary to dry them, and a final lengthy period was employed to burn them in crude kilns. These old methods were too slow for modern wants. But they still are in vogue alongside of modern inventions, as in all ages the use of old arts and implements have continued along by the side of later inventions and discoveries.

No useful contrivances are suddenly or apparently ever entirely supplanted. The implements of the stone age are still found in use by some whose environment has deprived them of the knowledge of or desire to use better tools. The single ox pulling the crooked stick plough, or other similar ancient earth stirrer, and Ruth with her sickle and sheaves, may be found not far from the steam plough and the automatic binder.

But the use of antiquated machinery is not followed by those who lead the procession in this industrial age. Consequently other means than the slow processes of nature to dry brick and other ceramics, and the crude kilns are giving way to modern heat distributing structures.

Air and heat are driven by fans through chambers, in which the brick are openly piled on cars, the surplus heat and steam from an engine-room being often used for this purpose, and the cars so laden are slowly pushed on the tracks through heated chambers. Passages and pipes and chimneys for heat and air controlled by valves are provided, and the waste moisture drawn off through bottom drains or up chimneys, the draft of which is increased by a hot blast, or blasts of heated air are driven in one direction through a chamber while the brick are moved through in the opposite direction, or a series of drying chambers are separated from each other by iron folding-doors, the temperature increasing as cars are moved on tracks from one chamber to another.

Dr. Hoffmann of Berlin invented different forms of drying and burning chambers which attracted great attention. In his kiln the bricks are stacked in an annular chamber, and the fire made to progress from one section of the chamber to another, burning the brick as the heat advances; and as fast as one section of green brick is dried, or burned, it is withdrawn, and a green section presented. Austria introduced most successful and thorough systems of drying brick about 1870. In some great kilns fires are never allowed to cease. One kiln had been kept thus heated for fifteen years. Thus great quantities of green brick can at any time be pushed into the kiln on tracks, and when burned pushed out, and thus the process may go on continuously day and night.

To return to pottery: As before stated, Wedgwood of England revolutionised the art of pottery in the eighteenth century. He was aided by Flaxman. Before their time all earthenware pottery was what is now called "soft pottery." That is, it was unglazed, simply baked clay; lustrous or semi-glazed and enamelled having a harder surface. Wedgwood invented the hard porcelain surface, and very many beautiful designs. To improve such earthenware and to best decorate it, are the objects around which modern inventions have mostly clustered.

The "regenerative" principle of heating above referred to employed in some kilns, and so successfully incorporated in the regenerators invented since 1850 by Siemens, Frank, Boetius, Bicheroux, Pousard and others, consisting in using the intensely hot wasted gases from laboratories or combustion chambers to heat the incoming air, and carrying the mingled products of combustion into chambers and passages to heat, dry or burn materials placed therein, has been of great service in the production of modern pottery; not only in a great saving in the amount of fuel, but in reduction in loss of pieces of ware spoiled in the firing.

The old method of burning wood, or soft coal, or charcoal at the bottom of a small old-fashioned cylindrical fire brick kiln attended to by hand, and heating the articles of pottery arranged on shelves in the chamber above, is done away with to a great extent in large manufactories for the making of stone and earthenware – although still followed in many porcelain kilns.

Inventions in the line of pottery kilns have received the aid of woman. Susan Frackelton of the United States invented a portable kiln for firing pottery and porcelain, for which she obtained a patent in 1886.

As in drying clay for brick, so in drying clay for porcelain and pottery generally, great improvements have been made in the drying of the clay, and other materials to be mixed therewith. A great step was taken to aid drying by the invention of the filter press, in which the materials, after they are mixed and while still wet, are subjected to such pressure that all surplus water is removed and all air squeezed out, by which the inclosure of air bubbles in the clay is prevented.

Despairing of excelling the China porcelain, although French investigators having alleged their discovery of such methods, modern inventors have contented themselves in inventing new methods and compositions. Charles Aoisseau, the potter of Tours, born in 1796, rediscovered and revived the art of Palissy. About 1842, Thomas Battam of England invented the method of imitating marble and other statuary by a composition of silica, alumina, soda, and traces of lime, magnesia, and iron, reducing it to liquid form and pouring it into plaster moulds, forming the figure or group. His plaster casts soon became famous. In the use of materials the aid of chemists was had in finding the proper ingredients to fuse with sand to produce the best forms of common and fine Faience.

Porcelain Moulding, and its accompanying ornamentation and the use of apparatus for moulding by compression and by exhaustion of the air has become since that time a great industry.

Porcelain Colours.– Chemists also aided in discovering what metallic ingredients could best be used when mixed with the clay and sand to produce the desired colours. As soon as a new metal was discovered, it was tested to find, among other things, what vitrifiable colour it would produce. In the production of metallic glazes, the oxides generally are employed. The colours are usually applied to ware when it is in its unglazed or biscuit form. In the biscuit or bisque form pottery is bibulous, the prepared glaze sinks into its pores and when burned forms a vitreous coating.

The application of oil colours and designs to ware before baking by the "bat" system of printing originated in the eighteenth and was perfected in the nineteenth century. It consists of impressing oil pictures on a bat of glue and then pressing the bat on to the porous unbaked clay or porcelain which transferred the colours. This was another revolution in the art.

One manner for ages of applying colours to ware is first to reduce the mixture to a liquid form, called "slip," and then, if the Chinese method is followed, to dip the colour up on the end of a hollow bamboo rod, which end is covered with wire gauze, then by blowing through the rod the colour was sprayed or deposited on the ware. Another method is the use of a brush and comb. The brush being dipped into the coloured matter, the comb is passed over the brush in such manner as to cause the paint to spatter the object with fine drops or particles. A very recent method, by which the beautiful background and blended colours of the celebrated Rookwood pottery of Cincinnati, Ohio, have become distinguished, consists in laying the colour upon the ware in a cloud or sheet of almost imperceptible mist by the use of an air atomiser blown by the operator. By the use of this simple instrument, the laying on a single colour, or the delicate blending and shadings of two or more colours in very beautiful effects is easily produced.

This use of the atomiser commenced in 1884, and was claimed as the invention of a lady, Miss Laura Fry, who obtained a patent for thus blowing the atomised spray colouring matter on pottery in 1889; but it was held by the courts that she was anticipated by experiments of others, and by descriptions in previous patents of the spraying of paint on other objects by compressed air apparatus known as the air brush. However, this introduction of the use of the atomiser caused quite a revolution in the art of applying colours to pottery in the forming of backgrounds.

Enamelled ware is no longer confined to pottery. About 1878 Niedringhaus in the United States began to enamel sheet iron by the application of glaze and iron oxide, giving such articles a granite appearance; and since then metallic cooking vessels, bath tubs, etc., have been converted in appearance into the finest earthenware and porcelain, and far more durable, beautiful and useful than the plain metal alone for such purposes.