Inventions in the Century

by William Henry Doolittle

If there are some who regard modern discoveries and inventions in iron and steel as lessening the number of workmen and cheapening the product too much, thus causing trouble due to labour-saving machinery, let them glance, among other great works in the world, at Krupp’s at Essen, where on January 1st, 1899, 41,750 persons were employed, and at which works during the previous year 1,199,610 tons of coal and coke were consumed, or about 4000 tons daily. Workers in iron will not be out of employment in the United States, where 16,000,000 tons of coke are produced annually, 196,405,953 tons of coal mined, 11,000,000 tons of pig iron and about 9,000,000 tons of steel made. The increase of population within the last hundred years bears no comparison with this enormous increase in iron and fuel. It shows that as inventions multiply, so does the demand for their better and cheaper products increase.

As the other metals, gold, silver, copper and lead often occur together, and in the same deposits with iron, the same general modes of treatment to extract them are often applied. These are known as the dry and the wet methods, and electro-reduction.

Ever since Mammon bowed his head in search for gold, every means that the mind of man could suggest to obtain it have been tried, but the devices of this century have been more numerous and more successful than any before. The ancient methods of simply melting and “skimming the bullion dross” have been superseded. Modern methods may be divided into two general classes, the mechanical and the chemical. Of the former methods, when gold was found loose in sand or gravel, washing was the earliest and most universally practised, and was called panning. In this method mercury is often used to take up and secure the fine gold. Rockers like a child’s cradle, into which the dirt is shovelled and washed over retaining riffles, were used; coarse-haired blankets and hides; sluices and separators, with or without quicksilver linings to catch the gold; and powerful streams of water worked by compressed air to tear down the banks. Where water could not be obtained the ore and soil were pulverised and dried, and then thrown against the wind or a blast of air, and the heavier gold, falling before the lighter dust, was caught on hides or blankets. For the crushing of the quartz in which gold was found, innumerable inventions in stamp mills, rollers, crushers, abraders, pulverisers and amalgamators have been invented; and so with roasters, and furnaces, and crucibles to melt the precious metal, separate the remaining impurities and convert it to use.

As to chemical methods for the precious metals, the process of lixiviation, or leaching, by which the ore is washed out by a solution of potash, or with dilute sulphuric acid, or boiling with concentrated sulphuric acid, is quite modern. About 1889 came out the great cyanide process, also known as the MacArthur-Forrest process (they being the first to obtain patents and introduce the invention), consisting of the use of cyanide potassium in solution, which dissolves the gold, and which is then precipitated by the employment of zinc. This process is best adapted to what are known as free milling or porous ores, where the gold is free and very fine and is attracted readily by mercury.

In 1807, Sir Humphry Davy discovered the metal potassium by subjecting moistened potash to the action of a powerful voltaic battery; the positive pole gave off oxygen and the metallic globules of pure potassium appeared at the negative pole. It is never found uncombined in nature. Now if potassium is heated in cyanogen gas (a gas procured by heating mercury) or obtained on a large scale by the decomposition of yellow prussiate of potash, a white crystalline body very soluble in water, and exceedingly poisonous, is obtained. When gold, for instance, obtained by pulverising the ore, or found free in sand, is treated to such a solution it is dissolved from its surrounding constituents and precipitated by the zinc, as before stated.

Chlorine is another metal discovered by Scheele in 1774, but not known as an elementary element until so established by Davy’s investigations in 1810, when he gave it the name it now bears, from the Greek chloras, yellowish green. It is found abundantly in the mineral world in combination with common salt. Now it was found that chlorine is one of the most energetic of bodies, surpassing even oxygen under some circumstances, and that a chlorine solution will readily dissolve gold.

These, the cyanide and chlorination processes, have almost entirely superseded the old washing and amalgamating methods of treating free gold—and the cyanide seems to be now taking the lead.

Alloys.—The art of fusing different metals to make new compounds, although always practised, has been greatly advanced by the discoverers and inventors of the century. As we have seen, amalgamating to extract gold and silver, and the making of bronze from tin and copper were very early followed. One of the most notable and useful of modern inventions or improvements of the kind was that of Isaac Babbitt of Boston in 1839, who in that year obtained patents for what ever since has been known as “babbitting.” The great and undesirable friction produced by the rubbing of the ends of journals and shafts in their bearings of the same metal, cast or wrought iron, amounting to one-fifth of the amount of power exerted to turn them, had long been experienced. Lubricants of all kinds had been and are used; but Babbitt’s invention was an anti-friction metal. It is composed of tin, antimony, and copper, and although the proportions and ingredients have since been varied, the whole art is still known as babbitting.

Other successful alloys have been made for gun metal, sheathing of ships, horseshoes, organ pipes, plough shares, roofing, eyelets, projectiles, faucets, and many and various articles of hardware, ornamental ware, and jewelry.

Valuable metals, such as were not always rare or scarce, but very hard to reduce, have been rendered far less in cost of production and more extensive in use by modern processes. Thus, aluminium, an abundant element in rocks and clay, discovered by the German chemist Wöhler, in 1827, a precious metal, so light, bright, and tough, non-oxidizing, harder than zinc, more sonorous than silver, malleable and ductile as iron, and more tenacious, has been brought to the front from an expensive and mere laboratory production to common and useful purposes in all the arts by the processes commencing in 1854 with that of St. Clair Deoville, of France, followed by those of H. Rose, Morin, Castner, Tissier, Hall, and others.