Page:Popular Science Monthly Volume 23.djvu/828

This page has been proofread, but needs to be validated.

The quantity of gold used in the arts, in interior and exterior decorations, in photography, electro-gilding, water-gilding, the ornamentation of china, etc., is very large, and the greater part is practically lost. Jewelers' sweepings from the floors of the workshops are carefully collected, and even the clothes of the workmen are generally saved and sent to the refiner. After a large gold coinage at the Royal Mint, there is always a great deficiency in waste and sweep. The sweep is composed of cinders or dust from the forge, the sweepings of the workshops, broken crucibles, the dross which adheres to the ingots of metal after fusion, and of every waste which can possibly contain minute particles of the metal. This is generally sold. The silver and gold from photographers' waste is also now carefully collected, and forms a considerable item of economy. A method of utilizing the waste of gold-leaf, used in printing and the arts, is by converting it into what is called fleece-gold. The composition is used like the ordinary bronze, except that rather more copal is mixed with it. It is used for all fancy papers for which gold-leaf and bronze have hitherto been used.

The waste of the glass-furnaces—such as pieces of broken glass, flaw-glass, the hearth-droppings, and the glass remaining adherent to the blower's pipe—is utilized again, serving a purpose in the manufacture of glass, similar to rags in paper-making. Agate glass is made by melting waste pieces of colored glass. One to two thousand tons of cullet, or broken glass, are collected in the metropolis alone, and sold to the few city glass-works to be remelted. Broken bottles are now collected and utilized. Thousands of tons of these are broken every year in London alone. Broken "wines" and broken "sodas" are converted to many useful purposes, the latter especially. The broken bottles are utilized for the manufacture of cheap jewelry, chimney-ornaments, and inferior household glass for the manufacturing districts. They are also used for the manufacture of emery powder, glass paper, etc. Some idea of the number of "sodas" broken in the process of filling, corking, cleaning, and distributing may be gathered from the circumstance that one great mineral-water manufacturer in London sold last year one hundred tons. The value of the "metal," as it is styled, is somewhere about ten shillings per ton, but it varies according to the demand. When the market for "fancy goods" is active, broken bottles command a better price. A revival of trade sets this particular industry in motion along with others, and broken bottles are enhanced in value. In fact, broken glass and broken pottery serve many purposes, though it is only lately that economic science has learned how to turn them to account.

The utilization of blast-furnace slag is not new, but has made great progress. Scattered throughout the iron-making districts of Great Britain are many million tons of scoria or refuse from the blast furnaces, which is technically known as "slag." This slag goes on accu-