Page:Popular Science Monthly Volume 66.djvu/448

444 the field of technical chemistry as possible, I could doubtless with equal propriety have selected others. We can simply mention such important questions as the hygienic preservation of food, the flameproofing and preservation of wood, prevention of the corrosion of structural iron and steel, the great problems of chemical metallurgy, et cetera. We must, however, note some of the more recently developed forces and phenomena of nature, the application of which to technical chemistry forms problems for to-day. One of the most important of these is electricity. Thanks to the triumphs of modern electrical engineering we are now able to call to our aid unlimited amounts of this agent at a cost comparable to that of other forms of energy. Possibly the simplest, though not the earliest, method of utilizing electrical energy in chemical processes is in supplying the heat necessary to carry on a reaction directly at the point where the reaction takes place. In a number of chemical industries, for example, the manufacture of phosphorus, it was previously necessary to produce within thick walled retorts a very high temperature. The result was that a great deal of heat was wasted, the retorts deteriorated very rapidly and the reaction was carried on at a low efficiency. By using an electric furnace for the manufacture of phosphorus these expensive retorts are eliminated. In addition much cheaper raw materials may be used, the process is made continuous and a high efficiency obtained. By the substitution of electrical heating for the closed retorts previously used in the preparation of carbon bisulphide the manufacture of this chemical has been placed upon an entirely new basis. The economy introduced by supplying the heat at the point where the union of carbon and sulphur takes place is clearly indicated by the low price at which this material can now be sold and its enormously increased consumption.

With the ability to obtain temperatures far above that which is possible by the ordinary combustion of fuel there was opened up a new field in synthetic chemistry. Reactions which it was impossible to carry out on a technical scale and others the existence of which was not suspected are now through the application of electrical energy become the bases of large manufacturing enterprises. Calcium carbide, carborundum, artificial graphite and many hitherto unknown alloys are the commercial products of the electric furnace where temperatures in the neighborhood of 3000° C. obtain.

The third and more strictly chemical application of electrical energy is in the use of the current for electrolysis. Faraday long ago determined the laws according to which chemical compounds break up when subjected to the passage of an electric current. It is only in recent years, however, that the cost of electrical energy has made it possible to apply the knowledge thus furnished by this great