The Romance of Modern Chemistry

CHEMISTRY AND ELECTRICITY plays in the chemical world. As was said at the be- ginning of the chapter, the relationship between chemistry and electricity is one of mutual indebtedness. We have seen how chemical changes have been utilised in the production of electrical energy ; suppose we glance now at one or two of the ways in which electricity has contributed to the advance of chemical knowledge and practice. It will be found that some of the most recent achievements of industrial chemistry have been rendered possible only by the co-operation of the chemist and the electrical engineer. It must be remembered that in some cases the electric current has been used only indirectly in order to bring about chemical changes. It is a familiar fact, illustrated by the common electric glow lamp, that the passage of a current through any body produces heat The greater the opposition offered by the body to the passage of the electricity, the more intense is the heat gener- ated by a given current If, therefore, we employ very powerful currents, and pass them through bodies which offer a stout resistance, an enormous amount of heat is generated, and a very high temperature is reached, much higher, in fact, than is attainable by any ordinary methods. Many substances which are usually quite in- different to each other, react readily at such high tempera- tures, so that the electric current, merely by its heating action, has been extremely useful in extending the chemist’s field of knowledge. Some of the interesting facts which have thus been discovered at the high temperature of the electric furnace have already been described in chapter xvii. It is, however, not only by virtue of its heating effect that the electric current has been of service to the 296