The Romance of Modern Chemistry

CHAPTER XVII CHEMISTRY AT HIGH TEMPERATURES IT is not only into the region of low temperatures that such a surprising advance has recently been made. Much has been achieved also in the other direction, and it has lately become possible to realise within a limited space a degree of heat far beyond what can be produced with the aid of ordinary fuel alone. This attainment of extremes of heat and cold has immensely widened the range of temperature over which the chemist can study the properties of matter, and as a result many new substances, as well as new methods of making old substances, have been discovered. One result of low temperature research, as we have seen, is that all the known gases have been reduced to the liquid state, and in many cases even solidified. Similarly, by the recent application of very high tempera- tures, the most refractory solids have Leen melted and even vaporised. Apart, however, from the extremc'ly high temperatures reached by recent methods, there are easily attainable temperatures at which many substances, existing ordinarily as stable solids, are first melted and then converted into vapour. Now the possibility of changing any substance into vapour without decomposing it involves a great deal; for it means that a distillation can be carried out, and as a method of separating and purifying chemical compounds, 193 n