The Electric Furnace (Paperback)

PREFACE TO THE ENGLISH EDITION To understand fully the importance of this work, it is necessary to go back to the time of our first experi- ments with the electric furnace, that is, to the latter part of 1892. At that time, acetylene was still an uncommon gas, which could only be obtained pure with calcium carbide was un- great difficulty. Crystallized known, as were the richer alloys of chromium, man- ganese, vanadium, and titanium with iron. Finally, a large number of refractory metals, and more especially chromium and manganese, were real museum curiosities, and their properties in the pure state were unknown. This was not due to the lack of experiments along these lines. Following the important discovery and application of the electric arc by Sir Humphry Davy, came the work of Despretz, the interesting furnace of Siemens and Huntington, in which, however, they were unable to melt any considerable amount of tungsten, and the commercial methods of Cowles, who used the electric arc to prepare alloys of aluminium and copper. Since we began our work on this subject, the group of metallic carbides, then almost unknown, has received many additions, as have also the groups of the silicides and borides. Further, among the refractory metals, for which we have described an easy method of preparation, we may mention uranium, whose interesting properties have attracted the attention ofmany physicists. The most important result of our work with the electric furnace has been to obtain temperatures of 3,500-4,000 C., and to show that under these conditions all the known elements and compounds may be vaporized. Those bodies which rernain undecomposed by heat are all liquefied and volatilized.Further, at these high temperatures, chemistry assumes a special aspect, and series of new compounds are formed, some of which we have studied. It is interesting to note that while we were extending the province of chemistry at high temperatures, the carried to its study of low temperatures was being furthest limits by Cailletet, Olzweski, and Dewar. So that the chemist has at his disposal to-day a scale of temperature ranging from 257 to 4,000 C. But Sir James Dewar, who has been able to liquefy and solidify hydrogen in considerable quantities, has been more for- tunate than ourselves in one respect he has determined accurately the temperatures in the neighbourhood of the absolutezerobygasandelectrical resistance thermometers. These new discoveries enable chemists to undertake researches which were formerly impossible old methods have been modified, and inorganic chemistry, whose field has been thus extended, enters on a new era of develop- ment in which phenomena may be studied under all conditions of temperature. Many chemists and manufacturers have repeated our experiments. Some of these have found it difficult to obtain our results, and the opinion has been expressed that success in this work requires a special imodus faciendi. In reality, the i modus faciendi consists in repeating the same experiment many times over till success is assured. We may remark, however, that, since it is impossible to measure these very high temperatures, it is of vital importance to follow exactly the working conditions we have laid down as to the size of the furnace cavity, the diameter of the electrodes, the strength of the current, and the duration of the experiment. If these precautions be taken, the experiment may be carried out successfully, although the exact temperature may not be known...