INTRODUCTION. 



Most of the literature of the metallic carbides is of recent date, yet the 

 beginnings of the studies upon compounds of carbon with metals take 

 us back to the very dawn of the present century, for during its first years 

 chemists described such compounds. The relation of carbon to iron in 

 steel was said to be that of a true chemical compound as early as 1800, 

 and in 1808 Davy prepared the carbide of potassium. At intervals from 

 that time to the present new carbides have been described. 



In looking over the old references one cannot but notice that, with few 

 exceptions, the carbides described therein are of those metals concerning 

 which there is to-day the greatest doubt as to their forming such com- 

 pounds at all. For example, about sixty years ago a general method was 

 given for forming the carbides of iron, copper, lead, zinc, bismuth, silver, 

 tin, and manganese by heating in a retort their sulphocyanides, air being 

 excluded during the operation. It was said that sulphide of carbon and 

 nitrogen were evolved ; the reactions working parallel to this : — 



Fe(SCN)2+heat=FeC+CS2+N2. 

 The preceding list contains at least four elements which are not, at this 

 time, supposed to form carbides. Frequent mention of other carbides is 

 made in old works on chemistry. In the light of recent investigation 

 these seem of doubtful worth, as the compounds mentioned find no place 

 in modern works, or else their existence has been denied. Some of these 

 old references are given later without comment as to their value, the 

 reader being free to accept or reject any of them. 



In consideration of the interest manifested by chemists recently in this 

 class of bodies, it seems that a brief review of the work done to date may 

 be of considerable interest to the general reader ; while this, in conjunc- 

 tion with the bibliographical references, it is hoped may be of some value 

 to the chemical student or investigator. With these two ends in view the 

 following pages were compiled. 



The general plan has been to give a very condensed account of the 

 methods of preparation, physical and chemical properties of the carbides 

 now known, considering them in alphabetical order. Following each 

 descriptive portion are the references to the literature bearing thereon. 

 The titles of original papers are in most cases given in full, that the scope 

 of the article may be judged therefrom. Minor articles and abstracts are 



