lii Annual Report of the Council. 



acid does not attack glass, served in recent years to facilitate the 

 investigation of its properties. 



In 1 89 1 Moissan was elected a member of the Academy 

 of Sciences to fill the chair left vacant by the death of 

 Cahours. 



The main reason which impelled him to pass from the study 

 of fluorine to the high-temperature researches, which from 1892 

 onwards absorbed so much of his attention, seems to be 

 closely connected with a desire, which he had long entertained, 

 to solve the mystery of the origin of the diamond. The hope 

 that the great activity of fluorine for other elements would help 

 in the quest not being realised, he was led to a methodical study 

 of the behaviour and transformation of the three allotropic 

 modifications of carbon. This study, which is an excellent 

 example of the logical application of experiment, resulted in 

 the artificial production of diamond, and at the same time added 

 greatly to our knowledge of the peculiar metamorphoses 

 which characterise this element. 



In electric furnace work Moissan's pre-eminent position is 

 due, not to the design or discovery of a special form of furnace, 

 but rather to the skill with which he investigated in detail a 

 number of individual chemical reactions. In each case he 

 devoted great care to the purification and analysis of the raw 

 materials required in the process, and submitted the products to 

 minute examination and quantitatively determined their com- 

 position. Thus his preparation of chromium, tungsten, moly- 

 bdenum, uranium, titanium, and many other metals in a fused 

 form and high degree of purity greatly enriched our knowledge 

 of the chemical and physical properties of these elements. 



Of still greater importance was the methodical following up 

 of the chance formation of calcium carbide which he observed 

 around the carbon electrodes in his early furnace experiments. 

 From this observation he was led to discover and determine 

 fully the nature and properties of a large number of metallic 

 carbides, borides, and silicides, most of them hitherto 



