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CHEMICAL DISCOVERY AND INVENTION 



the adjoining illustration. The body of the furnace is formed of 

 blocks of good lime, a material which resists without change the 

 highest temperatures produced by the oxyhydrogen flame. In 

 the arc lime slowly fuses and volatilises. As the diagram shows 

 the carbon poles pass through the sides of the box and, being 

 connected with the source of the current, are brought into 

 contact with each other immediately over the object to be heated 



FIG. 40. MOISSAN'S ELECTRIC FURNACE. 



which is placed in the central cavity. On withdrawing the 

 carbons apart, the arc is formed by the current carried across by 

 a stream of carbon particles and vapour. The temperature 

 produced in this way is higher than the temperature of any flame. 

 It probably exceeds 3000 or 3500 C., but is difficult to estimate. 

 All ordinary metals not only melt in this furnace, but boil and 

 pass off in vapour. Even lime and magnesia, among the most 



research, but, encouraged by Deherain, he set to work privately to prepare for 

 his degree, which he ultimately obtained. Subsequently he received an appoint- 

 ment at the Ecole Superieure de Pharniacie, where a few years later he succeeded 

 to the chair ol toxicology, arid afterwards that of inorganic chemistry. At the time 

 of his death he held the professorship of inorganic chemistry in the Faculty of 

 Sciences of the University of Paris, where he had succeeded Troost in 1900. 



To Moissan we owe the isolation (in 1886) of the elusive element fluorine, 

 perhaps his most interesting work from the scientific point of view, and the dis- 

 covery of the conditions of formation of the diamond. The latter discovery 

 resulted from the experience he had gained in the application of the electric arc. 

 to the production of very high temperatures, 



