CHLORIDES OF CARBON. 377 



which Regnault found by experiment to be 815?. It should 

 from its formula contain 



8 volumes carbon vapour. . . 3371 

 12 volumes chlorine. . . . 29284 



32655 



If these form a combining measure of 4 volumes, the most 

 usual of all combining measures, the weight of 1 volume or 

 density of the vapour is 8164, which almost coincides with 

 the experimental result.* 



The perchloride of carbon is a volatile crystalline solid, having 

 an aromatic odour resembling that of camphor, fusible at 320 

 and boiling at 360 (Faraday), of sp. gr. 2, soluble in alcohol 

 ether and oils. It was prepared by Faraday by exposing 

 the Dutch liquid to sunlight in an atmosphere of chlorine, 

 which was several times renewed, as the chlorine was ab- 

 sorbed. 



Protochloride of carbon, C 4 C1 4 . This compound was prepared 

 by Mr. Faraday by passing the vapour of the perchloride through 

 a glass tube filled with fragments of glass, and heated to redness. 

 A great quantity of chlorine becomes free, and a colourless li- 

 quid is obtained, which when purified from perchloride of car- 

 bon and chlorine as much as possible, boils at 248 (Regnault), 

 has asp. gr. of 1.5526, and in its chemical relations is very 

 analogous to the perchloride of carbon. The density of the 

 vapour of the protochloride decides the nature of its constitution. 

 It was found by Regnault to be 5820, which corresponds to 

 the composition by volume: 



8 volumes carbon vapour. . . 33 71 

 8 volumes chlorine. 19523 



Density = 



It must, therefore, contain 4 atoms of carbon and 4 of chlo- 

 rine, and its formula be C 4 C1 4 , or we have come at last to de- 

 fiant gas C 4 H 4 with its whole hydrogen replaced by chlorine. 



* Regnault ; De 1' Action du Chlore sur la liqueur des Hollandais et sur le 

 Chlorure d'Alde"hydne. An. de Ch. et de Ph. t. 69, p. 151. Idem, Sur les Chlo- 

 rures de Carbon, ib. t. 70. p. 104. 



