Intelligence and Miscellaneous Articles. 156 



ing matter, or perhaps into water and carbonic acid. — Ann. de Ch. 

 et de Phys., Juillet 1847. 



ON THE EQUIVALENT OF TITANIUM. BY M. ISIDORE PIERRE. 



The author remarks that chemists generally agree that it would 

 be difficult to add to the precision of the numbers which represent 

 the equivalents of hydrogen, carbon, chlorine, bromine, iodine, phos- 

 phorus, arsenic and silicon, as determined by the researches of Du- 

 mas, Marignac and Pelouze. 



M, Pierre thinks however that this is not the case with titanium ; 

 and that if the labours of different periods respecting this substance 

 be examined, it will be evident that its equivalent requires renewed 

 examination. 



M. H. Rose originally obtained, by various methods, numbers 

 which varied between 380 and 450 ; but he afterwards found that 

 the sulphuret of titanium which he employed in his experiments, 

 was procured free from titanic acid with great difficulty. 



In his last experiments, M. Rose made use of chloride of titanium, 

 which he decomposed by water. He precipitated with ammonia the 

 titanic acid derived from this decomposition, and afterwards treated 

 the filtered liquor with nitrate of silver, in order to separate the 

 chlorine in the state of chloride of silver : this method gave him 

 303*686 as the equivalent of titanium. 



The chloride of titanium used by M. Pierre was not prepared from 

 rutil, but from calcined artificial oxide of titanium : it was free from 

 oxide of iron and from chloride of silicium, and its boiling-point was 

 perfectly stationary. The chloride employed had been kept in a small 

 tube from the time of its preparation hermetically sealed : it was 

 broken by agitation in a stopped bottle, one quarter filled with distilled 

 water. By frequent agitation, Avithout unstopping the bottle, the 

 whitish cloud at first produced above the liquid disappears. Without 

 this precaution there would be a probable loss of hydrochloric acid 

 in opening the bottle too soon, or by introducing the solution of 

 silver, which would expel a small quantity of this vapour. 

 The following results were obtained : — gr. 



I. Chloride of titanium employed. . 0"8215 



Silver 1'84523 



indicating Chlorine 0'60623 



Titanium by difference 0*21727 



These results gave 314*76 as the equivalent of titanium. 

 II. Chloride of titanium employed. . 0*774 



Silver 1*73909 



indicating Chlorine 0*57 136 



Titanium by difference 0*20264 



These numbers give for the equivalent of titanium 314*37. 

 III. Chloride of titanium employed. . 0*7775 



Silver 1*74613 



indicating Chlorine 0*57367 



Titanium by difference 0*20383 



The equivalent of titanium deduced from this experiment is 31 4*94 . 



