mcnaccan - 



TITANIUM. 95 



L But it was the composition of menaccanite Analysis of 

 which induced me to fix upon 6 as the true ato- he. 

 mic weight of titanic acid. We have four dif- 



o 



ferent analyses of menaccanite- by Gregor, Kla- 

 protli, Lampadius, and Chenevix ; but, as the ore, 

 in the state in which it occurred in the valley of 

 Menaccan, is a mixture of menaccanite and 

 small grains of octahedral iron ore, and as none 

 of these gentlemen seems to have taken the 

 trouble to separate the true menaccanite from 

 the iron ore, no dependence can be put upon 

 the results which they obtained. The specimen 

 of menaccanite analyzed in my laboratory had 

 been given me by Mr. Gregor himself, to whom 

 we owe the first knowledge of the substance. 

 He had collected it himself; and he assured me 

 that it was a portion of the very quantity which 

 he had himself subjected to analysis. The largest 

 particles of the ore were picked out, and great 

 care was taken to reject every particle which 

 was in the slightest degree obedient to the mag- 

 net. 



The ore was reduced to a very fine powder, 

 and was digested in a platinum matrass, with 

 muriatic acid, till all action was at an end. The 

 titanic acid remained, and was collected on a 

 filter, and washed with water acidulated with 

 muriatic acid. It was then dried, ignited, and 

 weighed. 



The filtered liquid had a greenish yellow co- 



