210 Prof. Connell on the Chemical Examination of 



tution of pyi'ope can hardly be brought within the garnet 

 formula ; and although in external characters it approaches 

 more nearly to the precious varieties, yet it deviates more 

 from them than from some of the other kinds of garnet in 

 chemical nature, containing a much smaller proportion of 

 oxide of iron, the amount varying from 10 to 15 per cent. 

 Pyrope is also well known to contain from 2 to 6 per cent, of 

 one or other of the oxides of chrome, although it may admit 

 of doubt, as will be afterwards seen, whether this is an 

 essential constituent. There were thus evidently data for 

 attempting to determine, by chemical evidence, whether the 

 Elie mineral belongs more to the ordinary precious garnet 

 or to pyrope. 



A search was also made for yttria, as it was announced a 

 few years ago by Dr Apjohn that he had detected that consti- 

 tuent in pyrope ; but as no farther communication has been 

 made by him on the subject, although promised, it is probable 

 that this result has not been confirmed ; and, indeed, was 

 improbable in itself, as no such constituent has been noticed 

 by the other eminent analysts who have examined pyrope. 



Before the blowpipe, with salt of phosphorus, the Elie 

 mineral gave only the most ambiguous traces of a chrome 

 reaction ; whereas, in the same circumstances, Bohemian 

 pyrope yielded a decided greenish tint. 



Twenty grains of the Elie mineral, in finest poAvder, were 

 fused by a charcoal fire, with four times their weight of car- 

 bonate of potash. The mass was treated with muriatic acid, 

 and no smell of chlorine observed. The usual steps were 

 taken to separate silica. The precipitate subsequently ob- 

 tained by ammonia was dissolved in muriatic acid, and the 

 solution boiled with excess of caustic potash, which took up 

 the alumina ; and the matter left by the potash redissolved 

 in muriatic acid. Into this muriatic solution, after adding 

 tartaric acid and excess of ammonia, a current of sulphur- 

 etted hydrogen was conducted, which threw down sulphuret 

 of iron with a little sulphuret of manganese. The filtered 

 liquid was then evaporated to dryness, and the residue 

 incinerated. It was pure white, and was carefully ex- 

 amined to ascertain whether it contained yttria. It was 



