344 M. Arfivedson's Analysis of some Minerals. [May, 



which in its external characters bore a strong resemblance to 

 the cinnamon stone of Ceylon ; and he afterwards, by a compa- 

 rative set of experiments before the blowpipe, satisfied himself 

 that the two minerals possessed very similar characters. I hope 

 by the following analytical experiments to be able to show that 

 this mineral comes very near cinnamon stone even in its chemi- 

 cal composition. 



By concentrated muriatic acid, the stone is not in the least 

 acted upon, at least not while cold, excepting that the few 

 attached fragments of calcareous matter are gradually dissolved. 



1*526 gramme of the mineral purified in this way, and after- 

 wards reduced to a fine powder, were heated with three times its 

 weight of carbonate of potash. The fused greyish mass was 

 dissolved in muriatic acid. There remained a quantity of silica, 

 which, after being heated to redness, weighed 0*625 gr. (a). 



The muriatic solution was precipitated with caustic ammonia 

 with the usual precautions to prevent the alumina from being 

 again dissolved ; and the precipitate which evidently contained 

 iron was collected on a filter, and washed with hot water. It 

 was again dissolved in muriatic acid, and supersaturated with 

 caustic potash ; by which the precipitate which fell at first was 

 again redissolved, with the exception of a little oxide of iron, 

 which, after exposure to a red heat, weighed 0-067 gr. Being 

 again dissolved in muriatic acid, it was found to contain 0*007 

 gr. of silica (b) ; consequently the weight of the oxide of iron was 

 0*06 gr. (c). 



From the alkaline solution, the alumina was separated by 

 muriatic acid and carbonate of ammonia. Its weight, after 

 exposure to a red heat, was 0*321 ; but when dissolved in 

 sulphuric acid, it left 0*007 gr. of silica (d) ; so that the true 

 weight of the alumina is 0*314 (e). 



From the liquid which had been treated with caustic ammonia, 

 and which had been again rendered neutral by a few drops of 

 muriatic acid, the lime was precipitated by oxalate of ammonia. 

 The oxalate of lime obtained was well washed with warm water, 

 dried, heated to redness mixed with a little liquid carbonate of 

 ammonia, and heated gently till all the ammonia was disengaged. 

 The carbonate of lime obtained in this way amounted to 0*920 

 gr. equivalent to 0*518 gr. of pure lime (f). 



The liquid thus freed from lime was mixed with a sufficient 

 quantity of carbonate of potash, and evaporated to dryness. The 

 dry residue when dissolved in water left a substance, which, 

 after being exposed to a red heat, weighed 0*006 gr. and which 

 possessed the characters of oxide of manganese mixed with a 

 little magnesia (g). 



A determinate quantity of the mineral in coarse powder was 

 exposed to a red heat in a platinum crucible; but lost no 

 weight. 



