1818.] with the Analysis of a New Mineral. 367 



salt, which after exposure to a smart red heat for half an hour in 

 platinum foil left a dark slate-coloured powder weighing T 5 -g- of a 

 grain. This powder gave a fine amethyst colour to borax, before 

 the blow-pipe, and proved to be the oxide of manganese. It had 

 no magnetic property when heated. It dissolved with violent 

 effervescence m warm muriatic acid, disengaging the smell of 

 chlorine gas. 



(D.) — The insoluble residue, mentioned in B, being mixed 

 with four times its weight of bi-carbonate of potash was exposed, 

 during an hour, in a platinum crucible to a heat above redness. 

 The result of this alkaline fusion had then a bright and very 

 beautiful orange colour : its surface upon being cooled exhi- 

 bited a laminary crystallization. The mass was then moistened 

 with a few drops of distilled water, and muriatic acid being added, 

 it yielded gelatinous silica ; this being washed and dried, 

 weighed 14-^- grains. 



(E.) — The supernatant fluid from D, together with all the 

 washings of the silica, being collected, bi-carbonate of potass 

 was added to neutralize the acid. The same a/kali being after- 

 wards added to excess, there fell down a precipitate, leaving the 

 liquid perfectly limpid above it, which when washed and dried 

 weighed 6-j% grains. 



(F.) — The precipitate from E being boiled in muriatic acid 

 lost only 4-^ of its weight : there remained an insoluble residue, 

 weighing, when washed and dried, two grains which proved to 

 be silica ; to be added therefore to the silica in D. 



(G.) — From the solution in F, the acid being first neutralized, 

 ammonia threw down a precipitate, which when washed and 

 dried weighed 4-j^ grains and proved to be pure alumina. 



From all the preceding observations, therefore, it appears that 

 the constituents of Leelite are as follow : 



&::::::;;::::: 7 I> 



8 



Alumina 22-00 



Manganese 2*50 



Water of absorption 0*50 



100-00 



Specimens of Leelite are at present more common than those 

 of Petalite, and if persons more experienced in the analysis of 

 minerals shall hereafter find that, like Petalite, it is one of the 

 substances containing lithion, it is perhaps no more than might 

 be expected. But in the consciousness of having spared no 

 pains in its examination, I have ventured to send you this state- 

 ment : and I remain, &c. &c. 



Cambridge, April IS, 1818. EDWARD DANIEL CLARKE. 



P. S. Iii the accounts published of the alloy used for the silver 



