1 98 Description and Analysis of the [Skpt. 



weight of the whole alumina would have amounted to 0-737 

 gramme. To this must he added what adhered to the filter in 

 paragraph o, from which the matter was scraped otFto be boiled in 

 the alkaline ley. Its weight was increased 0-124 gramme. If we 

 consider this as a hydrate of alumina, it will be equivalent to 0-0S1 

 gramme of ignited alumina ; so that the weight of the whole 

 alumina separated from the silica by means of muriatic acid is 

 equivalent to 0-818 gramme. 



y. — The liquid (paragraph 7i) freed from its alumina and iron by 

 means of caustic ammonia, being filtered and evaporated, was 

 mixed boiling hot with carbonate of ammonia. It deposited a 

 quantity of carbonate of lime, which, being washed, and dried on 

 the sand-bath, weighed 0-092 gramme ; indicating, according to 

 Berzelius, 0*0519 gramme of pure lime. 



r. — The liquid thus freed from lime, being evaporated to dry- 

 ness, and heated in a platinum crucible, to separate the sal ammo- 

 niac, left 0-03 gramme of muriate of potash, which, being dis- 

 solved in water, formed a granular precipitate with the solution of 

 platinum, and yielded cream of tartar when treated with tartaric 

 acid. This 0-030 gramme of muriate of potash contains, according 

 to the estimate of Bucholz, 0-02 gramme of pure potash. 



The preceding analysis gives us the constituents of hauyne as 

 follows : — 



Water 1-20 



cm- (^ 1*6905 ? o C . Q 



S,hca J », 0-00205 



ai • W;' 0-0825? 10Q ^ 



Alumina \p 0-8180 5 18<8 ' 



Sulphate of lime m 1-0368 21 "73 



t- C* 0-0750? „ __ 



Lime "-; ; £f o-osisS 2 * 66 



Oxide of iron o 0'G 1-16* 



Potash S n Q, 7172? 1W5 



mash [r 0-02003 15 45 



Sulphureted hydrogen and loss 3*45 



100-00 



As my method of analysing hauyne was the same as that of 

 Vauquelin, it may be worth while, in order to account for the 

 great loss which is exhibited in his table, to consider the nature of 

 the constituents of this mineral with some attention. 



It is obvious, in the first place, that the sulphate of lime cannot 

 be completely separated from the other salts by means of alcohol. 

 Hence it would have been better to have determined the quantity 

 of sulphuric acid in the first place by means of muriate of barytes, 

 and then having removed the excess of barytes, to have precipitated 

 the whole of the lime in the state of carbonate. 



