1820.] and ExamimtioH of t/ie€hemical Properties ofLilhia. 343 



Sulphuric acid 69"2 



Lithia 31"8 



100-0 



But it is obvious that there is a mistake in these numbers ; the 

 number for hthia, instead of 31-8, should have been 30-8. From 

 my analysis, it follows that lithia is composed of 



Lithium 58-05 



Oxygen , , 41-95 



100-00 



Chaiikal Aiia/^sis of' Pelalitc, 



(A.) 



■a. One hundred parts of petalite, when exposed to a red heat, 

 were reduced to 97-83 parts. Hence the loss of weight amounted 

 to 2-17. 



(k 97-83 (2 grammes) parts of petalite, which had been 

 exposed to a red heat, were mixed with four times their weight 

 of carbonate of potash, and exposed for two hours to a strong 

 red heat in a platinum crucible. The fused mass was dissolved 

 in nmriatic acid, and the solution evaporated to dryness in a 

 platinum cup. The residual powder was boiled in water acidulated 

 with muriatic acid, and the silica separated by the filter. After 

 being washed, and dried, and heated to redness, it weighed 

 73-37, 



c. After the separation of the silica, the solution was decom- 

 posed by caustic ammonia; this threw down a Avhite precipi- 

 tate, which, when subjected to the requisite trials, exhibited the 

 properties ofalumina. After being washed, dried, and heated to 

 redness, it weighed 17'41. 



d. To the solution was now added a portion of oxalate of 

 ammonia. A precipitate fell consisting of oxalate of lime, 

 which, in order to convert it again into carbonate of hme, was 

 exposed to a red heat, and then heated in contact with carbo- 

 nate of ammonia. The quantity of carbonate of lime thus 

 obtained was equivalent to 0-32 of pure lime, 



e. The re.^ridual solution was now mixed with carbonate of 

 potash, and boiled. A precipitate fell, which might have be^en 

 considered as magnesia; but it vvas insoluble in sulpluu'ic acid, 

 and exhibited the properties of silica. Its weight was 0-8. 



Thus the constituents of 100 parts of petalite by the preceding 

 analysis are as follows : 



