Jl W. Mallet on the Atomic Weight of Lithium. 353 



with advantage, using a larger amount of a carefully prepared 

 salt, better adapted to the purpose than the sulphate, and requir- 

 ing the process of analysis to be varied. The salt chosen was 

 the chlorid of lithium, and I shall describe first the mode of its 

 preparation, and then the experiments which have been made 

 upon its composition. 



Crystallized spodumene from the granite of Groshen (Mass.), 

 where the mineral occurs with blue tourmaline, beryl, and rose 

 mica, was finely pulverized, and 1 part mixed with 3 or 4 of 

 unslaked lime and about three-fourths of sal-ammoniac. The 

 mixture was heated in large crucibles to the highest temperature 

 of a good wind-furnace. This is the process proposed by Prof. 

 J. L. Smith* for the analysis of silicates, except that he uses car- 

 bonate of lime instead of the caustic earth. The nearly fused 

 mass was pulverized, mixed with water, and treated with sul- 

 phuric acid in excess. The solution was filtered off from the 

 sulphate of lime and other insoluble matter, and the latter washed 

 with plenty of water upon a cloth filter. The still milky liquid 

 was boiled down to a moderate bulk, and precipitated with chlo- 

 rid of barium ; the sulphate of baryta thrown down was washed 

 by decantation, and the solution was filtered through paper. 

 The filtrate was now a solution of chlorid of lithium, free 

 from sulphuric acid, but containing the chlorids of several 

 other metals in admixture. It was carefully evaporated to dry- 

 ness to get rid of any silicic acid, re-dissolved, precipitated with 

 ammonia, sulphuret of ammonium, and carbonate of ammonia, 

 filtered, evaporated to dryness, and the residue heated until all 

 ammoniacal salts were expelled. The residue was then re -dis- 

 solved, the solution boiled with a little pure milk of lime, and 

 filtered from magnesia. The lime in the filtrate was removed 

 by oxalate of ammonia, and the solution was evaporated to dry- 

 ness, and heated to expel salts of ammonia. The residue, now 

 containing only the alkaline chlorids, was moistened with a 

 little water and again dried at a gentle heat, not over 100° C. 

 The dry mass was introduced into a glass-stoppered bottle, and 

 a mixture of equal volumes of ether and absolute alcohol was 

 poured upon it — solution of the chlorid of lithium being aided 

 by shaking the bottle from time to time. After a few hours the 

 clear liquid was decanted, and the alcohol and ether were dis- 

 tilled off. The dry residue left by the distillation of this first 

 alcoholic solution was again treated with ether and alcohol, the 

 liquid again decanted and distilled, and finally the same process 

 of purification was repeated a third time, nothing being now left 

 undissolved by the ether-alcohol. The pure chlorid of lithium 



* Amer. Jour, of Science, [2.], xv, 234 ; xvi, 53. 

 SECOND SERIES, VOL. XXII, NO. 66. — NOV., 1856. 



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