Chemical Science. 407 



causticity. It does not dissolve very readily in water, and 

 seems to be nearly soluble alike in hot or cold water. In this 

 respect it resembles lime. It evolves heat on solution. 



Alcohol, of sp. gr. ,85 dissolves only a small quantity. Weak 

 alcohol, added to an aqueous solution of lithia, in a well-closed 

 vessel, forms, after some hours, a precipitate of lithia, in the 

 state of a white powder. 



Phosphate of lithia appears to be insoluble in water. When 

 phosphoric acid is dropped into solution of sulphate of lithia, 

 there is no precipitate. But when the acid is saturated with 

 ammonia, the phosphate of lithia falls in the state of white 

 flocks. When a drop of phosphoric acid is put into a very 

 weak solution of carbonate of lithia, no precipitate is formed, 

 but on heating the liquor the carbonic acid gas is disengaged, 

 and phosphate of lithia falls. 



In consequence of the insolubility of the phosphate of lithia, 

 an easy means is offered of separating this alkali from potash 

 and soda. The lithia may be precipitated by means of phos- 

 phoric acid and excess of ammonia. The phosphate of lithia 

 may be dissolved in acetic acid, and the phosphoric acid be 

 precipitated by means of acetate of lead. The acetate of lithia, 

 which remains in solution, may afterwards be treated in any way 

 that may be required. 



Dr. Gmelin has had occasion to observe, during his experi- 

 ments, the effect of boracic acid in reddening turmeric paper. 

 This effect, as well as similar effects of other acids, were pointed 

 out some time ago in this Journal, Vol. V. p. 125, and Vol. VI. 

 p. 152. It does not take place when paper tinged with rhubarb 

 is used. 



12. Sulphate of Magnesia. — M. Gay Lussac has lately expe- 

 rimented on the sulphate of magnesia, and finds that the pro- 

 portions given by M. Longchamj> are not correct, but that the 

 old numbers are very near the truth. The sulphate of magne- 

 sia, when crystallized, contains, 



Dry sulphate of magnesia 48.57 



Water 51.43 



100. 



