484 LITHIUM. 



\ideioc, stony,) was applied to it, from its having been first 

 derived from an earthy mineral. The metal was obtained by 

 Davy by the voltaic decomposition of lithia, and observed to be 

 white, resembling sodium, and to be highly oxidable. The 

 equivalent of lithium is much smaller than that of any other 

 metal, and its oxide has therefore a high saturating power. 



Lit hid; LO. The only known oxide of lithium is a pro- 

 toxide. It exists in small quantities in the minerals spodumene, or 

 triphane, petalite, and lepidolite, of which the latter can be pro- 

 cured in largest quantity. The separation of lithia from this 

 mineral rests upon its decomposition by means of lime at a 

 high temperature, and the formation of silicate of lime. By a 

 protracted digestion of the ignited mass in boiling lime-water, 

 the liberation of the lithia is completed, and it dissolves in that 

 liquid. The oxides in solution are converted into chlorides, by 

 the addition of hydrochloric acid, and must be submitted to 

 several additional operations to separate iron, lime, and potash. 

 The chloride of lithium is finally taken up by absolute alcohol, 

 in which the chloride of potassium is not soluble. For the ne- 

 cessary directions for conducting this difficult process, I must 

 refer to Berzelius. (Traite, t. 1 p. 303.) 



The hydrate of lithia resembles hydrate of potash in causti- 

 city, but is less soluble in water, and loses its combined water 

 at an elevated temperature. Sulphur acts upon it in the same 

 manner as upon potash. 



The chloride is very soluble in water, as well as in absolute 

 alcohol, and fuses at a high temperature. 



The carbonate of lithia has a certain degree of solubility, and 

 its solution has an alkaline reaction, properties upon which the 

 claim of lithia to be ranked among the alkalies, instead of the 

 alkaline earths, is chiefly rested. The fluoride of lithium has 

 the sparing solubility of the carbonate. 



The sulphate of lithia is soluble, and presents itself in fine 

 crystals, which are persistent in air. The nitrate and acetate 

 are both very soluble and deliquescent. 



The neutral phosphate of lithia is slightly soluble in water, but 

 considerably more so than the double phosphate of lithia and 

 soda, which remains as an insoluble powder when the solution 

 of lithia is evaporated to dryness with that of phosphate of soda. 

 Hence phosphate of soda is used as a test of lithia. The salts 

 of lithia are also recognised, when heated on platinum wire 

 before the blow-pipe, by tinging the flame of a red colour. 



