32 HEAVY-SPAR, CELESTINE, AND GYPSUM. 



The filtered solution is carefully neutralized with 

 hydrochloric acid, the sulphuric acid precipitated by 

 chloride of barium, and the precipitate treated as in 

 No. 3. 



The earthy carbonates are dissolved in dilute nitric 

 acid, taking care to obtain a nearly neutral solution, 

 which is then evaporated to perfect dryness in a flask 

 capable of being closed. The saline mass is treated 

 with about twice its volume of a mixture of equal 

 volumes of ether and absolute alcohol, with which it 

 is allowed to digest, in the closed flask, for a long time, 

 being frequently shaken, but not heated. The mix- 

 ture dissolves the nitrate of lime only. The mixture 

 is filtered, and the undissolved nitrate of strontia 

 washed with absolute alcohol in a closely covered 

 funnel. 



The alcoholic solution is diluted with water, the 

 greater part of the alcohol evaporated, and the lime 

 precipitated, as in No. 12, by oxalate of ammonia. 



The nitrate of strontia is dried at 100 and weighed, 

 or may be converted into a sulphate with sulphuric 

 acid. 



To separate carbonates of baryta and strontia they 

 are dissolved in nitric acid, the solution concentrated 

 and the baryta precipitated by freshly -prepared hy- 

 drofluo-silicic acid, previously mixed with an equal 

 volume of alcohol. The silico-fluoride of barium is 

 collected on a weighed filter, washed with weak spirit, 

 and dried. 



The filtrate containing the strontia is mixed with 

 sulphuric acid, evaporated to dryness, the sulphate of 

 strontia ignited, and weighed. 



If baryta and lime only are to be separated, the 

 solution is largely diluted, the baryta precipitated by 

 sulphuric acid, and the lime separated from the filtrate 

 by oxalate of ammonia, after previously neutralizing 

 with ammonia. 



