486 NITRATES OF EARTHS. 



lain retort, by a regulated heat, the deutoxide may be obtained. (See 

 note, p. 215.) 



(g.) Strength of affinity. Not decomposed by any single base 

 or acid, except by the sulphuric and the phosphoric ; decomposed 

 by all the soluble sulphates, and by the carbonates of the alkalies. 



4. PROPORTIONS. This salt is anhydrous. If it is a compound 

 of 1 proportion of nitric acid, and 1 of baryta, its composition should 

 be baryta, 78, per cent. 58.4 



nitric acid, 54, 41.6 



Its equivalent, 132 100. 



From this result, the analyses of several of the most eminent chem- 

 ists are not very remote. 



Clement and Desormes, 40 acid, 60 base. 



Jas. Thomson, 40.7 59.3 



Berzelius, 41.54 58.46* 



5. USE. 



!a.) To afford pure baryta by its decomposition by heat. 

 b.) To detect sulphuric acid. In examining the nitric acid for 

 this purpose by the nitrate of baryta, the latter must be dilute unless 

 the former is so, otherwise the strong nitric acid will precipitate crys- 

 tals of nitrate of baryta, presenting a false indication of impurity ; 

 their ready solubility in more water will however distinguish them. 



Remark. After the expulsion of the nitric acid by the compound 

 blowpipe, the earth of this salt, if urged by the heat, exhibits on char- 

 coal a deep yellow flame, and ultimately melts. 



NITRATE OF STRONTIA. 



1. DISCOVERY. By Dr. Hope, of Edinburgh. 



2. PREPARATION. 



(a.) By dissolving carbonate of strontia, 1 part, in nitric acid 1, 

 and water I ; the action is rapid; carbonic acid is disengaged, and 

 the nitrate of strontia, being evaporated over a lamp, the crystals pre- 

 cipitate during the process. 



(b.) JBy decomposing the sulphate of strontia by ignition with char- 

 coal and then decomposing the resulting sulphuret by nitric acid ; 

 or it may first be turned into a carbonate by a carbonate of an alkali. 



3. PROPERTIES. 



(a.\ The crystals are octahedra or six sided prisms.-^ 

 (b.) Taste pungent and cooling, 

 (c.) Sp. gr. 3. 



* Quoted by Henry. 



t See Ann, of Phil. N. S. VII, 288. 



