Salts. 199 



100 parts of it contain, when well dried, 

 about 33 of acid, 32 of calcareous earth, and 

 35 of water. 



It exifts in old mortar, and the mother 

 liquor of nitres alfo in chalk rocks near 

 Rocheguyon. Macquers Dil. Nitre. 



SPECIES XIX. 

 Nitrous Epfom 



Deliquefces, does not deflagrate, does not 

 render the nitrous folution of filver turbid, 

 is precipitated by cauftic volatil alkali, and 

 alib by the acid of fugar, but the precipita- 

 tion is fcarce apparent, unlefs fpirit of wine 

 or evaporation be applied. If nitrous fele- 

 nite and nitrous Epfom be mixed, and both fo- 

 lutions be faturated, a precipitate will alfo ap- 

 pear ; neither vitriolic acid nor mild magnefia 

 occafion any turbidity in its folution. 



100 parts of it contain about 36 of real 

 acid, 27 of magnefia, and 37 of water. 



It exifts in old mortar, and is found in the 

 mother liquor of nitre. 



O 4 SPECIES XX. 



