Chap f 7-1 Properties of Sal Ammoniac. 43 



Holland. This kind is made in the Eaft Indies. 

 * Sal ammoniac is, however, now made in large 

 quantities in Britain. The volatile alkali is obtained 

 in an impure liquid ftate from foot/ or bones, or any 

 other fubftance which affords it j to this the vitriolic 

 acid is added, and the vitriolic ammoniac thus pro- 

 duced is decompofed by common fait, by a double 

 affinity, or elective attraction ; the vitriolic acid com- 

 bining with the mineral alkali, and the marine acid 

 with the volatile alkali. The liquor therefore contains, 

 Glauber's fait and fal ammoniac, which are feparated 

 by cryftallization ; and the fal ammoniac is fublimed 

 into cakes for fale. Lord Dundonald extrads volatile 

 alkali from pit- coal j but whether it can be afforded 

 cheaper for the general purpofes of commerce, than 

 that of the above procefs, is not, I believe, yet afcer- 

 tained.* ' 



The tafte of fal ammoniac is penetrating, acrid, 

 and urinous. The form of its cryftals is a hexahedral 

 pyramid. Cubical cryftals are fometimes, though 

 rarely, formed in the middle of the concave and 

 hollow parts of the loaves which are produced by fub- 

 limation. 



This fait poflefies a fingular property, namely a kind 

 of duclility, fo that it rebounds under the hammer, and 

 may be bended ; a circumftance which renders it dif- 

 ficult to pulverife it. 



Sal ammoninc is not decompofed by clay, and by 

 magnefia very imperfectly. Lime, and likewife pon- 

 derous earth, feparate the volatile alkali, even without 

 the ailiitance of heat. - If fal ammoniac is triturated 

 with quick-lime, the ftrong fmell of alkaline gas i$ 

 immediately perceived. 



* Fourcroy's Chemiftry. Note of the Translator. 



