Chap. 6.3 Citrons Ammcn'ua;. JI 



alkal-i has a ftronger attraction for its acid than the mi- 

 neral. This fact is very eafily (hewn. If a heated 

 folution of cubic nitre is divided into two parts, and 

 the cauftic vegetable fixed alkali added to one of them, 

 it will afford prifmatic cryftals during its cooling; no 

 cryltals, however, will be obferved in the other part 

 becaufe cubic nitre does not cryftallize by mere cooling 

 without evaporation. 



The neutral falts hitherto examined produce no 

 effect whatever on cubic nitre ; if thefe falts are dif- 

 folved together in the fame water, they cryftallize 

 feparately, and each in its ordinary manner ; the nitre 

 and Glauber's fait by cooling ; the vitriolated tartar 

 and cubic nitre by evaporation. All thefe properties 

 fhew, that cubic nitre differs from common nitre. 



NITROUS AMMONIAC, or nitrac of ammoniac, is 

 compofed of the nitrous acid and volatile alkali. It is 

 more foluble and more fufible than the vitriolic am- 

 moniac. When the heat is increafed a little above 

 what is neceffary for its fluidity, it is converted into 

 copious vapours. The degree of heat necefiary for 

 its fufion is a little above that oj boiling water ; and if 

 more heat is fuddenly employed, it has the fmgular 

 property of undergoing deflagration, though no in- 

 flammable fubftance mould be added to it, and even 

 in a clofe veffel. This feems to depend on the de- 

 compofition of the volatile alkali. 



M. Berthollet having expofed ammoniacal nitre to the 

 action of heat in a pneumato-chemical and diftilling ap- 

 paratus, and having obferved the phenomena of this ope- 

 ration more carefully than had been done before, re- 

 marks, that it is not a true detonation which takes place, 

 but a fudden and inftantaneous decompofition, in which 

 part of the volatile alkali is entirely deftroyed. The 

 water obtained in the receiver contains a fmall part of 



the 



