152 Memoir en the Nature offal Sulsfances. 



When joined with ammonia, this acid yields a salt unalterable 

 in the air, soft, fusible like suet, and easily soluble in water : 

 this solution does not becomes frothy by agitation ; the nitrate 

 of silver forms in it a magma like pitch, and which is coloured 

 in the light. The sulphate of iron occasions a deposit which 

 collects in clots like a fatty matter. 



This same acid combined witli lime furnishes a soluble salt, 

 the solution of which evaporated spontaneously leaves a very 

 white, shininsf, opaque and enamel-like residue. Tins salt is 

 sapid, and unalteiable. in the air. With magnesia it gives a 

 transparent combination, Vthivrh leaves a coat of varnish on the 

 vessels, from which we may detach it with the point of a knife : 

 it then resembles mica. 



To conclude: this salt is unalterable in the air, and soluble in 

 water: we know that the mucites of lime and magnesia are in- 

 soluble. It forms with oxide of zinc a wliite salt tolerably so- 

 lu'ile. We see that this acid has by no means the characters of 

 the mucous acid : it seems, on the contrary, to resemble closely 

 the pyro-sebacic acid of M.Thenard. 



jdction of the weak Nitric Acid upon Suet. 



Twenty grammes of nitric acid at 39'^, diluted with one-half 

 its weight of water, were put in tbuililion for three quarters of 

 an hour with twenty grammes of beef suet : the latter was en- 

 tirely decomposed, although but a small quantity of nitrous gas 

 was extricated, mixed with azotic gas and carbonic acid : the 

 greasy matter when well washed in boiling water had not sensi- 

 bly lost its weight ; but it was much softer than the suet em- 

 ployed, and was of a slight yellowish colour. This substance 

 vhen heated with alcohol was dissolved in it with astonishing 

 promptitude; the solution in cooling went into a white mass, 

 which when contained in a fine cloth was subjected to the ac- 

 tion of the press: I obtained an alcohohc liquid, which left after 

 its evaporation about five grammes of a yellowish oil very solu- 

 ble in alcohol, in ether, and in the alkalies. The solid matter 

 left in the cloth formed the greater part of the suet thus altered 

 by the nitric acid. It was very white and pulverulent : but in 

 order to be very certain of obtaining it in all its pinity, it was 

 treated with essence of turpentine and pressed between some 

 folds of gray paper : a substance was obtained analogous to white 

 wax, but much drier, falling into powder between the fingers, 

 and capable of waxing bodies. When melted and cooled, it pre- 

 sents a lamellated crystalline structure like certain kinds of adi- 

 poeire, but not in fine and pearly needles like those which we 

 have obtained by the action of a great quantity of nitric acid at 

 30^ on the suet. 



Tq- 



