42 Notices of the Labours of Continental Chemists. 



the acid salt, but a compound of the acid mellitate with nitrate 



of potassa, K N + 4 K Me 9 + 10 aq. By heating it loses 



7 per cent, water, or 6 atoms ; the other 4 atoms are not driven 

 off before the salt decomposes ; its rational formula is, there- 

 fore, K N + 4 (K Me + H Me) + 6 aq. The true acid 

 mellitate of potassa forms large transparent crystals, easily 

 soluble (K Me + H Me)-f 4aq. |thsof the water is driven 



off by heat. Mellitate of ammonia (N 2 H 8 O + Me), when 

 heated to 150° C, loses ammonia and water, and is converted 

 into two new substances, both of which contain nitrogen. 

 One of them is an acid, and this is probably the first case 

 known of the production of an organic acid containing nitro- 

 gen from the ammonia salt of one which contains no nitrogen. 

 The metamorphosis may be easily produced by exposing a 

 thin layer of the mellitate for several hours to a temperature 

 of 150° to 160° in an oil-bath. The operation must be con- 

 tinued until no more ammonia is evolved. The temperature 

 must not rise above 160°. (A concentrated solution of melli- 

 tate of ammonia, if contained in a sealed tube, may be ex- 

 posed for hours to a temperature of 200° without any change 

 being effected.) The pale yellow powder which remains is 

 treated with cold water, which separates it into two substances ; 

 it is washed with cold water as long as the filtered solu- 

 tion reacts acid. On evaporating an acid salt is obtained as 

 a scarcely crystalline mass. The insoluble body is called 

 paramid, the acid in the soluble ammonia salt, euchronic acid 

 (evxpoos, beautiful colour). Paramid is white, and forms hard 

 conglomerated masses ; becomes yellow in the air ; perfectly 

 tasteless and inodorous; when moistened looks and smells 

 like wet clay; insoluble in water, alcohol, nitric, and even 

 nitro-muriatic acid; is dissolved by hot sulphuric acid, but 

 is separated unchanged by water. Heated to 200° undergoes 

 no change ; does not lose water. When heated more strongly 

 is decomposed, gives off cyanide of ammonium, and forms a 

 sublimate which is partly bluish-green and half fused, and 

 consists partly of sulphur yellow crystals of a very bitter taste. 

 Paramid is dissolved by long (several days) boiling with water, 

 and on evaporating an ammonia salt is obtained. At a tem- 

 perature of 200° this change is soon effected. The salt pro- 

 duced is acid mellitate of ammonia. Hence this body belongs 

 to the class of the amides. The composition of paramid is 

 C 8 H 2 N 2 O 4 . Two atoms of mellitate of ammonia lose 1 atom 

 of ammonia and 4 atoms of water, O H 16 N 4 8 , or 2 (N 2 



