460 My. Field on the Products of the 



on the other hand, if submitted to a gentle heat, loses only 

 two equivalents of water, the residue of both base and acid 

 combining to form oxamide, and only by a strong and brisk 

 application of heat Doebereiner converted it into cyanogen, 

 the rest of the hydrogen being eliminated in the form of water. 



The dry distillation of oxalate of ammonia thus affords the 

 prototypes of two series of compounds, which may arise from 

 ammoniacal salts by the elimination of two or four equivalents 

 of water respectively. There are few cases, however, in which 

 the decomposition of ammoniacal salts have been carefully 

 studied, and the instances in which we are acquainted with 

 the representative of the two types are exceedingly scarce. 

 We are indeed intimate with a very great number of amidogen 

 compounds analogous to oxamide (fumaramide, salicylamide, 

 succinamide, anisylamide, &c.), but only few of these have 

 been obtained from ammoniacal salts by the action of heat. 

 The greatest number of these bodies were produced by the 

 change most compound aethers suffer under the influence of 

 ammonia, a beautiful mode of decomposition pointed out 

 first by Professor Liebig in the transformation of oxalate of 

 ethyl into oxamide, or by the action of gaseous ammonia on 

 other substances related in some manner with the acid : thus 

 was chloride of benzoyle converted into benzamide by Wohler 

 and Liebig, and lately lactide into lactimide by Pelouze. 



As yet, however, the members of the second class, those 

 compounds standing to other acids in the same relation as 

 cyanogen to oxalic acid, are very rare. From a beautiful ex- 

 periment of Pelouze, we know that the vapour of formiate of 

 ammonia, when passed through a red-hot tube, is converted 

 into water and hydrocyanic acid. In their investigation on 

 the radical of benzoic acid, Wohler and Liebig obtained a 

 peculiar oil by the action of heat on benzamide, which at that 

 time they did not study more closely. The same body was 

 at a later period obtained in the dry distillation of benzoate 

 of ammonia, and fully examined by Fehling, who found that 

 this interesting substance, to which he gave the name henzo- 

 nitrile, has the composition C14 H5 N, and is produced from 

 benzoate of oxide of ammonium, exactly in the same manner 

 as cyanogen and prussic acid are formed respectively from 

 oxalate or formiate of ammonia. These facts did not long 

 remain isolated. Schlieper, in an excellent examination he 

 has lately published on the products of oxidation of gelatine 

 by chromic acid, discovered that in these reactions, among 

 other products, the body C,o Hg N is formed, valeronitryle or 

 valerianate of ammonia — 4 equivs. of water. 



The members of this class acquire every day a greater 

 degree of importance. A remarkable paper, read before the 



