403 COMPOUNDS OF HYDROGEN. 



2N H 3 and S O 2 , Cl == N H 2 , S O 2 and N H 4 , Cl. 



M. Regnault did not succeed completely in separating sulph- 

 amide from the hydrochlorate of ammonia ; these bodies are 

 nearly equally soluble, both in water and alcohol, and separate 

 very imperfectly by crystallization. Sulphamide has a great 

 attraction for moisture, and quickly deliquesces in the air, in 

 which respect it differs completely from the product N H 3 , S O 3 , 

 resulting from the combination of anhydrous sulphuric acid 

 with dry ammoniacal gas, and which some chemists have viewed 

 as a hydrated sulphamide, N H 2 , S O 2 + H O. The solution of 

 sulphamide, in water, does not undergo any spontaneous change ; 

 a solution even acidulated with hydrochloric acid and mixed 

 witlf chloride of barium, in a close vessel, was not sensibly dis- 

 turbed by the formation of sulphate of barytes in the course of 

 a month. But at the boiling point, sulphamide changes slowly 

 into the ordinary sulphate of ammonia by the fixation of the 

 elements of water ; and the presence of a strong acid facilitates 

 that transformation. 



Carbamide, N H 2 , C O. Chlorocarbonic gas (page 378) con- 

 denses ammoniacal gas, forming a compound which has hitherto 

 been viewed as a chlorocarbonate of ammonia, 2N H 3 -f- C O, Cl, 

 but which M. Regnault finds to be a mixture of carbamide and 

 hydrochlorate of ammonia, N H 2 , C O and N H 4 , Cl. This 

 compound is not deliquescent, dissolves easily in water and in 

 alcohol slightly diluted. Carbamide is not decomposed by 

 acetic or oxalic acid, nor by the strongest acids if diluted, but 

 concentrated nitric acid occasions the evolution of carbonic acid. 

 Its solution is not disturbed by chloride of barium. The ele- 

 ments of urea, N 2 H 4 , C 2 O 2 , are the same as those of carbamide, 

 but the equivalent of the former, inferred from its capacity of 

 saturation as an organic base, is double that of the latter.* 



AMMONIA. 

 Eg. 214.48 or 17.19; NH 3 or HAd; density 591.5; 



Ammonia is a volatile alkali, which derives its name from sal 

 ammoniac, a salt from which it is generally extracted, and which 

 received its title from being first prepared in the district of 



* Regnault, An.de Ch. et de Ph. t. 69, p. 180. 



