248 HYDROGENATED COMPOUNDS OF NITROGEN. 



water of the calorimeter, where it is mixed with the excess of 

 potash. 



The apparatus just described is very complicated, but the 

 experiment is in itself very simple ; it admits of a very accurate 

 measurement of the heat given off, and the conditions at the 

 commencement being ascertained with exactness, it is possible 

 to arrive at a strictly definite final condition in one operation. 



4. In order to calculate the decomposition of pure hydroxy- 

 lamine, it is necessary to measure 



(1) The total heat given off in the reaction just described. 



(2) The heat given off by an equal weight of the same potash 

 reacting upon the weight of pure water contained in the 

 calorimeter. 



(3) The heat absorbed by the solution of an equal weight 

 of pure hydroxylamine hydrochloride in the same quantity of 

 water. 



(4) The heat given off when the hydroxylamine hydrochloride 

 in a weak solution is decomposed by the diluted potash ; in this 

 case the hydroxylamine is set at liberty at first without being 

 destroyed. 



All these data being obtained by special experiments, it is 

 easy to calculate the heat given off by the simple destruction* of 

 an equivalent of hydroxylamine. 



5. The results deduced from the experiments are as follows : 



3NH 3 dissolved = N 2 + NH 3 + 3H 2 disengaged 1 + 57'3 & + 56'7; mean 



+ 57-0 Gal 



Other distinct experiments have given : 



NH 3 diss. + HC1 dilute at 24 liberates 2 + 9'2 



NHgOHCl cryst, (1 p. of salt + 90 p. of water) in dis- 

 solving at 24 - 3-31 



(NH 3 0) 2 S0 4 H 2 cryst. + 100 parts of water at 12-5 ... - 2-90 



(NH 3 0) 2 dilute + H 2 S0 4 dilute, at 12-5 + 10-8 



6. Formation from the elements : 



N + H 3 + = NH 3 dissolved liberates ... . + 19-0 



N + H 3 + + HC1 dilute = NH 3 OHC1 diss + 28-2 



N + H 4 + + Cl gaseous = NH 3 OHC1 cryst. ... , + 70-8 



N 2 + H 6 + 2 + S0 4 H 2 dilute = (NH 3 0) 2 H 2 S0 4 diss.. + 29'8 



N 2 + H 8 + 6 + S ~ (NH 3 0) 2 H 2 S0 4 cryst + 138-8 



7. Different modes of formation : 



OXIDATION OF AMMONIA. 



NH 3 diss. + = NH 3 diss. will absorb ... - 2-0 



NH 3 HC1 diss. + = NH 3 OHC1 diss - 7-2 



NH 3 HC1 cryst. + = NH 3 OHC1 cryst. ... - 5'9 



1 In the calculation of the experiments the formation of a little nitrogen 

 monoxide was taken into account, say 3 to 4 per cent., under the conditions in 

 which I was working. 



2 According to the decomposition of pure hydrochloride dissolved in 

 water, by dilute potash. 



