4 jo Experiments on Ammonia. 



with a pale yellow flame. The combustion, liowcver, is 

 not suffii ienlly vivid lo render the process of any use in the 

 analysis of ammonia. 



With nitrous oxide (containing only 5 per cent, impu- 

 rity) ammonia forms a mixture which is extremely com- 

 bustible. If the nitrous oxide be in excess, the proportions 

 have a considerable range ; for any mixture may be fired by 

 electricity, of which the anunonia is not less than one-sixth 

 of the whole. The combustion is followed by a dense 

 cloud, sometimes of .in orange-colour. When the nitrous 

 oxide greatly exceeds the amn)onia, (as in the proportion, 

 for cxample^.of 100 lo 30) there is little or no diminution 

 after firing: and the residuum is composed of a small por- 

 tion of undccomposcd oxide, some oxygen gas, and a con- 

 j^idcrable quantity of nitrogen, the last of which, however, 

 is'not in its full proportion. When the nitrous oxide is 

 further increased, still more oxygen is foundin the resi- 

 diuin!. 



When, on the contrary, the alkaline gas is redundant, 

 combustion does not take |)lace unless the nitrous oxide 

 forms one-third of the mixluie. A little diminution takes 

 place on firing, but no cloudiness is observed ; and the re- 

 sidue is composed of hydrogen and nitrogen gases, with 

 occasionally a small portion of undccomposcd ammonia. 

 As an example of what takes place, I select the following 

 experiment from several others. 



A n)ixiurc of 41 measures of ammonia, with 40 of ni- 

 trous oxide (= 38 pure), in all 81 measures, were reduced 

 by con}hustion to lo, which were found to consist of 16 

 hydrogen and 59 nitrogen gases. To explain this experi- 

 ment, we may assume (as is consistent with your own 

 analysis*) that 100 measures of nitrous oxide are equiva- 

 lent to 52 measures of oxygen gas and 103 of nitrogen. 

 The oxygen in 38 measures of nitrous oxide will, therefore, 

 be 19'7, to which, when the oxygen spent in burning the 

 residuum (viz. 8 m.) is added, we obtain 27'7 for the total 

 oxygen consumed ; and imiltiplyiug bv 2, we have •55-4 for 

 the hydrogen saturated. From the residuary nitrogen (59) 

 deduct 39 measures arising from the decom})osition of the 

 nitrous oxide f 2 m., mingled with k as an impurity =41, 

 and tl^e remainder, 1 8 measures, is the nitrogen lesultingfrom 

 the volatile alkali ; and as 4 1 measures of ammonia give 55*4 

 4- IS = 73*4 measures of permanent gas, 100 would give 1 79 

 measures, in which the hydrogen and nitrogen would exist 



* Researches, Res. ii. Div. 1, or Thomson's System of Chemistry, 3d 

 cJir- ii. lis, ' ■ 



in 



