1825.] On the Formation of Ammonia, $c. 143 



the two paler ones the most, and that to such a degree, that it 

 would hardly have been supposed they had once formed part 

 of the same pieces of glass as those which had been set aside. 

 Thus it appears that the sun's rays can exert chemical powers 

 even on such a compact body and permanent compound as glass. 



On some Cases of the Formation of Ammonia, and on the 

 Means of Testing the Presence of Minute Portions of Ni- 

 trogen in certain states*. 



THE importance of the question relative to the simple or com- 

 pound nature of any of the substances considered as elementary 

 in the present state of chemical science, is such as to make any 

 experimental information respecting it acceptable, however im- 

 perfect it may be. An opinion of this kind has induced me to 

 draw up the following account of experiments relative to the 

 formation of ammonia, by the action of substances apparently 

 including no nitrogen. The experiments are not offered as 

 satisfactory, even to myself, of the production of ammonia with- 

 out nitrogen ; indeed, I am inclined to believe the results all 

 depend upon the difficulty of excluding that element perfectly, 

 and the extreme delicacy of the test of its presence afforded by 

 the formation of ammonia : yet as, on the contrary, notwith- 

 standing my utmost exertions, I have failed to convince myself 

 that ammonia could not be formed, except nitrogen were pre- 

 sent, it has been supposed that the information obtained, 

 though incomplete, might be interesting. 



Having occasion, some time since, to examine an organic sub- 

 stance with reference to any nitrogen it might contain, I was 

 struck with the difference in the results obtained, when heated 

 alone in a tube, or when heated with hydrate of potassa : in the 

 former case no ammonia was produced ; in the latter, abun- 

 dance. Supposing that the potash acted, by inducing the com- 

 bination of the nitrogen in the substance with hydrogen, more 

 readily than when no potash was present, and would therefore 

 be useful as a delicate test of the presence of nitrogen in bodies, 

 I was induced to examine its accuracy by heating it with sub- 

 stances containing no nitrogen, as lignine, sugar, &c. ; and was 



* Quarterly Journal of Science, xix. 16. 



