Formation of Ammonia, Sfc. 313 



immersed in the water, so as to exclude the air from every 

 part, even of the stop-cock. The first jai* of gas was thrown 

 away, and only the latter portions used. 



The gas being ready, the experimental tube was attached 

 to the transferring jar by a connecting piece, so that the part 

 of it containing the zinc and potash was horizontal, whilst the 

 other portion descended directly downwards. A cup of clean 

 mercury, the metal being about an inch in depth, was then 

 held under the open end of the tube, and by lowering the jar 

 containing the hydrogen in the water of the pneumatic trough, 

 so as to give sufficient pressure, and opening the stop-cock, 

 the hydrogen in the jar was made to pass through the tube, 

 and sweep all the common air before it. When from 100 to 

 150 cubic inches, or from 200 to 300 times the contents of 

 the tube, had passed through, the cup of mercuiy was raised 

 as high as it could be, so as to prevent the passage of any more 

 gas, the pressure from the jar in the water-trough was partly 

 removed, and the stop-cock closed ; then, by lowering the 

 cup of mercury a little, the surface of the metal in it was made 

 lower than that within the tube ; and in this state of things the 

 flame of a spirit lamp applied to the contracted part of the 

 tube sealed it hermetically, without the introduction of any 

 air, and separated the apparatus from the jar on the water- 

 trough. 



In this way every precaution was taken that I could devise 

 for the exclusion of nitrogen ; yet, when a lamp was applied 

 to the potash and zinc, the alkali no sooner melted down and 

 mingled with the metal, than ammonia was developed ; which 

 rendered the turmeric paper brown, the original yellow re- 

 appearing by the application of heat to the part. 



Witli regard to the evidence of the nature of the substance 

 produced, it was concluded to be annnonia in the experiments 

 made in hydrogen, from its changing the colour of turmeric 

 paper to reddish brown ; from the disappearance of the red- 

 dish brown tint and re-production of yellow colour by heat; 

 irom its solubility in water, as evinced by the greater depth of 

 colour on moist turmeric paper than oji dry; from its odour; 

 and from its yielding white fumes with the vapour of muriatic 

 acid. Wlien formed in open tubes, its nature was still further 

 tested by its neutralizing acids and restoring the bhie colour 

 of reddened litmus paper; by its rendering a minute drop 

 of sul|)hate of copper on a slip of white paper deep blue; and 

 also, at the suggestion of Dr. Paris, by introducing into it a 

 slip of pa})cr moistened in a mixed solution of nitrate of silver 

 and arsenious acid, the yellow tint of arsenite of silver being 

 immediately produced. 



Vol. 05. No. S24. Ai>ril 1825, R r Potash 



