1314.] Constituents of Azote. \ 91 



hydrogen; but in its more essential properties it will be seen to be 

 distinctly different from it. 



It combines with potash, and forms with it a compound insoluble 



in water. This salt, if it may be so called, is of a dead black 



iur, and is not acted on by acids or alkalies. Among tbe many 



made, not one acid Iras yet been found to possess so 



g an affinity for tbe different bases as this singula* gas. 



It combines also with soda, forming a velvety black compound, 



equally insoluble in water, and undecomposable by acids or alkalies. 



It unites also to pure barytes, and forms a very soluble salt. This 



solution is decomposed by the acetate of lead, which throws down 



a dark precipitate, consisting of the acid gas combined with the 



oxide of lead. The barytes salt is also decomposed by carbonate of 



potash, a precipitate is thrown down o^ a grey colour, doubtless a 



mixture of the potash salt with the carbonate of barytes^ This 



would prove that the acid gas exerts a nearer affinity to the acid gas 



than barytes does. The results of these experiments are seen in the 



subsequent table. 



Tbe action of ammonia on the acid gas presents the most singula? 

 anomaly, and deserves a more particular mention. The action of 

 the fixed alkalies and metallic solutions invariably have diminished 

 the volume of the mixed gas; but liquid pure ammonia lias a 

 rary effect, and expands its volume, 100 measures of mixed 

 gas being enlarged to 121 measures. This residuum, it will appear 

 strange, contains no hydrogen that is discoverable by the usual 

 tests. The solution acquired a greenish tinge, and a very slight 

 pitate collected. This fluid and precipitate, by exposure 

 to air, acquired an orange-yellow colour. The following are tbe 

 particulars of the experiment. Into a tube containing 0-1 / 5 cubic 

 inches of gas over mercery was sent up 0' 11 cubic inches solmion 

 of pure ammonia; a white smoke appeared to pervade the 

 the fluid became tinged of a brownish green colour. The 

 however, expanded in volume to 0*215 cubical inches, indicating 

 ■lit of 22*85 per cent. Two other exp< riments pro- 

 duced similar results. The mean increase of volume in the time 

 trials was 22 per cent. ' ■ r sidue was not in flam nor 



would it detonate with oxygen- Four days aft< i transferred 



u- 1 cubic inch of this residuum into Volta's eudiometer with 

 <.)• 1 1 cubic inches of atmo cury, into which a 



ion of tbe solution and precipitate had unavoidably introduced 

 itself. No explosion or variation < is produced by the 



electrical discharge; but some hours afterwards I perceived tbe 

 I, before of a dark j reen colour, was converted into an orange 

 yellow, ai d the inside of the tube \ ilso covered with an orange 

 I coat. Firing afterwards several shocks through it, no 

 to be produced. 

 '1 he acid | laces the carbonic acid from its combinations; 



with bicarbouate of potash the insoluble combination ol acid 

 . potash is precipitated, and e. 



