1846 Dr Davy on the Combinations of 



but I cannot find that he did. Other more interesting and im- 

 portant inquiries, it may be inferred, diverted him from his 

 purpose. 



Since that time the carbonates of ammonia have been ably in- 

 vestigated, in relation to composition, by several chemists, espe- 

 cially by M. Gay Lussac, Dr Ure, and Mr Richard Phillips. 

 These gentlemen have established, in a satisfactory manner, the 

 existence of three definite compounds, namely, carbonate, ses- 

 quicarbonate, and bicarbonate. Whether another compound, 

 such as my brother supposes he had obtained, is capable of be- 

 ing formed, is still undecided. To endeavour to determine this 

 question, I have gradually been led into a set of experiments, 

 concerning the combinations of carbonic acid and ammonia ge- 

 nerally, much more extensive than I had at first contemplated, 

 the results of which I now beg leave to communicate, — not, in- 

 deed, in the order in which they were obtained, but in that in 

 which they can be most easily and briefly given. 



1. On the direct combination of Carbonic Acid and Ammonia. 



Since the publication of M. Gay Lussac''s very original paper 

 on the combination of gases in definite volumes, in the year 

 1808 *, it has generally been admitted, that carbonic acid gas, in 

 uniting with ammoniacal gas, condenses of the latter exactly 

 twice its volume ; and, further, that this acid and alkali are not 

 capable of uniting in any other proportions, without the inter- 

 vention of water -|-. 



Not having met with any account of the repetition of the ex- 

 periment on the direct combination of the two gases, and con- 

 sidering it desirable that every fundamental experiment should 

 be repeated, I have been induced to make it for my own satis- 

 faction, using every precaution possible to insure accuracy. The 

 glass tubes for transferring the gases, and for their combination, 

 were carefully graduated, and scrupulously cleaned and dried J. 

 The mercury of the trough, over which the combination was 



• Memoires d*Arcueil, torn. ii. 



+ Some chemists, I perceive, allude in their writings to an anhydrous bi- 

 carbonate of ammonia ; but it would appear only hypothetically. 



:J; The tube for combination, was of capacity 5^ cubic inches, about 10 

 inches long, with a funnel-shaped mouth graduated to eighths of a cubic inch. 



