Aqueous Solutions of Acids and Alkalies. 457 



at 42° F. a solution of the chemical strength of 1120°, so 

 that this third hydrate is easily obtainable at a temperature 

 between 42° F. and 62° F. ; and the preparation of even the 

 second hydrate (N 2 H s O -f H 2 0) is perhaps possible at a lower 

 temperature. At 62° F. however, the solution of 1000° was 

 the strongest I could prepare. 



An examination of this table leads naturally to the ques- 

 tions, how far is it to be relied on ? how nearly does it 

 agree with the results of experiment ? I cannot answer these 

 questions better than by giving an abstract of a series of ex- 

 periments made expressly to test the validity of the hypo- 

 thesis. These experiments are embraced in Table XVII. 



Table XVII. — Ammonia. 



Experiments on the Specific Gravity of Solutions of Ammonia, 

 of known chemical strength. Temperature 62° F. 



Phil. Mag. S. 3. Vol. 29. No. 196. Dec. 1846. 



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