, Mr GRAHAM'S Account of the Formation of Alcoates. 191 



their formation is the difficulty, and frequently the impossibility, 

 of rendering the salts perfectly anhydrous, before their solution 

 in alcohol is attempted. 



I am not aware of any other compounds in the solid form of 

 the same class as the hydrates and alcoates. But there is an 

 oxide, classed by Dr THOMSON in his System of Chemistry, 

 with water and other neutral and unsalifiable oxides, the habi- 

 tudes of which with certain salts are exceedingly remarkable, 

 and have been looked upon as anomalous, but on which the es- 

 tablished properties of hydrates and alcoates appear to me to 

 throw some light. I refer to the deutoxide of azote or nitrous 

 gas. 100 volumes pure water are capable of absorbing only 5 

 volumes of this gas, according to the experiments of Dr HENRY. 

 But Dr PRIESTLEY and Sir H. DAVY ascertained that certain 

 metallic salts, particularly the protosalts of iron, are capable of 

 absorbing this gas in large quantities; and again emit the 

 greater part of it unaltered, on being heated. That the absorp- 

 tion of deutoxide of azote by these salts, is not dependent upon 

 the oxygen of their bases, or the water which they contain, I 

 have proved in two ways, in the case of protomuriate of iron. 

 By heating this salt to redness in a glass-tube, it is reduced to 

 the state of protochloride of iron. Now, I find that this chloride 

 in the dry state absorbs deutoxide of azote, although in a com- 

 paratively small proportion. And the alcoholic solution of the 

 chloride, where neither oxygen nor water interferes, appears to 

 exceed the aqueous solution of the protomuriate in its capacity 

 for deutoxide of azote. 



Deutoxide of azote, formed by the action of dilute nitric acid 

 on copper, was conducted into a globular receiver surrounded 

 by cold water, and thence through a glass-tube of two feet in 



