Mr. Graham's Account of the Formatiori ofAkoaies. 33$ 



peared to be formed. The same was the case with the vege-< 

 table acids soluble in alcohol. 



It is probable that many more alcoates of salts may be 

 formed, particularly of the metallic chlorides. The great ob- 

 stacle to their formation is the difficulty, and frequently the 

 impossibility, of rendering the salts perfectly anhydrous, be- 

 fore 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 ha- 

 bitudes of which with certain salts are exceedingly remarkable, 

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

 established properties of hydrates and alcoates appear to me 

 to throw some light. I refer to the deutoxide Of azote or ni- 

 trous 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 absorption of deutoxide of azote by these salts, is not de- 

 pendent upon the oxygen of their bases, or the water which 

 they contain, I have proved in two ways, in the case of pro- 

 tomuriate 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 comparatively 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 sur- 

 rounded by cold water, and thence through a glass-tube of 

 two feet in length, filled with small fragments o£ chloride of 

 calcium. Thus dried, the deutoxide of azote was passed slowly 

 over carefully prepared protochloride of iron in the state of 

 powder, and contained in a glass-tube of small diameter. The 

 protochloride immediately became darker in colour ; and upon 

 being withdrawn, after exposure to the current of gas for some 

 time, was found to retain the smell of nitrous gas, and to have 

 increased in weight. In one case, 30 grains chloride had in- 

 creased to 31*1 grains; and in another case, 25 grains chloride 



to 



