332 Mr. Graham's Account of the Formation of Alcoates. 



be wholly reduced [to magnesia] in a glass-tube by the heat of a 

 spirit-lamp, and yet a sand-bath heat of 600° or 700° is not suf- 

 ficient to drive off all its water of crystallization. But a partial 

 decomposition of this salt is of no great consequence, as alcohol 

 dissolves the undecomposed portion of the salt, while the mag- 

 nesia resulting from the decomposition precipitates, and may 

 be separated by decanting the solution, or by filtering. 



Four parts alcohol at 60° dissolve one part nitrate of mag- 

 nesia, and boiling alcohol dissolves more than half its weight 

 of this salt. From the great difference between the solubility 

 of this salt at high and low temperatures, the alcoate is ob- 

 tained with facility. A hot solution, containing a greater pro- 

 portion of nitrate than one part to three parts alcohol, became, 

 upon cooling, an irregular dry mass, which could be indented 

 by the point of a glass-rod, but was much harder than the al- 

 coate of chloride of calcium. In solutions considerably weaker 

 crystals were deposited on cooling, which sometimes resembled 

 the crystals of the former alcoate, but were much smaller, and 

 less distinct ; but more frequently, the crystals were exceed- 

 ingly minute, and detached, without any regular form which 

 could be discerned. But the great mass of crystalline matter 

 precipitated in scales of a pearly lustre and whiteness, but ap- 

 parently made up of the small crystals. 



Dried by pressure, in blotting paper, this alcoate much re- 

 sembled the alcoate of chloride of calcium in external charac- 

 ters. It sank in water, but floated on the surface of a saline 

 solution of the specific gravity 1*1. Heated, it melted readily ; 

 boiled, and much alcohol was given off. When boiled vio- 

 lently, red fumes rise with the alcohol-vapour ; but when dried 

 slowly, no loss of acid takes place. 



Upon cautiously heating 13*4 grains alcoate of nitrate of 

 magnesia to dryness, there remained 3*56 grains nitrate of 

 magnesia. This gives 9*84 alcohol to 3*56 nitrate of magnesia. 

 But the atomic weight of anhydrous nitrate of magnesia is 

 9*25. Now, 3*56 : 9-84 : : 9*25 : 25*57. 



In another case, 16 grains alcoate were reduced to 4*2 grains. 

 This gives 1 1*8 grains alcohol to 4*2 grains nitrate of magnesia. 

 4-2 : 11-8:: 9*25: 25-99. 



On the supposition that this alcoate consists of one atom 

 nitrate of magnesia united with nine atoms alcohol, the alcohol 

 should amount to 25*875, a number intermediate between the 

 two results. This alcoate will be thus represented : 



One atom nitrate of magnesia 9*25 



Nine atoms alcohol 25*875 



35*125 



III. Alcoate 



