334- Mr. Graham's Account of the Formation of Alcoates. 



be expected. The composition of this alcoate may therefore 



be expressed by 



One atom protochloride of manganese 8* 

 Three atoms alcohol 8*625 



16-625. 

 V. Alcoate of Chloride of Zinc, 



Alcohol dissolves chloride of zinc with great facility, and 

 the solution when filtered is of a light amber colour. This 

 solution may be concentrated to a very great extent without 

 injury, and becomes so viscid when cold, that it may be in- 

 verted without flowing perceptibly. It is not till so concen- 

 trated that it begins to deposit crystals, which are small and 

 independent, but apparently of no regular shape. A viscid 

 solution, in which crystals formed, was found to be composed 

 of 20 parts chloride of zinc, and 7 parts alcohol. The small 

 proportion of alcohol is astonishing; yet no more alcohol was 

 given out when the chloride was heated nearly to redness, and 

 began to volatilize; nor did a portion of the chloride thus 

 heated take fire when exposed directly to the flame of a 

 candle. 



The crystalline matter was dried with difficulty by pressure 

 in blotting paper. When dry, it possessed the usual waxy 

 softness of the alcoates, and was of a yellowish colour. Heated, 

 it entered into a state of semifusion, and gave off its alcohol. 

 Nine grains alcoate were reduced by the application of suffi- 

 cient heat to 7*65 grains. Hence the alcoate consisted of 7*65 

 chloride of zinc, and 1*35 alcohol. But the atomic weight of 

 chloride of zinc is 8*75. 



7-65: 1-35:: 8*75: 1*54.4.. 



1*54.4? slightly exceeds 1*4375, or half an atomic proportion 

 of alcohol. It is probable that the excess was owing to the 

 difficulty of freeing the alcoate completely from the viscid so- 

 lution. According to this view, the alcoate of zinc consists of 



Two atoms chloride of zinc ... 17*5 



One atom alcohol 2*875 



20*375 

 Besides these alcoates, similar compounds of chloride of 

 magnesium and of protochloride of iron and alcohol were 

 formed, although in quantities too minute to enable me to as- 

 certain their proportions. Alcohol is retained with great force 

 by chloride of iron, and is partially decomposed when heated, 

 as is the case with many metallic chlorides. 



As I had it only in my power to present the fixed alkalies 

 to absolute alcohol in the state of hydrates, no alcoate ap- 

 peared 



