232 ON ACETIC ACID AND ACETATES* 



least five or six times. I took no particular care, either to 



produce or to prevent it. 



Acetate of fhe acetate of manganese crystallizes better than the 



manganese. • 



acetate of zinc. Rhomboidal laminae may be distinguished 



among its crystals. Its colour resembles the smoky topaz, 



if it be formed with vinegar; but with acetic acid it is 



whiter. It coutains less water of crystal iizution than the 



acetate of zinc, yet it liquefies at a high temperature. 



Difficult to Whatever precautions 1 took to obtain these salts in a 



have the ace- „ , _ , " 



tates perfectly state ot dr y ness > 1 cannot venture to say, that 1 have sue- 

 free from wa- ceeded. Those that crystallize well, as the acetates of fil- 

 ter. 



ver, copper, and nickel, may be considered as in a state 



nearly uniform. But the acetate of zinc retains a very 

 large proportion of water in the mass of its confused crys- 

 tals; and unless it be reduced to very tine particles, it re- 

 mains in it, and occasions its liquefaction. 

 Real acetic I would have endeavoured to analyse these salts, if I 



known. na( ^ conceived any hope of doing it to my satisfaction : but 



I am not acquainted with the real acetic acid, and I believe 

 it is unknown in chemistry. Some rule however is necessary, 

 by which we may appreciate the state of the substances, on 

 ■which I operated. The proportion of its weight that each 

 of them loses at a heat capable of decomposing it entirely 

 may serve us as a guide: and accordingly I exposed a known 

 quantity of each to a high temperature iw a platina cruci- 

 ble, weighed before and after the operation. 

 Action of heat The acetate of silver exposed to the flame of a candle 

 on the acetates alone gives out a strong smell of acetic acid, and is reduced 

 almost without any change of appearance, so that it resem- 

 bles native plume silver, It becomes very white, and does 

 not retain carbon, like the other metallic acetates, unless 

 the contact of air be excluded. In open vessels it loses 

 3*631 of its weight out of 10*000. 

 cooper The total decomposition of the acetate of copper is per- 



fectly accomplished in a glass vessel. Exposed in a cap- 

 sule on a heated sandbath, it first decrepitated. A light va- 

 pour of acetic acid then manifested itself at a very low tem- 

 perature; and the salt became brown round the sides of the 

 veMel. This colour spread gradually to the middle, and 



the 



