ON ACETIC ACID AND ACFT4TES* 229 



Vfwi in that of the acetate obtained by the union of this al- 

 kali with the product of acetate of copper. This it is that Purification of 

 obliges the druggists to expose what they call foliated earth ^ a 

 of tartar to a moderate heal, in order to render it white. 

 Lastly, when Mr. Berthollet imagined, that by means of 

 acetic acid he had expelled acetous acid from its combina- 

 tion with potash, it was because we can in fact obtain an 

 acid milder than tne acetic, and nearer to the state of vine- 

 gar, by distiiling acetic acid from an aretate of potash in 

 which all the vegetable matter has not been destroyed by 

 heat. Fart of this, I believe, is carried off by the fresh 

 acid, till the equilibrium of affinity between it and the salt ' 

 in which it existed before is restored. 



From these experiments it follows, that the specific gra- Spec. gfav. no 

 vity is not a faithful index of the quantity of acetic acid lest 0I acidit ?* 

 contained in vinegar, and in the product of the distillation 

 of acetate of copper, because neither of them is a pure and 

 simple solution *>f acetic acid in water. 



To place all this in a more striking light, T availed myself Acetate of 



of the researches of Lassonne and Monnet, who have in- ,ei " , ; orof anc 



yields more 



structed us, that the acetate of lead, or of zinc, distilled like spntthau that 

 that of copper, gives us a larger quantity of the spirituous of C( W er » 

 liquor. Accordingly I subjected to distillation two pounds 

 of acetate of lead, and collected the produce in three porti- 

 ons. The first was nothing but weak acetic acid ; the second, 

 rectified by distillation to dryness, was of the specific gra- 

 vity of 09234; and the third, of 0'85t>7. Their acidity 

 was in the ratio of 4*421 to 5*46-2, and the spirituous liquor 

 as 60-50 to 83-25. 



Comparing the various properties of lead and copper, and Other metallit 

 particularly their reducibleness, with the difference of the s; \ lls compar- * 

 results in the distillation of their acetates, I was led to in- 

 quire into the action that takes place between some other 

 metals and vegetable acids in similar circumstances, in 

 hopes of connecting together the phenomena of the distil- 

 lation of metallic acetates, ami deducing from them a 

 general law respecting the formation of the pyroacetic 

 spirit. 



The resistance, that any salt opposes to the action of heat, Resistance of * 

 is proportional, cattris paribus, to the affinity of the acid iait t0 **** *• 



