1815] Ekmenti r^f Organic Nature are combined. IJ'S 



Acetic acid 2G-97 31-48 lOO'OOO 



Oxide of lead 58'71 68-52 217-(i62 



Water 14-32 53'140 



100-00 100-00 



But 2l^-G62 of oxide of lead contain 15-56 of oxygen, whicli 

 differs little from the analysis of acetate of lime. The oxygen of 

 53-14 water is 46-L>; but 15*56 x 3 = 46-68; that is to say, that 

 rhc water contains tiiree times as much oxygen as the base. 



To find the number of volumes of oxygen in acetic acid, I 

 examined the subacetate of lead. It is known that acetate of lead 

 digested on oxide of lead dissolves a portion of it, and forms a 

 soluble subacetate ; while a portion of the oxide of lead is converted 

 into a white voluminous powder, little soluble in water, and con- 

 stituting a subacetate with a greater proportion of base. 



The soluble subacetate attracts carbonic acid from the atmos- 

 phere with avidity, and cannot be concentrated in open vessels. To 

 obtain it in a dry form, I exposed a solution of subacetate of lead in 

 a vacuum with sulphuric acid. When half the liquid was evapo- 

 laied, 1 found a great quantity of a white matter, not at all crystal- 

 lized, deposited at the bottom. I removed this matter from the 

 liquid, washed it in alcohol, and then dried it in a vacuum along 

 with sulphuric acid. 



Tiie subacetate thus prepared, when heated in a retort, gives no 

 symptoms of containing moisture, and of course does not contain 

 any combined water. Analyzed by combustion, it gives 86-77 per 

 cent, of oxide of lead. 



The liquid from which this salt had been deposited, when mixed 

 with alcohol, lets fall a new portion of the salt ; vvliich, being 

 analyxed, gave the same result as the preceding. Hence this 

 subsalt is composed of 



Acetic acid 13-23 100 



Oxide of lead 86-77 656 



100-00 



But 217-66 X 3 = 652-9H, which differs very little from 656. 

 Hcitcc it follows that in this subsalt tiic acid is combined with 

 thrice -as much base as in the acetate. 



The subacetate at a maximum, formed when the preceding sub- 

 acetate is digested with more oxide of lead, can hardly be obtained 

 in a state of purity in that manner. I prej)ared it by pouring a 

 great excess uf caustic anunonia into the concentrated solution of 

 the preceding subacetate. The mixture is at fiiit tlan^^pa^cnt ; but 

 it Kfxjji depositcs ubundance of subacetate at a maximum. 1 sepa- 

 lad'd it by a filter, and washed it well witli annnonia and water. It 

 w.is then dried in a vacuum. Heated a little abuvc 212" in tiie 

 vacuum, it disengaged three per cent, of iu weight of water, and 



