244 Mr. Donovan on the nature and combinations 
liquor was then filtered, and the turbid liquor which came 
through, was heated until it became clear ; it was then suf- 
fered to rest. As it cooled, it let fall a powder, but when this 
was filtered off, the liquor remained clear, and in an hour a 
great profusion of crystals was let fall. The mass which 
remained on the filter contained some gritty particles. 
Thus it is evident, that malate of lead was decomposed by 
sorbic acid, which could not happen unless the latter were a 
distinct substance. The malate was only partly decomposed, 
the oxide of lead united to the excess of sorbic acid forming 
super-sorbate of lead, while the disengaged malic acid dis- 
solved as much as it could of the remaining undecomposed 
malate, forming super-malate of lead. The brown colour was 
produced by disengaged malic acid. The super-malate, as it 
cooled, deposited its malate in the state of powder, and the 
super-sorbate soon after deposited sorbate of lead in the state 
of crystals ; and the original mass was found to contain gritty 
particles of sub-sorbate. 
In the same manner, when a precipitate, obtained by acetate 
of lead from the juice of the Sorbus berries, is washed with 
boiling water, scarcely any malate of lead is deposited ; and 
if the fluid contain much free sorbic acid, the iridescent pellicle, 
which is a characteristic of malate of lead, does not appear. 
I shall now proceed to the combinations of this acid, so as 
to distinguish it from malic acid : and first the salts which it 
forms with lead should be briefly recapitulated. 
The sub-sorbate is insoluble in water; if in a mass, it is 
dense and hard ; if in powder, it is gritty. 
The neutral sorbate, if obtained by precipitation, is a white 
powder, but if obtained from solution in its own acid, it is in 
