of a newly discovered vegetable acid. 235 
to discover what would be the habitudes of malate of lead 
obtained by other means. 
Scheele showed that the primary action of nitrous acid on 
sugar is to form malic acid. I therefore heated together 
equal weights of these substances, until the effervescence 
ceased. The brown residue was diluted with lime water, 
and when the oxalic acid that might have been formed, was 
in this manner separated, the remaining acid substance was 
saturated with potash. Acetate of lead was added, and the 
malate of lead thus formed was collected and edulcorated. 
It now remained to ascertain whether this malate possessed 
the property of crystallizing, like that prepared from apple 
juice. I accordingly poured on it different portions of boiling 
water which were received in different vessels : the washings 
were all of a brownish yellow colour, from a small quantity 
of malate of lead held dissolved. At the end of 4,8 hours 
this salt was all deposited in the state of a brown subtile 
powder, but there was no formation whatever of crystals. 
On the surface of each washing was an iridescent pellicle of 
some lustre, which I found to be characteristic of the 
malic acid. This experiment, as Scheele directs, was made 
with weak nitric acid ; I repeated it with an acid of con- 
siderable strength, but after sixty hours there was not one 
crystal. 
It deserves attention, that the matter which remained on 
the filter in these two experiments, after washing with boil- 
ing water, were as soft and pasty as when first collected ; 
whereas the salt of lead obtained from the berries of the 
Sorbus, had grown dense, hard, and was much diminished. 
The saturnine compound that had been formerly obtained 
