120 ON THE ACIDS OF THE NATIVE CURRANT. 
calcium had been previously boiled with the ammonia and the pre- 
cipitate of carbonate filtered off), the whole allowed to stand for 
some time, filtered, and then evaporated to a very small bulk. A 
mere trace of precipitate separated, indicating probably a small 
quantity of citric acid. 
d. To the solution from (c), after filtration, a large bulk of 
strong alcohol was added, when a very bulky precipitate was im- 
Portion 1 was suspended in water, decomposed by sulphuretted 
hydrogen, and the acid liquid evaporated to dryness on the water 
. The residue, when slowly heated in a test tube, gave the 
crystalline sublimate characteristic of malic acid. 
Portion 2 was dried at 100°; and here it may be stated that 
in the 
by lead malate. There being some doubt as to the amount of 
water retained by this compound, the mass dried at 100° was fur- 
ther heated at 200° till constant in weight, so that, if lead malate 
it were, it might be converted into fumarate. A weighed portion 
was then converted into lead sulphate with the following result :— 
Weight taken, Found. Calculated for PbC,H,0s. 
829 gramme, "787 PbSO, 
= ‘5376 Pb 
= 64°84 ¥ 64°49 7% 
This seems to prove conclusively that the greater part of the 
acidity of these currants is due to malic aci 
In order to estimate approximately its quantity, 5 grammes of 
PO otis soiihed wih ae 
sulphur- 
that in 
sepa 
large bulk of alcohol added. The calcic malate was then 
off, washed with alcohol, dried, and ignited to convert it into.@ 
bonate. resi ed with a dilute solutiot. 
ammonic carbonate in order to dissolve out any remaining three 
chloride, again filtered, ignited, and then treated two 0% 
times with ammonic carbonate in the ordinary way till n0 
