/ 
[ 494 ] 
Experiment X. 
With the acid of plums. 
Having got a quantity of the larger fort of the 
green plums, I caufed the ftones to be picked out, 
and the plums to be bruifed and put into a large 
china bowl; I then poured about two quarts of wa- 
ter over them, and faturated their acid with the 
fofiil alkali; after they had hood 24 hours, I 
/trained off the liquor, filtered, and evaporated it, till 
there remained only a few ounces, when it was fet 
in a cool place for four days, at the end of which 
time I found that a cryffallifation had taken place; 
but, upon pouring off the fuperfluous liquor, I 
could not obferve any general form of cryftailifa- 
tion ; the whole was made up of a number of very 
thin, flat, longifh cryftals, from about to 4 of an 
inch long, and from to 4 or 4 of an inch broad, 
of an irregular figure, laid without any particular 
form, and mixed every where with a mucous and 
black oily matter; when dry, the whole appeared 
like a confufed mafs, where however the form of 
fome of the cryftals was to be obferved, as is to be 
leen at a, a , in fig. 10 ; in fome places the cryftals 
feemed to be laid with their edges uppermoft, and 
in others in a different manner, as at b, b> &c. 
In order to know the regular and true form of 
the cryftaiiifation of this fait, 1 feparated a quan- 
tity of the pureft from the large mafs, diffolved it 
in boiling water, filtered it through paper, and 
cryftallifed it a fecond time in a tea cup. It now 
appeared in a more regular form; the cryftaiiifa- 
tion 
