56 
Selected Articles. 
ART. XVII.— ON THE EXISTENCE OF THE BI-MALATE OF LIME 
IN THE BERRIES OF THE SUMACH; AND THE MODE OF PRO- 
CURING IT FROM THEM IN THE CRYSTALLINE FORM. 
By William B. Rogers, Prof, of Chemistry and Natural Philosophy in Wil- 
liam and Mary College. 
The berries of the Rhus glabrum and Rhus copallinum, 
the two species of sumach common in Virginia, have long 
been remarked for their acidity and are still used in some 
places as a substitute for lemons in different forms of beve- 
rage as well as for various other purposes in domestic econo- 
my and medicine. In some experiments made more than two 
years ago upon the acid liquor obtained by macerating the 
berries in warm water, I have found it to contain a large quan- 
tity of an acid salt of lime which I have since determined to 
be the bi-malate. At the same time too a microscopic exami- 
nation of the berries of the R. glabrum enabled me to disco- 
ver the pure crystals of this salt on the outside of the berries 
mingled with the down. To observe the form of the crys- 
tal distinctly, the berries should be slightly moistened and then 
allowed to dry. The crystals may then be readily seen by 
the naked eye, and when viewed through the microscope 
they appear as beautiful hexagonal prisms of the most per- 
fect symmetry. 
The existence of this salt in the berries of the Rhus is a 
fact which appears to have hitherto escaped attention. The 
only experiments relating to the acid of these plants which I 
have met with, are those of Mr. I. Cozzens of New York, 
published in the first volume of the Annals of the Lyceum of 
that city; and that chemist seems to have regarded the infu- 
sion of the berries of the Rhus glabrum as containing malic 
acid uncombined with any base but "merely contaminated 
with a small portion of gallic acid which probably proceeds 
from the pulp of the berries." In his paper on the subject he 
does not mention having tested the acid liquor for lime, which 
he would have discovered at once either by evaporating a 
