ON PHLORIDZINE. 
239 
ride of silver 54.75 grains. The chlorine in 54.75 grains of 
chloride of silver is 13.5 grains. Subtracting this from 24.5 
grains, we have 11 for the weight of the metallic bases of the 
alkalies. The oxygen equivalent to 13.5 grains of chlorine is 
3 grains. 
By the rule, 5x3 or 15, less 11, the weight of the metals, 
is half the weight of the soda; the soda is, therefore, 8 grains. 
The weight of oxygen, 3 grains, less one-fourth of the soda, 
2 grains, gives one-sixth of the weight of the potassa. The 
potassa is therefore 6 grains. 
It is readily seen that the general principle to which these 
results refer themselves, may be used with great effect in 
avoiding a difficult step in chemical analysis, by the substitu- 
tion of a less direct, but more simple one, aided by easy cal- 
culations. 
This problem is only a particular case of a general one, well 
deserving the attention of analytical chemists. 
Journ. Franklin Instit. 
ART. XXXVII.—ON PHLORIDZINE. By L. De Koninck, M. D. 
As yet, the history of phloridzine, a bitter principle exist- 
ing in the bark both of the trunk and roots of apple, pear, 
cherry and plum trees, has been traced in a very imperfect 
manner; this deficiency has been supplied by the following 
account of this article, read by Dr. De Koninck before the 
meeting of naturalists at Bonn. 
The principal properties of phloridzine are the following: 
it has a very bitter taste; it crystallizes in silky spiculae of a 
dead white colour when in masses, or in long slender prisms 
or tables when crystallized with care. In this case it has 
a yellow tinge, and the crystals have a pearly reflection. 
Water from 32° to 71° only dissolves about T5 ^. From 71° 
to 212° F. this fluid dissolves it in all proportions; it is also 
