Intelligence and Miscellanies, 215. 
The author designs to publish a more circumstantial ac- 
count of his observations.—Annales de Chimie et de Physi- 
que, Aout, 1828. 
25. Autumnal coloration of Leaves.—A memoir on this 
subject, by M. Macaise-Princep, read before the Societé de 
Physique et D’histoire naturelle de Geneve, concludes as fol- 
ws: 
1. Ali the colored parts of vegetables appear to contain 
a particular substance, (which the author, in conjunction 
with Prof. DeCandolle, agrees to call Chromule,) suscepti- 
ble of a change of color by slight modifications. 
2. It is to the fixation of oxygen, and to a sort of acidifi- 
cation of the chromule, that we are to ascribe the autumnal 
change in the color of leaves—Idem. 
26. Singular Galvanic trough.—M. Watkins, philosophi- 
cal instrument maker of London, has constructed a Voltaic 
pile, with a single metal and without any liquid. It consists 
of from 60 to 80 plates of zinc, four inches square, fixed in a 
wooden trough at a short distance from each other, having 
only a thin plate of air between them. One side of each 
polished faces are all turned in one direction. If one ex- 
tremity of the pile be made to communicate with the ground, 
and the other with an electroscope, the latter immediately 
indicates one or other of the two electricities, according : 
the pole with which it isin contact. The humidity of the air 
favors the action of the pile, which may be consid a 
kind of dry pile in which air is substituted for paper, and the 
27. On a method of measuring some varieties of Chemical 
action, by M. Babinet—In producing the disengagement of 
a gas in close vessels, the chemical action ceases when the 
gas acquires a sufficient elastic force ; and this action Is sus- 
pended until the compressed gas is liberated, the force of 
