Prof. LeConte on the Correlation of Forces. 133 
battery* of two cells, while a wire connects the negative pole of 
the battery with the mercury. The mercurial ring now flattens 
itself out, and strong currents pass through the solution from the 
zinc to the mercury. Very dilute sulphuric acid is now added 
drop by drop, until all at once the currents in the solution stop, 
and the whole of the inner edge of the mercury is thrown into 
large waves of equal size which flow rapidly round the circle, the 
mercury assuming the appearance of a ring with large rounded 
teeth in rapid rotation. A further addition of acid increases the 
rapidity of the undulations, and at the same time decreases the 
size of the waves, until at last it stops them altogether, and the 
mercury becomes contracted. The mass of the mercury has no 
rotatory movement even when the undulations are the most ener- 
getic. At first the waves often pass in opposite directions in 
different parts of the ring, until the longer set compels the 
shorter to change its course, and they all pass round in the 
same direction. 
XVIII. The Correlation of Physical, Chemical, and Vital Force, 
and the Conservation of Force in Vital Phenomena. By JosnrH 
LrConte, Professor of Geology and Chemistry in the South 
Carolina College, Columbia. 
yp Stree constantly changes its form, but is itself inde- 
structible, except by the same power which called it 
into being. The same quantity of matter exists in the uni- 
verse at all times. So also force changes its form constantly, 
but is itself indestructible, incapable of increase or diminution, 
and the same absolute amount of force exists in the universe at 
all times and for ever. The mutual convertibility of the various 
forms of force is called “ correlation of forces.” The invariability 
of the absolute amount in the midst of constant change is called 
“conservation of force.” This principle of correlation and con- 
servation of force must be looked upon as one of the grandest 
generalizations in modern science,—a principle startling at first, 
but when clearly understood and firmly grasped, almost axiom- 
atic. It must be considered a necessary truth, and, as such, is 
a legitimate basis of deductive reasoning. 
The correlation of physical forces is universally recognized as 
a principle in science, and not only so, but has already been pro- 
* T have for some years used}this battery, in which the platinum and 
nitric acid of Grove’s battery are‘changed for the thinnest sheet zinc 
brushed oyer with a very dilute solution of chloride of platinum, and a 
nitro-sulphuric acid consisting of five parts by measure of sulphuric acid 
to one of nitric acid. Zinc is not acted upon by this mixture. 
T From Silliman’s American Journal for November 1859. 
