360 H.. A. Rowland—Diamagnetic Constants of 
Art. XLIL—On the Diamagnetic Constants of Bismuth and 
Cale-spar in Absolute Measure. 
Part I.—By H. A. Rowiann, Professor of Physics in the Johns 
Hopki 
oO 
pkins University. 
SINCE my experiments on the magnetic constants of iron, 
nickel and cobalt, I have sought the means of determining 
those of some diamagnetic substances, and to that end have 
page 357). As Mr. Jacques, Fellow of the University, was 
t 
a 
As, however, the relative results of these experiments and those 
of Faraday can be accepted as reasonably exact for diamagnetic 
substances and weak paramagnetic ones, it is only necessary 10 
make a determination of one substance such as bismuth, and 
in counting the number of vibrations made by a bar hung in 
the usual manner between the poles of an ee atti 2" The 
nown, we 
can then calculate the force acting on the body, and the com 
more exact description to be given by Mr. Jacques in 
experimental part. 
The first operation to be performed is to find a formula © 
express the force of the field at any point, and an eget 
