bic 
C. &. Peirce—On a Method of swinging Pendulums. 115 
I had the advantage many years ago of learning the main 
characteristics of the mutual influence of pendulums from Pro- 
fessor Benjamin Peirce. As my father’s studies of the subject 
were never, I believe, written out, I am unable to say definitely 
what I derive from that source. But the truth is the little 
T9,. €%. gs 
tT IP: 
d’s. 
1, EP =I Pe 
These equations are exactly like what we have in the case of 
a single pendulum on a flexible support; an I have shown 
their correctness in my paper on that subject. 
There would be no difficulty in making the two pendulums 
so nearly alike that they might be ed as entirely so in 
their actions on the stand, the whole amount of which is small. 
Am. Jour. —— Serres, Vou. XVIIL—No. 104, Avavst, 1879. 
