BRUSH— A KINETIC THEORY OF GRAVITATION. 



177 



TABLE II. 

 Long Pendulums. 



Periods. 



Single Beats per minute. 



Long Pendulums, Single Bobs 39.834 



" " Double Bobs 39-993 



Short Pendulums, Single Bobs 51-54^ 



Double Bobs 51.752 



The single and double bobs on the shorter rods were compared as 

 before, with results shown in lower part of Table II. But reversal 

 of the larger and smaller time quantities in columns i and 2 lead to 

 strong suspicion of experimental errors, probably due to insufficient 

 care in exchanging the bobs after synchronizing. Unfortunately, as 

 the last experiments were made quite recently, there has not been 

 time to repeat them. 



Effect of Greater Diameter of Zinc Bobs on Center of Gyration. — 

 In last year's paper this efifect, with the long pendulums, was esti- 

 mated to account for about 10 per cent, of the whole zinc-bismuth 

 effect as experimentally found, and somewhat more than this by 

 computation. But the fact that this correction should be doubled 



