T. C. Mendenhall—Acceleration of Gravity at Tokio, Japan. 127 
and upon examination was found to be very closely spherical 
and homogeneous. It could be suspended by means of a small 
concave cup to which the ball would cling when it was rubbed 
with a little tallow. To this cup a suspending wire was fas- 
tened, the other end of which was secured to the end of a small 
eylinder projecting down from the knife edge. In a line with 
this and above the knife edge was a set of adjusting screws, by 
means of which this part of the apparatus, independent of the 
wire and ball, was made to vibrate in approximately the same 
period as that of the pendulum. Experiment proved that this 
adjustment might be very considerably disturbed without sen- 
sibly affecting the time of vibration of the pendulum, but it 
was, nevertheless, carefully attended to. After a number of trials 
the cup was rejected as a useless and somewhat uncertain part of 
the apparatus, and in its stead, in the final series of experiments, 
the wire was securely fastened to the ball by means of a small 
drop of solder which was fused on the end of the wire and after- 
_ secured to it was a strong wooden beam, upon which 
cou 
the small circular plane table which was elevated by means of 
