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R. Spice—Sympathetic Resonance of Tuning Forks. 411 
- (2.) Repulsion of 40° or 50°; return to zero point; remained 
nearly stationary at zero point; sudden and large deflection 
toward flame, when it was extinguished. 
(3.) Same as last. 
(4.) Repulsion of about 5°, attraction 60°. 
antagonistically, and when the disc is vertical, often balance 
each other more or Jess perfectly for quite an interval. O 
extinguishing the flame, the vertical current is greatly weakened, 
while the horizontal one is not much affected, hence the violent 
deflection toward the heated side of the flask. 
New York, June 27th, 1876. 
Art. XLIV.—Ezxperiments on the Sympathetic Resonance of 
uning Forks; by RoBERT SPICE. 
be employed to exhibit their resonance. Ee oe 
It is also well known that a pair of forks having a vibration 
double the number of impulses are delivered in a second, 
If this explanation be sufficient, the following result should 
: Forces radiating from a center obey the law of inverse 
Squares ; hence, if the amount of motion (or force?) received by 
an Ut? fork at a distance of six feet from its excited fellow be 
teresented by 2; then (assuming an Ut* fork to have double 
ree etey of an Ut? fork,) clearly, the amount of motion 
*eelved by an Ut* fork at a distance of twelve feet from its 
*xcited fellow, should be represented by = But so far is this 
tip being the case, that the intensity instead of being one-half 
*Scaleulated) is more than double. In fact, at twenty feet the 
