VOL. XLI.] PHILOSOPHICAL TRANSACTIONS. 3'2J 



and placed sideways to each other, so near that when the pendulums were at 

 rest, they were little more than about two feet asunder. 



The odd phaenomena observed in them were these : in less than two hours 

 after they were set a going, one of them, called N° 1 , was found to stop ; and 

 when set a going again, as it was several times, it would never continue going 

 two hours together. A.s it had always kept going with great freedom, before the 

 other clock, N° 2, was placed near it, this led Mr. E. to conceive its stopping 

 must be owing to some influence the motion one of the pendulums had upon 

 the other ; and on watching them more narrowly, the motion of N° 2, was 

 found to increase as N'' I diminished ; and at the time that N° 1 stopped, N° 2 

 described an arch of 6°, that is nearly 2 degrees more than it would have done, 

 if the other had not been near it, and more than it moved in a short time after 

 the other pendulum came to be at rest: this made Mr. E. imagine that they had 

 a mutual influence on each other. 



On this he stopped tiie pendulum of N° 2, leaving it quite at rest, and set 

 N° 1 a going, the pendulum describing as large an arch as the case would per- 

 mit, viz. about 5°. In about 20 minutes after, he went to observe whether 

 there was any motion communicated to the pendulum N° 2, when, to his sur- 

 prise, he found the clock going, and the pendulum to describe an arch of 3", 

 whereas at the same time N° 1 did not move 4°. In about half an hour after, 

 N° 1 stopped, and the motion of N° 2 was increased to very near 5°. He then 

 stopped N° 2 a second time, and set N° 1 a going, as before ; and standing to 

 observe them, he presently found the pendulum of N° 2 begin to move, and 

 the motion to increase gradually, till in 17'" 40* it described an arch of 2° 10', 

 at which time the wheel discharging itself of the pallets, the clock went. 



The arches of the vibrations continued to increase, till, as in the former ex- 

 periment, the pendulum moved 5°; the motion of the pendulum N° 1 gradually 

 decreasing all the while, as the other increased ; and in three quarters of au 

 hour after, it stopped. 



He then left the pendulum of N° 1 at rest, and set N° 2 a going, making it 

 describe an arch of 5° ; it continued to vibrate less and less, till it described but 

 about 3°; in which arch it continued to move all the time he observed it, which 

 was several hours. The pendulum of N° 1 seemed but little affected by the 

 motion of N° 2, 



Mr. E. tried these experiments several times over, without finding any re- 

 markable difference. The freer the room was from any motion, as people's 

 walking about in it, &c. he found the experiments to succeed the better ; and 

 once he found N° 2 set a going in 16™ 20*, and N^ 1 at that time stopped in 

 36"" 40«. 



VOL. viii, Tt 



