324 PHILOSOPHICAL TRANSACTIONS. [aNNO I739. 



the largest vibrations. But as they had so large a quantity of motion given 

 tiiem at first, neither of them lost so much during the period it was acted on 

 by the other, as to have its work stopped, but both continued going for 

 several days, without varying one second from each other ; though when at a 

 distance, as was before observed, they varied 1"" 36* in 24 hours. While they 

 conthiued thus going together, he compared them with a third clock, and found 

 that N° I went !•" 17' faster, and N° 2 went ig' slower, than they did when 

 placed at a distance, so as to have no influence on each other. 



On altering the lengths of the pendulums, the period in which their motions 

 increased and decreased, by their mutual action on each other, was changed ; 

 and would be prolonged as the pendulums came nearer to an equality, which, 

 from the nature of the action, it was reasonable to expect it would. This dis- 

 covers the reason why the pendulum of N° 2, when left at rest, would be set a 

 going by the motion of N° 1 ; whereas if N° 1 was left at rest, it would not be 

 set a going again by the motion of N" 2. 



For he found, by several experiments, that the same pendulum, when kept 

 in motion by a weight, would go faster, than when it only moved by its own 

 gravity. On this principle, which may easily be accounted for, it follows, that 

 during the time in which the shortest pendulum, N° 2, was only acted on by 

 N° 1 , it would move slower, and the times of its vibrations approach nearer to 

 an equality with those of N" 1, than after it came to be kept in motion by the 

 weight ; and by this means the time which N° 1 would continue to act on it, 

 would be prolonged, and be more than was required to make the pendulum de- 

 scribe an arch sufficient to set the work a going. But, on the contrary, while 

 the pendulum of N° 1, which was the longest, was only acted on by N' 2, as 

 it would move slower, the difference of the times of the vibrations would be 

 increased ; and consequently the time which N° 2 would continue to act on it, 

 would for this cause be shortened, so that before the pendulum of N° 1 would 

 describe an arch sufficient to set the work agoing, the period of its being acted 

 on would be ended, and it would begin to act on N° 2, at which time its vibra- 

 tions would immediately decrease, and continue to do so till it came to be 

 almost at rest. And thus it would continue, sometimes to move more, and at 

 other times less, but never sufficiently to set the clock a going. 



A Wound in the Cornea of the Eye successfully cured. By Mr. Thomas Baker, 

 Surgeon to St. Thomas's Hospital. N''453, p. 135. 



A young woman, about 15 years of age, on the 6th day of Nov, 1733, re- 

 ceived a wound just in the pupil of her right eye, by the point of a common 



