156 PHILOSOPHICAL TRANSACTIONS. [aNNO I667 . 



Another day, near the same place, when the pendulum was adjusted, and 

 made a little shorter, there having been but 58 vibrations in a minute the for- 

 mer day. 



Ball (A) lead (B) at 14 fathoms, returned in 324-. 



A second trial a little after in the same place returned in 33. In making of 

 which trial the vibrations were told aloud, and the lead having been let down 

 by a line, was found to touch the bottom in just half the time, the ball staid 

 under water. By a second trial the ascending and descending were found to be 

 in equal times. And by a third trial with another lead, the very same was 

 found, viz. 164- descending, and 1 64- ascending. This lead and ball let down 

 without a line, the ball returned in 1 3 vibrations ; a sign it went not to the 

 bottom. 



A trial made with a lead, the iron crook being fastened at the top of it, like 

 that in fig. 4, succeeded very well, and the ball returned in 34^. But by reason 

 of the current, the experimenters could not perceive when the lead touched the 

 bottom. This lead being let down without a line, the ball returned in 32-i-. 

 The depth of the water was now found by the ship's lead to be 14 fathoms. 



Another trial was made with a line, bowing the point of the lead, like that 

 in fig. 5, and the ball returned in 34. The same let down without a line, the 

 ball returned in 6 or 7 vibrations ; a sign again, it went not to the bottom. 



In a trial with another lead, the ball returned in 34. 



Repeated again with the same success. 



In a trial with a lead having the nail set awry, like that of fig. 6, the ball 

 returned in 34. After which trial, the depth was found to be just 14 fathoms. 



The last lead and ball being let down without a line, the ball returned at 35. 



In another trial with a lead that never failed, the ball returned in 34, and the 

 lead touched the bottom at 1 7 . 



By a trial with another lead, the same time was found exactly. 



By a third trial with this last, the very same. 



These trials were made near about high-water, at the depth of 14 fathoms 

 exactly : and in them the motions seem to be 5 feet every second. 



In all these trials, the greatest difficulty was in the use of conical figures, 

 with iron crooks, to bend the iron that it might be sure to carry down the ball 

 with it to the bottom, and when come thither to let it go: for almost every one 

 of these leads failed in one of these requisites, till by several trials they had been 

 adjusted. 



It is not to be omitted, that the last trials being made near high water, the 

 ball was found to rise (by the boat being permitted to drive) far off upon one 

 side out of the way, that any light thing suffered to swim on the water would 



