432 PHILOSOPHICAL TRANSACTIONS. [anNO I7I9. 



are very unfit to show the minute difference, as it increases and decreases, be- 

 tween equal and apparent time. 



Soon after this clock was sent to Spain, I made others for Mr. Quare, which 

 showed apparent time by lengthening and shortening the pendulum, in lifting it 

 up and letting it down again, by a roller somewhat in the form of an ellipsis, 

 through a slit in a piece of brass, which the spring at the top of the pendulum 

 went through. By this means every vibration of the pendulum would agree 

 to a second of time with the sun's apparent motion ; that roller which lifted 

 up the pendulum, and let it down again, being continually moving about all 

 the year ; so that it may seem very strange that this author never heard of it, 

 so many years after they were made : for one of those, and not the first, made 

 with the rising and setting of the sun, Mr. Quare sold to the late king William, 

 and it was set up at Hampton-Court in his life-time, where it hath been ever 

 since. This contrivance of lengthening and shortening the pendulum, I 

 thought of several years before I made any of them. Since then, I have made 

 others for Mr. Quare likewise, which showed the difference between equal 

 and apparent time according to the equation tables, by a hand moving both 

 ways from the top of a circle; on one side showing how much a clock keep- 

 ing equal time ought to be faster than the sun, on the other side how 

 much slower. 



So that I think I may justly claim the greatest right to this contrivance of 

 making clocks to go with apparent time; and I have never yet heard of any 

 such clock sold in England, but what was of my own making, though I have 

 made them so long. 



An Account of some new Experiments, relating to the Action of Glass Tubes 

 on Water and Quicksilver. By James Jurin, M, D- Reg. Soc. et Coll. Med. 

 Lond. Soc. N°363, p. 1083. 



In the Phil. Trans. N° 355, I asserted, that the suspension of water in a 

 capillary tube, was owing to the attraction of a small annular surface on the 

 inside of the tube, which touched the upper part of the water. Among the 

 several experiments made to prove this assertion, was that of a glass funnel of 

 several inches diameter, having its small end drawn out into a very fine tube; 

 which being inverted and filled with water, the whole quantity of water con- 

 tained was sustained above the level by the attraction of that narrow annulus 

 of glass, with which the upper surface of the water was in contact. 



Soon after that discourse was printed, a book was published by a very learned 

 and ingenious member of this society, in which that experiment was accounted 

 for in the following manner. 



