VOL. XXX.J PHILOSOPHICAL TRANSACTIONS. 431 



and those experiments in which the bladders fell straight down, and the most 

 regularly, have this (*) mark before them. 



A pail of water thrown down, met with such a resistance in falling 2/2 feet 

 through the air, that it was all turned into drops like rain. 



j4 Letter from Mr. Joseph Williamson, IVatchmaker , asserting his Right to the 

 curious and useful Invention of making Clocks to keep Time with the Sun^s 

 Apparent Motion. N° 363, p. 1080. 



Having been informed of a French book lately published, wherein the author 

 speaks of making clocks to agree with the sun's apparent motion; and supposes 

 that it was a thing never thought of by any before himself: the following is a 

 short account of what I have performed in that matter myself. 



And in the first place I must take notice of the copy of a letter in this book, 

 written by one P. Kresa a Jesuit, to one Mr. Williamson, clockmaker to his 

 Imperial Majesty, of a clock found in the late king Charles II of Spain's 

 cabinet, about the year 1699 o^ 170O; which shows both equal and apparent 

 time according to the tables of equation; and which went 400 days without 

 v;inding up. This I am well satisfied is a clock of my own making ; for about 

 6 years before that time, I made one for Mr. Daniel Quare, which agrees with 

 the description he gives of it, and went 400 days. This clock Mr. Quare 

 sold, soon after it was made, to go to the said king Charles II of Spain: 

 and it was made so, that if the pendulum was adjusted to the sun's mean 

 motion, the hands would show equal time on two fixed circles, on one the 

 hour, and on the other the minute. But there were two other moveable 

 circles of the same kind, that moved forwards and backwards, as the time of 

 the year required ; on which the same hands showed apparent time likewise 

 according to the equation table. This method the author asserts he knew of, 

 and applied the same motion to pocket watches 12 or 14 years since; which I 

 own I never did; being well satisfied that watches with springs and balances 



