( loSi ) I 
But thefe Clocks that I then made to agree with the 1 
Sun’sApparent Time,were done according tothe Equation ■ 
Tables, which I found nor to agree very exactly with the t 
Sun’s apparent Motion : neither can any other be made 
to keep equal Time that will gain and lofe all the Year a- 
greeable to the faid Tables: for though the Tables them- 
(elvesmay be true, yet fome difference in Motion does 
proceed, in both forts of Clocks, from Cold and Heat al- 
tering the length of their Pendulums* This difference by 
fome Obfervations I have made, I fuppofe to be about 
the 77, part of an Inch in the length of a Pendulum vibra- 
ting Seconds, which will alter the Motion of the Clock 
about 1 1 Seconds in xq Hours. Hut to make my Clocks 
made for keeping Apparent Time to go as exad as poffi- 
blc, I made a Table my felf by Obfervation ; For obferv- 
ing the Sun, as often as it was to be feen, when it came on 
the Meridian, for feveral Years together, always fetiing 
down the Difference between its coming to the Meridian 
and the Time by a Clock I had adjufted as well as I could 
to equal Time, and always taking notice how much my 
Equal-Time Clock gain’d or loft at the end of every Year, 
1 compleated my Table in the Year lyti. Since then I 
have made a confiderable many of thefe Clocks, feveral 
of which I fold to Perfons of great Note and Ingenuity; 
and in particular one I made about five or fix Years fince 
for the Right Honourable the Lord Parker, at prefent 
Lord High Chancellor of Great Britain ; and all of them 
have given good content to thofe that bought them So 
that I think I may juftly claim the greateft right to this 
contrivance of making Clocks to go with Apparent Time ; 
and I have never yet heard of any fuch Clock fold in 
England^ but what was of my own making, though I 
have made of them fo long. 
Ik An 
