[ 49 ‘ ] 
1200 vibrations, before it had loft half a degree, and 
was obferved to have a lenlible motion above 2 c 
hours afterwards ; and the clock, when firft put to- 
gether, was kept going, for feveral days, by a weight 
of only eleven ounces, hung to the end of a iingie 
line. But it was not long, before I difcover’d, that 
this great freedom made it liable to be confiderably 
affedted by the lead: motion. 
A remarbable indance of this I communicated to 
•this Society, which was publifhed in the Philo foph, 
cal ‘TranfaSiions , N° 4f3- But the greated objec- 
tion to this method was, the points being fubjedt to 
wear ; and I found, that the lead alteration in them 
would occafion the clock to vary much more, than 
(without having made the trial) I could have ima- 
gined. To remedy this inconvenience, I made the 
pendulum to move upon edges, like thofe, on which 
the beam of a pair of fcales turns (a method I had 
good reafon to believe had been made ufe of with 
fuccefs) ; but I found thefe likewife liable to wear, 
tho’ not in fo fhort a time as the points ; fo that, after 
much time fpent in making feveral experiments, in 
order to remedy this inconvenience, I found myfelf 
obliged to lay this method wholly afide, and to hang 
the pendulum upon a fpring, as ufual. 
In making this alteration, I obferved one circum- 
dance, which I think deferves to be taken notice of. 
Before I made any alteration in the work, I took par- 
ticular notice to what height the pendulum required 
to be raifed, before the pallets would efcape from the 
wheel. I next obferved the number of degrees of 
each vibration of the pendulum, when mov'd by the 
clockwork ; and then, the clockwork being remov’d, 
Qjj q 2 the 
