[ 47 ] 
In building my winter habitation on Saint John’s 
Ifland, I conftrudted a ftrong done chimney ; to the 
back of which I fecured the clock with the greatefl 
precaution j and the room was kept temperate by ail 
iron dove. In a few days, the clock was regulated 
to mean or equal time; and always examined and 
compared by equal altitudes of the fun and dars, at 
or near the time when any immerfions or emerfions 
were to be obferved. As the going of this clock is 
not inferior to any made by that renowned artid Mr. 
Graham ; it will not be neceffary to infert here a 
multitude of equal altitudes of the fun, and other 
obfervations, to prove the exadtnefs of this clock j 
but only mention, that I have made ufe of Monlieur 
De la Lande’s Tables * to rectify the equal altitudes 
of the fun, for the alteration of the fun’s declina- 
tion during the time of obfervations. 
1765. 
t Obfer. January 20. Obferved an emerfion 
of the fird fatellite of Jupiter, at 7 hours, 42 mi- 
nutes, 3 feconds, equal or mean time. Mr. Haldi- 
mand, who obferved with Mr. Dollond’s telefcope, 
perceived the fatellite two feconds later than I did 
with Mr. Short’s ; the latter having the fecond power 
magnifying 150 times. As this w>as the fird ob- 
fer vation, we began too foon to obferve, and fa- 
tigued our eyes lo much, that we w'ere not fure to a 
few feconds. 
* See Monfieur De la Lande’s Jjlrcnomip^ Article 6^7, 
F a T 279. 
2 Obfer. 
