[ 3 6 + ] 
matic telefcope of Dollond, the end at o h oj' 55" 
apparent time. The celebrated M. L. Euler, who 
has computed feveral obfervations of this eclipfe 
made in different places, finds, by my obfervation, 
the difference of meridians between Paris and Ponoi 
2 h 25' 33", that is, 38° 5 P Eaft of Paris. 
2°. On the obfervation of the tranfit of Venus. 
I obferved, with the fame telefcope, the interior 
contact at the entry at io h 15' 4" apparent time. 
I have computed very fcrupuloufly the effect of 
parallax on the moment of this contact; I made ufc 
of the fame elements that M. de la Lande gives in his 
Memoire, printed in 1764, excepting that I affume 
the neareft diftance of the centres of Venus and the 
Sun, feen from the centre of the Earth io' 27"; 
which quantity I deduced from the whole duration, 
obferved at Hudfon’s Bay, by Meff. Dymond and 
Wales, as given in the news-papers. I find the 
effect of parallax 7' 03" of time, whereby I muff 
have feen the contat fooner than at the earth’s 
centre. The computation of my obfervation gives 
moreover the moment of the conjunction at 1 2 h 
46' 2 if" apparent time at Ponoi, and the geocentric 
latitude of Venus for that moment io' 3 3 // > 9 - 
If the neareft diftance of the centres be taken 5" 
lefs, I find the effet of parallax 7' 11" of time, 
that is, 8" greater, the latitude becomes 5" lefs, and 
the moment of the conjunction i / 28" later. 
3 0 . I have made a great number of obfervations for 
determining the force of gravity and the length of 
the fimple pendulum Twinging leconds. I ufed an 
invariable pendulum which M. de la Condamine got 
conftruted at Quito, when the French academicians 
went 
