M. de Z ach's . Afironmkal Obfervationh 
fyl 
SIR , Lyons,. Mays 4, j 783- 
LATELY I received from the Obfervatory at Marfeilles the 
obiervation of the trail fit of Mercury, which happened the 12th 
Nov. 1782. The Iky not being very favourable, only the two in- 
ternal contacts were obferved;' the firft internal contadl was ob » 
ferved by M. St. Jacqu.es de Sylvabelle, at 3 h. iff 30" 
apparent time ;; the lafb internal contahl by M. St. Jacques, at 
4 m 30' i6 // ; by M. Bernard, his Adjunctus, at4h. 29' 13T. 
The nearefl diffances of Mercury’s limb to that of the fun in 
the northern part of its difk were at 
it; 
3 33 Ml 31 j 
3 42 57 l 34 l parts- of the micrometer. 
4 22 17J 19. J 
The apparent diameter of the fun was 2174 parts of this mi- 
crometer r I fuppofe the before.- mentioned 21 74 parts= 32/ 
26", 9* P conclude farther, by the obfervations, the middle of 
the tranfit at 3 h. j /y , 2,. 5, whereas I fix, by interpolation, 
the diffances of the- limbs ■ at 3 h...54 / j" ^3 1=z '3$ // 9&'i I have 
therefore femi- diameter of the fun nr 161 rAha. — ac /7 .6 ~ 
I 5 / 37 /7 ?S -p femi-diameter of Mercury — 6 // rr 1 5' 43 v , 8 — to the 
ieaff diffance of centers of the fun and Mercury. By M. de 
ea Lande’s- tablesht is- 15/ \2 r/ , only a difference of i AS. 
M.W allot at Paris has obferved this traniit at the. Roy ah 
€)bfervatory,. 
Pirff external contact 
Firft internal contact' 
Second 
Second external 
h'. 
/ // 
56 28 
o 
3 2 
4 17 18 
4 22 53 :- 
on 
