288 | Mr. Bowditch on the transit of Venus, June 3, 1769. 
conjunction deduced from the fourth contact agrees nearly with other 
observations, but the three first contacts make ‘the conjunction too 
late by nearly a minute. Mr. Ferrer in his calculation in vol. vi. of 
the same Transactions, rejects the first contact, and subtracts one min- 
ute from the second and third; but this correction does not appear to 
be warranted by the observations. For if we suppose the regulation 
of the time-keeper to be correct, there must have been a mistake in 
reading off the three first observations, which is improbable ; and if 
we suppose the regulation of the time-keeper to be erroneous by one 
minute, it will not make the observations accord without allowing al- 
so an error of one minute in the last contact. These reasons/have in- 
duced me to reject the observations, as not having been made with 
sufficient accuracy to be used in calculating the longitude of Philadel- 
. 
phia. : Ns 
Transit of Venus June 8, 1769. : 
The elements of this transit for June 3, 1769, at 10/. 2 $41 mean 
time at Greenwich, are as follows. oe 
©’s longitude by Delambre’s tables of 1806 = « 73° 27’ 1879 © 
2’s See deduced from the observations atGreen- 73 27 18. *9 
9's latitude —f wich, Paris, and Prince of Wales’ Fort. 10 14 +32 N. 
’s horary motion pa - - - . 143 -46_ 
?’s horary motion in longitude eo eS a - 94 *144 
Q’s horary motion in latitude —- “ F : —35 450 
_9’s horizontal parallax  - ‘ s ge 30 *45 
©)’s horizontal l en “ a 2 . 8 °67 
©’s semidiameter by T. 2. P. 470 0f La Lande’s Astronomy 15 43-71 
Q ‘s semidiameter — - % eg ee | * 28 
©’s right ascension —- EN ae - -. Ah. 48 13 423 
Horary increment of right ascension - - ~ 10 °27 
The mean of the observations of Messrs. Maskelyne, Dollond, 
Nairn, Hirst, Hitchins, Horsley, and Dunn, at the Royal Observatory 
at Greenwich; as given in the first volume of the Transactions of the 
Philosophical Society of Philadelphia, make the first external contact 
at 7h. 11’ 19 and the first internal contact at 74. 29° 19"1. ‘The 
