248 TRANSIT or VENUS 
limb would be exa@ly coincident with that of the fun; and 
therefore determined to wait till there fhould appear a {mal} 
thread of light between them. As the contact drew 
near, the thread of light began to form, and feemed to: 
dart on each fide of the planet for feveral feconds without 
being fixed or fettled. At 2° 48’ 44”, with a feeming- 
uncertainty of not more than 7” it became clofed and fix- 
ed; Venus then appeared wholly within the fun, feparat=. 
ed from its limb by a fine ftream of light flowing gently 
roundit. This I fixed upon as the zxfernal contac?, though 
this might alfo be the conta& not of Venus but of her 
atmofphere with the fun. Not having a micrometer or 
hairs fixed in the refle&tor, inftead of making any further 
obfervations, we could only enjoy the pleafure of viewing 
this curious phenomenon, and fhowing it to a number of 
gentlemen that had affembled on the occafion. 
To determine the latitude of the place, we took the: 
meridian altitude of the fun on the day of the tranfit, by 
tran{mitting his rays from a ftyle 10 feet high, upon a 
large horizontal platform. From this obfervation our la=- 
titude came out 43° 2’ north. Sufpecting the obfervation: 
was not fufliciently accurate, I have fince carefully exa-. 
mined the matter, and from feveral obfervations which 
nearly agree, I find it to be but 42° 57’. With regard 
to our longitude, the mean of fix or feven obfervations of 
the eclipfes of Jupiter’s firft fatellite, gives it about 4" 42’ 
30" welt from Greenwich. 
In the above account of the contacts, the duration of 
the ingrefs, or paflage of Venus over the fun’s limb, 1s 
18’ 30"; near a minute longer than in mott of the Ame- 
rican obfervations. By theory it fhould be 18’ 56”, but 
as this muft have been contracted at the place of obferva- 
tion, 15”, by parallax, the apparent duration of the in- 
grefs, would be but 18’ 41"; that is, 11” longer than 
it was made by obfervation. I much doubt whether it 
was polflible to difcern the planet fo foon as 11" atter ed 
r 
