294 Mr. Bowditch on the transit of Mercury, Nov. 5, 1789. 
which is 5h. 10’ 1’*2 W from Paris, corresponding to 5h. 0' 40’"2 W 
from Greenwich. Mr. Ferrer’s calculation is made by the three ob- 
servations just named, and those of the transit of Mercury of 1782 
and the annular eclipse of 1791. These last observations I have re- 
jected for the reasons stated in the former part of this memoir. Sub- 
tracting 1”-4 from the longitude of Philadelphia, gives the longitude 
of Lewistown 5h. 0’ 39*7, and by adding 52” the longitude of Norri- 
ton is obtained 5/. 1’ 33"°1 W from Greenwich. 
Messrs. Owen and Biddle found, by a trigonometrical survey, 
that the Light House on Cape Henlopen was 29"*8 N, and 13”1 in 
time E from their observatory at Lewistown. Hence the Light 
House is in the latitude of 38° 47’ 8” N, and in longitude 5A. 0’ 26% 
W from Greenwich. 
The same transit of 1789 was dusivcs at enopetesce as - 
lows. 
App.time. (§-©)Par.long. Par.lat. App. time conj- 
IL contact 20h. 3’ 10” 3"*570 1-884 22h. 16 48'0 
III. contact O 53 45 0 +239 3 °368 17 23 °9 
IV. contact O 55 10°53 0 +219 3 372 17 03 °9 
The mean of these three observations makes the conjunction at 
22h. 17 5"°3, which subtracted from 3h. 23’ 59’-8, gives the longi- 
tude of Williamsburg by this observation 54. 6’ 545. The solar 
eclipse of Sept. 17, 1811 makes it 5h. 6’ 48"4. The mean of both 
observations may be assumed as the longitude of William and Mary 
College 5h. 6' 51-5 W from Greenwich, which is about 52” less than 
the computation of Mr. Ferrer from the end of the solar eclipse of 
June 1806, an imperfect observation, which it was thought best to Fe 
