260 $$ Mi, Bowditch on the Longitude of Cambridge. 
The mean of all these observations, reduced to the meridian of the 
Observatory of Paris, give for the first internal contact 8h. 40/ 40-2 
A.M. second internal contact 14. 10’ 15’°7, second external contract 
1h, 12' 10’*5 apparent time. These times differ a little from those given 
in volume I, page 53 of the Memoirs of the American Academy of 
Arts and Sciences, owing toa difference in the reduction of the observa- 
tions of the internal contacts, observed by Cassini senior, and the exter- 
nal contact by Le Monnier. From these observations, computing the 
parallaxes for each of the contacts, the difference of meridians between 
Paris and Cambridge is 4h. 53’ 53°3,* and by subtracting the differ- 
ence of meridians of Paris and Greenwich, 9’ 21”, there remains the dif- 
ference of meridians of Greenwich and Cambridge, 44, 44’ 32”°3. 
The fourth observation is the solar eclipse of April 3,1791. This 
was observed at Cambridge by Professor Webber. The beginning 
at 6h. 1'27”, formation of the annulus 7A. 8’ 7’, breaking of the annu- 
lus 7h. 12’ 56”, end of the eclipse 84. 28’ 26” A. M. apparent time. 
The olsservations at Greenwich were, the beginning OA, 18’ 40"0,. 
the end 3/, 6’ 47" apparent time. At the Royal Observatory at Par- 
is, beginning Of. 33’ 37"*4, end 34. 17’ 36-0 apparent time. The ob- 
servations at Greenwich, make the conjunction at 0. 42’ 1”+3 apparent 
time. Those at Paris 0/. 51’ 20"*1 apparent time, from which sub- 
tracting 9° 21", leaves the apparent time of the conjunction at Green- 
wich Of. 41’ 59”*1. The mean of this and the former estimate is Oh. 
42’ 00"-2, the difference between this and the time of the conjunction 
at Cambridge 19/, 57” 29"°1, leaves the difference of Meridums $ of 
Cambridge and Greenwich Ah, 44! 3h: 1. 
* In the computation in vol. i. page 55 of the Memoirs a the Academy, 
the longitude of the nonagesimal is too great by 30°, which renders the paral 
Jaxes there calculated incorrect. There is a similar mistake in vol. ii, p- 28 
