Mr. Bowditch on the solar eclipse, Oct. 27,1780... 285 
The greatest obscuration at Long Island was at 0/, 31’ 18” appar- 
ent time, when an arch of 42° or 43° of the sun’s disc was visible. 
Supposing this arch to be 42° 30’, the sun’s semidiameter 16’ 05’"16, 
the moon’s augmented semidiameter 16’ 29”-97, it is easy to find that 
the apparent distance of the centres of the sun and moon was 26°57, 
observing that the diameter, passing through those centres, bisects 
perpendicularly the chord connecting the extreme visible points of the 
sun’s limb. At this time the ()—©) parallax in longitude was 11’ 
20’0; in latitude 49’ 13’*6, the apparent difference of longitudes of the 
centres of the sun and moon, found from the tables correcting the 
moon’s longitude for the error — 5"*7 was 21°52, From the appar- 
ent distance of the centres and their apparent difference of longitude, 
it is easy to find the apparent difference of latitude 15"°6, which ad- 
ded to the parallax in latitude, gives the latitude by this observation 
42/292; this subtracted from the tabular latitude 49’ 44’"3 gives the 
error in latitude by this observation — 15"-2. ” 
At the same place at 0A. 28’ 48” the lucid part of the sun when 
least, measured by a micrometer, was 24”.7. This added to the >’s 
augmented semidiameter 16’ 29°99 and the ©’s semidiameter sub- 
tracted from the sum, gives the apparent distance of the centres of the 
sun and moon 4953. The ()—Q) par. in long. was 11' 46"0, and 
the apparent difference of longitude (found as above) was $7"*1, con- 
sequently the apparent difference of latitude 32”°8, which added to the 
parallax in latitude 49’ 04-9, gives the latitude by observation 49 
37"°7, which subtracted from the tabular latitude 49’ 52’°6 leaves the 
error of the tables in latitude by this observation — 14"9. 
At Beverly at 0/. 21’ apparent time the sun was eclipsed 114 24, 
which makes the lucid part 96"52. The sun’s semidiameter was 
then 16’ 05’-16, the moon’s augmented semidiameter 16’ 30! “Ai, the 
(20) paral. in longitude was 12’ 43-5, paral. in latitude 47’ 440, 
” 
