BY J. J. DE FERRER. 359 



Observation in the City of Philadelphia. 



Formation of annulus. 18 46 11,5 Apparent time } 



Break of annulus. . . 18 50 28,5 . . C. Observed by Mr. Rittenhouse 



End of the eclipse. . 20 03 42 . . J 



» ' » h ' » bf» 



Apparent time of the observation. . 18 46 11,5 18 50 28,5 20 03 42 



Cs latitude bv the tables + 10",3 N. 00 47 37,5 00 47 25,5 44 01,9 



Parallax in latitude — 47 07,1 46 59,3 43 58,5 



Apparent latitude of the £ . N . 00 30,4 00 26,2 00 03,4 



Parallax in longitude 24 35,3 24 28,3 20 35,4 



Cs apparent semidianieter. . , 14 57,35 14 57,56 15 00,74 



Semidiamcterof the sun. - . . 16 00,42 16 00,42 16 00,42 



Dill- and sum of £ and 0's semidiameters. 1 03,07 1 02,86 31 01,16 

 With the corrections — 0",5 for the difference of semidiameters and — 4",4 for the sum 

 of seniidiameters, according to the residts of the observations at Cambridge, we have the 

 following results : — 



Coni. by the formation of the annulus. Mean time. 19 1 ' 44' 37"} 



By the breaking of the annulus . . . . 19 44 38 C 191i 44' 37" 3 6 



By the -end of the eclipse. 19 44 38 j 



Longitude of Philadelphia west from Paris. . . = 5 10 01, 4 



Observations at George Town, Maryland. 



b ' » 



Formation of annulus. 18 36 43 Apparent time} 



Break of annulus. . 18 39 57 . . > Observed by Andrew Ellicott. Esq 



By the end of the eclipse. 19 52 21 . . J 



h 1 u 



Conjunct, by the formation of annulus, mean time. 

 By the breaking of ditto. 

 By the end of the eclipse. 

 Longitude of George Town west from Paris. 



Note. I have subtracted 1' of time from the formation and the breaking of the annulus. 

 from the observations at Philadelphia, and added 1! of time to the formation of the annulus 

 at George Town, those errors having been discovered by the result of the observations. 



By the combination of the observations of the annular eclipse of the sun, April 3, 17S1, 

 lhave determined the corrections of the 

 Irradiation of Ihe Q's semidiameter =— 1",70 inflex. of <C's semidiameter =— 2",00 



Pa"e 298 r 1806 - Tot »l eclipse of the — 1,87 _ 1/93 



of this J 1"64. Annular eclipse of the Q — 2, 15 1 3$ 



Volume >1«U1- Occupation of* ltR© • -L 82 



vomme. t lr9U- p a39age f $ ove r tlie © — 1, 50 ..... 



Mean correction of the irradiation . . — 1, 80 . inflexion. . . 1, 75 



Recapitulation oj the results of longitudes of Philadelphia and Cam- 

 bridge IV. from Paris. 



Philadelphia. Cambridge. 



1769- Passage of Venus. , 5 10 03,7 4 54 0U,5 



1782. Passage of Mercury. . . 5 10 10 4 53 53,0 



1789. Passage of Mercury. . . 5 09 54 4 53 40 



17'J1. Q's annular eclipse. . . 5 10 01,4 4 53 58,5 

 1806. Solar eclipse, page 297- . 5 09 57,0 



Mean results. . . 5 10 01,2 4 53 53 



B b 



