BY J. J. DE FERRER. 357 



Annular eclipse, April 3d, 1791. 



Elements from the Astronomical tables published at Paris, in the 

 year 1806, by order of the Commissioners of longitude. 



b / » 



1791. April 3. Astronomical mean time at Paris. . . 54 40 



0's longitude from the apparent equinox. . . . 13°4l 58 



0's right ascension id time. . . . . . O 1 " 50 25 



Q's se'midiamcter. ....... 0°1(J 00,42 



Equation of time. . . • • • . -j- 3 17,53 



Q's horary motion in longitude. 2 27,59 



Horary motion in Q's right ascension in time 9,10 



Horary diminution of the equation of time. ..... 0,90 



(C's longitude from the apparent equinox. ..... 13°41 37,8 



C's north polar distance. 89 15 05,9 



C's equatorial horizontal parallax 54 36,1 



Q's equatorial horizontal parallax. ...... 8,6 



Apparent obliquity of the ecliptic . 23 27 53,0 



Moon's horary motion in longitude. 30 12,97 



Moon's horary motion in latitude S. ...... 2 46,72 



Horary diminution of iC's horizontal parallax. . . . 00,75 



Equation of 2d order of the Cs horary motion in longitude. . — 00,40 



ditto ditto ditto in latitude. . -f- 011,11 



Proportion of the equatorial horiz. parol, and the (C's horiz. diameter. 60 : 32 45,1 



Proportion of the equatorial and polar diameters of the earth = 330 : 329 



Observations made by the Rev. Nevil Maskelyne, at Greenwich, 



Oh 18' 40" Apparent time, beginning of the eclipse. 

 1 44 51 Least distance of the limbs. 12' 52" 



3 06 47 End of the eclipse. 



By the mean result of 8 observations, 0's diameter was . 31' 57'',0 



bin bin h / » 



Apparent time of the observations at Greenwich. 18 40 1 44 51 3 06 47 



Difference of C and ©equatorial parallaxes. 54 27,8 54 26,7 54 25,8 



Parallax in longitude —18 02,4 —29 07,0 —38 05,0 



Parallax in latitude. . . . . —34 47,1 —30 18,6 —27 10,4 



K's apparent semidiameter— 2'' inflexion. . 15 02,2 15 01,0 14 59,0 



0's semidiameter — 2" irradiation. ... 15 58,4 15 58,4 15 58,4 



Conjunction at Greenwich by the combination of the beginning and 



the end of the eclipse. . . apparent time. . . h 45' 16",S 



Correction of latitude by the tables. ... . • . -j- 13 



By the least distance of the limbs. . . . . -f- 13,6 



Supposing the irradiation of the sun's semidiameter . = 1",8 



The ©'s diameter was observed . . • 31' 57", 



By the tables. . . . . 32 00, 8 



32' 00" 8 V 12' 52" 



The corrected distance of the limbs = — — _ — — = 12 53",5 



oJ,5r 

 The double irradiation. . . . . . — 3, 6 



True distance of the limbs. . . . . . 12 49, 9 



And the correction of moon's latitude corrected from the effect of refraction =-+-' - 

 Conjunction at Paris =(0'' 45' 16",5-(-9' 21") =00'' 54' 37",5 



Observations at tfie National Observatory of Paris. 



Beginning of the eclipse, apparent time. . . • ■= 1 ' 36' 55'',4 

 End of the eclipse. 3 20 52 



