TOTAL SOLAE ECLIPSE OE JULY 18, 1860. 349 
Tables, as derived fi-om the Special Circular issued by the Superintendent of the Nautical 
Almanac. 
For the totality the apparent positions were calculated for 3 h. 0 m. and 3 h. 5 ni. 
Greenwich mean time, with the following results : — 
Zenith distance of sun’s centre 40° 33'. 
Angle at sun between pole and zenith . . . 47° 59'. 
Moon’s semidiameter 16' 33"-0. 
Sun’s semidiameter 15' 44"‘8. 
Totality began at 3 h. 0 m. 37'4 s. at 101° 38' on the sun. 
Totality ended at 3 h. 4 m. 1’6 s. at 312° 56' „ 
Direction of motion from 297° 17' to 117° 17' „ 
Relative motion during totality 92"-8. 
Nearest approach of centres 13"-0. 
Duration 3 min. 2 4 "2 secs. 
For the first contact the apparent positions were calculated for 1 h. 40 m., 1 h. 50 m., 
and 2 h. 0 m. Greenwich mean time, with the following results : — 
Zenith distance of sun’s centre 28° 49'. 
Angle at sun between pole and zenith .... 35° 50'. 
Moon’s semidiameter 16' 34"’6. 
First contact at 1 h. 47 m. 56 ‘0 s. at 296° 54' on the sun. 
Rate of approach of centres per minute . . . 24"-87. 
For the last contact the apparent positions were calculated for 4 h. 0 m., 4 h. 10 m., 
and 4 h. 20 m. Greenwich mean time, with the following results : — 
Zenith distance of sun’s centre 52° 45'. 
Angle at sun between pole and zenith .... 51° 36'. 
Moon’s semidiameter 16' 30"’ 7. 
Last contact at 4h. 10 m. 15’2 s. at 117° 20' on the sun. 
Rate of retreat of centres per minute .... 29"’85. 
The formulae used in computing the moon’s parallax and apparent semidiameter were 
6=M. of zen. m= 
q COS (p' Sin/) 
cos S 
Q sin a' sin p 
n— - ■ 
sin y 
a' — a= — gj ^ ^ w^^sin 2 . m^sin 3 . 
sin 
w.siny— sin 2 . y— w^sinS.y— S 
tan y=tan <p'. 
cos « 
cos (fl — 2«' + «) 
R'=R. sin (y— S') . cosec (y— S). 
3 B 
MDCCCLXII. 
