EAR 



Mean distance of earth from sun 93,321,724 English tnilaa. 

 Aphelion distance = 94,839,528 miles. 

 Perihelion do. = 91, 753,920 miles. 

 Eccentricity .01G8, ax. maj. being 1. 



Time of sidereal revolution 3fi5rf. 6/i. 9m. 11,5*. 



Do. tropical 3(>5d. 5A. 48m. 51 fit ; being less than in th 



time of Hipparchus by 11,?." 



Mean velocity of earth in its orbit 59'. 10,7" each day. 



Velocity in its perihelion lo. 1'. 9,9." 



Do. in aphelion 57.' 10,7" 



Revolution about the line of the apsides, or anomalistic year, 3654. 6ft. 

 14m. 2*. 



Tropical revolution of apsides performed in 20,931 years. 



Inclination of axis to Ecliptic 23. 7'. 57"., which decreases at the rate 

 of 52,1". in a century, but this decrease can never exceed 2. 42'. 



Nutation of axis = 19,3". 



Precession of the equinoxes 50,1" annually, or 1. 23'. 30". in a century, 

 A complete revolution performed in 25868 years. 



Length of sidereal day 237z. 5fiw. 4,1*. j and has not varied the hundredth 

 part of a second since the time of Hipparchus. 



The interval between the vernal and autumnal equinoxes is (on ac- 

 count of the excentridty of ths earth's orbit and ifcs unequal velocity 

 therein) nearly eight days longer than the interval between the autum- 

 nal and vernal equinoxes. These intervals are at present nearly aa fol- 

 lows : 



d. h. .in. 



d, h. m. 

 185. 35. 20, 



From spring equinox to snmm*>rl 09 o] 45 ^ 



solstice J "" ' / 



From summer solstice to autuni-7 TO bk A 



f SO. lo, <>Q, t 



nal equinox -> j 



From autumn aquinox to winter! gg j^ 47 "\ 



solstice > ' / 



From winter solstice to spring") go 3 42 V 



equinox ,., ,....,-^ 



equinox . 



Difference 7. 16. 51. 



E3 



