SATURN. 215 



working out at 1,014,322,100 miles, whereas if Earth and Saturn 

 were in a direct line with the sun's centre, there would have been 

 the greater distance of 61,804 miles). While Saturn is now actually 

 elevated above the plane of the Earth's orbit, the plane of his rings 

 is much lower because of their great tilt, and so we are at present 

 looking upon the northern side of the ring system, which will con- 

 tinue until 1899, when they will extend beyond the two poles of 

 the ball, and be at their widest opening, and the planet will then 

 be 20° in Saggitarius ; at present he is in the sign of Libra. 



The diameter of the ball of Saturn, according to Professor E. 

 E. Barnard's latest micrometrical measurements, is 76,470 miles 

 equatorial and polar 69,770, so that the polar compression would 

 seem to be r — 11*42; therefore the volume of Saturn follows at 

 822 times that of our Earth. 



Saturn requires nearly 29^ of our years to complete his annual 

 journey of almost 5,559f millions of miles around the sun, at an 

 average speed of 5*95 miles per second; so that while he sways 

 once around his mighty orbit, our comparatively small globe, that 

 is flying through space at a rate of over eighteen miles per second, 

 is completing its thirtieth revolution, or year ; but a day with us 

 equals 2^ of Saturn's days 1 This latter difference arises from the 

 rapid axial rotation of the great planet, which turns completely 

 around once in every loh. 14m. 30s., while we rotate once in 

 23h. 56m. 4'o9S. The equatorial circumference of Saturn is no 

 less than 241,040 miles, as he is seen from limb to limb, or over 

 ten times that of the solid Earth ; so that while matter is carried 

 around at our equator at the rate of about 1,000 miles per hour, 

 matter at Saturn's equator will be whirled around 23^ times faster, 

 or 23,560 miles an hour. This surface velocity at Saturn's equator 

 is strong proof in favour of his being in a highly heated condition, 

 as suggested also by his low mean density, the lowest known in 

 the Solar system. His seasons, for such there must be, judging 

 from his axial pose of 26° 43' 23" to the plane of his orbit, we 

 cannot possibly picture what they are like. Their lengths, we can 

 say, must each cover a period of over seven of our years, and that 

 from the Saturnian autumnal to vernal equinox there must be an 

 interval of nearly fifteen of our years. 



The disc as seen is not necessarily the ball that forms the solid, 



