1874.] The Saturnian System. II 
family. One would be led to suspect that Hyperion is but 
one member of a zone of small satellites travelling between 
the paths of Titan and Japetus. It appears to me to bea 
confirmation of this view that the path of Hyperion does 
not correspond with the general arrangement of the scheme, 
but bears somewhat the same sort of relation to it that we 
should recognise in the orbit of one of the innermost of the 
asteroids if taken, instead of the zone of asteroids, to 
represent the orbit intermediate to the paths of Mars and 
Jupiter. 
As we proceed onwards towards Saturn we are struck 
with the comparatively close order of the orbits of the inner 
satellites. The distance separating the orbit of the inner- 
most from that of the fifth Rhea is less than half the 
distance separating the orbit of Rhea from that of Titan 
the sixth. The following table of distances has been 
calculated on the assumption that the sun’s equatorial 
horizontal parallax is 8°g16” :— 
N Distance in mean Distance Difference. 
ane: radii of Saturn. in miles. in miles. 
Ee Mimas 3°3607 1152333 2,66 
II. Euceladus  4°3125 148,000 : ie 3 
TT. Tethys 5°3396 183,250 ee a 
IV. Dione 6°8395 ZANT i ie 
Ni Rhea 9°5528 527:540 ee 
VI. ‘Titan 22°1450 759,999 Ta0"Ro 
VII. Hyperion 26°7834 919,170 
VIII. Japetus 6 4°3590 2,208,720 7789550 
Passing yet farther inwards, after crossing the orbit of 
Mimas, we come upon the ring-system. The outer edge of 
the outer ring lies at a distance of 83,460 miles from the 
centre of Saturn, or 31,875 miles from the orbit of the 
innermost satellite. It is noteworthy how uniformly the 
distances from this ring outwards to orbit after orbit of the 
four inner satellites proceed. This uniformity somewhat 
resembles what we notice in the case of the four terrestrial 
planets, since we see that the distance from the sun to 
Mercury, thence to Venus, and thence to the earth, are very 
nearly equal (being roughly 35, 32, and 35 millions of miles), 
while the distance to Mars, though greater, belongs to the 
same order of distances. ‘The remaining elements, which 
are convenient for reference in treating of the ring-system, 
are the following :— 
