26 D. Trowbridge on the: Nebular Hypothesis. 
ing to circumstances. The outer rings would approximate to 
the first case, and the inner ones, to the second case; whil 
traction, to have different angular velocities ; Just as we have 
aration of the rings from the 
the primitive spheroid, their den 
that the velocity of the outer p 
imately by Kepler’s third law. 
able that the velocity of the inn 
outer parts. When the rin 
will in a great measure re 
complete rings, 
such planets will, at first, be performed ina 
to that of their motions around the central 
quence of the 
planetary rings abandoned byt 
29 
Peirce in G ronom: ¢, ii, 17-18. 
_ ® Observation seems to show that the Rings of Saturn are gradually approaching 
the body of the planet; but it by no means follows that they will ever come 
contact with the body of the planet. They have existed too long for us to suppose 
‘obability th: th Rings are to be precipitated upon the body of 
ge before our eyes, as it were. — 
itt See Annual of Scientific Discovery for 1852, p. 377. 
_ “Professor Kirkwood has pointed this out in his article in this Journal, [2], 
iii, 2-4: and | show that in certain case: rota- 
volume xxxvii, page 51, wh re Prof. 
same thing that we have arrived at in the text. 
