TWENTY-NINTH ANNUAL MEETING. 47 
Now, putting these two facts together, we may see, first, that if the moons of 
Uranus and Neptune were formed in harmony with the nebular hypothesis, they 
acquired their anomalous backward movement of revolution around their pri- 
maries through the proximity of one or more large comets that at the time of the 
change were passing through our system; or, second, the comets moving along 
orbits that were at certain points close to the orbits of the planets were so com- 
pletely captured as to have their cometary orbits destroyed, and they themselves 
transformed into moons, ever after to exist as moons or comet satellites of Uranus 
and Neptune. In this manner, comets transformed into moons or comet satellites 
would, by the superior attraction of the planets and their proximity, necessarily 
change the character of their orbits from that of the parabola to that of the 
ellipse. 
Farther, instead of revolving around both the Sun and their captors, as many 
of them now do, with the Sun in the principal focus, the comet-satellites would 
move as do the moons of Jupiter and Saturn, merely attendants upon their pri- 
maries as the latter revolve about the Sun. It is pertinent to inquire how a comet, 
with a tail 50 or 100 millions of miles long, can be changed into a moon-like body. 
The nebular hypothesis tells how planets and satellites are formed out of rotating 
masses of nebulous matter; how a portion of that matter is thrown off, of which 
a controlling central mass has power sufficient to attract to itself all the other 
particles belonging to it; and how there results from this operation a compact 
body like that of a moon. A cdmet has a nucleus from which extends a tail 
longer or shorter, as the case may be. Near toand under the tremendous attrac- 
tion of a giant planet, the motion of the comet in its orbit will be set up; an 
attraction will begin to be exerted upon that part of the tail nearest the nucleus, 
and a drift of cometary matter started at once toward the now more powerful 
center of attraction located in the nucleus; and this attracting force will! increase 
as long as the cometary matter of the tail continues to flow toward the head. 
Portions of the tail may be lost in space, to be ever after invisible, or to become 
a meteoric swarm. 
When our solar system was still in a nebulous condition, and rings of matter 
were beginning to be thrown off, in all probability nebulous patches or wisps 
became disengaged, some from the original nebulous field, and afterward some 
from the planetary masses; and these in time began to exert a powerful influence 
upon other portions destined to become satellites. The disturbing effects of the 
nebulous wisps exerted in every direction were sufficient to produce the back- 
ward movements of some of the moons. 
This theory of necessity implies that the comets or nebulous patches may 
have been in that early formative state vastly more numerous than now, and of 
greater mass and density than the satellites themselves, or rather the masses of 
which the satellites were formed. Otherwise, such wonderful results could not 
have been produced. It may be supposed, too, that the nebulous patches or 
wisps referred to were assisted by immense cometary bodies that have not yet 
lost much ‘of their matter by disintegration. The interplanetary spaces may 
have been full of nebulous wisps and comets, each working out its own destiny 
and influencing the destiny of its neighbors, at the time of the world-making of 
our system. An examination of the nebule in Canes Venatici, in Virgo, in 
Orion, and of the wisps around the Pleiades, will show almost beyond a doubt how 
such wisp-like and cometary forms do their work. The well-known law of a 
moving bedy—that it will continue to move in the direction given it by the 
original impulse just so long as it remains solely under the control of that im- 
pulse —is universally true; but when acted upon by some other force not in the 
