S4 KANSAS CITY REVIEW OF SCIENCE. 
may be regarded as established as fully as any speculative principle can be with- 
out becoming a fact or truth. 
Broadly stated, it is as follows : At one time all the members of the solar 
system were united in a single mass of blazing matter rotating about an axis near- 
ly coincident with the present axis of the Sun, and, by reason of the expansion 
due to excessive heat and the operation of centrifugal force, extending its lenticu- 
lar form far beyond the orbit of the outermost planet. By the process of cooHng, 
the action of centrifugal force, and the law of gravitation, the outer portions of 
this chaotic mass became detached from the main body and broken into small 
fragments, thus forming an immense annulus, each member of which revolved 
around the original mass, just as planets revolve around the Sun. Some of these 
fragments afterward became united by gravity and collision and the result was a 
larger mass continually increasing in size by absorbing its smaller neighbors just 
as the earth now absorbs meteoric matter, and still revolving around the original 
mass. By a repetition of this process at the different stages at which the centrif- 
ugal force, increasing with the increase of velocity due to the gravitation of the 
denser portions of the nebula toward its center, would balance gravity, the solar 
system as it now stands was formed, the Sun being the remnant of the original 
chaotic mass — all of which, judging from the behavior of matter under somewhat 
analogous conditions here on the earth, is in perfect conformity with physical 
law. 
Now unless we are prepared to combat the Nebular Theory we must admit 
that at certain epochs of its development the solar system was swarming with 
millions of small meteor-planets; that these have either all been since consoli- 
dated into the masses of the few larger planets or that there are some still re- 
maining, which, owing to their peculiar situations and motions, have escaped the 
clutches of their more powerful neighbors. 
The latter is by far the most reasonable, since it is difficult to conceive how 
all these small bodies moving as they do, could be absorbed by the larger in any 
finite time — and here it may be well to remark that it must be owing to the great 
distance between the orbits of Mars and Jupiter that the asteroids have not been 
appropriated by one or the other of those planets, and to the peculiar positions 
of their orbits that they have not been united in a single mass. The Nebular 
Hypothesis therefore permits us to assume, if it does not force us to believe, that 
not only are there many small isolated bodies revolving around the Sun as planets, 
but also that these bodies revolve in groups and even in continuous rings. 
Suppose that one of these small bodies should revolve in an orbit of exactly 
the same period as the earth. It is evident that so long as this was kept up the 
small body would preserve its identity, but should its period be changed in even the 
smallest degree, it would become a question of time when the earth would trans- 
form it into either a meteor or satellite. Let S. represent the Sun ; A. N. E. the 
orbit of the earth; A. N. M. the orbit of meteor planets; A. S. T. the line of in- 
tersection of the planes of the two orbits. Suppose a group of meteors to re- 
volve in A. N. M. with a period differing from the period of the earth. It is 
