180 KANSAS CITY REVIEW OF SCIENCE. 
Before seeking the processes by which wandering orbs became reduced to 
orderly revolution in solar systems, the laws of motion will be given. 
First law. A mass of matter in space will move eternally in a straight line 
with uniform velocity, unless gravity turns it aside. 
Second. If a mass in space be attracted by another mass, its deviation from 
a right line will be in the direction of the attracting body, and proportional to 
the mutual gravity of the two masses. 
Third. Gravity and reaction caused by motion are equal and opposite. 
Fourth. If a mass in space be attracted by two or more bodies simultane- 
ously, it will not move towards either, but towards a vacant point between them, 
called their centre of gravity, and the motion is resultant. 
Fifth. All cosmical motion is resultant, and all paths traversed are 
curvilinear. 
The fourth and fifth are results of the three basic laws, and in a close 
train of reasoning might not be termed laws, but results. Their action is uni- 
versal and through them orbits of planets are formed. If the primeval gas, had 
solidified into one rigid ball, nature would have suffered eternal death, no power 
being able to separate the atoms. If into two balls separated by space they would 
have fallen on a straight line to collision and nature would have expired. If into 
three spheres of exactly equal mass and distance, they would have crushed 
together destroying all potency of matter save gravity, and nature would have 
terminated. But if into three globes of unequal mass, or equal in mass and 
separated by unequal distances, then they would inevitably form a solar 
system in regular revolutions. And the same results would follow with any 
number of spheres greater than three, lying in space within the attraction of an 
adjacent sun. i 
CENTRE OF GRAvITY.—When two bodies are joined by a rigid bar, there is 
always a point between them where they would balance if placed on a fulcrum. 
In space these are removed; but an imaginary bar and fulcrum have the same 
property, and the point is the centre of gravity. This vacant place has the 
remarkable attribute, that it attracts the third body with the same force as it 
would if the masses of both spheres were combined there. Therefore, if two 
globes attract another, the latter cannot fall toward either, but will move at once 
toward their centre of gravity by the law of resultant motion. 
FORMATION OF HELIOCENTRIC SvSTEMS.—To begin a solar system of three 
members, a sun and two planets, the globe wandering in space and destined to 
become a sun, will be designated A, and the smaller spheres to be made planets, 
Band C. They form a triangle in space, and obeying the only force to which 
they are subject—gravity, begin draw nearer one another. Instead of moving 
precisely towards each other, however, each globe journeys towards the centre 
of gravity of the two others. C moves toward the weight centre between A and 
B; B falls towards the attracting point somewhere between A and C, while the 
great sphere A moves slowly in the direction of the gravitation centre between C. 
