1876.] 
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NOTICES OF BOOKS. 
The Origin of the Stars, and the Causes of their Motions and 
their Light. By Jacob Ennis. London: Trlibner and Co. 
New York : D. Appleton and Co. 
This book offers us a solution of some most difficult ques- 
tions. In his prefatory address the author diredls the atten- 
tion of astronomers to the following discoveries contained in his 
book : — He pronounces that gravitation is not merely the force 
which now holds the stars in their orbits, but which first set 
them in motion. He adds “ a catalogue of some of the recent 
discoveries which have sprung from our knowledge of the pro- 
jectile or centrifugal force.” This catalogue we venture to 
quote : — 
“ 1. The demonstration that the nebular theory of the origin 
of the universe is true : not the nebular theory of Laplace, but 
a theory far more comprehensive, and now first unfolded in this 
volume. 
“ 2. The discovery that both the centripetal and centrifugal 
forces in astronomy, although antagonistic, are in all cases due 
to the same origin, the force of gravity. 
“ 3. The discovery that gravity was the force which originally 
gave all their peculiar arrangements to all stellar systems, 
whether they be sidereal, solar, or planetary. It determined not 
only the velocities of the celestial bodies, but the direction of 
their movements, the size and positions of their orbits, and even 
their separate existences. 
“ 4. The reason why the four outer planets have all the satel- 
lites but one, and why of the four inner planets the Earth alone 
has a satellite. 
“ 5. Why there is no planet interior to Mercury. 
“ 6. Why the distance of the innermost planet, Mercury, is 
35.000. 000 miles from the sun, whilst the distance of the inner- 
most satellites is only about a quarter of a million miles from 
their primary planets. 
“ 7. Why the interplanetary spaces are so large, from 
32.000. 000 miles to 1,000,000,000 miles, while the intersatellitic 
spaces are only from 134,000 to 1,300,000 miles. 
“ 8. Why Saturn has so many more satellites and rings than 
Jupiter. 
“ 9. Why the interplanetary spaces become less as we ap- 
proach the sun, and why the last interplanetary space is an 
exception. 
“ 10. Why the same fadls and the same exceptions occur in 
the systems of Saturn and Uranus. 
