184 Review of Recent Geological Literature. 
objections : If any chemical changes at all take place in the sun's at- 
mosphere (possibly in the outer atmosphere) they result in more con- 
densed substances which on settling toward the sun are again decom- 
posed by the increased temperature, and the heat generated by the 
chemical combination is re-absorbed by the decomposition, and there 
is no resultant general increment of heat in the sun. Again, as to the 
heat generated by the sun's impact on a supposed universal atmos- 
phere, and its being the supply for the heat it radiates into space. Mr. 
Kedzle introduces,' after his manner, a quaint but sufficiently conclusive 
illustration, which, to give the reader an idea of the familiar and com- 
monplace reasoning that characterizes the book, it will be well to quote 
entire. "Imagine a concave mirror large enough to enclose the sun 
and his proper atmosphere, — for according to Mr. Williams the sun has 
an atmosphere of its own. Suppose this mirror to reflect back to the 
sun every ray of heat radiated by him as well as exclude every ray ap- 
proaching him from without, the sun's heat would of course remain 
absolutely unchanged. We ignore, for the present, any supposed sup- 
ply of heat by contraction of the sun. Mr. Williams ignores this source 
entirely. Now open the windows of this hollow sphere, both behind and 
before the advancing sun. This hypothetical universal atmosphere 
would of course rush in, and an equal quantity of the sun's atmosphere 
proper would rush out of the windows in the rear. Would this process 
heat or cool the sun ? That would depend wholly on whether the atmos- 
phere of space is hotter or colder than that of the sun. It requires no 
prophet to predict the result. It is believed by all that the atmosphere 
of space, if such exists, is intensely cold. Remove the imaginary hol- 
low sphere entirely, and give the winds full sweep on all sides, and 
the blazing atmosphere of the sun would simply be swept away and its 
place supplied by one colder than the blasts that play around the north 
pole in midwinter." Other equally strong points are made against this 
theory. 
Sixth. Dr. C. W. Sieman's neiv theory supposes the exhaustless 
energy of the sun to be sustained by a grand endless circulation. This 
consists of the emanation of certain compounds, mostly in a gaseous 
condition, from the equatorial regions of the sun into space. These 
reach even beyond the orbit of the earth. In the interstellar spaces 
these compounds are rarifiied and decomposed, returning to their ele- 
mentary condition. But they are, in this condition, precipitated again 
upon the polar regions of the sun, where, by recombustion, they give 
out the heat which supplies the sun in perpetuity. Flowing toward 
the equator they are again projected from the sun, in a ceaseless 
round. Mr. Kedzie accords this theory the merit of not violating the 
theory of the conservation of force. It does not require, as nearly all 
others do, the radiation and loss in space of the vast energy of the sun. 
Still he notes the following objections : (a) The existence of an inter- 
stellar resisting medium, or universal atmosphere, other than ether, 
is not yet proved, to the satisfaction of scientists, (b) The dissociation 
