380 Eevievj of Recent Geological Literature 
the most dazzlingly white, and the hottest. 3rd. If the sun had no 
external source of suj^ply of heat it would only he a question of time, 
and according to the best authorities a brief time at that, when the 
sun would be so far cooled down as to render the earth uninhabitable.* 
4th. The heat of the photosphere is so intense that chemical affinity is 
suspended, or abrogated, and the elements exist, all or nearly all, in 
the condition of gases, descending gently or floating in flocculent 
clouds of fire throughout the whole expanded atmosphere. 
In the light of these considerations, and by resort to the theory of 
light and heat which has been presented, the reader will quickly ap- 
prehend the use the author makes of the sun's spots not only to fur- 
ther elucidate his general theory, but to offer a new theory of their 
cause. 
The spots are cooled places on the sjin's photosphere. They are shadows, 
not of intercepted light, but of force-waves of the surrounding ether. 
They are "spells of weather" produced by similar causes as those of 
our atmosphere, viz. : variations of temperature in the enveloping 
atmosphere and clouds. 
It is incumbent on the author to furnish a plausible cause for such 
sliadows. He attributes them to Jupiter and the other planets. They 
intercept waves of mechanical force, or gravitation, carried by the 
undulations of the ether, and produce about the sun's equator a 
deficiency of energy in the photosphere. The sun's poles are hotter 
than his equator. 
In order to show that this suggestion is plausible some arguments 
are drawn from the unequal rotation of the spots across the sun's 
disc. That is, since the equator is cooler than the poles there must be 
a circulation in the sun's envelop similar to that of the earth's atmos- 
phere. Consequently those spots that appear at the greatest distance 
from the equator will show the "lagging behind" or the accelerated 
rate which the circulating tides and the winds of the earth show in 
making their regular courses from north to south, or vice z^ersa. But 
the fact that the spots are most numerous in two equatorial belts is 
handled so convincingly that it proves one of the strongest arguments 
in favor of the author's theory. The average inclination of the planets' 
orbits to the axis of the sun is less than thirty degrees. They there- 
fore concentrate their force of interception upon the equatorial regions, 
and this appears in two beUs of maximum frequency of spots, each 
fading out toward the equator, because at the equator the downpour 
of the cooled elements toward the nucleus causes the spots to disap- 
pear in their deeper seated journey back to the poles, and the more 
heated superficial strata rush in to take their place. The sun's equa- 
torial region is therefore, like that of the earth, one of greater atmos- 
pheric commotion, with occasionally "cyclonic" spots. 
The periodicity of the maxima of sun-spots is made to throw further 
evidence on the interception theory of their cause. It is found that 
^Newcoml)'s "Popular Astronomy." p. 518. 
