Researches on Solar Physics. ‘399 
importance to communicate at once, reserving a more elaborate 
and accurate investigation to a future occasion. — 
We think it will very likely be found that, at those periods 
when the planets Jupiter and Venus cross the solar equator, 
there will be a tendency of the spotted area to approach the 
equator, and at those periods when the heliographical latitude 
of these planets is greatest there will be a tendency for spots to 
spread out from the solar equator. 
Reserving the action of Jupiter to a more complete investiga- 
tion, we have derived the following result regarding the action 
tor when the heliographical latitude of Venus is 0°, and are most 
distant from the solar equator when this planet attains its greatest 
heliographical latitude. 
51. Concluding remarks.—The following question may occur 
to our readers, How is it possible that a planet so far from the 
sun as Venus or Jupiter can cause mechanical changes so vast 
as those which sun-spots exhibit? We would reply in the fol- 
lowing terms to this objection 
The molecular state of the sun, just as that of the cannon or 
of fulminating powder, may be extremely sensitive to impres- 
sions from without; indeed we have independent grounds for 
Supposing that such is the case. We may infer from certain ex- 
Pecunia, especially those of Cagniard de Latour, that at a very 
igh temperature and under a very great pressure the latent 
heat of vaporization is very small, so that a comparatively small 
* It is, however, a possible inquiry whether these phenomena do not imply a 
certain loss of motion in the influencing planets. 
