of the Atmospheres of the Earth and the Sun. 191 



would be at the equator ; were it acted upon only by the 

 forces that act on the earth's atmosphere, the barometric 

 maxima would be on the polar side of Lat. 20° 19^ 20" (in 

 the earth's atmosphere they are about 28°) ; but they are 

 intermediate between the two, about Lat. 15°, I infer from 

 this, in addition to other facts, that the sun's atmosphere 

 is acted on by both sets of forces, and that the observations 

 tabulated by Mr Carrington show a resultant effect from the 

 two. 



The solar spots are most numerous in the zones north and 

 south of the equator, and never appear near the poles ; they 

 are seldom seen on the equator itself. It is very probable 

 tliat they are cyclones, and we know that cyclones cannot 

 be formed on a planet's equator, though they may drift on 

 to it. But this will not account for their absence near the 

 poles ; on the contrary, were all other things equal (which, 

 however, is not the case in the earth's atmosphere), the 

 tendency to the formation of cyclones would be greatest at 

 the poles ; as it is, there the rotation of any planet is most 

 rapid in relation to an axis drawn perpendicular to its sur- 

 face. The production of spots in the lower latitudes is 

 probably due to the greater number of meteors that fall in 

 there, causing greater mechanical disturbance, as well as by 

 the greater heat of those latitudes, which must give rise to a 

 more energetic vertical circulation of the atmosphere. Such 

 vertical circulation is certainly proved to exist by the pheno- 

 mena of the sun's atmosphere, especially by the " rose- 

 coloured protuberances" seen during solar eclipses, which 

 are in all probability cumulus clouds. 



The following short resume of the most novel and im- 

 portant points of this paper was read as a communication 

 from me in Section A of the British Association at New- 

 castle, 1863. 



" Seech i of Eome has ascertained that the sun's equator 

 is sensibly hotter than his poles. That this should be the 

 case follows from the meteoric theory of solar heat. The 

 asteroids which revolve round the sun and fall into its at- 

 mosphere as meteors, probably occupy, like the entire solar 

 system, a lenticular space having its greatest diameter nearly 

 coincident with the sun's equator, emd if so, a greater num~ 



