234 Original Articles. [| April, 
equator. Let it be further assumed (still in analogy with assumptions 
not regarded as unreasonable in the meteoriferous ring), that the dis- 
tribution of the circulating matter in it is not uniform—that 1é has a 
maximum and minimum of density at nearly, but not quite, opposite 
points, and no great regularity of gradation between them. It is very 
conceivable that the matter of such a ring introducing itself with 
planetary velocity into the upper and rarer regions of the sun’s atmo- 
sphere, at an incidence oblique to its regular and uniform equatorial drift, 
might create such disturbances as, either acting directly on the photo- 
sphere, or intermediately through a series of vortices or irregular move- 
ments propagated through the general atmosphere, should break its 
continuity and give rise to spots, conforming in respect of their 
abundance and magnitude to the required law of periodic recurrence. 
If the change of density from the maximum to the minimum were 
gradual, but from the minimum to the maximum more abrupt, so as to 
allow the disturbances to subside gradually, and recommence ab- 
ruptly—the fresh and violent impulse would be delivered first of all 
on a region remote from the equator (by reason of the obliquity of the 
ring), and would give rise to a recommencement of the spots in com- 
paratively high latitudes. 
If the section of such a ring as we have supposed at its aphelion 
were nil, the period of 11:11 years would be strictly carried out; the 
maxima and minima would succeed each other with perfect regularity, 
and the paucity and abundance of the spots in the several phases of the 
same period would follow a fixed ratio. But if not, the several parts of the 
ring would not revolve in precisely equal times—the period of 11-11 years 
would be that of some dominant medial line, or common axis of all the 
sections in which a considerable majority of its matter was contained— 
and the want of perfect coincidence of the other revolutions would 
more or less confuse, without obliterating the law of periodicity, which, 
supposing the difference to be comprised within narrow limits, might 
still stand out very prominently. Nowit might happen that there were 
two such medial lines, or more copiously stocked ellipses, each having 
a& maximum and minimum of density, and that their difference of 
periodic times should be such as to bring round a conjunction of their 
maxima in 56 or any other considerable number of years: and thus 
would arise a phenomenon the exact parallel of Dr. Wolf’s long period 
and his series of greater and lesser maxima. 
Tt will, of course, be objected that the resistance of the solar atmo- 
sphere would retard and ultimately destroy such a ring. But we must 
bear in mind the extreme tenuity of this atmosphere in its upper regions, 
and that our ring need not consist of mere vaporous matter. It might 
be a collection of exceedingly small planetules, which, however thinly 
dispersed over an immense space in aphelio and in the remoter parts of 
their orbits, would become crowded together in perihelio, acting as it 
were by a joint rush to produce the disturbance, but each individually 
suffering a resistance infinitesimal compared to its inertia. The comet 
of 1843 passed within the region we are contemplating, and its motion 
was not destroyed. 
The orbits of our planetules would in fact be, par ewcellence, 
