helion, the density of the ether externally is changing in the
subduplicate ratio of these distances and consequently at these times
there will be the greatest disturbance of the electric equilibrium. How
far our views of the internal structure of our globe, (considered along
a diameter as a solid crust, then a fused mass separated from the lower
ocean by another solid crust, and separated from a similar arrangement
on the opposite side by an interposed mass of water, perhaps also
possessing a solid nucleus,) may affect this question, is difficult to
say; but that the agent is electric, appears highly probable; and very
recently it has been discovered, by M. Ratio Menton, that a piece of
iron, suspended by attraction to a magnet, will fall on the approach of
an earthquake; thus indicating that the power of the magnet is
temporarily weakened by the action of some disturbing force.

FOOTNOTES:

[22] Hum. Cosmos, art Aerolites.

[23] We shall in all cases use this abbreviation for the extremely
awkward word zodiacal.

[24] It is here assumed, that all the vortices are at their apogee at
the same time, and, consequently, they lie in different longitudes, but
the central being between, its position is taken for the average
position of the three.

[25] It is far from improbable that the effect produced in one zone of
climate, may be reversed in another, from the nature of the cause.

[26] That the 11th, 12th, and 13th of May should recede 2d in
temperature as determined by Maedler from observations of 86 years, at a
time when the power of the sun so rapidly augments, is strongly
confirmatory of the theory. See _Cosmos_, p. 121.

[27] Plucker first discovered that a plate of tourmaline suspended with
its axis vertical, set axial.

[28] Silliman's Journal for March and April, 1853.

[29] Humboldt, _Cosmos_ p. 193, London ed.

[30] See Silliman's Journal for September, 1853.

[31] See Silliman's Journal for September, 1853.

[32] This was the central vortex ascending.

[33] Reid's Law of Storms, p. 350.

[34] Humboldt, _Cosmos_, p. 203.

SECTION FOURTH.

THE SOLAR SPOTS.

We have yet many phenomena to investigate by the aid of the theory, and
we will develop them in that order which will best exhibit their mutual
dependence. The solar spots have long troubled astronomers, and to this
day no satisfactory solution of the question has been proposed; but we
shall not examine theories. It is sufficient