this matter; for the reason that, whatever the cause, it operated not
only under, but south, and far south of the belt of precipitation. It
could not have been spots upon the sun, or other general cause, for then
it would have operated in New Mexico and California, and at the
north-western stations. It operated most intensely in Florida and the
South-Eastern States, which approach most nearly the volcanic areas of
South America and the West Indies. I believe it to have been occasioned by
volcanic action affecting the local magnetism of our intense area; but it
is a most important development, and should be thoroughly investigated. We
may find in it the key to the mysterious, but unquestionable, influence of
volcanic upon magnetic action; and I hope the distinguished
surgeon-general will cause the records of that month to be published "in
extenso."

In May and June, the trade became more concentrated, a perfectly developed
belt from the Rio Grande to the Lakes and British possessions, and
doubtless to the Atlantic, with every where a central focus of excessive
precipitation, gathering to itself in one vast wave the current that
should have been spread out over the whole country; and leaving every
where on its eastern and southern borders, down to the northern edge of
the inter-tropical belt of rains--(which extended up to lines drawn from
Baton Rouge to Charleston)--a _perfectly well developed_ and _defined
drought_. That drought will long be remembered. The following cuts show,
approximately, the location of the belt of precipitation and drought for
those months, and the table which follows will show their correctness.

The tables also show that this wave was occasionally a double, or divided
one--evinced by an intervening _partial_ precipitation. Tables IV., V.,
and VI., also show the commencement of the drought at the several
stations, as the wave moved to the west and north.

[Illustration: MAY.]

[Illustration]

TABLE VI.

JAN. FEBR. MAR. APR. MAY. JUNE. JULY. AUG. SEPT.
Fort Brown 0.45 1.50 1.15 0.05 4.10 7.65 4.25 5.00 11.31
Mean 1.61 2.25 1.20 0.56 2.21 4.55 1.95 2.76 6.73
Ringgold Barracks 0.70 1.69 0.22 0.00 2.83 10.98 4.06 1.58 3.02
Mean 1.24 1.18 0.72 1.08 2.09 3.47 3.18 1.50 3.22
Fort Merrill 0.11 1.99 0.05 1.16 7.66 4.70 5.44 3.13 5.01
Mean 0.23 2.09 0