onvincing.

I have assumed, pp. 187, 351, that the transits were greater in some
seasons than others; that the drought of 1854 was owing to an extreme
northern transit, or to an extension west of the concentrated
counter-trade, or both, leaving us less supplied with moisture than
usual.

In point of fact, it appears from these observations that it resulted from
_both_ causes, operating _connectedly_; and the annals of Science rarely
furnish a more striking instance of analogical inference proved true by
subsequent investigation.

Commencing then with the commencement of the northern transit about the
1st of February, we are enabled to trace the then location of our
concentrated trade, and its subsequent progress to the north till August,
and its influence upon temperature and precipitation. And we can also
trace the situation during the same period, of the intervening drought,
and the inter-tropical belt of rains, and the extension of the latter
north over Florida and the cotton-planting States.

On the 1st of February, 1854, our counter-trade was somewhat more
concentrated on its extreme winter curve, over the Southern States, than
usual. Its line of excess reached up from Fort Brooke, on the peninsula of
Florida, to the northwest, a little east of Pensacola on the gulf, cutting
Mount Vernon Arsenal north of Pensacola, and extending thence
north-westwardly on to Eastern Louisiana, and curving thence and passing
N. E. or E. N. E., to the Atlantic, about the waters of the Chesapeake
Bay. It thinned out to the west over New Orleans and Baton Rouge,
supplying them moderately, but did not extend to the forts of Texas on the
west, nor the posts in the Indian Territory at the N. W. It was east of
Fort Towson, which is the south-eastern one. It did not reach St. Louis on
the north, nor extend north of the Ohio River, as will appear from the
tables hereinafter given. The following cut shows substantially its
situation on the 1st of February.

[Illustration]

Now, during the month of January, we find the following state of things.
_Under_ this concentrated trade, the temperature was above the mean, even
if Forts Monroe and McHenry on the Atlantic are included; but Mr. Blodget
discredits their returns, and some others which do not conform to general
results. On the west and north of its curving line, both precipitation and
temperature were below the mean.

Under the counter trade, we have the following stations, with