however, must be maintained, and one of those modifying hypotheses which
have made meteorology such a complicated piece of patch-work, must be
invented; some "deflecting forces" found. There is the Great Desert,
bordering upon the ocean, north of the Cape de Verde Islands, for a
distance of six hundred miles, widening as it extends inland, whose
temperature, as he says, "_must be exceedingly great_;" and doubtless is
so, and yet the air, instead of blowing in upon it in a hurricane, is
actually drawing off from it, and blowing towards the S. W., where the
water and air do not rise above 84 deg.. Well may he be "perplexed and
astonished."

Turning south, however, to the distance of five hundred miles or more, he
finds the S. W. monsoon winds, which in those months blow under the belt
of rains, toward the land, in the direction of, but at a great distance
from, Sahara. It is an easy matter to suppose that they reach the Great
Desert and supply its vortex of rarefaction, inasmuch as they blow in a
direction toward it, and distance is no impediment to supposition.

Then it is necessary to _suppose_ that the S. E. and N. E. trades, at the
south-west, draw so strongly to the westward as to create a partial vacuum
to the S. W. of Sahara, which is filled by the winds which draw off shore,
and then we have the supply brought from the distance of five hundred
miles or more, by an ascending vortex, which creates a vacuum, and the air
near the vortex taken away in _another_ direction by a _partial_ vacuum;
and so an ascending _vortex_, which creates a vacuum is supplied from a
distance, and a _partial vacuum_ at a distance is supplied by the air near
the perfect vacuum. Such an idea of a supply by a circuitous route, and
secondary influence, is not very philosophical, to say the least, and
Professor Coffin feels it; and to the question, Why is it so? which, he
says, may very naturally be asked, he confesses there is no answer. And
there would be none, even if his suppositions were based upon facts. But
other questions might be asked equally difficult to be answered, viz.:

1st. Is there any rarefaction which can draw the trades to the west, and
in that particular locality, in opposition to the supposed vortex of
Sahara, by creating a _partial vacuum_?

2d. Are they in fact so drawn?

3d. Do the S. W. winds, south of the Cape de Verdes, and _under the rainy
belt_, which in the summer months extend up to these islands, _reach the