their natural course, after passing the equatorial belt, would continue on
to the north-west until they passed the limits of the N. E. trades, and
curve in upon the western portion of our continent below 45 deg., and supply
it bountifully with rain, are, in part, perhaps, diverted along the
eastern side of those mountains to swell the volume of our counter-trade,
and in part pass them, almost exhausted of their supply of moisture by
their contiguous reciprocal action. Hence, too, the deficiency of
precipitation at the base of the Andes, on the western side, and the
peculiar and irregular character of the winds under the western lee of the
Andean range. Baffling airs and bands of calms prevail on this portion of
the Pacific, except where the mountains fall off, and then there is a
westerly or south-westerly monsoon under the equatorial belt. Says
Lieutenant Maury in his Charts, sixth edition, p. 731:

"The passage, under canvass, from Panama to California, as at present
made, is the most tedious, uncertain, and vexatious that is known to
navigators.

"My investigations have been carried far enough to show that at
certain seasons of the year a vessel bound from Panama to California,
must cross at least three, at some seasons four, such meetings of
winds or bands of calms, before she can enter the region of the N. E.
trades. Hence the tedious passage."

Such will ever be the state of things on this continent and upon the
eastern Pacific, so long as the S. E. counter-trades are compelled to pass
over the mountain chain of South and Central America.

Again, if we examine carefully the belt or zone of extra-tropical rains,
we shall find that the focus of greatest precipitation is considerably
north of its southern limit, and that, other things being equal, this
focus travels north in summer, and gives to higher latitudes their needed
summer rains. This is very apparent upon the north-western portion of our
continent, as the following table will show:

+-----------------------------------------------------------
| | Lat. |Jan.|Feb.|Mar.|Apr.|May.|June.|
| |-------|----|----|----|----|----|-----|
|San Diego, Cal. |32 deg. 41'| 0.3| 1.7| 1.1| 0.9| 0.5| 0.0 |
|San Francisco. |37 deg. 48'| 1.7| 0.5| 4.4| 2.1| 0.4| 0.0 |
|Cant., Far W., Cal.|39 deg. 02'| 3.3| 0.6| 6.4| 2.2| 0.9| 0.0 |
|Astoria, Oregon. |46 deg. 11'|27.0|10.9| 6