Burlington hawk-eye. [volume] (Burlington, Iowa) 1845-185?, 1850-04-25

/ deem it proper briefly to mention the
causes which produce these changes, and
which, it will be seen, as this report pro-
ceeds, must exercise a controlling inf1u-
ence on the commercial prosperity and re-
sources Of the country.
1t is a well-established theory, that the
currents of air under which the earth pas
ses in its diurnal revolutions follow the
line of the suns greatest attraction. These
currents of air are drawn towards this line
from great distances OH each side of il; and
as the earth revolves from west to east,
they blow from northeast and southeast,
meeting. and OF course causing calm, on
the line.
Thus, whenth sun is directly, in COM
mon parlance, over the equator, in the
month OF March, these currents of air blow
from some distance north of the topic of
Cancer, and south of the tropic of Capri
corn, in an oblique direction towards this
line of the suns greatest attraction, and
forming what are known as the northeast
and southeast tradewinds.
As the earth, in its path round the sun,
gradually brings the line ofa.traction north,
in summer these currents of air are carried
uih il; so that about the middle of May
the current from the northeast has extend
ed as far as the 3Sth or 18th degree of
north latitude, and by the twentieth of
June, the period Of the suns greatest
northern inclination, TO the northern por-
tons of California and the southern sec
ton CT Oregon.
These northeast winds, in their pro-
gress across the continent, towards the
Pacific ocean, pass over the snow-capped
ridges of the Rocky mountains and the
Sierra Nevada, and are of course deprived
of all the moisture which can be extracted
from them by the low temperature Of those
regions of eternal snow, and consequently
no moisture can be precipitated from them
in the form OF dew or rain, in higher
temperature than that to which they have
been subjected. They therefore pass
over the hills and plains of California,
where the temperature is very high in
summer, in very dry state and so far
from being charged with moisture, they
absorb, like sponge, all that the atmos-
phere and surface Of the earth can yield,
until both become, apparently, perfectly
dry,
This process commences, as have said,
when the liue of the suns greatest at
traction comes north in summer, bringing
with it these vast atmos pherie movements,
and on their approach produce the dry
season in California, which, governed by
these laws, continues until some time al
ter the sun repasses the equator in Sep
tembeY. when. about the middle of No
vember, the climate being relieved from
these northeast currents Of air, the south
west winds sci in from the ocean charged
with msrstnre--the rains commence and
cor A,haao fall, not constantly, as some
pes e.ltave represented but with sufii-
ciefhfreiuency to designate the period OF
their continuance, from about the middle
of November until the middle Of May, in
the latitude Of San Francisco, as the Uet
season.
1t follows, as matter of course, that
the dry season commences first, and con-
t!nueS longest in the southern portions oil
the Territory, and that the climate of the
northern part is influenced in a much les
degree, by the causes which | have men,
toned. than any other section oE the ccun-
try. Consequently. we find that as low
down as latitude 800 rains are sufficiently
frequent in summer 10 render irrigation
quite unnecessary to the perfect maturity
Of any crop which is suited to the soil ard
climate.
There Is an extensive ocean current OF
cold water, which comes from the north
ern regions OF the Pacific, or. perhaps,
from the Arctic, and flows alorg the coast
Of California. 1t comes charged with,
and emits in its progress, air, which ap-
pears in the form Of log when il comes in
contact with higher temperature on the
American coast, as the gult-s'ream OF the
Atlantic exhaes vapor when il meets, in
any part Of lis progress, lower tempe
rature. This current has moi been sur
veyed, and therefore, its source, tempera
tnre, velocity, width and course, have not
been accurately ascertaned.
1t is believed by Lieutenant Maury, OF
what he considers sufficient evidence
and no higher authority can he cited
that this current comes from the coasts of
China and Japan, flows northwardly 10
the peninsula of Kantschl'ka, and max
ing circuit TO the eastward, strikes the
American coast in about latitude 40 or
400. II passes thence sonthwardiy, and
finally loses itself in t,e tropics.
Below latitude thirty nine, and west Of
the foothills Of the Sierra Nevada, the
forests OF California are limited TO some
scattering groves OF oak in the valleys and
along tie borders Of the streams, and Of
red wood on tho ridges and in the gorrc>
of the hill<-<omctincs extending into the
plains. Some Of the hills are covered
with dwarf shrubs, which may be used as
fuel. Wnlr these exceptions, Tie whole
territory presents SURFACE without trees
or shrubbery. II is covered. however.
with various species OF grass, and for
many miles from the coast with wild oats.
which, in the valleys, grow mos, lux
Hriartly. These grasses aud oa's mature
and rpen early in the dry season, aid
soon cease to protect the soil from the
scorching rays OF the sun. As the stun
mer advances. the moisture in the atro>-
phere and the earth. TO a considerable
Iepth. soon becomes exhausted; and the
radiation of heat. from the extensive na-
l. a.,l l;lt ,c