The evening telegraph. [volume] (Philadelphia [Pa.]) 1864-1918, 1870-12-13

Captain Aver Adams contributes TO New
Bedford paper his views about the trade
winds, and relates a very curious experience
with desert dust which he met with thousands
of miles from sea-
SIN looking over the textbooks used in
our schools, treating on physical geography,
there seems to be a lack of information in
regard to the natural forces working to sup
ply this country with rain. Thinking that
my unusual experience in that direction may
be of some value, L have here made state
ment of the main facts for puhlication:--
Having passed several years of sea life on
different oceans, in search of whales, a por-
ton of my voyages have been spent in the
Atlantic Ocean. especially in the belt of the
northeast trade winds, where section of
them sweeps over breadth of ocean and
sea, on a track over one thousand miles wide
of latitude, and length of over four thou
sand miles of longitude, reaching from Africa
to Mexico, crossing the West India Islands
and portion of Florida.
''While cruising in this belt off the coast
of Africa, often experienced q warm, dry
wind, from the desert, always accompanied
with fine yellow DUST as light apparently as
smoke, which have known to extend third
of the way across the ocean, and SO dense at
times as to make the navigation dangerous
around the islands off the coast; while the
hest of the desert winds, converted into ocean
trades, was often scorching to vegetation on
shore, besides causing great evapo-
ration on that part of the ocean, prob
ably the greatest ever taken from any
other portion of the globe. While cruis-
ing in the longitude of fOrty-five degrees
west, in mid-ocean, the atmosphere would
become so loaded with moisture, it was often
impossible to see whales spout, even when
their backs were visible from tho deck: the
atmosphere and spouts being SO near alike in
density and temperature, making it impossi-
BILE to keep run of them, difficulty seldom
experienced on other oceans, where spout is
as distinct as puff of steam in clear weather;
while here they are rendered SO invisible as
to give security to the largest breeding places
of the sperm whale in the Atlantic Ocean.
.''My cruises generally ended in zigzag
courses, while drifting with the winds and
currents OF these humorous trades, through
the various passages of the West India
Islands, where / saw portion of the exceed
inEly moist atmosphere condensed by the
mountains and precipitated; yet with the re-
mainder have been waited on into the Gulf
of Mexico, even to the mouth of the Missis-
sippi river, where L resorted for supplies
while the humid winds passed on to water
the great valley beyond.
81 know it is generally supposed that the
northeast trades, SO called, precipitate their
humidity on the northern coast of South
hmoIlCd ullu tu0 odSterH SlOp6 VI OeuUra
America and Mexico, which they do in part
and give these regions thorough drenching;
but also know, from long experience, that
the northern portion of the trades often blow
from the south of east, so much SO, in fact,
l have sailed from the vicinity of the West
India Islands, making nearly an east course,
two-thirds of the distance across the ocean.
In fact, the veering of the trades will COM
pare favorably with the great rain-storms that
sometimes spread over a portion of the
United States.
II have often thought that the West India
Islands, extending as they do from the centre
of the trades 1900 miles to the northwest,
may serve to divert large amount of vapor
in that direction. Thus it is reasonable to
suppose that portion of the evaporation of
those desert-heated trades are waited over
the United States, where the variable winds
and the level nature of the country facili-
tate o wide and even distribution of rain.
The evaporation being greatest in summer,
the average fall of rain should generally be
greater during that season. 1 am also led to
believe that hurricanes, moving as they do
from the centre of the great evaporation des-
cribed, convey a large amount Of vapor
towards the United States; and that the
heated winds from Sahara assist in keeping
up the temperature of the Gulf Stream, as
well as swelling its volume"