Sacramento daily record-union. [volume] (Sacramento [Calif.]) 1875-1891, 1888-03-10
THE ARID REGION.
Greely's Statement of Rainfall Beyond
the Mississippi.

Oeneral a. w. Ureely, CnleI Slgnal vi
ficer, gave to the Washington Philossph
ical Society, at its regular meeting, Febru-
airy 18th, the partial results of study he
is now engaged upon of the rainfall in the
trans-Mississippi region. He had before
him number of maps upon which had
been charted the observations which were
the basis of his study, and referred to them
constantly as he spoke. He said that the
idea that there is any part of the West
that is absolutely rainless is now ban
ished myth. During the past ten years
the number of stations for observation has
been doubled, so that there are, in twelve
States and Territories, nearly one hundred
stations: and the observations, if reduced
to single one, would cover period of
nearly five thousand years. The result of
charting these observations has been to re-
duce very greatly the areas of small rain
fall. The area in which the annual pre-
cipitation was supposed to be less than
five inches has almost disappeared, and
that in which the rainfall was put down
at less than fifteen inches has been reduced
by a quarter of a million of square miles
since the census map of 1880 was made.
General Greedy discussed the question of
what constitutes an arid region, and said
that he does not agree with Major j. w.
Powell, who placed the minimum amount
of precipitation necessary for successful
agriculture at twenty inches per annum.
He said that millions of bushels of wheat
are raised every year where the rainfall is
less than twenty inches, and referred to
the statistics of Dakota, where more than
100000 bushels were raised in the two
counties of Richland and Stutsman in 1885,
and 100000 in 1887, with an average
rainfall of 1877 to ISL inches.
General Greedy also mentioned the in
teresting fact, that, while the rainfall in
creases as the rivers which flow directly
into the Gulf of Mexico or into the Pacific
ocean are followed up from their mouths,
it increases with the distance from the
mouths of such as empty into other bodies
of water, like the Colorado.
General Greely's charts also prove that
much of the rainfall in what has been
known as the arid region, and where it
was formerly supposed that the precipita-
ton was five inches or less, was not re-
ported. In some of these places the actual
rainfall is as much as sixteen inches, and
in one it is thirty-seven. This explains
why water is found SO abundantly in wells
in some parts of Southern California,
where the annual rainfall has been re-
ported as ten, twelve and thirteen inches !;
the actual precipitation is twenty-four
inches.
General Greedy said that he had caused
to be placed upon the charts the maximum
and the minimum rainfall of the various
stations, not expecting that they would in
dictate anything, but that the curves were
almost as those on the annual maps He
explained that the small average amount
of rainfall formerly reported was due in
part to the fact that so large a number of
stations had been situated along the line
of the Pacific Railroad, which, seeking
low gradients had been built through a
section of country in which the precipita-
ton was small. He spoke also of the
prevalent opinion that the rainfall in the
West is increasing, and said that he thinks
this opinion to be correct, and closed with
the remark that it was not fair to treat
that country on the basis of seasonable
rains, since the larger portion of the pre-
cipitation took place during different
months in different sections of the region.
In the brief discussion which followed
the address, Prof G. K Gilbert said it was
not safe to fix any given amount of rainfall
as the minimum necessary for successful
agriculture, without qualifications. Very
much depends upon the time when the
rain falls, and the rapidity with which
evaporation takes place More rain is re-
quired in Arizona than in Dakota, and
many unsuccessful agricultural expert
ments have been made in Utah near Camp
Douglass, where the annual precipitation
is as much as eighteen inches.
Professor Fernow said that he had COM
pared the amount of rainfall during the
five months of vegetation, in Philadelphia,
Buffalo, Dodge City and North Platte. 1t
ranges from fifteen to seventeen inches, the
largest amount of precipitation being at
North Platte. There was no lack of rain
fall at the Eastern stations, but at North
Platte it was impossible to raise crop.
He learned also from Utah that the amount
of water needed to irrigate land there was
less after two or three years than when it
was first turned on.
Prof. C. V. Riley spoke of the frequency
and violence of the rainfall as modifying
in an important degree its effect.-Science