The New York herald., 1873-12-25


finest in the world
Rainfall Produced by tho Firing OF
Artiilcry-How the Wa ste Places OF
the Earth Can BE Reclaimed.
Professor Edward Powers, of Chicago, is en-
gagged in endeavoring to demonstrate the prac-
ticability Of controlling and distributing rain
fall by means of conclusions produced by the
firing of artillery. This subject, if not en-
tirely new is of great Importance, and should
be thoroughly investigated by the government.
Our Western domain, to say nothing of the
vast desert wastes of other portions of the
earth, demands irrigation. General Grant
called attention to this necessity in his recent
Message, and though we are at loss to know
recognizes the general truth we have pro-
claimed. Mr.. Powers theory is deduced
from an examination of one hundred and
thirty battles that were succeeded by
copious rains. He claims that about
sixty per cent of all battles or lombard
ments of Importance are followed by rain
within the first twenty-four hours from
the commencement of the heavy firing. A
calculation made from the observed average
number of rainy days in the year when there
are no battles shows that only thirty-two per
cent would be SO followed within that time
if the battles had no influence in produc-
ing the rain. About ninety per cent
Of such battles are followed by rain
within the first forty-eight hours after the
commencement of the heavy firing All great
battles in which much artillery was used were
followed by rain $50 far as definite informa-
of time between the commencement of the
heavy firing and the beginning of the rain is
twenty-six and half hours. Rain following
great battles, in which much artillery is used,
is almost always very heavy. Engagements
other than great battles, in which much artil-
lery is used, are also generally followed by
heavy rain, but musketry firing does not
bring much rain. Rains follow battles not
only in the spring and summer, but also in
autumn and winter Rains follow battles not
only in this country and in Europe, but in
the dry season in Mexico. Heavy rains fol-
low great battles fought in times of drought
The rains following battles are generally
accompanied with thunder and lightning.
The theory of rain generally accepted by
philosophers is that it is produced by the
union Of two bodies of air, one Of which is
colder than the other, and both saturated
experiments that when two such bodies of air
are mixed they cannot when mixed, contain as
much vapor as they did before, the reason for
which is explained by the principle that warm
air has greater capacity for vapor than cold
Dir, and that this capacity diminishes in o
Now, the trade winds take up large quantities
of vapor from the ocean, which vapor is car
ried north and south by the equatorial cur
rents. Hence there are generally above us
currents of warm air saturated with vapor
To explain how cannon firing produces rain,
it is only necessary to explain how these cur
rents are caused to mix with the colder currents
above them. The explanation is that it does
so by rarifying the humid current 1t rarifes
it by condensing small portion of the vapor
which it contains. 1t condenses this small
amount of vapor by concussion, which is
similar to sudden pressure, and we know that
by pressure aqueous vapor is condensed and
its latent heat is given out-that is, when
cannon firing brings rain there is condensa-
ton of vapor in two ways; first, little con-
densation by the pressure Of the shocks Of
concussion, which causes an evolution Of heat
and ratification of the air, and, second,
great condensation caused by the rise of the
colder one above it. AS it will natur-
ally take q little time for an
air current hundreds, and perhaps thou
sands, of feet in thickness to rise into the
colder current after being rarifed by the con-
cussions, and as in the meantime, the air SO
rarifed will be carried along by the current,
it follows that the rain will not commence at
the place where the firing takes place. 1t will
generally work back to that place in the path
of the current, however, arriving, as before
stated, in an average time of twenty-six and
one-half hours from the commencement Of the
firing. Unless the firing is heavy and con-
tinued for two or three hours, so as to rarity
larger area and volume of the air current as it
passes over, there will be no rain, or if there
is rain somewhere on the path of the air cur
rent it will not reach the place where the firing
takes place, as the equilibrium between the
two currents will be restored before the rain
reaches that point.
Battles followed by heavy rain are:-First
Bull Run, Fair Oaks, Pittsburg Landing (or
Shiloh), Malvern Hill, Second Bull Run, Stone
River, fredericksburg Charlottesville, Get
tysburg, Spottsylvania Court House, Cold Har-
Dor, Nashville. During the second day of the
battle of Buena Vista, Mexico, there were two
violent showers, though this was in the dry
season, and it had not rained before and did