The Wheeling daily register. [volume] (Wheeling, W. Va.) 1864-1878, 1874-01-07
Artificial Production Of RaIn-Lec-
ture by Mr.. Edward Powers.
Mr.. Edward Powers. q well known

Mr.. EdWard fCWere, q well Known
civil engineer Of Chicago, said in re-
cent lecture. that he has examined a
large number Of cases Of rain following
battles, from which he deduces the fol-
lowing approximate conclusions, viz:
That all great battles in which much
artillery is used are followed very soon
by rain. That about 80 per cen. Of all
battles and bombardments OF impor-
tance are followed by rain within the
first 4S hours after the beginning OF the
heavy firing. That about 80 per cent
are 30 followed within the first "a
hours; whereas, on an average, only 81
per cent would be followed by rain with-
in that time if the battles had no influ-
ence in bringing t,this percentage being
calculated from the average number OF
rainy days in the year when there are
no battles. That the rains following
great battles are generally very
heavy, also that rains following
other engagements than great
battles, in which much artillery
is used, are heavy. That rain follows
battles fought in fall and winter as well
aa in spring and summer. That the
came thing occurs In the dry season in
Mexico, as well as in the United States
and Europe. That heavy rains follow
great battles fought in a time oI
drought, and that the rains following
battles are usually accompanied with
thunder and lightning. Mr.. Powers, in
stating the above conclusions, gave
many interesting facts in illustration
The theory by which he accounts fol
the assumed production OF rain by bat
ties or artillery firing. may be briefly
stated as follows: Rain, according tc
the commonly accepted theory, is caus'
ed by the union OF two bodies OF air
one OF which is warmer than the other
and both saturated with aqueous
vapor. When two such bodies
OF air are mixed together they cannot
when mixed, contain as much vapor a.
they did before. This follows from tht
principle that warm air is capable o
containing more yspor than cold air
and that its capacity for vapor increas'
ca and diminishes in o much greater
ratio than the temperature. Now
there must be currents OF warm air sat
ratued with vapor in the atmosphere
above US, for the trade winds take ~
large quantities OF vapor from the
ocean, which vapor is carried north
ward and southwark by the great eqa'
torial currents. Hence, in explaining
how artillery firing brings rain, it ii
only necessary to show how it cac
cause such q current TO mix
with the colder current above
lit. Mr.. Powers explanation
which is original with himself, is tba
it does 30 by rarifying the air in th'
humid current, thus causing it to rise
1t rarifies it by condensing small
portion Of the aqueous yapor which i
contains. 1t condenses this small
amount OF vspor by conclusion, which
is similar in Its action to sudden pres
sure, and we know that by pressure
acqueus vapor is condensed and it
latent heat evolved. When artillery
firing brings rain there is, in othe
words, condensation OF vapor ia TIVE
vays-first, very small amount o
condensation by the pressure OF tn
shocks OF conclusion, and secondly.
great condensation caused by the ming
ling OF the humid current with th
colder current above it. Th
first and small amount OF conden'
sation leads to the second anC
greater condensation, because the laten
heat evolved from the vapor which i
condensed rarifes the humid current
must be very extensive, being perhap
thousands OF feet in thickness, it vii
take a little time, after such q curren
has been rarified by concussion for it t
rise into the colder current above ii
and as in the meantime this portion o
the current would pass on, we coult
not expect that the rain would com
meuce at the place where the firm
takes place. The fact that the BATH
field is generally included in its ares
however, shows that after commencinI
it works back on the path OF the cur'
rent.
Mr.. Powers thinks that some expert
ments ought to be made to determine
we cannot as well produce those mo
tions in the upper air which lead t
rain as to watch for their productio
by natural causes and foretell their ap
proach, as is now done by the sigma
service OF the army.