Richmond palladium. [volume] (Richmond, IA [i.e. Ind.]) 1839-1854, 1839-05-18
From the Raleigh Register

TIE RAIN PRODUCING THEoRY.-Proiessor J.
p EspY, Of Philadelphia, III letter TO the EdI-
tors of the "National Gazette" gives a summa-
nv of the reasons and facts which have Infiucn-
ced him in supposin. that RAIN can be produc Cd
by human agency. The following are the rea-
sons which have satisfied him that the expert
ment ought to be tried:
"lst--It is known by experiment that II mr.
should be expanded into double the volume, by
diminished pressure, 1t would Gc cooled about
ninety degrees Fahrenheit.
2nd-I have shown by experiment, that II air
at the common dew point in tho summer sea-
son, in zine OF drought, II degrees, should go
ID III a column to n height sufficient to expand 1t,
BY diminished pressure, into double the volume,
it would condense into water or visible cloud, by
the cold of expansion, more than one malt "t us
vapor-a quantity sufficient to produce nearly
three inches of rain.
3rd.-It is known by chemical principles, tina,
the caIoric of elasticity given out during the
condensation of this vapor, would be- equal to
abou. 30 900 tons of anthracite coal burnt on
each sauare milo over which the cloud extended
4th-I have shown by experiment that this
caloric of elasticity would prevent the air from
cooling only about half as mach as 1t would 1t 1t
had vapor i'll it, or about 40 degrees al me
height assumed, which cause the air in the cloud
to be Mt that height, about as degrees warmer
Than tho air on the outside of the cloud at the
same height. | have shown from these princI-
pies (sec journal of tho Franklin Institute Tor
1851 that the barmometer would tall, under
the cloud thus formed, in favorable circumstances
a quantity as great as it i. known to TALL some
times under the middle OF a dense nnn ioity
cloud, and that consequently the arr would rush
in on all sides towards the centre OF the cioua
AID IDS ,h: middle and 'h ms pna,"n
the condensation OF the vapor and inc 'ofh'a'o'
Of cloud and the generation OF ram.
Fifth have shown also that the air does move
;nwards on all sides towards the centre o the space
or region where great rain IS fai!ing, an" :"
course upwards. after il comes IN under mo c'o''"
which is so much lighter than the SURROUNDING
air: at least. that il does SO IN all STORMS "h'c'
have been investigated, winch now amount 70 SIX
:een besides several tornadoes, In all oil wni.i
the trees were thrown with their tops inwards.
Mr. F. then proceeds to argue, that large
body of air can be made to ascend IN column
nv means Of FIRE, under favorable circumstances
and that circumstances are even more hkeiv u
he found favorable in times OF drought than 10
o,her seasnns-for the reason, that in dry wealth
or the vapor Is constantly ascending ana increas
mo and that then the atmosphere rs more likely
To he in a quiet state, which IS necessary Tor ths
success Of the experiment. In support Oh me po
: sition that FIRE cal be made the agency IN pro
ducinu R.in he recnrs TO several incidents IL
show Ina, The Rains have succeeded large Fires
and the bursting out Of Volcanoes, SO ifeqnen'i,
/ add concurrentlv as to jisiiiylng the assertion
/ tina. they were Il primary cause IN producing
them This he maintains Is not elected rs Ma
been supposed, by the smoke forming INTO vnpo
but by the column Of air forced up by the II
/ itself.
/ Mr. ESpy remarks in conclusion
t sIf should be encouraged TO go on with IN
! ex,e,,men.. | mean TO have large mass {
combus,ibles prepared ready for use, and who"
have found all the circumstances mentioned d
fore. favorable in time OF drought, woh'a 81
Ere 70 the circume: ence in various places Mt one
Soon after the fire commences, | will expect
/, see clouds begin to form. about rs many n"
dred wards high rs the temperature OF the ar
ABOVE the dcw-point in degrees oil f"hrenhe".
, oil, expect to see this cloud rapidly increase
size-ii its top is not swept off by cnrren'
. nj, at n considerable distance above the EARN
, mill il becomes SO lofty as to ram shi"
lit .s !, advances and the next day sh
:, zee, the re ion to the South of where the ="
fell. 10 be visited by rain; for reason explain
j. in nv writings"