New-York tribune., 1874-11-09
EFFECT OF WIND ON SOUND WAVES.
BIZ Prof joseph Henry

Prof. Henry stated that he had presented
series of observations subject at the last meet
ing of the Academy. but since then he had hade many
additional observations and Prof. Tyndal had aSo oeou
investigating the matter IL Is In accordance WIN
the most extended observations and with inc cApeoH0o
of all who have given attention to the SUBJECT vi o
propagation of sound that the audibity II it Is much
influenced by the wind and that general RUE "
which there are some EXCEPTIONS sound Is heard 'nore
distinctly when proplgated in tho direction OF the VIM
than wnen ID opposition to IL. Tlere are soiho ~
authenticated Cases. however, In when soih ha'
beord M greater distance against tao Wlhd
than with It, The effect of the Wlnd on rOuhu 10 "
means a simple pheT omenon OF ready explanation. AZ
frsf sirt it might appear that sound was carried
onward with The vii wncn the TWO WeII
direction and that IL retarded when IN an Opposite
direction this explanation Is not suicieht 10
count for the phenUmenJn wnel We coH'i ei " -
sound at lie rata OF upward OF 7Co nes a % ~
while wind OF miles nOur is sucleHI 70 eto
a penetrating power to given sound OF uoGpie tue ~ ~
tnsity whereas from the foregoing , To- ,,iy
should have effect OF Cly one per cent. tIo o,,,o
EXPLANATION which has been offered for the phenomenh
is that III river of ar OF c9hslueit.uno .no 49,
moving over the surface OF the earth inc IoWer
part moves with less velocity on account OF ctn p
Than the upper part, and tnaS consequent, y LIZ .iio
tendency would tip sound wave 90 as 10 thrO"
the sand downward toward the earth IN tne case ol o
in the same direction as inc Wnu anu 70
I ct IL inward IN case the movement is IN an Oppo
direction throwing It Into the air aD0Ve lne e OI
observer. This hypothesis gives ready e1 1patIJn
OF ali phenomena observed ana was fully lIlustrad
by a series OF experiments made by froi henfy III tne
vicinity OF tho hghi-ship on sandy BOOK iaso
summer, Two steamers we're supplied with Whistles
nlodncng the same tone and sent TO the wcstW rd
and one TO the eastward wind was DiowlnS from tne
west az the time witn velocity OF Gi miles an hour
The whistles steamer was ueiru u' ~ slcua
n1iIe from the ghlshIp which the observers were
statOned while the s"uOd Of the OtIer, Wnl was cdf-
I.ed by the wind, was heard y miles. IAi' %as 10
accordance with the experience or the enect OF
wind IN accelerang the sound waves. Az noon, no y,
ever the experiment was repeated IN deal eal, anu
rho same effect was observed, the sound from tue
steamer that sailed eastward being heard aud haf
times as far as sound from the other steamer Again
m the afternoon The rment tried ater the Wlu
A med
t%e were SURPRISED to ind change IL the
result Apparently the course OF Inc Win hII no enct
upon the velocity OF the sound Prof. uehry was
occurred only earts surface, and that river Ol
wind was flowing steadily from the west all the time
similar conditions, wind tdlng TO calm and then
sh1iDg as before He sent up small balloons at the
same Iue and fouud the idea to be correct steady
rurrput from tie west prevailed all the tnc. By this
beuutf experiment the truth OF his Theory as 10 the
uniform effect on wind on sound was completely de-
mOnstrated. .,.,,
re of the s0nd and the apparently con-
Trajectory effect times The winds action, rerefs the
U.cuomcna To nOccul condition of the htnoSpAcre
UrOduCe1 by the mIbslnS hi AK aId 'apVITT Gnu ~
matches Of AIR different LemDerltue PrOI heDrY sau
mat fOs been shown 10 nave no apparent cct ou
the penetrating power VI sound. u souhl hts
Storms have effect. Vdpor IN the ar ,i colu
rot, therefore, produce the pncnonlcna as iSi,ai
supposes. Tho fault with Iyndalrs experiments
were hat they were all made IN one lrecllon' Hu
these partial experiments derived his theory OF the
acoustic opacity OF the atmosphere. LasI ounlhcr
Prof Henry placed large steam tru1pet on steamer
Tne VIVID was from the west, ana inc truLlpes WIS
pointed nOrthwari. The steamer salleu to"dIu tHo
wind and carried sound only 81 miles, but III sas
in contrary direction the sOdni was He'l ioi 80,
tance OF eight miles II Prof. TTudl hai oostrlcu .no
sound from direction only, ne would nave ceu tuo
day Opaque; If from the other ony he WOULD nave con
Guided II was quite clear