New-York tribune., 1871-12-29
SOUND.
uvsrrR,Es OF THE VOICE AND THE EAR


RrrORE THE AMERICAN INSTITUTE, Al ihE
ACADEMY OF MUSIC.
Prof Ogden y. Rood of Columbia CoileS"
sclverd last evening ut the Academy OF Music o''"ro
tho American Institute the following lecture on sound
the Voice, and the Ear -
Probably every person who IA present 'o-n'eh' "
st somo time stood sen beach, and "atrh''
IRE long lines 81 advancing waves as thy swept ih"ar"
only 10 hr followed by others. In perpetual mon"'o
,. succcss,op so that II seemed though the Ocean
was actually sending toward the coast vast naFseS Z"
water from i,s Nhausilc maca7ines But TINS e'"u
t,ful aprcarancc Ike mach else In our world pd''S
,lu.ory The water transported toward tn" coast
ar1 n tc tide hap,cns TO bc ebhnr II may have rrd''
though slow uoton away from it. The waves are pro-
drccd merely ~ rn"mcrtary hcapnG up of tie drops
~, water along great lire parallel To ~" 'hore-an III
stot nftc,wa' the drops fan t' old level ana Hon
,av tie wave h. passed that spot
.n trcu 'nrrc up and down Ir"ti3n produce The ap-
pearau-c of advancing wav"i Yes IL NAV mo
t,,n ls ,x,crtcd IN suitable time. rs / VIII chow
N IN iisiiut, hut l"t me first add. that the mo-
tin We are c,lsi!crinc can also he reversed
tlC wave afcr IL has strurk on lrccrit"S rocE' IL
driven t,c, irm nc shore travels outward TO ~" re-
,s. ,i,, -. !, hr:, .. d:,u> of water mean While
,',,, - .r -, ~ ,-,-r nal u,~ifinis moving for the
MOI =. II -, ur,ard AMI GOwrward When tins re-
y''sai 81 'r Mh> n lt i'l MT ~ ,ns infinitely
,.aa.lrr r,l -! re rejected Ir"m hrT"r
y - ~ ir,i>uis .., ard reflection ~ wavr en-
-, ..,- ~, ul.r circ, w. winch forbid the
dra a'y i'"'i n "f IT n-"riaii'n lAVr 'hs r. very
r,.! ma wn,u ~rihc Il with my hand N.Ti:-
c.l'. N"; the wave " irh rlus along II. whole
,rcr ardth ri'" %: M "l'' -" IN ,hr hahn H' my
a.. .ii WI" holds thr 'H"r 'rd of II, u rchr trd T.
tGi- :, i.c. atdn ncc, and 80 ON. nnmmr "f
t:urs li ID" porli i'4 "i brass IN ms 'N"rlch' are
u,Ntt Il htT iJiNail nor h"chward the! sIlDly tlse
Irria,, ~, tact may We made Ill evident with
littlc .'rp .r'tn, '.NI %r"rS az" We now nave
." c @ row Of n1 II' % At rS fH0iu can .D
c.,in,nuui,':" 10 them "tv" i, melton YOU see
d,i:ncj ~aNr> advancing along tier Whole 'nEtn' arg
arCu.h ti-c wave, l,a pray nctic" thai oat II
PAY c'r ;.rr " ami liS. In >u2Hl" tii" Hence
tinp vii, ad,an . bot ;he uaicria md Ills advance
of the uo, 81: y b. brought Ihnu, ~ We have Scc' lv
au"v'mc,' - n,icrrl mril les at right Angles 10
tie dIr, e 80 of ',o. advancing wave.
wAvHs IHouI cEr BY CoNIF>> ZION ANh EXrASs!"N.
~tIqn civ ,Hp":h tl"Te Is another hiid 0f In"'''n
Ni'ch C,u lee communicated 10 row OF material par
tcacs which a~o Will general" along them, waves, hit
,v.vc- ~ dGr9cIt character. In thcs" new waves.
isch = ., ' - r.,th occGp ca t"nich', the PR
ii ' ", 81 >i. ont ol me- ~ IN waves "f water
- l.t. i; l. ", i,,'art are 'r""d'd t"H'hcr. and
-' ire" Iav, ecnr.ycig in!' pee, Of ap
Ilrtu~ 'H' y u inf" The 'tH 81 III, aihI'i M ~,
h.!it, rrc.t rntr't'i Ta'jici"S, ana yod ~ 'd'IE
GLOW ~, a:ic 'onlN:'i@n and rNp2mr 3M ;,I al
n,v i,l .it.al ra'i,le for observation. You
nearer II, r,.! Ns md the rcN retreats from them,
.,,h I.Iii % h inning and en- 'c h9 swaylnc motion
~ iSl t." & a. tie general Eject il that Of wave in
r'.,u. c,e m experimental lilu-t1ion OF the hTS
ut IL. er.i> wI Just a,I!y transmit the waves We
low n,riirs t"anrh "' c"0:.c you could not see
thm II y"u >ir,ld hold the end Of u" cord nWouid
ho~cyr, hr able 10 feel them. for when thoy stlucS
,c'I ha'.d tl"c would rye II little push and rnl
r tin i">tc box viii answer our pnrl"'c la,ach
tie end q! the Cr to IT, and send alcnG IT one ot these
wavc; a, it stlihcs rAr box sharp distinct sound Il
Iroiicc. In fact stics. owing TO el"at"d reflections
a. Tie wave which generated merely by pulling back
Nth my hnc,rr f"r an instant "@ o. the Sli;as
n-mt;inc suoh waves - these. iA when they 'kr
liI,o,, We her sound. cannot AZ all
'"rrht even mdi'ai the experiments ana rta-
'"!ins With 'o'ny years 9r? forced rh, . 81,
-orai-vavc,. which tNcy had never seen and
ncp ID os"c; hut perhaps may do hotter than
@ IN ,S ,r ,a aI m 1vc win supposH fer simplicity,
Ia, Il. rsoircci Wv single Impulse You Know that
~i"n stone . r'wn into quiet pool OF water the
more ana more surface Srt Away retains the form
90 ir c; aa' analogy tells us that our sound
c,i-t not o,,N ho,1ontaly hut upward. downward IL
az nnr .c or i1 cs % "?% Now Gors wH arc thn
'1iidcd call spheres: the son ID dwa,e ought mon tI
ofIolow bubble inch is swiftly growing lncer' 80
mu,h. theory would indicate.
WAVES ~ suVHD RENDERED VISIBLE.
wcudciful as it may seem. the recent advances of
s,ncc have actually placed in onr hands the means OF
rcriu. visible hc~" Of .ound, and although 1t
would be quite ont Of place this occasion TO
enter INTO detailed account Of the method by which
~, marr1l triumph achieved still yon may he in:
a
ti,usi' followed by Pr0f TOcpicr 10 whom VIC owe
these beautiful observations.
ar whirh is and OF another which If less com
pressed l'n the surrounding amosphere fact; ot a
uaveng through the atmosphere meets with dcnser
a,r rs uny nt tarnsn %ch t 0st Df s
render the layer actually visible proper optical means
.rr employed LIT NE give rough experimental Illus
tron Of taa All the lenses Of tho magic lantern have
been rruoved. and the screen is illuminated by rays OF
liclt wLrh enanate from the iGntd lime-that L.
Whch from point Tho bottle IN my hand con-
,,ii- drops Of s,suri ether. and the upper part
4 n il q led with It's vdpOr which. know, looks
ir,t Ike the ar that ia II Is nvisiheis in fact, kind
>: itsf lut dcnsrr than our ATMOSPHERE when The
bottle rkcd can pour ont this dense air, and y0u
tn" screen how the divergent beams OF light
sW and can follow the Wavy ancustions it is sub,
)ccted by currents Of ar If had used the hot rarcr
oen equally Visible at distance of many inches above
the flame itself
dcnser than the atmosphere by the aid Of deNii-
son Of the light which they caused and 1t is very evil
y concernSI eDr D thus rid Of the
glare OF the unaffected light. the whole phenomenon
to do thi. very thing by the aid Of peculiar screen and
thus able to deal with the far more subtle variations
Bnt q steady light like the have employed
would have been of use in such an experiment the
sound travels fast "a cannon ball, and light
of this character would render visible neither one nor
the other II should be illuminated by instantaneous
ta>h Of light hat the would not have chance
pcrceptiby hiie lighted up and for this pur-
pose the electric spark was just what was wanted Let
Inc make experiment 10 illustrate this point: We
have before u disc six feet In diameter which Is
turned rapidly that you cannot see the design
painted the disc looks merely gray. The gas lights
havinc been turned down, | illuminate our swiftly
Il To- stand @ and readily see that actually
painted in great black and white sectors. This tai
cnttd young German ply sicst used then the electric
spark to illuminate his sOund-wayes, and the snap Of
second electric spark 10 generate them.
We have upon the screen the greatly enlarged
representation Of Of these by Toepler
method 1t spherical, expected, and beautifully
shaded.
I'll, Appy ISCF or REyI Ec1rn COZ rn w.vrs
Still more remarkable is the Circumstance that this
iS also succeeded IN observing the reflection OF