~Jt.BJt£1 1.
A F.eport tor Ge~e~al Carl Soaatz
oreoared b;- Y.aurlce Ewlng
Undor a contrnct w1 th the i:breau of Shlc.s, we hmte
prove~ thot ~her~ 1~ a ~cund channel 1n the ocean wltr 1ta
axis at a ~1ench of '"bot.:.t 4606 fee€. Conflrld.nf D. nredletlion
.made by tt:".O wr1 tor, a four oound bomb fired at thlS depth
bas been heard at a d!.stance of -2:300 nt1les, using • hy.~rop'bone·
at the ~ame depth as a receiver. 1'h.!.5 range enormc.v.sly
exee1.1ds anyth1ne before achieved, o.nd 1~ possible pr111111r111
becausa the so~!rco aod the receive:- are placed at th• most
advantaaeoua depth. Th3 slGnal strengt~ indicates that
far :!reater ranees ca;, be vnta1ned 111 thoclt change or eq>l1naent.
At a typical place in the ocean, the speed or
eound at tt,e surface 1s 5001 tt/sec. It decreases to 4888 tt/aeo
at a depth of 4000 feet. 'it.n.:i ~hen 1.ncreases to 5065 !"t/aec,
at a depth or 16.200 feet. Tb1e situation 1s~escr1beo a•
a sound channel .. 1tb 1t& axis at 4000 feet, because all 801.l'ild
rays are deflected downwar~ at points above the axis and u~ard
at ooints below it. Detailed cal~;lation ot the bending of
tho ray lJaths due to -presat:re and teu;pera ture shows that all
ra~s leaving a sound source on the axta 1n directions within
lzg or the no~izontal are refraoted back and forth across t~
ax1a and can tr&Yel unlimited d1ataneea w1thnut contact with'
aurtace or bottom, hence the long ~ea. A eimilar calculation
ror a sound aouree nea~ the· surtace abo•• that all raya :DU•t
be reflected at aart~ee and bottom many timoa 1n the course
of a tn tmndred ::tlilca, hence the 11m1ted range of detect1qrt
of or::11nar;r shallow explosions, and the ocourence ot skip
~1stancea. ·
~·sound fro~ an explosion at the axis ot th6.80ucd
channel baa a duration of abo,tt 12 aeconda per thousand mtlea
of travel, a."'ld an umalatak&ble pe.ttem or a gra~ual bu1ld1!1l6
up to :ax111Uil 1ntena1ty wttb a very sharp cut-ott. 'rhta
laat feature 1a ot great importance beoauae 1t perm1ta aoc~rate
trlansulation w1tb A network or three 11aten1ng ata~1ona,
the rate of ta nsm1aa1on be1n~ about one !Idle per ,••oond.
(Rete renee 1)