It is impossible to ~ake reall1 detailed calculattons
of the ~ax~mum ra~e without better info~1nt1or. about temperature
and sound velocity 1n locations from 45,000 to 90,000 feet,
for it ls there tMt the ereatest frictional losse!' will oc~ur.
However·, Jt ~tt aare to nt"e1tet that a bomb eonta1n1r-.~ a few.
'lOttl"ld~ or TNT OAn be h•ard rro!!l 4000 to 5000 1'111l.oa. 'l'he
chance t~at 1t could be heard to the rarthoet po1n: on eartb
1! '110 l"tb eon~ 1derat1on.
It is r:ry belle! tr..at a larse rocket or Jet propul·-
sion :notor passing the a.:-:1!! of the sound channel would also
b~ detectable by l1!te~1r.g at ~everal thousand miles, and
subject to location by tr!a:t<?.ulation if hea r.j by tbree sui tlably
chosen eta tiona. ln t1llle of war this tr1angl.tlat.1on COl.J.ld
locate the l~nohini, site~ of the enemy, and 1h peaee time
it is conceivable that ~~!tably ehos6n Jlsten~n£ $t&tlons
could monitor tho entire wot•ld to detect klld locate ..ny
unusual rocket or jet prop\.Ol::ion axperlmente, thus mln1.rn1z~ng
the danger of surcr!se a.~tack:; -;;it"t st.~c!"et weapons. '
The moat prom1a1ne. .eJ"PC'• oi: li6tening etatlon
accord1:1.; to my present lmowledge would·IUke uae eltber ot
the b1gber ~nta1n8 ot the world or or tree balloons to .
gain adequate belgbt. It 1a unknown at pr•sent: b7 how ra*
the receiver •7 be re110ve~ .t'rows the pre~er. red height withqut
prohibit1'Ye eacr1t1ce ot sound channel prooertiea. Hawcner,
1~ the aub:a.rine sound. channel we have bad fairly good
rece~tlon with the hydropbone at 20VO teet when tno axle ot
the ehaDnel waa at 4000 feet. Benee, it 1~ not beyond I
reason that t~e taller ~ounta1nP might ~rovide sufficient ·
altitude or themaelvea~
Small atratoaphere balloons. provided with radio
~•ana tor tranam1aa1on or sound 1~1••• to a receiving ,
station either fixed or .ob1le, probabl1 provide the .oat 1
readily &Yailable ltstentne •rra~.ent.
8i8A"'