aeroplanes and dirigibles of war-µÚ29ÕÂ
°´¼üÅÌÉÏ·½Ïò¼ü ¡û »ò ¡ú ¿É¿ìËÙÉÏÏ·ҳ£¬°´¼üÅÌÉ쵀 Enter ¼ü¿É»Øµ½±¾ÊéĿ¼ҳ£¬°´¼üÅÌÉÏ·½Ïò¼ü ¡ü ¿É»Øµ½±¾Ò³¶¥²¿£¡
¡ª¡ª¡ª¡ªÎ´ÔĶÁÍꣿ¼ÓÈëÊéÇ©ÒѱãÏ´μÌÐøÔĶÁ£¡
below¡£¡¡¡¡Naturally¡¡the¡¡latter£»¡¡directly¡¡it¡¡observed¡¡the¡¡airman's
object£»¡¡would¡¡endeavour¡¡to¡¡elude¡¡the¡¡pursuing¡¡trawling¡¡mine£»
either¡¡by¡¡crowding¡¡on¡¡speed¡¡or¡¡by¡¡rising¡¡to¡¡a¡¡greater¡¡altitude¡£
The¡¡aeroplane£»¡¡however£»¡¡would¡¡have¡¡the¡¡advantage¡¡both¡¡in¡¡point¡¡of
speed¡¡¡¡and¡¡powers¡¡of¡¡climbing£»¡¡while¡¡there¡¡is¡¡no¡¡doubt¡¡that¡¡the
sight¡¡of¡¡the¡¡mine¡¡swinging¡¡in¡¡the¡¡air¡¡would¡¡exert¡¡a¡¡decisive
moral¡¡effect¡¡upon¡¡those¡¡in¡¡the¡¡airship¡£
Attempts¡¡to¡¡render¡¡the¡¡mine¡¡harmless¡¡by¡¡discharging¡¡it
prematurely¡¡with¡¡the¡¡aid¡¡of¡¡rifle¡¡and¡¡machine¡gun¡¡fire¡¡would£»¡¡of
course£»¡¡be¡¡made¡¡by¡¡the¡¡crew¡¡of¡¡the¡¡airship£»¡¡but¡¡the¡¡trawling¡¡mine
would¡¡prove¡¡a¡¡very¡¡difficult¡¡target¡¡to¡¡strike¡£¡¡¡¡If¡¡such¡¡a¡¡missile
were¡¡used¡¡against¡¡an¡¡airship¡¡of¡¡the¡¡proportions¡¡of¡¡a¡¡Zeppelin¡¡the
mine¡¡would¡¡inevitably¡¡be¡¡trawled¡¡across¡¡the¡¡vessel¡¡sooner¡¡or
later¡£¡¡¡¡Once¡¡the¡¡airship¡¡had¡¡been¡¡fouled£»¡¡the¡¡aviator¡¡would
merely¡¡have¡¡to¡¡drive¡¡ahead£»¡¡dragging¡¡the¡¡wire¡¡and¡¡its¡¡charge¡¡
across¡¡the¡¡gas¡bag¡¡until¡¡at¡¡last¡¡one¡¡of¡¡the¡¡contact¡¡levers¡¡of¡¡the
mine¡¡was¡¡moved¡¡by¡¡being¡¡dragged¡¡against¡¡some¡¡part¡¡of¡¡the¡¡vessel£»
when¡¡the¡¡mine¡¡would¡¡be¡¡exploded¡£¡¡¡¡In¡¡such¡¡operations¡¡the¡¡aviator
would¡¡run¡¡a¡¡certain¡¡risk£»¡¡as¡¡he¡¡would¡¡be¡¡more¡¡or¡¡less¡¡above¡¡the
airship£»¡¡and¡¡to¡¡a¡¡certain¡¡degree¡¡within¡¡the¡¡zone¡¡of¡¡the¡¡ultimate
explosion¡£¡¡¡¡But¡¡there¡¡is¡¡no¡¡doubt¡¡that¡¡he¡¡would¡¡succeed¡¡in¡¡his¡¡
¡¨fishing¡¨¡¡exploit¡¡within¡¡a¡¡very¡¡short¡¡time¡£
This¡¡ingenious¡¡scheme¡¡has¡¡already¡¡been¡¡tested¡¡upon¡¡a¡¡small¡¡scale
and¡¡has¡¡been¡¡found¡¡effective£»¡¡the¡¡trawling¡¡bomb¡¡being¡¡drawn
across¡¡its¡¡target¡¡and¡¡fired¡¡by¡¡contact¡¡within¡¡a¡¡few¡¡minutes¡£¡¡¡¡The
experiment¡¡seems¡¡to¡¡prove¡¡that¡¡it¡¡would¡¡be¡¡simpler¡¡and¡¡more
effectual¡¡to¡¡attack¡¡a¡¡hostile¡¡aircraft¡¡such¡¡as¡¡a¡¡Zeppelin¡¡in¡¡this
manner¡¡than¡¡to¡¡drop¡¡free¡¡bombs¡¡at¡¡random¡£¡¡¡¡Moreover£»¡¡we¡¡cannot
doubt¡¡that¡¡the¡¡sight¡¡of¡¡a¡¡mine¡¡containing¡¡even¡¡ten¡¡or¡¡twelve
pounds¡¡of¡¡high¡¡explosive¡¡dangling¡¡at¡¡the¡¡end¡¡of¡¡a¡¡wire¡¡would
precipitate¡¡a¡¡retreat¡¡on¡¡the¡¡part¡¡of¡¡an¡¡airship¡¡more¡¡speedily
than¡¡any¡¡other¡¡combative¡¡expedient¡£
The¡¡advocate¡¡of¡¡this¡¡mine¡trawling¡¡method£»¡¡who¡¡is¡¡a¡¡well¡known
aviator£»¡¡anticipates¡¡no¡¡difficulty¡¡in¡¡manoeuvring¡¡a¡¡mine¡¡weighing
30¡¡pounds¡¡at¡¡the¡¡end¡¡of¡¡300¡¡feet¡¡of¡¡fine¡¡wire¡£¡¡¡¡Success¡¡depends
in¡¡a¡¡great¡¡measure¡¡on¡¡the¡¡skill¡¡of¡¡the¡¡aviator¡¡in¡¡maintaining¡¡a
constant¡¡tension¡¡upon¡¡the¡¡line¡¡until¡¡it¡¡falls¡¡across¡¡its
objective¡£
The¡¡process¡¡calls¡¡for¡¡a¡¡certain¡¡manifestation¡¡of¡¡skill¡¡in
manoeuvring¡¡the¡¡aeroplane¡¡in¡¡relation¡¡to¡¡the¡¡airship£»¡¡judgment¡¡of
distance£»¡¡and¡¡ability¡¡to¡¡operate¡¡the¡¡aeroplane¡¡speedily¡£¡¡¡¡The
rapid¡¡ascensional¡¡capability¡¡of¡¡the¡¡airship£»¡¡as¡¡compared¡¡with
that¡¡of¡¡the¡¡aeroplane£»¡¡is¡¡a¡¡disadvantage£»¡¡but¡¡on¡¡the¡¡other¡¡hand£»
the¡¡superior¡¡mobility¡¡and¡¡speed¡¡of¡¡the¡¡aeroplane¡¡would¡¡tell
decisively¡¡for¡¡success¡£
Among¡¡the¡¡many¡¡wonders¡¡which¡¡the¡¡Krupp¡¡organisation¡¡is¡¡stated¡¡to
have¡¡perfected£»¡¡and¡¡which¡¡it¡¡is¡¡claimed¡¡will¡¡create¡¡considerable
surprise£»¡¡is¡¡the¡¡aerial¡¡torpedo¡£¡¡¡¡Many¡¡of¡¡the¡¡Krupp¡¡claims¡¡are
wildly¡¡chimerical£»¡¡as¡¡events¡¡have¡¡already¡¡proved£»¡¡but¡¡there¡¡is¡¡no
doubt¡¡that¡¡considerable¡¡effort¡¡has¡¡been¡¡expended¡¡upon¡¡this¡¡latest
missile£»¡¡for¡¡which¡¡the¡¡firm¡¡is¡¡said¡¡to¡¡have¡¡paid¡¡the¡¡inventor
upwards¡¡of¡¡L25£»000125£»000¡£¡¡¡¡Curiously¡¡enough¡¡the¡¡projectile
was¡¡perfected¡¡within¡¡gunshot¡¡of¡¡the¡¡British¡¡aerodrome¡¡of¡¡Hendon
and¡¡is¡¡stated¡¡to¡¡have¡¡been¡¡offered¡¡to¡¡the¡¡British¡¡Government¡¡at
the¡¡time£»¡¡and¡¡to¡¡have¡¡met¡¡with¡¡a¡¡chilling¡¡reception¡£¡¡¡¡One¡¡fact£»
however£»¡¡is¡¡well¡¡established¡£¡¡¡¡The¡¡inventor¡¡went¡¡to¡¡Germany£»¡¡and
submitted¡¡his¡¡idea¡¡to¡¡Krupp£»¡¡by¡¡whom¡¡it¡¡was¡¡tested¡¡without¡¡delay¡£¡¡
Upon¡¡the¡¡completion¡¡of¡¡the¡¡purchase£»¡¡the¡¡great¡¡armament
manufacturers¡¡did¡¡not¡¡fail¡¡to¡¡publish¡¡broadcast¡¡the¡¡fact¡¡that
they¡¡had¡¡acquired¡¡a¡¡mysterious¡¡new¡¡terror¡¡of¡¡the¡¡skies¡£¡¡¡¡That¡¡was
some¡¡three¡¡years¡¡ago£»¡¡and¡¡in¡¡the¡¡interval¡¡the¡¡cleverest¡¡brains¡¡of
the¡¡German¡¡firm¡¡have¡¡been¡¡steadily¡¡devoting¡¡their¡¡time¡¡and
energies¡¡to¡¡the¡¡improvement¡¡of¡¡the¡¡missile£»¡¡the¡¡first¡¡appearance
of¡¡which¡¡was¡¡recorded£»¡¡in¡¡a¡¡somewhat¡¡hazy¡¡manner£»¡¡in¡¡the¡¡closing
days¡¡of¡¡December¡£
While¡¡the¡¡exact¡¡mechanism¡¡of¡¡this¡¡missile¡¡is¡¡a¡¡secret£»¡¡the
governing¡¡principles¡¡of¡¡its¡¡design¡¡and¡¡operation¡¡are¡¡known¡¡to¡¡a
select¡¡few¡¡technicians¡¡in¡¡this¡¡country¡£¡¡¡¡Strange¡¡to¡¡say£»¡¡the
projectile¡¡was¡¡designed¡¡in¡¡the¡¡first¡¡instance¡¡in¡¡the¡¡interests¡¡of
peace¡¡and¡¡humanty£»¡¡but¡¡while¡¡engaged¡¡upon¡¡his¡¡experiments¡¡the
inventor¡¡suddenly¡¡concluded¡¡that¡¡it¡¡would¡¡be¡¡a¡¡more¡¡profitable
asset¡¡if¡¡devoted¡¡to¡¡the¡¡grim¡¡game¡¡of¡¡war¡£¡¡¡¡At¡¡the¡¡time¡¡the
military¡¡significance¡¡of¡¡the¡¡airship¡¡and¡¡the¡¡aeroplane¡¡were
becoming¡¡apparent£»¡¡hence¡¡the¡¡sudden¡¡diversion¡¡of¡¡the¡¡idea¡¡into¡¡a
destructive¡¡channel¡£
This¡¡aerial¡¡torpedo¡¡is¡¡a¡¡small¡¡missile¡¡carrying¡¡a¡¡charge¡¡of¡¡high
explosive£»¡¡such¡¡as¡¡trinitrotoluene£»¡¡and¡¡depends¡¡for¡¡its
detonation¡¡upon¡¡impact¡¡or¡¡a¡¡time¡¡fuse¡£¡¡¡¡It¡¡is¡¡launched¡¡into¡¡the
air¡¡from¡¡a¡¡cradle¡¡in¡¡the¡¡manner¡¡of¡¡the¡¡ordinary¡¡torpedo£»¡¡but¡¡the
initial¡¡velocity¡¡is¡¡low¡£¡¡¡¡The¡¡torpedo¡¡is¡¡fitted¡¡with¡¡its¡¡own
motive¡¡power£»¡¡which¡¡comes¡¡automatically¡¡into¡¡action¡¡as¡¡the
missile¡¡climbs¡¡into¡¡the¡¡air¡£¡¡¡¡This¡¡self¡contained¡¡energy¡¡is¡¡so
devised¡¡that¡¡the¡¡maximum¡¡power¡¡is¡¡attained¡¡before¡¡the¡¡missile¡¡has
lost¡¡the¡¡velocity¡¡imparted¡¡in¡¡the¡¡first¡¡instance£»¡¡the¡¡result
being¡¡that¡¡it¡¡is¡¡able¡¡to¡¡continue¡¡its¡¡flight¡¡in¡¡a¡¡horizontal
direction¡¡from¡¡the¡¡moment¡¡it¡¡attains¡¡the¡¡highest¡¡point¡¡in¡¡its
trajectory£»¡¡which¡¡is¡¡naturally¡¡varied¡¡according¡¡to¡¡requirements¡£¡¡
But¡¡there¡¡is¡¡no¡¡secret¡¡about¡¡the¡¡means¡¡of¡¡propulsion¡£¡¡¡¡The¡¡body
is¡¡charged¡¡with¡¡a¡¡slow¡burning¡¡combustible£»¡¡in¡¡the¡¡manner¡¡of¡¡the
ordinary¡¡rocket£»¡¡whereby¡¡it¡¡is¡¡given¡¡a¡¡rapid¡¡rotary¡¡motion¡£
Furthermore¡¡it¡¡is¡¡stated¡¡to¡¡be¡¡fitted¡¡with¡¡a¡¡small¡¡gyroscope¡¡in
the¡¡manner¡¡of¡¡the¡¡torpedo¡¡used¡¡in¡¡the¡¡seas£»¡¡for¡¡the¡¡purpose¡¡of
maintaining¡¡direction¡¡during¡¡flight£»¡¡but¡¡upon¡¡this¡¡point¡¡there¡¡is
considerable¡¡divergence¡¡of¡¡opinion¡¡among¡¡technicians£»¡¡the¡¡general
idea¡¡being¡¡that¡¡the¡¡torpedo¡¡depends¡¡upon¡¡an¡¡application¡¡of¡¡the
principle¡¡of¡¡the¡¡ordinary¡¡rocket¡¡rather¡¡than¡¡upon¡¡a¡¡small¡¡engine
such¡¡as¡¡is¡¡fitted¡¡to¡¡the¡¡ordinary¡¡torpedo¡£¡¡¡¡The¡¡employment¡¡of¡¡a
slow¡¡combustible¡¡ensures¡¡the¡¡maintenance¡¡of¡¡the¡¡missile¡¡in¡¡the
air¡¡for¡¡a¡¡period¡¡exceeding¡¡that¡¡of¡¡the¡¡ordinary¡¡shell¡£¡¡¡¡It¡¡is
claimed¡¡by¡¡the¡¡Germans¡¡that¡¡this¡¡projectile¡¡will¡¡keep¡¡aloft¡¡for
half¡an¡hour¡¡or¡¡more£»¡¡but¡¡this¡¡is¡¡a¡¡phantasy¡£¡¡¡¡Its¡¡maintenance¡¡of
flight¡¡is¡¡merely¡¡a¡¡matter¡¡of¡¡minutes¡£
The¡¡belated¡¡appearance¡¡of¡¡this¡¡much¡lauded¡¡projectile¡¡and¡¡its
restricted¡¡use¡¡suggest¡¡that¡¡it¡¡is¡¡unreliable£»¡¡and¡¡perhaps¡¡no¡¡more
effective¡¡than¡¡the¡¡aerial¡¡torpedo¡¡which¡¡appeared¡¡in¡¡the¡¡United
States¡¡during¡¡the¡¡Spanish¡American¡¡War£»¡¡and¡¡proved¡¡a¡¡complete
failure¡£¡¡¡¡An¡¡effective¡¡and¡¡reliable¡¡means¡¡of¡¡combating¡¡or
frustrating¡¡a¡¡dirigible¡¡attack£»¡¡other¡¡than¡¡by¡¡gun¡fire¡¡or¡¡resort
to¡¡the¡¡drastic¡¡remedy¡¡of¡¡ramming¡¡the¡¡enemy£»¡¡has¡¡yet¡¡to¡¡be
devised¡£
CHAPTER¡¡XVII
WIRELESS¡¡IN¡¡AVIATION
In¡¡a¡¡previous¡¡chapter¡¡the¡¡various¡¡methods¡¡of¡¡signalling¡¡between
the¡¡ground¡¡and¡¡the¡¡airman¡¡aloft¡¡have¡¡been¡¡described¡£¡¡¡¡Seeing¡¡that
wireless¡¡telegraphy¡¡has¡¡made¡¡such¡¡enormous¡¡strides¡¡and¡¡has
advanced¡¡to¡¡such¡¡a¡¡degree¡¡of¡¡perfection£»¡¡one¡¡naturally¡¡would
conclude¡¡that¡¡it¡¡constitutes¡¡an¡¡ideal¡¡system¡¡of¡¡communication
under¡¡such¡¡conditions¡¡in¡¡military¡¡operations¡£
But¡¡this¡¡is¡¡not¡¡the¡¡case¡£¡¡¡¡Wireless¡¡is¡¡utilised¡¡only¡¡to¡¡a¡¡very
limited¡¡extent¡£¡¡¡¡This¡¡is¡¡due¡¡to¡¡two¡¡causes¡£¡¡¡¡The¡¡one¡¡is¡¡of¡¡a
technical£»¡¡the¡¡other¡¡of¡¡a¡¡strategical¡¡character¡£
The¡¡uninitiated£»¡¡bearing¡¡in¡¡mind¡¡the¡¡comparative¡¡ease¡¡with¡¡which
wireless¡¡installations¡¡may¡¡be¡¡established¡¡at¡¡a¡¡relatively¡¡small
expense£»¡¡would¡¡not¡¡unreasonably¡¡think¡¡that¡¡no¡¡serious
difficulties¡¡of¡¡a¡¡technical¡¡character¡¡could¡¡arise£º¡¡at¡¡least¡¡none
which¡¡would¡¡defy¡¡solution¡£¡¡¡¡But¡¡these¡¡difficulties¡¡exist¡¡in¡¡two
or¡¡three¡¡different¡¡fields£»¡¡each¡¡of¡¡which¡¡is¡¡peculiarly¡¡complex
and¡¡demands¡¡individual¡¡treatment¡£
In¡¡the¡¡first¡¡place£»¡¡there¡¡is¡¡the¡¡weight¡¡of¡¡the¡¡necessary
installation¡£¡¡¡¡In¡¡the¡¡case¡¡of¡¡the¡¡dirigible¡¡this¡¡may¡¡be¡¡a
secondary¡¡consideration£»¡¡but¡¡with¡¡the¡¡aeroplane¡¡it¡¡is¡¡a¡¡matter¡¡of
primary¡¡and¡¡vital¡¡importance¡£¡¡¡¡Again£»¡¡under¡¡present¡¡conditions£»
the¡¡noise¡¡of¡¡the¡¡motor¡¡is¡¡apt¡¡to¡¡render¡¡the¡¡intelligent
deciphering¡¡of¡¡messages¡¡while¡¡aloft¡¡a¡¡matter¡¡of¡¡extreme
difficulty£»¡¡especially¡¡as¡¡these¡¡are¡¡communicated¡¡in¡¡code¡£¡¡¡¡The
engine¡¡noise¡¡might¡¡be¡¡effectively¡¡overcome¡¡by¡¡the¡¡use¡¡of¡¡a
muffler¡¡such¡¡as£»¡¡is¡¡used¡¡with¡¡automobiles£»¡¡but¡¡then¡¡there¡¡is¡¡the
further¡¡difficulty¡¡of¡¡vibration¡£
This¡¡problem¡¡is¡¡being¡¡attacked¡¡in¡¡an¡¡ingenious¡¡manner¡£¡¡¡¡It¡¡is
proposed¡¡to¡¡substitute¡¡for¡¡audible¡¡signals¡¡visual
interpretations£»¡¡by¡¡the¡¡aid¡¡of¡¡an¡¡electric¡¡lamp£»¡¡the¡¡fluctuations
in¡¡which¡¡would¡¡correspond¡¡to¡¡the¡¡dots¡¡and¡¡dashes¡¡of¡¡the¡¡Morse
code¡£¡¡¡¡Thus¡¡the¡¡airman¡¡would¡¡read¡¡his¡¡messages¡¡by¡¡sight¡¡instead
of¡¡by¡¡sound¡£
This¡¡method£»¡¡however£»¡¡is¡¡quite¡¡in¡¡its¡¡infancy£»¡¡and¡¡although
attractive¡¡in¡¡theory¡¡and¡¡fascinating¡¡as¡¡a¡¡laboratory¡¡experiment
or¡¡when¡¡conducted¡¡under¡¡experimental¡¡conditions£»¡¡it¡¡has¡¡not
proved¡¡reliable¡¡or¡¡effective¡¡in¡¡aeronautical¡¡operations¡£¡¡¡¡But¡¡at
the¡¡same¡¡time¡¡it¡¡indicates¡¡a¡¡promising¡¡line¡¡of¡¡research¡¡and
development¡£
Then¡¡there¡¡are¡¡the¡¡problems¡¡of¡¡weight¡¡and¡¡the¡¡aerial¡£¡¡¡¡So¡¡far¡¡as
present¡¡knowledge¡¡goes£»¡¡the¡¡most¡¡satisfactory¡¡form¡¡of¡¡aerial¡¡yet
exploited¡¡is¡¡that¡¡known¡¡as¡¡the¡¡trailing¡¡wire¡£¡¡¡¡From¡¡300¡¡to¡¡700
feet¡¡of¡¡wire¡¡are¡¡coiled¡¡upon¡¡a¡¡reel£»¡¡and¡¡when¡¡aloft¡¡this¡¡wire¡¡is
paid¡¡out¡¡so¡¡that¡¡it¡¡hangs¡¡below¡¡the¡¡aeroplane¡£¡¡¡¡As¡¡a¡¡matter¡¡of
fact£»when¡¡the¡¡machine¡¡is¡¡travelling¡¡at¡¡high¡¡speed¡¡it¡¡trails
horizontally¡¡astern£»¡¡but¡¡this¡¡is¡¡immaterial¡£¡¡¡¡One¡¡investigator£»
who¡¡strongly¡¡disapproves¡¡of¡¡the¡¡trailing¡¡aerial£»¡¡has¡¡carried¡¡out
experiments¡¡with¡¡a¡¡network¡¡of¡¡wires¡¡laid¡¡upon¡¡and¡¡attached¡¡to¡¡the
surface¡¡of¡¡the¡¡aeroplane's¡¡wings¡£¡¡¡¡But¡¡the¡¡trailing¡¡wire¡¡is
generally¡¡preferred£»¡¡and¡¡certainly¡¡up¡¡to¡¡the¡¡present¡¡has¡¡proved
more¡¡satisfactory¡£
The¡¡greatest¡¡obstacle£»¡¡however£»¡¡is¡¡the¡¡necessary¡¡apparatus¡£¡¡¡¡The
average¡¡aeroplane¡¡designed¡¡for¡¡military¡¡duty¡¡is¡¡already¡¡loaded¡¡to
the¡¡maximum¡£¡¡¡¡As¡¡a¡¡rule¡¡it¡¡carries¡¡the¡¡pilot¡¡and¡¡an¡¡observer£»¡¡and
invariably¡¡includes¡¡a¡¡light¡¡arm¡¡for¡¡defence¡¡against¡¡an¡¡aerial
enemy£»¡¡together¡¡with¡¡an¡¡adequate¡¡supply¡¡of¡¡ammunition£»¡¡while
unless¡¡short¡¡sharp¡¡flights¡¡are¡¡to¡¡be¡¡made£»¡¡the¡¡fuel¡¡supply
represents¡¡an¡¡appreciable¡¡load¡£¡¡¡¡Under¡¡these¡¡circumstances¡¡the
item¡¡of¡¡weight¡¡is¡¡a¡¡vital¡¡consideration¡£¡¡¡¡It¡¡must¡¡be¡¡kept¡¡within
a¡¡limit¡¡of¡¡100¡¡pounds£»¡¡and¡¡the¡¡less¡¡the¡¡equipment¡¡weighs¡¡the¡¡more
satisfactory¡¡it¡¡is¡¡likely¡¡to¡¡prove£»¡¡other¡¡things¡¡being¡¡equal¡£
The¡¡two¡¡most¡¡successful¡¡systems¡¡yet¡¡exploited¡¡are¡¡the¡¡Dubilier
and¡¡the¡¡Rouget¡£¡¡¡¡The¡¡former¡¡is¡¡an¡¡American¡¡invention£»¡¡the¡¡latter
is¡¡of¡¡French¡¡origin¡£¡¡¡¡Both¡¡have¡¡been¡¡tested¡¡by¡¡the¡¡British
Military¡¡Aeronautical¡¡Department£»¡¡and¡¡the¡¡French¡¡authorities
have¡¡subjected¡¡the¡¡French¡¡system¡¡to¡¡rigorous¡¡trials¡£¡¡¡¡Both
systems£»¡¡within¡¡their¡¡limitations£»¡¡have¡¡proved¡¡satisfactory¡£
The¡¡outstanding¡¡feature¡¡of¡¡the¡¡Dubilier¡¡system¡¡is¡¡the¡¡production
of¡¡sine¡¡waves¡¡of¡¡musical¡¡frequency¡¡from¡¡continuous¡¡current£»¡¡thus
dispensing¡¡with¡¡the¡¡rotary¡¡converter¡£¡¡¡¡The¡¡operating¡¡principle¡¡is
the¡¡obtaining