where　it　has　been　attempted　in　the　present
  conflict；　it　was　foiled。
  The　opposing　force　was　ready　to　meet　the　attack
  with　equal　or　superior　numbers。　The　eye
  of　the　army；　the　aeroplane；　detected　the　movements
  in　every　instance。
  THE　AEROPLANE　DETECTING　THE　MOVEMENTS　OF
  ARMIES。In　the　early　stages　of　the　war；　when
  the　Germans　drove　the　left　of　the　French　army
  towards　Paris；　the　world　expected　an　investment
  of　that　city。　Suddenly；　and　for　no　apparent
  reason；　the　German　right　was　forced　back　and
  commenced　to　retreat。
  It　was　not　known　until　weeks　afterwards　that
  the　French　had　assembled　a　large　army　to　the
  west　and　northwest　of　Paris；　ready　to　take　the
  Germans　in　flank　the　moment　an　attempt　should
  be　made　to　encircle　the　Paris　forts。
  The　German　aviators；　flying　over　Paris；　discovered
  the　hidden　army；　and　it　is　well　they　did
  so；　for　it　is　certain　if　they　had　surrounded　the
  outlying　forts；　it　would　have　been　an　easy　matter
  for　the　concealed　forces　to　destroy　their　communications；
  and　probably　have　forced　the　surrender
  of　a　large　part　of　the　besiegers。
  The　aeroplane　in　warfare；　therefore；　has　constantly
  noted　every　disposition　of　troops；　located
  the　positions　and　judged　the　destination　of　convoys；
  the　battery　emplacements；　and　the　direction
  in　which　large　forces　have　been　moved　from
  one　part　of　the　line　to　the　other；　thus　keeping　the
  commanders　so　well　informed　that　few　surprises
  were　possible。
  THE　EFFECTIVE　HEIGHT　FOR　SCOUTING。It　has
  been　shown　that　aeroplane　scouting　is　not　effective
  at　high　altitudes。　It　is　not　difficult　for　aviators
  to　reach　and　maintain　altitudes　of　five　thousand
  feet　and　over；　but　at　that　elevation　it　is　impossible
  to　distinguish　anything　but　the　movement
  of　large　forces。
  SIZES　OF　OBJECTS　AT　GREAT　DISTANCES。At　a
  distance　of　one　mile　an　automobile；　twenty　feet
  in　length；　is　about　as　large　as　a　piece　of　pencil
  one　inch　long；　viewed　at　a　distance　of　thirty…five
  feet。　A　company　of　one　hundred　men；　which　in
  marching　order；　say　four　abreast；　occupies　a　space
  of　eight　by　one　hundred　feet；　looks　to　the　aviator
  about　as　large　as　an　object　one　inch　in　length；　four
  and　a　half　feet　from　the　eye。
  The　march　of　such　a　body　of　men；　viewed　at
  that　distance；　is　so　small　as　almost　to　be　imperceptible
  to　the　eye　of　an　observer　at　rest。　How
  much　more　difficult　it　is　to　distinguish　a　movement
  if　the　observer　is　in　a　rapidly…moving　machine。
  For　these　reasons　observations　must　be　made
  at　altitudes　of　less　than　a　mile；　and　the　hazard
  of　these　enterprises　is；　therefore；　very　great；
  since　the　successful　scout　must　bring　himself
  within　range　of　specially　designed　guns；　which
  are　effective　at　a　range　of　3000　yards　or　more；
  knowing　that　his　only　hope　of　safety　lies　in　the
  chance　that　the　rapidly…moving　machine　will　avoid
  the　rain　of　bullets　that　try　to　seek　him　out。
  SOME　DARING　FEATS　IN　WAR。It　would　be　impossible
  to　recount　the　many　remarkable　aerial
  fights　which　have　taken　place　in　the　great　war。
  Some　of　them　seem　to　be　unreal；　so　startling　are
  the　tales　that　have　been　told。　We　may　well　imagine
  the　bravery　that　will　nerve　men　to　fight
  thousands　of　feet　above　the　earth。
  One　of　the　most　thrilling　combats　took　place
  between　a　Russian　aeroplane　and　a　Zeppelin；　over
  Russian　Poland；　at　the　time　of　the　first　German
  invasion。　The　Zeppelin　was　soaring　over　the
  Russian　position；　at　an　altitude　of　about　a　mile。
  A　Russian　aviator　ascended　and　after　circling
  about；　so　as　to　gain　a　position　higher　than　the
  airship；　darted　down；　and　crashed　into　the　great
  gas　field。
  The　aviator　knew　that　it　meant　death　to　him；
  but　his　devotion　led　him　to　make　the　sacrifice。
  The　Zeppelin；　broken　in　two；　and　robbed　of　its
  gas；　slowly　moved　toward　the　earth；　then　gradually
  increased　the　speed　of　its　descent；　as　the
  aeroplane　clung　to　its　shattered　hulk；　and　by　the
  time　it　neared　the　earth　its　velocity　was　great
  enough　to　assure　the　destruction　of　all　on　board；
  while　the　ship　itself　was　crushed　to　atoms。
  One　of　the　most　spectacular　fights　of　the　war
  occurred　outside　Paris；　when　one　of　the　German
  Taubes　attempted　to　make　its　periodical　tour
  of　observation。　One　of　the　French　aeroplanes；
  which　had　the　advantage　of　greater　speed；
  mounted　to　a　greater　altitude；　and　circled　about
  the　Taube。
  The　latter　with　its　machine　gun　made　a　furious
  attack；　during　these　maneuvers；　but　the　French
  ship　did　not　reply　until　it　was　at　such　an　elevation
  that　it　could　deliver　the　attack　from　above。
  Then　its　machine　gun　was　brought　into　play。　As
  was　afterwards　discovered；　the　wings　and　body
  of　the　Taube　were　completely　riddled；　and　it　was
  a　marvel　how　it　was　possible　for　the　German　aviator
  to　remain　afloat　as　long　as　he　did。
  Soon　the　Taube　was　noticed　to　lurch　from　side
  to　side；　and　then　dart　downwardly。　The　monoplane；
  in　the　pursuit；　gradually　descended；　but　it
  was　not　able　to　follow　the　destroyed　Taube　to　the
  earth；　as　the　latter　finally　turned　over；　and　went
  swirling　to　destruction。
  The　observer；　as　well　as　the　aviator；　had　both
  been　killed　by　the　fire　from　the　monoplane。
  In　the　trenches　on　the　Marne；　to　the　northeast
  of　Paris；　where　the　most　stubborn　conflict　raged
  for　over　a　week；　the　air　was　never　clear　of　aeroplanes。
  They　could　be　seen　in　all　directions；　and
  almost　all　types　of　machines　were　represented。
  The　principal　ones；　however；　were　monoplanes。
  THE　GERMAN　TAUBE。The　German　Taube　is　a
  monoplane；　its　main　supporting　surfaces；　as　well
  as　the　tail　planes；　are　so　constructed　that　they
  represent　a　bird。　Taube　means　dove。　It　would
  have　been　more　appropriate　to　call　it　a　hawk。
  On　the　other　hand；　the　French　monoplane；　of
  which　the　Bleriot　is　the　best　known　example；　has
  wings　with　well　rounded　extremities；　and　flaring
  tail；　so　that　the　two　can　be　readily　distinguished。
  On　one　occasion；　during　the　lull　in　the　battle；
  two　of　the　Taubes　approached　the　area　above　the
  French　lines；　and　after　ascending　to　a　great
  height；　began　the　volplane　toward　their　own　lines。
  Such　a　maneuver　was　found　to　be　the　most　advantageous；
  as　it　gave　the　scouting　aeroplane　the
  advantage　of　being　able　to　discover　the　positions
  and　movements　with　greater　ease；　and　at　the　same
  time；　in　case　of　accident　to　the　machine；　the　impetus
  of　the　flight　would　be　to　their　own　lines。
  Three　of　the　French　aeroplanes　at　once　began
  their　circling　flight；　mounting　higher　and　higher；
  but　without　attempting　to　go　near　the　Taubes。
  When　the　French　ships　had　gained　the　proper
  altitude；　they　closed　in　toward　the　German　ships；
  before　the　latter　could　reach　their　own　lines　in
  their　volplaning　act。
  This　meant　that　they　must　retreat　or　fight；　and
  the　crack　of　the　guns　showed　that　it　meant　a
  struggle。　The　monoplanes　circled　about　with
  incredible　skill；　pouring　forth　shot　after　shot。
  Soon　one　of　the　Taubes　was　seen　to　flutter。
  This　was　the　signal　for　a　more　concentrated　attack
  on　her。
  The　army　in　the　trenches；　and　on　the　fields　below；
  witnessed　the　novel　combat。　The　flying
  ships　were　now　approaching　the　earth；　but　the
  gunners　below　dared　not　use　their　guns；　because
  in　the　maneuvers　they　would　be　as　likely　to　strike
  friend　as　foe。
  The　wounded　Taube　was　now　shooting　to　the
  earth；　and　the　two　monoplanes　began　to　give　their
  attention　to　the　other　ship；　which　was　attempting
  to　escape　to　the　north。　The　flash　of　the　guns　of
  all　the　fliers　could　be　plainly　seen；　but　the　sounds
  were　drowned　by　the　roar　of　the　great　conflict　all
  about　them。
  The　Taube　could　not　escape　the　net　around　her。
  She；　too；　was　doomed。　A　shot　seemed　to　strike
  the　gasoline　tank；　and　the　framework　was　soon
  enveloped　in　flames。　Then　she　turned　sidewise；
  as　the　material　on　one　side　burned　away；　and
  skidding　to　the　left　she　darted　to　the　earth；
  a　shapeless　mass。
  It　was　found　that　the　aviator　was　not　hurt　by
  the　shot；　but　was；　undoubtedly；　killed　by　the　impact
  with　the　earth。　The　observer　was　riddled
  with　bullets；　and　was　likely　dead　before　the　ship
  reached　the　earth。
  In　the　western　confines　of　Belgium；　near　Ypres；
  the　British　employed　numerous　aircraft；　many　of
  them　biplanes；　and　at　all　times　they　were　in　the
  air；　reporting　observations。　Many　of　the　flying
  fights　have　been　recorded；　and　the　reports　when
  published　will　be　most　thrilling　reading。
  HOW　AEROPLANES　REPORT　OBSERVATIONS。It
  may　be　of　some　interest　to　know　how　aeroplanes
  are　able　to　report　observations　to　the　commanders
  in　the　field；　from　the　airship　itself。　Many
  ingenious　devices　have　been　devised　for　this　purpose。
  SIGNAL　FLAGS。The　best　known　and　most　universally
  used　method　is　by　the　use　of　signaling
  flags。　Suppose　the　commander　of　a　force　is　desirous
  of　getting　the　range　of　a　hidden　battery；
  or　a　massed　force　in　his　front。　The　observer　in
  the　aeroplane　will　sail　over　the　area　a