ButthissamesummersawthereturntoEnglandofHenryCoxwell，andforsomeyearsthestoryoftheconquestoftheairisbesttoldbyfollowinghisstirringcareer，andhisowncommentsonaeronauticaleventsofthisdate。Wefindhimshortlysettingaboutcarryingoutsomereconnoitringandsignallingexperiments，designedtobeofuseintimeofwar。
Thiswasanoldideaofhis，andonewhichhad，ofcourse，beenlongentertainedbyothers，having，indeed，beenputtosomepracticaltestintimeofwarfare。Itwillbewelltomakenoteofwhatattentionthematterhadalreadyreceived，andofwhatprogresshadbeenmadebothintheoryandpractice。
WehavealreadymadesomementioninChapterIV。oftheusewhichtheFrenchhadmadeofballoonsintheirmilitaryoperationsattheendoftheeighteenthandbeginningofnineteenththecentury。Itwas，indeed，withinthefirsttenyearsafterthefirstinventionoftheballoonthat，underthesuperintendenceofthesavantsoftheFrenchAcademy，apracticalschoolofaeronauticswasestablishedatMeudon。ThenamesofGuyton，DeMorveau（adistinguishedFrenchchemist），andColonelCoutellearechieflyassociatedwiththemovement，andunderthemsomefiftystudentsreceivednecessarytraining。
Thepractisingballoonhadacapacityof17，000cubicfeet，andwasinflatedwithpurehydrogen，madebywhatwasthenanewprocessasappliedtoballooning，andwhichwillbedescribedinafuturechapter。Itappearsthattheballoonwaskeptalwaysfull，sothatanyopportunityofcalmweatherwouldbetakenadvantageofforpractice。Anditisfurtherstatedthataballoonwasconstructedsosoundandimperviousthatafterthelapseoftwomonthsitwasstillcapable，withoutbeingreplenished，ofraisingintotheairtwomen，withnecessaryballastandequipment。ThepracticaltrialfortheballooninrealservicecameoffinJune，1794，whenCoutelleinperson，accompaniedbytwostaffofficers，inoneofthefourballoonswhichtheFrenchArmyhadprovided，madeanascenttoreconnoitretheAustrianforcesatFleurus。Theyascendedtwiceinoneday，remainingaloftforsomefourhours，and，ontheirsecondascentbeingsighted，drewabriskfirefromtheenemy。Theywereunharmed，however，andthesuccessfulterminationofthebattleofFleurushasbeenclaimedasdueinlargemeasuretotheservicerenderedbythatballoon。
TheextraordinaryfactthattheuseoftheballoonwasformanyyearsdiscontinuedintheFrenchArmyisattributedtoastrangelysuperstitiousprejudiceentertainedbyNapoleon。LasCases（inhis\"PrivateLifeofNapoleonatSt。Helena\"）