But，erethis，anumberofsomewhatsimilarexperiments，onbehalfoftheFrenchGovernment，hadbeenentereduponbyCaptainsRenardandKrebsatChalais—Meudon。Theirballoonmaybedescribedasfish—shaped，165feetlong，and27。5feetinprincipaldiameter。Itwasoperatedbyanelectricmotor，whichwascapableofdrivingascrewoflargedimensionsatforty—eightrevolutionsperminute。Atitsfirsttrial，inAugust，1884，indeadcalm，itattainedavelocityofovertwelvemilesperhour，travellingsometwoandahalfmilesinaforwarddirection，when，byapplicationoftherudderandjudiciousmanagement，itwasmanoeuvredhomewards，andpracticallybroughttoearthatthepointofdeparture。
Amoreimportanttrialwasmadeonthe12thofthefollowingmonth，andwaswitnessedbyM。Tissandier，accordingtowhomtheaerostatconveyingtheinventorsascendedgentlyandsteadily，driftingwithanappreciablebreezeuntilthescrewwassetinmotionandthehelmputdown，whenthevesselwasbroughtroundtothewindandhelditsownuntilthemotor，byanaccident，ceasedworking。Alittlelaterthesameairshipmetwithmoresignalsuccess。Ononeoccasion，startingfromChalaisMeudon，ittookadirectcoursetotheN。E。，crossingtherailwayandtheSeine，wheretheaeronauts，stoppingthescrew，ascertainedthevelocityofthewindtobeapproximatelyfivemilesanhour。Thescrewbeingagainputinmotion，theballoonwassteeredtotheright，and，followingapathparalleltoitsfirst，returnedtoitspointofdeparture。
Startingagainthesameafternoon，itwascausedtoperformavarietyofaerialevolutions，andafterthirty—fiveminutesreturnedoncemoretoitsstartingplace。
Atabularcomparisonofthefournavigableballoonswhichwehavenowdescribedhasbeengivenasfollows:——
Date。Name。Motor。Vel。p。Sec。