Путешествие на Луну
The Hymn of the Cannon-Ball
"Hollow?thenitwouldbeashell?"
"Yes,ashell,"repliedBarbicane;"decidelyitmustbe.Asolidshotof108incheswouldweighmorethan200,000pounds,aweightevidentlyfartoogreat.Still,aswemustreserveacertainstabilityforourprojectile,Iproposetogiveitaweightof20,000pounds."
"What,then,willbethethicknessofthesides?"askedthemajor.
"Ifwefollowtheusualproportion,"repliedMorgan,"adiameterof108incheswouldrequiresidesoftwofeetthickness,orless."
"Thatwouldbetoomuch,"repliedBarbicane;"foryouwillobservethatthequestionisnotthatofashotintendedtopierceanironplate;itwillsufficetogiveitsidesstrongenoughtoresistthepressureofthegas.Theproblem,therefore,isthis—Whatthicknessoughtacast-ironshelltohaveinordernottoweightmorethan20,000pounds?Ourcleversecretarywillsoonenlightenusuponthispoint."
"Nothingeasier."repliedtheworthysecretaryofthecommittee;and,rapidlytracingafewalgebraicalformulaeuponpaper,amongwhichn^2andx^2frequentlyappeared,hepresentlysaid:
"Thesideswillrequireathicknessoflessthantwoinches."
"Willthatbeenough?"askedthemajordoubtfully.
"Clearlynot!"repliedthepresident.
"Whatistobedone,then?"saidElphinstone,withapuzzledair.
"Employanothermetalinsteadofiron."
"Copper?"saidMorgan.
"No!thatwouldbetooheavy.Ihavebetterthanthattooffer."
"Whatthen?"askedthemajor.
"Aluminum!"repliedBarbicane.
