Людина-невидимка
Certain First Principles
"Phew!"saidKemp. "That'sodd!ButstillIdon'tseequite... Icanunderstandthattherebyyoucouldspoilavaluablestone,butpersonalinvisibilityisafarcry."
"Precisely,"saidGriffin. "Butconsider,visibilitydependsontheactionofthevisiblebodiesonlight. Eitherabodyabsorbslight,oritreflectsorrefractsit,ordoesallthesethings. Ifitneitherreflectsnorrefractsnorabsorbslight,itcannotofitselfbevisible. Youseeanopaqueredbox,forinstance,becausethecolourabsorbssomeofthelightandreflectstherest,alltheredpartofthelight,toyou. Ifitdidnotabsorbanyparticularpartofthelight,butreflecteditall,thenitwouldbeashiningwhitebox. Silver!Adiamondboxwouldneitherabsorbmuchofthelightnorreflectmuchfromthegeneralsurface,butjusthereandtherewherethesurfaceswerefavourablethelightwouldbereflectedandrefracted,sothatyouwouldgetabrilliantappearanceofflashingreflectionsandtranslucencies—asortofskeletonoflight. Aglassboxwouldnotbesobrilliant,norsoclearlyvisible,asadiamondbox,becausetherewouldbelessrefractionandreflection.Seethat? Fromcertainpointsofviewyouwouldseequiteclearlythroughit.Somekindsofglasswouldbemorevisiblethanothers,aboxofflintglasswouldbebrighterthanaboxofordinarywindowglass. Aboxofverythincommonglasswouldbehardtoseeinabadlight,becauseitwouldabsorbhardlyanylightandrefractandreflectverylittle.
