第8部分(第7/7 頁)

　diameter。　On　all　sides　there　were　handholds；　a　narrow　metal　bench；　the　glowing　heat　lamps　overhead；　though　they　didn't　seem　to　do　much　good。

Ted　climbed　up　and　sat　on　the　bench　opposite　him。　They　were　so　close　their　knees　touched。　Below　their　feet；　the　pilot　closed　the　hatch。　They　watched　the　wheel　spin。　They　heard　a　clank　as　the　submarine　disengaged；　then　the　whirr　of　motors　as　it　moved　away。

Then　nothing。

〃What　happens　now？〃　Norman　said。

〃They　pressurize　us；〃　Ted　said。　〃Switch　us　over　to　exotic…gas　atmosphere。　We　can't　breathe　air　down　here。〃

〃Why　not？〃　Norman　said。　Now　that　he　was　down　here；　staring　at　the　cold　steel　walls　of　the　cylinder；　he　wished　he　had　stayed　awake　for　the　briefing。

〃Because；〃　Ted　said；　〃the　atmosphere　of　the　Earth　is　deadly。　You　don't　realize　it；　but　oxygen　is　a　corrosive　gas。　It's　in　the　same　chemical　family　as　chlorine　and　fluorine；　and　hydrofluoric　acid　is　the　most　corrosive　acid　known。　The　same　quality　of　oxygen　that　makes　a　half…eaten　apple　turn　brown；　or　makes　iron　rust；　is　incredibly　destructive　to　the　human　body　if　exposed　to　too　much　of　it。　Oxygen　under　pressure　is　toxic