t　some　points　in　the　West　End。 I　had　a　vague　memory

that　as　I　have　travelled　by　it　I　have　occasionally　seen　windows

just　above　my　head。 Now；　suppose　that　a　train　halted　under　such

a　window；　would　there　be　any　difficulty　in　laying　a　body　upon　the

roof？〃

〃It　seems　most　improbable。〃

〃We　must　fall　back　upon　the　old　axiom　that　when　all　other

contingencies　fail；　whatever　remains；　however　improbable；　must　be

the　truth。 Here　all　other　contingencies　HAVE　failed。 When　I

found　that　the　leading　international　agent；　who　had　just　left

London；　lived　in　a　row　of　houses　which　abutted　upon　the

Underground；　I　was　so　pleased　that　you　were　a　little　astonished

at　my　sudden　frivolity。〃

〃Oh；　that　was　it；　was　it？〃

〃Yes；　that　was　it。 Mr。　Hugo　Oberstein；　of　13　Caulfield　Gardens；

had　bee　my　objective。 I　began　my　operations　at　Gloucester

Road　Station；　where　a　very　helpful　official　walked　with　me　along

the　track　and　allowed　me　to　satisfy　myself　not　only　that　the

back…stair　windows　of　Caulfield　Gardens　open　on　the　line　but　the

even　more　essential　fact　that；　owing　to　the　intersection　of　one

of　the　larger　railways；　the　Underground　trains　are　frequently

held　motionless　for　some　minutes　at　that　very　spot。〃

〃Splendid；　Holmes！ You　have　got　it！〃

〃So　far……so　far；　Watson。 We　advance；　but　the　goal　is　afar。

Well；　having　seen　the　back　of　Caulfield　Gardens；　I　visited　the

front　and　satisfied　myself　that　the　bird　was　indeed　flown。 It　is

a　considerable　house；　unfurnished；　so　far　as　I　could　judge；　in

the　upper　rooms。 Oberstein　lived　there　with　a　single　valet；　who

was　probably　a　confederate　entirely　in　his　confidenc