'When did he fix the tank ?' 'I do not know.

I had no idea it was done until the night of the arrest of Rogers.' At this moment Casey and Keel entered.
'Stand by the man, Casey,' said the detective.

'Keel, follow me.' Downy went straight to the tank and, creeping under it, struck a match and examined the floor above on which it rested.

Two of the boards had been moved aside, and in the bottom of the tank there was an opening about eighteen inches in diameter with a sheet of iron to cover it, in such a way as to deceive any but the most careful seeker.

The detective ordered Keel to bring a candle, and when it was forth coming he drew himself up into the tank and struck a light.