It was tedious work, and toward the end needed great care so as not to excite suspicion.

But finally she was rewarded.
Through it she could see just a trace of daylight, and by squinting could see a row of bottles on a shelf opposite.
Then, through the hole, she pushed a long, narrow tube, like a putty blower.

When at last she placed her eye at it, she gave a low exclamation of satisfaction.

She could now see the whole of the little room.
It was a detectascope, invented by Gaillard Smith, adapter of the detectaphone, an instrument built up on the principle of the cytoscope which physicians use to explore internally down the throat.

Only, in the end of the tube, instead of an ordinary lens, was placed what is known as a "fish-eye" lens, which had a range something like nature has given the eyes of fishes, hence the name.