The problem was certainly simple enough, but for that very reason the more inexplicable.

If they were moving the explosion must have taken place; but if the explosion had taken place, why had they not heard the report?
Barbican's decision soon put an end to speculation.
"Conjecture being useless," said he, "let us have recourse to facts.
First, let us see where we are.

Drop the deadlights!" This operation, simple enough in itself and being immediately undertaken by the whole three, was easily accomplished.

The screws fastening the bolts by which the external plates of the deadlights were solidly pinned, readily yielded to the pressure of a powerful wrench.

The bolts were then driven outwards, and the holes which had contained them were immediately filled with solid plugs of India rubber.