front of the city the waters seemed to be sucked away,
slowly returning as the sea forced them to their level,
and at many points up and down the harbour there were
submarine detonations and upheavals of the water.

These were caused by the explosion, by concussion,
of every torpedo and submarine battery in the harbour;
and it was with this object in view that the
instantaneous motor-bomb had been shot into the mouth
of the bay.

The effects of the discharge of the motor-bomb
astonished and even startled those on board the
repellers and the crabs. At the instant of touching
the button a hydraulic shock was felt on Repeller No.
1. This was supposed to be occasioned the discharge of
the motor, but it was also felt on the other vessels.
It was the same shock that had been felt on shore, but
less in degree. A few moments after there was a great
heaving swell of the sea, which tossed and rolled the
four vessels, and lifted the steel protecting net
so high that for an instant parts of it showed
themselves above the surface like glistening sea-ghosts.

Experiments with motor-bombs had been made in
unsettled mountainous districts, but this was the first
one which had ever exerted its power under water.

On shore, in the forts, and in the city no one for
an instant supposed that the terrific phenomenon which