s vapor. The explosion produced an excavation measuring fully a cubic
yard. It was accompanied by a sharp detonation that may be compared to
the report of a cannon.

The first charge used, although a very small one, a mere pinch, blew
the men in every direction, and two of them were seriously injured.
Engineer Serko himself was projected several yards, and sustained some
rather severe contusions.

Here is how this substance, whose bursting force surpasses anything
hitherto conceived, is employed.

A small hole about an inch and a half in length is pierced obliquely
in the rock. A few grains of the explosive are then inserted, but no
wad is used.

Then Thomas Roch steps forward. In his hand is a little glass phial
containing a bluish, oily liquid that congeals almost as soon as it
comes in contact with the air. He pours one drop on the entrance of
the hole, and draws back, but not with undue haste. It takes a certain
time--about thirty-five seconds, I reckon--before the combination of
the fulgurator and deflagrator is effected. But when the explosion
does take place its power of disaggregation is such--I repeat--that
it may be regarded as unlimited. It is at any rate a thousand times
superior to that of any known explosive.

Under these circumstances it will probably not take more than a week
to complete the tunnel.

_September 19_.--For some time past I have observed that the tide
rises and falls twice every twenty-four hours, and that the ebb and
flow produce a rather swift current through the submarine tunnel. It
is pretty certain therefore that a floating object thrown into the
lagoon when the top of the orifice is uncovered would be carried out
by the receding tide. It is just possible that during the lowest
equinoctial tides the top of the orifice is uncovered. This I shall be
able to ascertain, as this is precisely the time they occur. To-day,
September 19, I could almost distinguish the summit of the hole under
the water. The day after to-morrow, if ever, it will be uncovered.

Very well then, if I cannot myself attempt to get through, may be a
bottle thrown into the lagoon might be carried out during the last
few minutes of the ebb. And might not this bottle by chance--an
ultra-providential chance, I must avow--be picked up by a ship passing
near Back Cup? Perhaps even it might be borne away by a friendly
current and cast upon one of the Bermudan beaches. What if that bottle
contained a letter?

I can