It was covered with a roof, six feet in thickness, formed of blue
tombstones, placed edgewise. Over this crater, rose a hollow cone, or
pyramid, made of heavy marble slabs, and filled with mill-stones, cannon
balls, blocks of marble, chain-shot, iron hooks, plough-coulters, and
every dangerous missile that could be imagined. The spaces between the
mine and the sides of each ship were likewise filled with paving stones,
iron-bound stakes, harpoons, and other projectiles. The whole fabric was
then covered by a smooth light flooring of planks and brick-work, upon
which was a pile of wood: This was to be lighted at the proper time, in
order that the two vessels might present the appearance of simple fire-
ships, intended only to excite a conflagration of the bridge. On the
'Fortune' a slow match, very carefully prepared, communicated with the
submerged mine, which was to explode at a nicely-calculated moment. The
eruption of the other floating volcano was to be regulated by an
ingenious piece of clock-work, by which, at the appointed time, fire,
struck from a flint, was to inflame the hidden mass of gunpowder below.

In addition to these two infernal machines, or "hell-burners," as they
were called, a fleet of thirty-two smaller vessels was prepared. Covered
with tar, turpentine, rosin, and filled with inflammable and combustible
materials, these barks were to be sent from Antwerp down the river in
detachments of eight every half hour with the ebb tide. The object was
to clear the way, if possible, of the raft, and to occupy the attention
of the Spaniards, until the 'Fortune' and the `Hope' should come down
upon the bridge.

The 5th April, (1885) being the day following that on which the
successful assault upon Liefkenshoek and Saint Anthony had taken place,
was fixed for the descent of the fire-ships. So soon as it should be
dark, the thirty-two lesser burning-vessels, under the direction of