of a shark and beaten it off with actual blows. It was the Thermopylae
of sharkdom, with numbers reversed--a Red Sea passage resonant with
psalms of victory.

There are novel difficulties as well as dangers to be encountered. The
native courage of the man must be tempered, ground and polished. On
land it is the massing of numbers that accomplishes the result--the
accumulation of vital forces and intelligence upon the objective
point. The innumerable threads of individual enterprise, like the
twist of a Manton barrel, give the toughest tensile power. Under the
sea, however, it is often the strength of the single thread, the
wit of the individual pitted against the solid impregnability of the
elements, the _vis inertiae_ of the sea. It looks as if uneducated
Nature built her rude fastnesses and rocky battlements with a special
view to resistance, making the fickle and unstable her strongest
barricade. An example of the skill and address necessary to conquer
obstacles of the latter kind was illustrated in Mobile Bay. There lay
about a sunken vessel an impenetrable mail of quicksand. It became
necessary to sink piles into this material. The obstacle does not
lie in its fickle, unstable character, but its elastic tension. It
swallows a nail or a beam by slow, serpent-like deglutition. It is
hungry, insatiable, impenetrable. Try to force it, to drive down
a pile by direct force: it resists. The mallet is struck back by
reverberating elasticity with an equal force, and the huge pointed
stake rebounds. Brute force beats and beats in vain. The fickle sand
will not be driven--no, not an inch.

Wit comes in where weight breaks down. A force-pump, a common
old-style fire-engine, was rigged up, the nozzle and hose bound to a
huge pile,

to equal which the tallest pine
Hewn on Norwegian hills, to be the mast
Of some great ammiral, were but a wand.

The pump was set to work. The water tore through the nostril-pipe,
boring a hole with such rapidity that the tall beam dropped into the
socket with startling suddenness. Still breathing torrents, the pipe
was withdrawn: the clutching sand seized, grappled the stake. It is
cemented in.

You may break, you may shatter the _stake_, if you will,

but--you can never pull it out.

Perhaps the most singular and venturesome exploit ever performed in
submarine diving was that of searching the sunken monitor Milwaukee
during the bay-fight in Mobile harbor. This sea-going