or, with the incendiary and explosive projectiles now used, to her
becoming, comparatively, an easy prey to an antagonist. Every possible
precaution, therefore, is to be taken to accommodate the full
allowance of powder completely; to guard it to the utmost against
injury and accidental explosion; and to deliver it at the magazine, as
required, with facility and certainty. To these ends, and in view of
the fact that all the powder for great guns is now put up in cubical
copper tanks, made water-tight, THE FORM OF MAGAZINES should be as
nearly rectangular as the shape of the vessel will admit, and they
should be built strong enough to resist sufficiently the effect of her
working in heavy weather, and also the pressure of water they will
have to sustain in case of being flooded.

189. All magazines should have a light-box for each alley at one end,
and a passage to deliver powder at the other; and the magazine and its
passage, considered as one, must be made perfectly water-tight by
caulking the bottom and sides, and then lining them internally, first
with white pine boards, tongued and grooved, and again with sheets of
lead of extra thickness, soldered together, over these boards. Both
these linings are to extend entirely over the bottom or floor, and all
the way up to the crown on all the sides.

190. When the magazine reaches the ceiling of the ship it must be
battened off two inches; the lining of the floor must be battened up
one, and also the magazine-deck, so that water leaking through the
sides of the vessel may run by and under, and not into the magazine.

An external lining of sheet-iron must also be resorted to as a
protection against fire, and to prevent the intrusion of rats.

191. A magazine aft in a ship is to have its passage for delivering
powder adjoining its forward part; and one forward in a ship is to
have this passage adjoining its after part, in order that it may not
be necessary to pass the powder over the light-box scuttle.

192. As many doors are to be cut in the bulkhead separating this
passage from the magazine-room as there are alleys to be left in the
latter, between the racks or shelves on which the tanks are stowed,
and these doors must correspond with those alleys. They are not only
to afford a means of entrance to the magazine, but also for passing
the tanks in and out. Through the upper part of each door a small
scuttle is to be cut,--two, if necessary,--for the purpose of passing