istern, with about 12
inches or 14 inches of water in it, is immediately obtained.

[Illustration: FIG. 9. Plug, with Standcock.]

(Fig. 9) is a plug with a standcock in it, to which hose may be
attached.

(Fig. 10) is a common single firecock with a round water-way 2-1/2
inches diameter.

[Illustration: FIG. 10. Single Firecock.]

(Fig. 11) is a double firecock, as laid down in Her Majesty's
Dockyards.

[Illustration: FIG. 11. Double Firecock, used at the Royal Dockyards.]

It will be observed, that the short piece of pipe between the main and
this firecock is not curved to the current of the water, but merely
opened a little; this is done with a view of increasing the supply by
steam power, and as the steam engines are, in most cases, situated in
a different direction from the tanks or reservoirs, therefore the
curve that would have assisted the current in one direction would have
retarded it in the other. It has been objected to these firecocks,
that the opening does not run through the centre of the key, therefore
only one side of the key covers the opening in the barrel, while in
the common firecock both sides are covered.

[Illustration: FIG. 12. Double Firecock, used at the British Museum.]

(Fig. 12) is a double firecock, as laid down at the British Museum.

This has a very good delivery, and is certain to be always tight, if
well made, as the pressure of the water forces the key into the
barrel; this also renders the cock somewhat difficult to be opened and
shut, if the pressure be great; but as a lever of any length may be
used, and the key, from its perpendicular position, may be loosened by
a blow, this objection is in a great measure obviated.

In Figs. 10 and 11 the openings in the street are large enough to
admit of the levers for opening the cock to be fixed, that no mistake
may occur from the lever being mislaid; but with those at the British
Museum, it was not thought necessary to have fixed levers, as a
crow-bar, or anything that could be introduced into the eye of the
spanner, would open them.

The plug and firecock have both certain advantages and disadvantages,
which are now described.

The plug, with a canvas cistern, is the easiest mode of obtaining
water; the plug-box being only the size of a paving-stone, is no
annoyance in the street, and the water has only one angle to turn
before it is delivered.

On the other hand, where the supply of water is limited, the plugs
give but