showing the shape of
the lugs and rear sight mass, and the position of the vents, is
furnished as a guide to the contractors.

19th. A standard foot-rule for verifying measures.

20th. A foot-rule of steel for measuring the masses, the length of the
trunnions, and for other purposes. The graduation should be extended
to each end.

21st. A set of ring-gauges, large, medium, and small, for inspecting
the projectiles used in proof.

22d. A small beam-calliper, with outside edges, for examining the
adjusting rings and the ring-gauges.

23d. A platform balance, for weighing the projectiles used in proof,
and for bringing the shells up to the standard weight. For use with
the above there should be provided a bag of dry sand, a funnel, some
wooden plugs for the fuze-holes, and a hammer.

24th. A set of implements for loading and cleaning, viz.:

A rammer, faced with hard wood or metal, with a graduated scale on
the staff, near the muzzle, to show the distance of the front of the
projectiles from the muzzle.
A bristle sponge with a worm in its end, for ordinary use in firing.
A sheepskin sponge, for drying the bore after cleaning it.
A gun-scraper.
A ladle.
A boring-bit.
A priming-wire.
A lock and lanyard, should navy primers be used in firing; but if
friction primers are used, then a lanyard with a hook in its end will
be required, only.
A breeching and a couple of tackles, if the guns should be fired on
skids.
Six handspikes.
Six buckets and a large tub, for washing out the guns.

If the firing is made into a butt, a couple of wheelbarrows, with two
or three pickaxes and half a dozen shovels, will be necessary.

25th. A searcher, with six or more points, to detect injuries or
cavities in the bore.

26th. A machine for taking the interior impression of vents.

This consists of a wooden head, one-half of which is cylindrical, and
the other half is of the shape of the chamber, both being rather
smaller than the parts of the bore that they are intended for. A
staff, flat on its upper side, and rounded on its under side to fit
the curve of the bore, is mortised into the circumference of the
cylindrical part of the head. A mortise is cut through the chamber
part of the head, extending several inches in rear and front of the
position of the vent. Into this mortise a loose piece is fitted,
capable of free motion upwards and downwards, the top of which is
pierced with holes to secure the wax