in Law and Logic, is that degree of evidence which carries conviction to the mind. It differs from demonstration, which is applicable only to those truths of which the contrary is inconceivable. It differs likewise from probability, which produces for the most part nothing more than opinion, while proof produces belief. See Probability.

The proof of crimes was anciently effected among our ancestors divers ways; viz. by duel or combat, fire, water, &c. See Duel and Ordeal.

Proof of Artillery and Small Arms, is a trial whether they stand the quantity of powder allotted for that purpose. The rule of the board of ordnance is, that all guns, under 24-pounders, be loaded with powder as much as their shot weighs; that is, a brass 24-pounder with 21 lb. a brass 32-pounder with 26 lb. 12 oz. and a 42-pounder with 31 lb. 8 oz.; the iron 24-pounder with 18 lb. the 32-pounder with 21 lb. 8 oz. and the 42-pounder with 25 lb. The brass light field-pieces are proved with powder that weighs half as much as their shot, except the 24-pounder, which is loaded with 10 lb. only.

Government allows 11 bullets of lead in the pound for the proof of muskets and 14.5, or 29 in two pounds, for service; 17 in the pound for the proof of carbines, and 20 for service; 28 in the pound for the proof of pistols, and 34 for service.

When guns of a new metal, or of lighter construction, are proved; then, besides the common proof, they are fired 200 or 300 times, as quick as they can be, loaded with the common charge given in actual service. Our light 6-pounders were fired 300 times in 3 hours 27 minutes, loaded with 1 lb. 4 oz. without receiving any damage.

**Proof of Powder**, is in order to try its goodness and strength. See Gunpowder.

**Proof of Cannon**, is made to ascertain their being well cast, their having no cavities in their metal, and, in a word, their being fit to resist the effort of their charge of powder. In making this proof, the piece is laid upon the ground, supported only by a piece of wood in the middle, of about 5 or 6 inches thick, to raise the muzzle a little; and then the piece is fired against a solid butt of earth.

**Tools used in the Proof of Cannon**, are as follows:

*Searcher*, an iron socket with branches, from 4 to 8 in number, bending outwards a little, with small points at their ends: to this socket is fixed a wooden handle, from 8 to 12 feet long, and 1½ inch in diameter. This searcher is introduced into the gun after each firing, and turned gently round to discover the cavities within: if any are found, they are marked on the outside with chalk; and then the

*Searcher with one point* is introduced: about which point a mixture of wax and tallow is put, to take the impression of the holes; and if any are found of one-fourth of an inch deep, or of any considerable length, the gun is rejected as unserviceable to the government.

*Reliever*, is an iron ring fixed to a handle, by means of a socket, so as to be at right angles; it serves to disengage the first searcher, when any of its points are retained in a hole, and cannot otherwise be got out. When guns are rejected by the proof-masters, they order them to be marked X thus, which the contractors generally alter WP thus; and after such alteration, dispose of them to foreign powers for Woolwich proof.

The most curious instrument for finding the principal defects in pieces of artillery, was lately invented by Lieutenant-general Delaguiers, of the royal regiment of artillery. This instrument, grounded on the truest mechanical principles, is no sooner introduced into the hollow cylinder of the gun, than it discovers its defects, and more particularly that of the piece not being truly bored; which is a very important one, and to which most of the disasters happening to pieces of artillery are in a great measure to be imputed; for, when a gun is not truly bored, the most expert artillerist will not be able to make a good shot.

**Proof of Mortars and Howitzers**, is made to ascertain their being well cast, and of strength to resist the effort of their charge. For this purpose the mortar or howitzer is placed upon the ground, with some part of their trunnions or breech sunk below the surface, and resting on wooden billets, at an elevation of about 70 degrees.

The mirror is generally the only instrument to discover the defects in mortars and howitzers. In order to use it, the sun must shine; the breech must be placed towards the sun, and the glass over-against the mouth of the piece: it illuminates the bore and chamber sufficiently to discover the flaws in it.

**Proof of Foreign Brass-Artillery.**

1st, The Prussians. Their battering-train and garrison artillery are proved with a quantity of powder equal to ¼ the weight of the shot, and fired 75 rounds as fast as in real service; that is, 2 or 3 rounds in a minute. Their light field-train, from a 12-pounder upwards, are proved with a quantity of powder = 1-3d of the weight of the shot, and fired 150 rounds, at 3 or 4 rounds in a minute. From a 12-pounder downwards, are proved with a quantity of powder = 1-5th of the shot’s weight, and fired 300 rounds, at 5 or 6 rounds each minute, properly spunged and loaded. Their mortars are proved with the chambers full of powder, and the shells loaded. Three rounds are fired as quick as possible.

2nd, The Dutch prove all their artillery by firing each piece 5 times; the two first rounds with a quantity of powder = 2-3ds of the weight of the shot; and the three last rounds with a quantity of powder = ½ the weight of the shot.

3rd, The French the same as the Dutch.

**Proof**, in brandy and other spirituous liquors, is a little white lather which appears on the top of the liquor when poured into a glass. This lather, as it diminishes, forms itself into a circle called by the French the *chapeclet*, and by the English the *bead* or *bubble*.

**Proofs of Prints**, were anciently a few impressions taken off in the course of an engraver’s process. He Life of Ho proved a plate in different states, that he might ascertain how far his labours had been successful, and when they were complete. The excellence of such early impressions, worked with care, and under the artist’s eye, occasioning them to be greedily sought after, and liberally paid for; it has been customary among our modern printellers to take off a number of them, amounting perhaps, to hundreds, from every plate of considerable value; and yet their want of rareness has by no means abated their price. On retouching a plate, it has been also usual, among the same conscientious fraternity, to cover the inscription, which was immediately added after the first proofs were obtained, with slips of paper, that a number of secondary proofs might also be created.

**Proof**, in the sugar trade. See Sugar.

**Proofs**, in printing. See Printing.