Brass and copper nails are extensively used for shipping, and some other pur poses. For nailing on the copper sheathing of ships, nails cast of an alloy of tin and copper are generally used; but great efforts were made by a manufac turer at Bristol, some years ago, to substitute for them nails of pure copper : these, for a time, obtained a preference in the navy yards, as well as the mer chants' yards; it having been shown that the bottoms of ships, whose sheathing had been nailed with the rough-headed cast metal nails, were extremely foul, and that to the head of almost every such nail was appended a barnacle, which materially impeded the sailing of the ships. Mr. Guppy (the manufacturer to whom we have alluded) made his nails with a smooth bright head (produced by the polished surface of the hammer,) which, being counter-sunk underneath, were driven down flush with the surface of the copper sheathing. The improve ment was evident, and experience showed that ships so sheathed sailed better and returned home from their voyages earlier, and with cleaner bottoms. This triumph, or rather success, was of short duration. Mr. Greenfell, who had for many years supplied the government with copper sheathing and nails, took the hint afforded by the smooth-headed. nails, (the admirable construction of which were in otherts the subject of a patent granted to Mr. Guppy,) and had the rough heads cast nails made fiat, smooth, and bright, on the upper smface, by turning in a simple kind of lathe ; and upon repeated trials of these, they were found in no respect inferior to Mr. Guppy's patent, while they were materially cheaper, and they have, in consequence, maintained their ground, to the almost total exclusion of the pure copper nails, for the peculiar purpose mentioned. Pure copper nails are, however, extensively used in ship-building, and sea-going boats, on account of their greater durability than iron, when exposed to the action of salt water. The principal kind in use are rose-clench, similar in form to the iron nails of that denomination, already explained and filmed. The manner of making these nails is similar to that of the other kinds, and may be readily explained and practised by our brief description. The copper nall-maker furnishes himself from the copper wire-drawer with square spire of the sizes of the intended nails.Suppose, for instance, he has to make
some rose-clench, two inches long ; he takes the square copper wire of the required thickness of the nail, anal, by means of his fixed shears, he cuts the wire into lengths of about 2 inches and A ; the A being required to form the head. They are all cut exactly of a length, by the wire being pushed against a stop before it is cut; this stop is fixed to the block, end is adjustable to any required distance from the edge of the shears. The only tools necessary to complete these pieces of wire into nails, are a strong smith's vice, a hammer, and a pair of clams, designed to hold wire of the size. The jaws of these clams open by a spring, and are closed by compressing the jaws of the vice ; when so closed they leave a cavity between them, which is occupied by a piece of the copper wire before mentioned, 1 of which project above the upper surface of the clams. The workman then, with one or two blows of Ins hammer, drives the wire firmly to the bottom of the groove made between the clams (or against a stop placed therein) ; this has the effect of spreading out the head sufficiently lo receive four more blows struck around it in an inclined direction, which produces four facets, meetinf at the top, called a rose-head : then, by turning the handle of the vice, the jaws of the clams open, the nail is taken out, and another piece of wire substituted to repeat the heading operation described. It is obvious, that by the same tools, and a different application of the hammer, a fiat, a diamond, or other formed head, may be made. To strengthen the heads underneath the upper edges of the clams are countersunk ; and in order that a single pair of clams may do for various of one sired of a shorter 1 a piece of wire wire, the is made the depth of the longest; and for any nail re is dropped in the groove, as a of such a length as, wi the intended nail, to fill the groove entirely. Should the nails thus made be required with flat points, they are flattened by a few blows upon an anvil, in the cold state. Copper in the cold state is worked under the hammer with about the same facility as iron at a cherr7-red heat.