The clear horn handles are sometimes stained so as to imitate the tortoise shell ; this is effected by laying upon the handle a composition of three parts of potash, one of minium, ten of quick lime, and as much water as will make the whole into a pulpy mass. Those parts of the handle requiring darker shades are covered thicker than the other. Af ter this substance is laid upon the handles, they are placed before the fire for a few hours, the time requisite for giving the proper effect.
Penknives. The manufacture of pen knives is divided into three departments; the first is the forging of the blades, the spring, and the iron scales; the second, the grinding and polishing of the blades ; and the third, the handling, which con sists in fitting up all the parts and finish ing the knife. The blades are made of the best cast steel, and hardened and tempered to about the same degree with that of razors. In grinding they are made a little more concave on one side than the other ; in other respects they are treated in a similar way to razors. The handles are covered with horn, ivory, and sometimes wood, but the most dura ble are those of staw-horn. The most general fault•n penknives is that of being too soft. The temper ought to be not higher than a straw colour, as it seldom happens that a penknife is so hard as to snap on the edge.
Scissors. The beauty and elegance of polished steel is not displayed to more advantage than in the manufacture of the finer kinds of scissars. The steel employed for the more valuable scissars should be cast steel of the choicest qua lities ; it must possess hardness and uni formity of texture, for the sake of assum ing a fine polish; great tenacity when hot, for the purpose of forming the bow or ring of' the scissar, which requires to be extended from a solid piece, having a hole previously punched through it. It ought also to be very tenacious when cold, to allow that delicacy of form ob served in those scissars termed ladies scissars. After the scissars are forged as near to the same size as the eye of the workman can ascertain, they are paired, and the two sides fitted together. The bows and some other parts are filed to their intended form, the blades are alio roughly ground, and the two sides pro perly adjusted to each other, after being bound together with wire and hardened up to the bows. They are afterwards heated till they become of a purple co lour, which indicates their proper temper. Almost all the remaining part of the work is performed at the grinding mill, with the stone, the lap, the polisher, and the brush. The latter consists of a circular piece of wood, fitted upon an axis, and set upon the face with very strong bris tles. It is used to polish those parts which have been filed, and which the lap and the polisher cannot touch. Previous
to screwing the scissars together for the last time, they are rubbed over with the powder of quicklime, and afterWards wiped clean with the skin of soft sheep leather. The quick lime absorbs the moisture from the surface, to which the rusting of steel is justly attributed. Scis sars are frequently beautifully ornament ed by blueing and gilding, and also with studs of gold or polished steel. They are at present most elegantly ornamented by the gold being inlaid on a level with the surface of the steel, the gold surface being afterwards increased. The very large scissars are partly of iron and partly of steel, the shanks and bows being of the former. These, as well as those all of steel, which are not hardened all over, cannot be polished ; an inferior sort oflus trp_hnwever.ic cr;ven to them by means of s burnish of hardened polished steel, which is very easily distinguished from the real polish by the irregularity of the surface. (For swords, see S Casting of Cutlery. From the great. al liance of pig-iron to steel, it has been long thought practicable to cast the steel into the articles required, and by that means save all the expense of forging, and at the same time make the articles much nearer their intended form than could possibly be done by the hammer. The steel in its perfect state is, however, incapable of this advantage, though when in a state of fusion it is capable of being cast into large ingots. It is so imper fectly liquid at that temperature, as to preclude the possibility of casting it into articles so small as knives or scissars. That species of pig-iron, called N°.1, is susceptible of so perfect a liquidity as to be cast into needles and fish-hooks, and has been employed for making a great variety of cutlery, particularly forks and scissars. Immediately after the articles are cast, which is generally into wet sand, they are as brittle as glass, and in that state could not be used for any purpose. By being stratified with sand, and kept at a red heat for twenty four hours, they as sume a degree of softness and tenacity, which will allow them to bend to aeon. siderable angle. This process is called annealing. This branch of manufacture has of late undergone very considerable improvement, by an invention of Mr. Lucas of Sheffield, for which he has ob tained a patent. The articles. are cast of the most fusible pig-iron, and are after wards converted into a state of steel by cementation. The pig-iron, which only differs from steel in containing an excess of carbon, is stratified in close vessels, with some substance capable of furnish ing oxygen, with which the carbon of the pig-iron combines, forming carbonic acid, which escapes in the form of gas. See the article STEEL.