4. The buttons are next freed from oxyde, by immersing them in diluted nitric acid, and by friction in a lathe. They are then put into a vessel containing a quantity of nitric acid supersaturated with mercury. The superior attraction of the copper for the acid, causes a portion of it to be absorbed; and the mercury held in solution by it, is deposited on the buttons, which are next put into a vessel containing an amalgam of mercury and gold.
5. The amalgam is formed by melting the two metals together, and afterwards pouring them into cold water. The composition having been put into a bag of chamois leather, and a part of the mercury pressed through the pores, the remaining portion is left in a condition approaching the consistency of butter, and in a fit state for use. Before the buttons are put into the amalgam, a small quantity of nitric acid is added.
6. The buttons having been covered with the amalgam, as before stated, the mercury is discharged, that the gold may adhere directly to the brass. This object is effected by heating the buttons in an iron pan, until the amalgam begins to melt, when they are thrown into a large felt cap, and stirred with a brush. This operation is repeated several times, until all the mercury has been volatilized. The whole process is finished by again burnishing them, and putting them on cards for sale.
7. White metal buttons are made of brass alloyed with different proportions of tin. They are cast, ten or twelve dozens at a time, in moulds formed in sand, by means of a pattern. The shanks are placed in the centre of the moulds, so that, when the metal is poured in, they become a part of the buttons. The buttons are next polished in a lathe, with grindstone dust and oil, rotten stone and crocus martis. They are then boiled with a quantity of grained tin, in a solution of crude red tartar or argol, and lastly, finished with finely-pulverized crocus, applied with buff leather.
8. Glass buttons are made of various colors, in imitation of the opal and other precious stones. While manufacturing them, the glass is kept in a state of fusion, and a portion of it for each button is nipped off out of the crucible with a metallic mould, somewhat similar to that used for running bullets, the workman having previously inserted into it the shank.
THE PIN-MAKER.
1. There is scarcely any commodity cheaper than pins, and none which passes through the hands of a greater number of workmen in the manufacture, twenty-five persons being successively employed upon the material, before it appears in these useful articles, ready for sale.
2. The wire having been reduced to the required size, is cut into pieces long enough to make six pins. These pieces are brought to a point at each end by holding them, a handful at a time, on a grindstone. This part of the operation is performed with great rapidity, as a boy twelve years of age can sharpen 16,000 in an hour. When the wires have been thus pointed, the length of a pin is taken off at each end, by another hand. The grinding and cutting off are repeated, until the whole length has been used up.
3. The next operation is that of forming the heads, or, as the pin-makers term it, head-spinning. This is done with a spinning-wheel, by which one piece of wire is wound upon another, the former, by this means, being formed into a spiral coil similar to that of the springs formerly used in elastic suspenders. The coiled wire is cut into suitable portions with the shears, every two turns of it being designed for one head. These heads are fastened to the lengths by means of a hammer, which is put in motion with the foot, while the hands are employed in taking up, adjusting, and placing the parts upon the anvil.
4. The pins are now finished, as to their form; but still they are merely brass. To give them the requisite whiteness, they are thrown into a copper vessel, containing a solution of tin and the lees of wine. After a while, the tin leaves the liquid, and fastens on the pins, which, when taken out, assume a white appearance. They are next polished by agitating them with a quantity of bran in a vessel moved in a rotary manner. The bran is separated from them, as chaff is separated from wheat.