BUTTON. A fastening for various parts of dress. Buttons may be divided into two general classes,—those with shanks, or loops of metal, for the purpose of attaching them to garments, and those without shanks; and each class is manufactured from a great variety of materials, and by a variety of methods. Of buttons with shanks the greater number are composed of metal, although glass and mother of pearl are also employed for the purpose. Metal buttons are formed in two different ways, the blanks or bases of the buttons being either cast in a mould, or stamped out of a sheet of metal ; the former method is generally employed for making white metal buttons, and the latter for plated and gilt buttons. To cast buttons, a great number of impressions of the pattern of the button are taken in sand, and in the centre of each impression is inserted a shank, the ends of which project a little above the surface of the sand, and fused metal is poured over the mould. When cool, the buttons are taken from the moulds, and after being cleansed from sand by brushing, are placed in lathes, the edges are turned, the face and back smoothed, and the pro jecting part of the shank also turned. The buttons are then polished by rubbing the faces upon a board spread with rotten stone of different degrees of fineness, and afterwards by being held against a revolving board covered with leather, upon which is spread a very fine powder of the same materials; finally, they are arranged on a sieve or grating of wire, and immersed in a boiling solution of granulated tin and cream of tartar, by which means their surfaces become covered with a thin layer or wash of the metal, which improves their whiteness without injuring their polish. The blanks of plated buttons are cut by a fly-press out of copper plate, coated on one side with silver. They are then annealed in a furnace and afterwards stamped by the descent of a weight, as in a pile driving machine, the die being fixed in the lower surface of the weight. The sol dering of the shank is performed on each button separately, by the flame of a lamp and a blow-pipe : the edges of plain buttons are next filed smooth in a lathe, and the buttons are afterwards boiled in a solution of cream of tartar and silver; they are then placed in a lathe, and the backs brushed, and afterwards burnished with blood-stone. The metal used for gilt buttons is an alloy of copper and zinc.
This metal is rolled out into sheets, and the blanks stamped out, which are then planished if intended for plain buttons, but if for figured buttons, the impres sion is now given. The shanks are next attached, which is effected as follows : each blank is furnished with a pair of small spring tweezers, which hold the shank down upon it on the proper place, and a small quantity of solder and resin is applied to each. They are then exposed upon an iron plate to a heat sufficient to melt the solder, by which the shank becomes fixed to the button; and whilst still warm they are plunged into nitric acid, to remove the oxide formed on the surface by the heat employed in soldering the shanks. They are then placed in a lathe, the edges rounded, and the surfaces rough burnished, which renders them ready for gilding. Five grains of gold are fixed by Act of Parliament as the least quantity to be employed in gilding a gross of buttons of l inch in diameter. An amalgam is formed of gold and mercury, and the buttons are placed in an earthen vessel along with the amalgam, together with as much aquafortis as will moisten the whole, and the mixture is stirred with a brush until the buttons are completely whitened. To dissipate the quicksilver the buttons are shaken in an iron pan, placed over a fire, until the quicksilver begins to melt, when they are thrown into a felt cap and stirred with a brush, to spread the amalgam equally over their surfaces; after which, they are returned to the pan, and the mercury volatilized completely by the increased heat, leaving the gold evenly spread in a thin film over the surface of the buttons; they are then burnished in a lathe, which completes the operation. The better sort of buttons undergo the gilding process twice or thrice, and are distinguished accordingly as " double ' or " treble gilt." Glass buttons are formed of glass compressed, while in the fluid state, in moulds, in which the shank is inserted, and when the glass becomes cold, the shank is firmly retained in its place. In mother-of-pearl buttons the method of inserting the shank is extremely inge nious : a hole is drilled at the back and undercut, that is, larger at the bottom than at top, and the shank being driven in by a steady stroke, its extremity expands; on striking against the bottom of the hole, it becomes firmly rivetted into the button, forming a kind of dove-tail joint.