FOuNDERY, of great guns and mortar pieces. The method of casting these pieces is little different from that of bells; they are run massy, without any core, be ing determined by the hollow of the shell; and they are afterwards bored with a steel trepan, that is worked either by horses or a water-mill or steam.
FOUxeERY, Letter, or casting of printing types. The first thing requisite is to pre pare good steel punches, on the face, of which is drawn the exact shape of the letter with pen and ink, if the letter be large ; or with a smooth blunted point of a needle, if small ; and then, with proper gravers, the cutter digs deep between the strokes, letting the marks stand on the punch ; the work of hollowing being ge nerally regulated by the depth of the counter punch : then he files the outside, till it is fit for the matrice.
They have a mould tol justify the ma trices by, which consists of an upper and under part ; both these are alike, ex cept the stool and spring behind, and a small roundish wire in the upper part, for making the nick in the shank of the letter. These two parts are exactly fit ted into each other, being a male and fe male gage, to slide backwards and for wards.
Then they justify the mould, by cast ing about twentysamples ofletters, which are set in a composing stick, with the nicks towards the right hand ; and com paring these every way with the pattern letters, set up in the same manner, they find the exact measure of the body to be cast.
Next they prepare the matrice, which is of brass or copper, an inch and a half long, and of a proportionable thickness to the size of the letter it is to contain. In this metal is sunk the face of the let ter, by striking the letter-punch the depth of an n. After this, the sides and face of the matrice are justified, and cleared, with files, of all bunchings that have been made by sinking the punch.
Then it is brought to the furnace, which is built upright of brick, With four square sides and a stone at top, in which is a hole for the pan to stand in. They have several of these furnaces.
Printing-letters are made of lead, hard ened with iron or stub-nails. To make the iron run, they mingle an equal weight of antimony, beaten small in an iron mor.
tar, and stub-nails together. They charge a proper number of earthen pots that bear the fire with the two ingredients, as full as they can hold, and melt it in an open furnace built for that purpose. When it bubbles, the iron is then melted, but it evaporates very much. This melted com post is ladled into an iron pot, wherein is melted lead, that is fixed on a furnace close to the former, 31b. of melted iron to 251b. of lead ; this they incorporate ac cording to art.
The caster, taking the pan off the stone, and having kindled a good fire, he sets the pan in again, and metal in it to melt. if it be a small-bodied letter, or a thin letter with great bodies, that he in tends to cast, his metal must be very hot, and sometimes red-hot, to make the let ter come. Then taking a ladle, of which he has several sorts, that will hold as much as will make the letter and break, he lays it at the hole where the flame bursts out ; then he ties a thin leather, cut with its narrow end against the face, to the leather groove of the matrice, by whipping a brown thread twice about the leather groove, and fastening the thread with a knot. Then he puts both pieces of the mould together, and the matrice into the matrice-cheek, and places the foot of the matrice on the stool of the mould, and the broad end of the leather on the wood of the upper haft of the Mould, but not tight up, lest it hinder the foot of the matrice from sinking close down upon the stool, in a train of work. Afterwards, laying a little resin
on the upper part of the mould, and having his casting-ladle hot, he, with the boiling side, melts the resin, and presses the broad end of the leather hard down on the wood, and so fastens it thereto. Now he comes to casting, when placing the under half of the mould in his left hand, with the hook or jag forward, he holds the end of its wood between the lower part of the ball of his thumb and his three hinder fingers ; then he lays the upper half of the mould upon the under half, so as the male gages may fall into the female ; and, at the same time, the foot of the matrice places itself upon the stool, and clasping his left hand thumb strongly over the upper half, he nimbly catches hold of the bow or spring, with his right hand fingers at the top of it, and his thumb under it, and places the point of it against the middle of the notch in the backside of the matrice, pressing it forwards, as well towards the Mould as downwards, by the shoulder of the notch, close upon the stool, while at the same time, whit his hinder fingers, as aforesaid, he draws the under half of the mould towards the ball of his thumb, and thrusts, by the ball of his thumb, the upper part towards his fingers, that both the registers of the mould may press against both sides of the matrice, and his thumb and fingers press both sides of the mould close together.
Then he takes the handle of his ladle in his right hand, and with the ball of it gives two or three strokes outwards upon the surface of the melted metal, to clear it of the scum ; then he takes up the ladle fnll, and having the mould in the left hand, turns his left side a little from the furnace, and brings the Beat of his ladle to the mouth of the mould; and turns the upper part of his right hand to wards him, to pour the metal into it, while, at the same instant, he puts the mould in his left hand forwards, to re ceive the metal with a strong shake, not only into the bodies of the mould, but, while the metal is yet hot, into the very face of the matrice, to receive its per fect form there as well as in the shank. Then he takes the upper half of the mould off, by placing his right thumb on the end of the wood next his left thumb, and his two middle fingers at the other end of the wood : he tosses the letter, break and all, out upon a sheet of waste paper, laid on a bench a little beyond his left hand ; and then is ready to cast ano ther letter as before, and likewise the whole number in that matrice.
Then boys, commonly employed for this purpose, separate the breaks front the shanks, and rub them on a stone, and afterwards a man cuts them all of an even height, which finishes the fount for the use of the printer. See the next ar ticle. A workman will ordinarily east 3000 of these letters in a day. The per fection of letters thus cast consists in their being all severally square and straight on every side ; and all generally of the same height, and evenly lined, without stooping one way or other ; neither too big in the foot nor the head ; well grooved, so as the two extremes of the foot contain half the body of the let ter ; and well ground, barbed, and scraped with a sensihle notch, &c. See