Various attempts were made during the early part of this century to cast type by machinery; but the first successful apparatus for this purpose was the invention of Elihu White of New York, which was modified and • repeatedly improved upon by David Bruce, a Scotchman resident in America. The type-casting machine was introduced into Great Britain, and patented by Miller & Richard, of Edinburgh, in 18-18. This machine, which requires a man to drive it, produces more than double the quantity that the hand-mold did, while the finish and regularity of the type so east are much more perfect. Another machine was constructed and patented some years after by the same firm, with the view to apply steam for driving, which was successfully completed in 1860, andis now the most advanced and approved system of casting.
The type-casting machine consists, first, of a small melting-pot, which contains the molten metal, and is placed over a small furnace having an outer case of east-iron. In the interior of the pot is arranged a forcing-pump and valve for admitting the metal under the piston, and also for preventing the return of the metal into the mass in the pot when the piston is depressed, and thus securing the full force exerted upon the piston. being transmitted by the piston to the molten metal under it, and forcing it through a narrow channel leading from the bottom of the chamber in which the piston works to the outside of the pot, where a nipple is inserted, with a small hole through it, communicating with this narrow channel. Against this nipple, the mold in which the type is formed is pressed at the moment at which the piston descends, and so receives the molten metal that forms the type. • The second part of the machine is that which carries the mold, and to which the mold is firmly bolted. The mold is similar to the old hand-mold, but modified to suit the machine; it is much stronger; the " jets " are shorter, and the orifice by which the metal enters is smaller, so that it may be brought exactly coincident with the small hole in the nipple in front of the pot. The mold—as the old hand-mold—is made in halves; the one-half being firmly bolted to an arm which, by cams and levers, is made to oscillate, and carry the mold to and from the nipple in front of, and above the pot; the other half of the mold is bolted to another arm, which, by a peculiarly formed hinge, is attached to the first arm, so that the two halves of the mold may be made to open and shut upon each other like the lid of a snuff-box; and so both sides of the mold oscillate togetheto and from the nipple in the pot from which they receive the molten metal. The furnace, with the pot and machine carrying the mold, are raised
upon cast-iron framing to a height convenient for a man standing to watch the working of the machine. The operation of the machine is as follows: The piston being raised in the chamber of the pump, and the chamber being supplied with metal through the valve, the mold is brought against the nipple; the valve closes to prevent the metal being forced back into the pot; the piston descends, and forces the metal through the narrow channel into the mold; the mold then recedes from the nipple, and in receding the two halves separate from each other and eject the type; the mold again approaches the nipple, and in approaching the two halves close together, and are ready for another operation.
A blast of cold air is directed upon each mold to keep it cool.
When the type is cast from the mold it is in a rough state, and as soon as a heap has accumulated on the caster's table they are removed by a boy, who breaks off a superfious tag of metal, or " jet," hanging at the end of each type. From the breaking-off boy the types are removed to another place, where a boy rubs or smoothes their sides upon a stone. Being now well smoothed, they are next removed to a table and set lip iu long lines upon a "stick;" they are then dressed or finished, and, after being examined by a. magnifying-glass, are ready for use. Whatever be the size of the types, they are all made of a uniform height, and must be perfectly true in their angles, otherwise it would be quite impossible to lock them together. A single irregular type would derange a whole page. The height of type made in this country is :4 of an inch ; those made in France, Spain, and Germany are higher. All the types of one class of any founder are always uniform in size and height, and, to preserve their individuality, all the letters, points, etc., belonging to one class, are distinguished by one or more notches or nicks on the body of the type, which range evenly when the types are set. These nicks, as we shall immediately see, are also exceedingly useful in guiding the hand of the compositor. Types are likewise all equally grooved in the bottom, to make them stand steadily.