As soon as a word is complete, he touches the “spacing” lever at the side of the keyboard. The action causes a “space” to be placed against the last die to separate it from the following word. The operations are repeated until the tinkle of a bell warns him that, though there may be room for one or two more letters, the line will not admit another whole syllable. The line must therefore be “justified,” that is, the spaces between the words increased till the vacant room is filled in. In hand composition this takes a considerable time, and is irksome; but at the linotype the operator merely twists a handle and the wedge-shaped “spaces,” placed thin end upwards, are driven up simultaneously, giving the lateral expansion required to make the line of the right measure. A word about the “spaces,” or space-bands. Were each a single wedge the pressure would be on the bottom only of the dies, and their tops, being able to move slightly, would admit lead between them. To obviate this a small second wedge, thin end _downwards_, is arranged to slide on the larger wedge, so that in all positions parallelism is secured. This smaller wedge is of the same shape as the dies and remains stationary in line with them, the larger one only moving. The line of dies being now complete, it is automatically borne off and pressed into contact with the casting wheel. This wheel, revolving on its centre, has a slit in it corresponding in length and width to the size of line required. At first the slit is horizontal, and the dies fit against it so that the row of sunk letters on the faces are in the exact position to receive the molten lead, which is squirted through the slit from behind by an automatic pump, supplied from a metal-pot. The pot is kept at a proper heat of 550° Fahrenheit by the flames of a Bunsen burner. The lead solidifies in an instant, and the “slug” of type is ready for removal, after its back has been carefully trimmed by a knife. The wheel revolves for a quarter-turn, bringing the slit into a vertical position; a punch drives out the “slug,” which is slid into the galley to join its predecessors. The wheel then resumes its former horizontal position in readiness for another cast. The assembled dies have for the time done their work and must be returned to the magazine. The mechanism used to effect this is peculiarly ingenious.