Leads form an essential part of a printer’s outfit, since it is scarcely
possible to set up a single page or job in which they may not be usefully
employed; but their chief purpose is for spreading the lines apart so
as to reduce the amount of matter in a page. Fine works are always
thus leaded. They are usually cast by letter-founders in a long mould,
and then cut to the required lengths. The bodies are regulated by Pica
standard, and they are usually cast four, six, or eight to Pica, but are
occasionally varied from one down to fourteen to Pica. Leads for jobbing
purposes are now cut to graduated lengths, like labour-saving rule.