is of immense economical advantage to the printer. Being cut to a
graduated scale, from one em to fifty ems Pica in length, advancing in
the shorter pieces by ens and in the longer by ems, all waste in cutting
is avoided by the printer, as rules of any length can be formed by
employing two or more pieces. This rule is put up in regular founts, of
various styles, with sufficient mitred pieces for outside bordering.
[Illustration]
Metal space-rules, cast by type-founders, are commonly used for
cross-rules in table-work; but the shorter pieces of labour-saving rule
will answer as well.
On the next page we insert a plan of a case for labour-saving rules, with
boxes suited for the various sizes, in which the rule should be kept when
not in use.
[Illustration: IMPROVED LABOUR-SAVING RULE CASE.]