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.] EARLIEST WRITTEN SOUNDS. The hieroglyphic is the most ancient form of written sounds. The earliest known monuments containing phonetic hieroglyphics date about forty centuries ago, or six hundred years before the time of Moses, who is supposed to have been versed in the knowledge of the hieroglyphs. Yet nothing worthy of the name of an alphabet existed till a later period, when the Phœnicians invented a purely alphabetic system, but suppressing the vowels, and from this has originated all the modes of alphabetic writing now used.[12] The Greeks introduced the vowels into their graphic system, and so brought to perfection the invaluable invention of alphabetic writing. The discovery of the Rosetta stone furnished a clue to the method of deciphering the Egyptian hieroglyphics; and Dr. Young and Champollion were the first to make use of the suggestive opportunity. The words _Ptolemy_ and _Cleopatra_ were made out; and these served as a key or incentive to further investigations; and extensive and curious volumes have been devoted to the interpretation of Egypt’s mysterious inscriptions on monuments and writings on papyrus.