MACHICOLA'TIONS, the apertures between the corbels supporting a projecting para pet. The machicolations are for the purpose of allowing projectiles to be hurled at an enemy when he approaches near the wall, as in scaling, undermining, etc. Such defenses are very common in castellated architecture, especially over gateways, towers, etc.
has within recent years been introduced for the purpose of superseding, in whole or in part, the manual operations of the engraver. The first step In this direction was the invention of the ruling-machine by Wilson Lowry for the pur. pose of engraving plain backgrounds, skies, or any other portions where the work AVIIS purely mechanical. The saving of labor effected by this instrument was very great, and as its work was performed in a most satisfactory mamier, it soon came into very 0.eneral use. But what is properly denominated machine engraving is executed whElly by machinery. This department consequently excludes all artistic work, and is generally restricted to the engraving of patterns, bank-notes, etc. For the engraving of bank-notes
several machines have been invented, but their mechanism cannot here be described, as, besides being very complex, it is, for obvious reasons, kept secret as far as pos sible. The Americans have particularly distinguished themselves in this branch of engraving, and, in fact, it is to °DC,' of that nation, Mr. Perkins, ,that,.the introduction of the.bank-note engraving-mat:bine is due. Perhaps the most perfect machine for engraving is that invented by Wagner of Berlin, and called by him the " universal rose engine, or guilloche machine," which consists of a number of machines capable either of separate or of combined action, the number of distinct instruments being co-extensive with the number of species of lines composing the pattern. The number and ari.auge ment of the different instruments can be so varied that a practically unlimited number of patterns may be obtained, aud the correctness and delicacy of these patter& is such as can hardly be surpassed.