The National Republican And Cincinnati Daily Mercantile Advertiser

Engraving by Pressure.-This is one of the most beautiful instances of the art of copying almost to an unlimited extent, and the delicacy with which the finest traces of the engraving tool can be transferred from steel to copper, or even from hard steel to soft steel, is most unexpected. We are indebted to Mr. Perkins for most of the contributions which have brought this at once to perfection; An engraving is first made upon soft steel, which is hardened by a peculiar process without in the least injuring its delicacy.
A cylinder of soft steel, pressed with great force against hardened steel engraving, is now made to roll slowly backward and forward over it, thus receiving the design but in relief. This is in turn hardened without injury, and if it be slowly rolled to and fro with strong pressure, on successive plates of copper, it will imprint on a thousand of them a perfect simile of the original steel engraving from which it is resulted. Thus the number of copies deducible from the same design is multiplied a thousand fold. But even this is very short of the limits to which this process may be extended.
The hardened steel roller, bearing the design upon it in relief, may be employed to make a few of its first impressions upon soft steel, and these being hardened become the representatives of the original engraving, and may, in their turn, be made the parent of other rollers, each generating copperplate like prototype. The possible extent to which fac similes of one engraving may thus be multiplied almost confounds the imagination, and appears to be for all practical purposes unlimited. There are two principles which peculiarly fit the art for rendering the forgery of bank notes a matter of great difficulty. The first is the perfect identity of every impression with every other, so that any variation, even in the minutest line, would at once be detected. The other principle is, that the plates, from which all the impressions are derived may be formed by the united labors of artists most eminent in the several departments; and as only one original of each design is necessary, the expense, even the most elaborate engravings is put out with the multitude of copies produced from it.