Diagrams A, B, C, and D, represent the appearance of various IMITATIONS of Geometric Lathe-work when magnified with a powerful glass. There is generally a studied effort to represent _white_ intersecting curved lines or Geometric Circles on a _black_ ground; in fact trying to imitate TRANSFERRING; but there will always be found, as in the above diagrams, nothing but confused black dots and semi-circular scratches, arranged so as to give it the same “_general appearance_” as the genuine, when held a little distance off. Sometimes there is no effort made to imitate the _white lines_, and there will be seen nothing but confused black dots and irregular black curved lines, mixed up together. Diagram E represents a magnified oblong-die, of alternating waved ruling, or eccentric parallels transferred. See the two dies containing the figure “20” in the steel plate illustration. This work is done by the Ruling Engine, and not by the Geometric Lathe; but as the work is very similar, and imitations of it fail in exactly the same manner, it is classed under the same rule. Diagram F is a representation of a magnified counterfeit or imitation of this work by hand; confused black dots on a _white_ ground, instead of true interwoven white lines of the genuine on a _black_ ground. RULE II. RULING ENGINE. (_Infallible when Imitated._) The Ruling Engine is used for shading the letters, skies, &c. in genuine Bank notes. Underneath, and sometimes on the lace of the letters in the title or name of the Bank, as well as other lettering, there appears a soft, smooth, pale grayish color, which to the naked eye appears to be painted with a brush, but on close examination it proves to be fine parallel lines, and when done by the Ruling Engine the lines are, 1st, all exactly of the same size; 2d, regular distances apart; 3d, perfectly parallel to each other; 4th, uniformity in their direction: and it is _perfection_ in these four points which gives it such a smooth and perfect appearance, and the least deviation from which will prove it to be hand-work. In counterfeits this shading is imitated by hand, and it is impossible to do it in this way as perfect as the Ruling Engine, as some lines will be coarser than others, some wider apart than others, not parallel, and some not perfectly straight, and all are apt to be more or less _tapered_ off when done by hand with the graver, which is not the case with the genuine, and which gives the whole a scratchy appearance; in fact, the least deviation in any of the points will show at once, and destroy the appearance of the whole. In titles, or the name of a bank, where the letters are alike, as for instance, [Illustration: THE BANK OF ----,]