the shading in the genuine always is done all the way across all at once, and there is a perfect _uniformity_ from beginning to end; the lines all point exactly in the same direction, whether horizontal or diagonal, on the “T” in “THE” as on “F” in “OF,” preserving the same angle and fineness throughout. In counterfeits, where the letters are shaded by hand, one letter at a time, if the lines pretend to be horizontal, some are apt to slant a little downwards or upwards, some letters shaded a little finer than others--that is where they are intended to be alike and uniform. This principle of UNIFORMITY in shading is very important, and should always be noticed. See the words “UNIVERSAL,” “DETECTOR,” “BANKS,” and “UNITED STATES,” in the steel plate, which are shaded by the Ruling Engine, while the word “COUNTERFEIT” is shaded by hand to illustrate counterfeit work. The sky in vignettes in the genuine is sometimes ruled by the Ruling Engine, and always appears soft, smooth, and perfectly done, and in this case the lines taper off gradually. Imitations of this by hand will appear uneven and scratchy, some lines coarser than others, and some wider apart than others. All genuine skies, however, are not done by the Ruling Engine, but are sometimes fine dots or wavy lines, which fade off into fine dots, and sometimes heavy rolling clouds, circular lines, but it is always done perfectly and beautifully, and looks smooth and natural, being always done in genuine bills by first class artists, while the sky in counterfeits is generally apt to appear coarse and scratchy, and not fading off gradually enough. [Illustration: G H _Magnified 5 to 10 times._] Diagram G serves to represent the style of genuine Ruling Engine work as it appears when magnified 5 to 10 times, and H an imitation of Ruling Engine shading as done by hand and magnified the same. A first-class Ruling Engine is said to cost $3000. RULE III. MEDALLION OR PENTOGRAPH RULING. (_Infallible when Imitated._)