JATHE ROOM. green centre, containing a "5" in white, all within a space not as large as a grain of coffee. By the aid of a glass every one of the lines whose crossings and recrossings constitute the pattern may be distinctly made out. The graver which has cut each of them in hard steel has passed many times over each, for at one stroke it will not cut sufficiently deep. At each passage it cuts about 300 part of an inch; about twenty cuttings are required to give the line its required depth. The machine must work with mathematical precision. A deviation of the half of a hair's breadth would destroy the whole work. The "Geometrical Lathe" which produces this work is perhaps the most ingenious piece of machinery ever invented. Its general principles are, of course, familiar to all educated machinists. It is the combination of all of them so as to work together with unfail ing accuracy which constitutes the marvel. We have watched it for hours, and at each moment have found something new in its working, when explained to us by its skillful operator; for after all the machine itself, to produce the required effect, must be under the direction of human intelligence. It will do the work which is set for it with unfailing precision, but its work must be laid out for it. The turn of a screw, the substitution of one wheel for another, with the variation of a single cog, the shifting of the axis of an eccentric, will produce an entirely new effect; it may give distortion where perfect regularity is demanded. This lathe was built by the Company at a cost of more than ten thousand dol HARDENING ROOM. lars, three years having been employed in its construction. It is the only one in existence, and its counterpart is, of course, wholly beyond the reach of counterfeiters; and yet, without it we can not see how they can successfully imitate its work. Notwithstanding its multifarious movements and complicated parts, its bearings are so accurate, that it is moved by the foot of the operator pressing upon a treadle, with the exertion of less force than is required to work an ordinary sewing machine. We have dwelt at length on this machine and its work, because we consider it a most important security against counterfeits; not exceeded in value even by the artistic perfection of the vignettes, portraits, and lettering. The machine work of the die having been performed, the letters and figures appearing upon it are engraved by hand, and the finished "check" or "counter" is ready to be transferred to the bank-plate. These dies, whether engraved by hand or by machinery, are made upon softened steel. They are hardened by placing them in crucibles which are filled up with animal carbon, hermetically closed, and placed in a furnace. The carbon, volatilized by the intense heat, combines with the steel, making it as hard as the finest razorblade. They are then brought to the Transfer Room, and by means of a powerful press a roller of softened steel is passed over them. The pressure is regulated by the foot of the workman acting upon a system of compound levers. In the largest machine he can give a pressure of 35 Under this pressure the softened roller is tons. made to revolve over the hardened die, and receives the impress of every line. This rolling must be repeated over and over, in order to make the impression of the required depth. The machine must therefore work with perfect accuracy, each line falling at every revolution in precisely the same place. The roller is then hardened; and when the particular design impressed upon it is wanted for a bank note, it is in the same manner passed over the plate, which thus receives a perfect copy of the original die. These rollers are in a sort the types from which a portion of a bank note is "set up." The selection and arrangement of them for any particular bank belongs to the Modeling Department. When a person wishes a note or series of notes prepared, he must first show that the bank is legally established, and that he is authorized to procure its plates. Without this precaution the Company will not undertake the work. In designing a note there are several points to be considered. The various denominations must all be different in appearance, and none of them must resemble any note of any other bank. Each must combine the various kinds of work adopted as securities against frauds, and must, moreover, present a handsome appearance. Then a bank frequently wishes its notes to have some special adaptation to its title or location. A "Farmer's Bank" will naturally wish an agricultural scene to appear on its notes; a "Merchant's Bank" will wish a commercial; an "Artisan's Bank" a mechanical scene; and so on. Then there will be prepossessions in respect to portraits. If the directors are Demo crats, they will probably wish Jefferson or Jack- Then the general style and arrangement of the son, Douglas or Wright; if Republicans, Lincoln or Seward, Scott or Chase. An Eastern bank will likely wish Webster, a Western one Clay, a Southern one Calhoun. The agent examines the port-folios containing proofs of the dies in the possession of the Company. He has ample scope for choice, for there are some 20,000 of them. Of these probably 5000 are vignettes, 5000 portraits and emblematical figures, and 10,000 checks and counters. Aided by the officers of the Company, who take care that in combination and arrangement the notes of each bank shall be easily distinguishable from those of any other, this part of the plate is agreed upon. lettering is settled, and a sketch of the note is made. The vignettes, portraits, checks, and counters are now put upon the plate in their proper places by the transferring machine, and the plate is passed to the Letter Engraving Room, where the lettering is performed by hand. Here also is room for the display of artistic talent, for a good and bad lettered line differ almost as much as a good and a bad vignette or portrait. The Lettering Room employs a much larger number of artists than the Pictorial Room, because the lettering of each note must be to a great extent peculiar to it, while vignettes or portraits may be used, in different combina tions, upon any one of a thousand. Here also the principle of division of labor comes in. One man's forte is German text; that of another is ornamental letters; that of a third is script. Each executes that part in which he excels, and the combined result of their skill appears on every note. Our plate is now finished: the main one, that is, which is to be printed in black; for most bank notes now have the back and a part of the face in colors, for which separate plates are used. This complicates the process, and renders the work of the counterfeiter more difficult. But its special object is to afford security against photographic imitations. At one time it seemed that photography and kindred arts would destroy every guarantee against counterfeit notes. Give the photographer a camera, a few dollars' worth of chemicals, and a quire of paper, and he could produce fac-similes of any note without limit. No matter how perfect the engraving, or how elaborate the machine work, he could in a few minutes make a copy exact to the minutest point. Science was invoked to remedy the evil which it had occasioned. Now photography can not, as far as we know, reproduce colors. Red, yellow, blue, and green, act like black upon the photographic plate. A red-haired man, for example, when photographed, wears a head of unimpeachable raven hue; the yellow of a footman's gorgeous plushes appears black in his photographic picture. So parts of bank notes were printed in red, blue, yellow, or green. These parts when photographed appeared black, as well as the part which were so in the genuine notes. But unfortunately all the colored inks in use were of such a nature that they could be discharged, with more or less facility, without disturbing the black ink. The counterfeiter would remove these colors, photograph the remainder of the note, and then print in the proper colors an imitation of the colored parts. An additional process was thus rendered necessary for the manufacture of a photographic counterfeit, but this was an easy one, and the labor was more than repaid by the security which was supposed to be given to any note printed in colors. The production of an indestructible colored ink thus became a desideratum. This has been held impossible. Absolutely it is probably so. We presume no ink can be devised which may not be removed by chemical or mechanical means, or by a combination of both. Thus the coloring matter of the black ink used by printers is carbon finely pulverized. Put this dry upon paper, and it may be brushed off with a feather; mix it with water, and when the liquid evaporates the powder can be rubbed off. In printer's ink the carbon is mixed with oil, which binds it to the surface of the paper. Now an alkali combined with oil produces soap, which can be washed away. Let a piece of printed matter be saturated with alkali; wash it carefully with water and the oil disappears, leaving the carbon free. The problem, however, was to produce a colored ink, not indeed absolutely indestructible, but one which could not be removed from a part of the note without, at the same time, discharging the black ink of the remainder. Even this was pronounced impossible. "The New American Cyclopædia" says: "No tint has yet been discovered which may not be chemically removed from the paper." This important desideratum has, we believe, been attained in the "Green Ink," for the use of which the American Bank Note Company holds the exclusive patent. Four years ago it was submitted to the examination of the most eminent chemists. Among these were Messrs. Hunt of Montreal, Gibbs of the New York Free Academy, Torrey of the Assay Office, Horsford of Harvard, Silliman of Yale, Henry and Hilgard of the Smithsonian Institute. The composition of the ink was explained to them, and they were requested to apply to it the most searching tests known to chemistry, with such new ones as they could devise. They all replied, in substance, that they knew of no chemical means by which the green ink could be destroyed without, at the same time, destroying the texture of the paper on which it was printed; and it could be removed mechanically only by means which would, at the same time, remove the black carbon ink combined with it on the same note. Most of these eminent chemists have recently been asked whether in the interim any new discovery has been, made which would lead them to change their former opinion. They all reply in the negative. We may therefore assume that the green ink which appears so largely upon the Bank Notes and United States Treasury Notes prepared by this Company, affords a perfect security against photographic counterfeits. The public must learn just what parts should be in green. If they do not in any bill appear of that color, or if they do appear in any other, the note may be assumed to be a photographic counterfeit. The finished plates are now deposited in the Plate Room, from which they can only be re moved when actually wanted for printing, and by double doors of "chilled iron," with burglarnever except by a written order from the Secre-proof locks. These doors are never unlocked tary of the Company. The importance of this room is shown by the care taken for its security. It is in the fourth story of the building, and can be approached only by narrow passages communicating with those leading to the various departments. At night these are patrolled by armed watchmen, who have duplicate keys to every room except this. Just before the door, and at the point where the passages converge, is the room of the Janitor, a gray-headed, jolly Hibernian, who seems to be always at his post. Through the half-opened door of his den we catch sight of a formidable brace of blunderbusses, a discharge from which would effectually sweep the narrow passages. He points out to us also a series of cunningly devised "peep-holes," as he calls them, through which he can watch every thing going on without himself being seen. Long habit has made him so watchful that he can not sleep comfortably without getting up half a dozen times in the night to take a peep through these holes to assure himself that all is right, and that the watchmen are duly performing their rounds. The entrance to the Plate Room is secured for a moment unless the keeper is within. Entering, the room looks like the casement of a fortress. Walls, roof, and floor are all of solid granite. The two windows, which look out upon the street, sixty feet below, appear like embrasures, showing the massive structure of the edifice. All around the room are cases with numbered compartments, in which the plates are de posited. An alphabetical register, comprised in several mercantile-looking volumes, tells the place in which every plate is deposited, so that it can be found at a minute's notice. Here are stored away plates for the entire issue of more than fifteen hundred banks in the United States; those for the Treasury Bonds of the United States and the Government of Canada; for the National Bank of Greece; for banks in Costa Rica, Guayaquil, Panama, and St. Thomas; for Swiss Railroad Bonds, and Postage Stamps of the British Provinces; besides those for Bonds, Drafts, Certificates, Bills of Exchange, and other Commercial Paper. In all, there are about 8000 plates deposited here. The falling of any one of these into improper hands would involve serious loss to the community. Well may every |