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ing, very easily and cheaply, and, to all practical purposes, without any limit. "A cylinder of soft steel, pressed with great force against the hardened steel engraving, is now made to roll slowly backward and forward over it, thus receiving the design, but in relief. This is, in its 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 facsimile of the original steel engraving, from which it resulted. Thus the number of copies, producible from the same design, is multiplied a thousandfold. But even this is very far 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 plates of soft steel, and these, being hardened, become the representatives of the original engraving, and may, in their turn, be made the parents of other rollers, each generating copper plates like their prototypes. The possible extent to which facsimiles of one original engraving may thus be multiplied, almost confounds the imagination, and appears to be, for all practical purposes, unlimited."*

The influence which has been exerted, by this art of copying, on the welfare of the human race, is wholly incalculable. To say nothing of the benefits bestowed by the other methods of copying, printing alone, by the stimulus which it has given to the mind, has created much of the science and art which we possess, and has conferred upon the multitude, in every country, almost all the light and civilization that they now enjoy. Previous to the invention of printing, and of the arts of manufacturing paper, (for without the latter the former would have been of little value,) books could be multiplied only by the slow and expensive process of transcribing. This Volume, of which several thousand copies can be printed in a few hours, in a large printing-office, could not be transcribed once, by a single hand, short of many

* Babbage.

weeks, and at an expense of from twenty to fifty dollars.* For this work, the cost of which does not now exceed a dollar, an individual would have had to pay, previous to the invention of printing, at least twenty times the same sum, and would have had, after all, an article vastly inferior, both in convenience and beauty. It is no exaggeration to say, that a library of one thousand volumes can now be purchased for less money than would have been required, previous to the invention of the art of printing, for the purchase of fifty.

Copying by Transfer.-Another method of copying, is, by a direct transfer of the lines to be copied, whether a printed or written page, or an engraved picture, to the surface of a lithographic stone, from which copies are printed to an indefinite extent. Attempts of this kind had been made, for a long time; but not proving successful, they were abandoned as impracticable, until, within a few years, one of our own countrymen succeeded in the experiment. A method of copying, by this process, was announced, in Paris, in 1839, as a new discovery, by Messrs. Duponts, (two brothers, one a printer, the other a lithographer ;) but we are assured, on undoubted authority,† that the same art was discovered and practised in this country as early as 1832, by Mr. Joseph Dixon, formerly of Salem, now of Taunton, Massachusetts. The minute details of the process are not revealed by either of the discoverers. It should seem, however, that substantially the same method is pursued by both, although we are not aware that there is any reason to suppose that either is borrowed from the other. By the dates which are given above, it will be seen, that the priority of discovery rests entirely with our countryman.

*The copyists of ancient days sometimes spent fifty years in transcribing and illuminating one copy of the Bible. Five hundred dollars was paid for a single MS. concordance, and about the same price, per volume, was paid, in one instance, for a copy of the works of Livy.

+ Papers of that date, and specimens of the work done at the time.

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KORAIT IBN ONAIPH.

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Mr. Dixon's method of transfer is applicable to any printing, whether old or recent. He first spreads a liquid, the composition of which he keeps secret, over the page or print to be copied. This page is then laid on a lithographic stone, to which, on being pressed, it immediately conveys a reversed facsimile of itself. From this stone, copies are multiplied, at pleasure, in the usual manner of lithographic printing. The essential peculiarity of the process seems to consist in the properties of the fluid applied to the surface of the print, by which the original ink, however dried and hardened by age, is made to act on the stone with an influence precisely similar to that produced by the common lithographic drawing. It is exceedingly curious, and adds greatly to the value of the discovery, that all this is done without the slightest tarnish to the original print, or the least diminution, in any way, of its clearness or depth of color. The whole is done with such facility, that a page has been taken from a volume, transferred to stone, several copies printed from it, and the leaf restored to its place, in its original state, im sixteen minutes. Mr. Dixon has kindly furnished us with the specimen, which is opposite to this page.

It would be interesting, if our limits would permit, to give a history of the steps of Mr. Dixon's discovery; as it would furnish another example of the happy influence of science in conducting an ingenious inquirer to a successful issue. The discovery was not accidental, but was the result of patient and long-continued research. Being a printer, and consequently familiar with the properties of the ink used in that art, and being also well versed in chemical science, it occurred to him, to seek for some substance that should exert such an influence upon the ink, as to enable him to obtain a copy. It was not until after many discouragements, and a long course of unsuccessful attempts, that he at length succeeded. In the mean time, his health became much impaired, and his pecuniary means exhausted, so that he has not been able to introduce his dis

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