Inhaltsangabe
This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1819. Excerpt: ... and imperfect press, it happened that by the splitting of the two wooden cylinders, each of them had a fissure, two inches wide; but as the diameter of the upper cylinder was large enough to print the whole page in one circumvolution, without the fissure touching the stone, I made shift with the cylinder as it was, placing it always so that the fissure did not touch the stone. But, in our new press, it was necessary that the upper cylinder, in order to lay hold of the stone, should draw it first between the two cylinders; before this could be done, however, it carried with it the cloth of the printing frame, till it would stretch no longer, and forced the « stone under the cylinder; but in this act, the paper under the printing frame was carried over the charged stone and spoiled. Every expedient I tried to remedy this inconvenience proved unsuccessful; and most likely I should have hit at last on the very simple mode of using leather, instead of the thin cloth, but I was too much perplexed and anxious about fulfilling our engagements, and therefore preferred having another press constructed, in which the pressure, as in the printing presses, was to be vertical and uniform. In less than a week this rough press was finished; the first trials promised success; but the greater stone plates did not give equal impressions, probably on account of the unevenness of the table, which was only of wood. I tried to increase the pressure as much as I could, and by means of a lever, and a stone of 300 pounds, which descended from a height often feet, I produced a pressure of more than fifty tons on the stone; by this means 1 did not fail to obtain good impressions, but after the second or third the stones always broke. To ascertain the vertical pressure requisite ...
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