On the Economy of Machinery and Manufactures

per dress, and each weigh six ounces; the cotton from which they are made weighing nearly six and two-ninth ounces avoirdupois weight. Weight of one square yard of each of the following articles(5*) Weight of Weight cotton used Value finished of in waking per yard one square one square Description of goods measure yard yard s. d. Troy grains Troy grains Caterpillar veils — 4 1/3 — Silk gauze 3-4 wide 1 0 137 — Finest patent net — 262 1/2 — Fine cambric muslin — 551 — 6-4ths jaconet muslin 2 0 613 670 Ladies' coloured muslin dresses 3 0 788 875 6-4ths cambric 1 2 972 1069 9-8ths calico 0 9 988 1085 1/2-yard nankeen 0 8 2240 2432 159. This enumeration, which is far from complete, of the arts in which copying is the foundation, may be terminated with an example which has long been under the eye of the reader; although few, perhaps, are aware of the number of repeated copyings of which these very pages are the subject. 1. They are copies, by printing, from stereotype plates. 2. These stereotype plates are copied, by the art of casting, from moulds formed of plaster of Paris. 3. These moulds are themselves copied by casting the plaster in a liquid state upon the moveable types set up by the compositor. [It is here that the union of the intellectual and the mechanical departments takes place. The mysteries, however, of an author's copying, form no part of our enquiry, although it may be fairly remarked, that, in numerous instances, the mental far eclipses the mechanical copyist.] 4. These moveable types, the obedient messengers of the most opposite thoughts, the most conflicting theories, are themselves copies by casting from moulds of copper called matrices. 5. The lower part of those matrices, bearing the impressions of the letters or characters, are copies, by punching, from steel punches on which the same characters exist in relief. 6. These steel punches are not themselves entirely exempted from the great principle of art. Many of the cavities which exist in them, such as those in the middle of the punches for the letters a, b, d, e, g, etc., are produced from other steel punches in which these parts are in relief. We have thus traced through six successive stages of copying the mechanical art of printing from stereotype plates: the principle of copying contributing in this, as in every other department of manufacture, to the uniformity and the cheapness of the work produced. NOTES: 1. The late Mr Lowry. 2. I posses a lithographic reprint of a page of a table, which appears, from the from of the type, to have been several years old. 3. The construction of the engraving becomes evident on examining it with a lens of sufficient power to show the continuity of the lines. 4. The Phalaena pardilla, which feeds on the Prunus padus. 5. Some of these weights and measures are calculated from a statement in the Report of the Committee of the House of Commons on Printed Cotton Goods; and the widths of the pieces there given are presumed to be the real widths, not those by which they are called in the retail shops.