ENGRA′′VING. The art of producing designs or figures on metal, wood, &c., by incision or corrosion, usually for the purpose of being subsequently printed on paper, calico, or other materials. The mechanical operations of the engraver do not come within the province of this work. Several of the materials which he employs in his trade will, however, be found noticed under their respective heads.
There is this important difference between engraving on metal plates and wood-engraving: in the former all the lines and dots that are to print black are hollowed out with a graving-tool, or ‘bitten in’ by acid; in the latter all the parts that are to appear white in the impression are cut away, and the lines which produce the imprint are left on the face of the block.
Casts of wood-blocks, or ‘stereos.’ are often used instead of the original blocks when a great number of impressions is required. To produce them stucco moulds are prepared, and from these the casts in type metal are taken. The casts are usually about 1⁄8 in. thick, and have to be screwed upon wooden blocks to bring them to the height of the types which are printed with them. As soon as one cast is worn out another may be taken, and the original block is thus preserved in the state in which it left the engraver’s hands.
For the reproduction of engraved metallic plates the ELECTROTYPE PROCESS is commonly employed. Woodcuts are also copied, though less frequently, by this process. The mode by which the postage-stamp plates are multiplied is as follows:—240 ‘queen’s heads’ or stamps (a pound’s worth) are engraved on one steel plate. This plate is then hardened, and an impression of it taken on a softened steel roller. This roller, in its turn, is also hardened, and softened steel plates being passed under it, an impression precisely like that of the original plate is produced on each of them. These plates are then hardened and employed for printing the penny postage stamps for sale. They last a long time; and when they are worn out they are destroyed, and their place is supplied by fresh ones, which are produced by the cylinder before referred to, which continues ready to supply any number that may be required. Bank-note plates are reproduced in the same manner. See Electrotype, Etching, &c.
Engravings, to Clean. Place the engraving on a smooth board, and cover it thinly with finely powdered and very clean common salt. Next squeeze lemon-juice upon the salt so as to dissolve a considerable portion of it. Now elevate one end of the board so that it may form an angle of about forty-five or fifty degrees. Next pour on the engraving boiling water from a tea-kettle until all the salt and lemon-juice are washed off. The engraving will then be found to be perfectly clean and free from stains. Care must be taken to dry it on the board or on some smooth surface very gradually. It will acquire a yellow tint if dried by the sun or before a fire.
Engravings, to Mount. Strain thin calico on a frame, then carefully paste on it the engraving, so as to be free from creases; afterwards, and when dry, give the engraving two coats of thin size (made by putting a piece of glue the size of a small nut into a small cupful of hot water); finally, when this dries, varnish the engraving with a varnish known as ‘white hard.’
ENTERI′TIS. See Inflammation of the Bowels.
ENTOZO′A. Parasitic animals which infest the bodies of other animals. See Worms.
ENTRY, Powers of. The Public Health Act thus defines the power of any local authority to enter into premises whereon a nuisance is supposed to exist; and the conditions under which this power is to be exercised.
“The local authority or their officer shall be admitted to any premises for the purpose of examining as to the existence of a nuisance thereon, or of enforcing the provisions of any Act in force within the district requiring fireplaces and furnaces to consume their own smoke at any time between the hours of nine in the forenoon and six in the afternoon, or in the case of a nuisance arising in respect of any business, then at any hour when such business is in progress or is usually carried on.