Towards the latter end of the 18th century, many projects were brought forward In France for multiplying engraved blocks or forms of type by processes more or less resembling that of stereotyping, under the names of polytype, stereotype, &c. In some of these, the form was imitated by striking upon a mass of soft metal in a state intermediate between perfect fusion and perfect solidity, on the prin ciple of the process now practised in France under the name of dachage. The extensive issues of &magnate by the revolutionary government gave an impulse to such schemes, of which many were devised, and some were brought Into operation, iu order to render the assiguats more difficult of imitation. In 1793 a stereotype edition of Virgil was published by the Didots and M. Herman ; and it appears from 1 f odgson that, before the close of the century, the wood-engravers of Paris sold metal casts of their wood-cuts.
Some of the early experiments of Senefelder, the inventor of litho graphy [SENEFELDER, in Moo. Div.], were directed to the discovery of a means of stereotyping by which he might be enabled to print his own works with a very small stock of type. He formed a composition of clay, fine rand, flour, and pulverised charcoal, mixed with a little water, and kneaded as stiff as possible; and with this paste he made a mould from a page of types, which became, in a quarter of an hour, so hard that he could take a very perfect cast from it in melted sealing wax, by mums of a hand-press. lie states that, by mixing a little pulverised plaster of Perim with the sealing-wax, the stereotype plates thus produced were much harder than the common typo-metal of lead and antimony. The want of pecuniary means for carrying on this project led him to abandon it, and to contrive n plan for printing from steno. Another ingenious proposal which may be hero mentioned, is that of Professor Wilson, of Glasgow, who, in 1797, devised a method of multiplying engraved blocks or plates by stereotype, or rather poly type, impressions, in glass or enamel, which, it was anticipated, would prove very durable, and ,night be applied with advantage to the pre vention of forgery. Hodgson gives specimens of two casts of small wood-cuts produced in this manner.
The revival and hatroductiou into common use of the stereotyping process is, in a great measure, due to the exertions of Earl Stanhope, about the commencement of the present century. Mr. Tilloch com municated to him the result of his experiments, and Foulis, who, as before stated, had been associated with Tilloch, assisted in the trials made at his lordship', sett at Chevening, in Kent. Andrew Wilson
also was connected with these operations, and exerted himself much to introduce the process. The latter individual, who received a gold medal from the Society of Arts in 1810, for his " great skill and exertion, In stereotype printing," produced several important stereo typed works, of which llodgson considers his edition of Walker's 'Pronouncing Dictionary; executed in 1809, to be the beat. A speci men of his work, which was printed in the 28th volume of the "fransactions' of the Society of Arts (pp. 323-4), shows that ho was then able to produce very good casting from typo as email as Nonpareil and Pearl. In 1803 or 1801 the process which hail been perfected at Cheveniug was communicated to the university of Cambridge, and shortly afterwards to that of Oxford ; but the first work printed in this way at the former place did not appear until 1807, and 1809 is the data of the earliest stereotyped book issued at Oxford.
In setting-up a form intended for stereotyping from, the ;parrs, or short piece. of metal by which the words are separated from each other, and the quadrats, or larger spaces by which blank lines are filled up, are cast higher than usual. The types are set up and formed into pages in the usual manner, with the illustrative wood-cuts, if there be ally ; but, instead of there pages being arranged into a form of suffi cient size to print a whole sheet, each page, if large, or every tree or four pages, if small, is separately locked up in a small frame or chase ; the pages being surrounded by fillets of wood or metal, which serve in the cast to form a border for attaching the plate to its mount. The face of the types is then moistened with oil, to prevent the mould i from adhering to them. A brass frame, rather larger than the page, is laid upon the chase, in order to retain the plaster while in a fluid state, and to regulate the thickness of the mould. The plaster is then poured on the types, and it soon sets into a solid mass, which must be removed from the types with great care, and trimmed on the edges with a knife. The phuder moulds are, in the next place, baked in an oven heated to about Filar , until thoroughly dry and hard. They are placed upright in a rack, and are usually dried in about two hours. Great care is required in this process, especially when the moulds are large, to prevent them from warping.