A very rapid process to make newspaper illustrations, called gelatinography, is described in the following:

A black glass plate or a tin plate coated with black varnish, as used by sign-painters, is covered with plaster of Paris (gypsum) to a thickness of four-ply cardboard. The plaster of Paris must be of the best quality and reduced to a very fine powder. Add thereto some alum and some sulphate of barium, and in order to prevent the coating from being too brittle, add also a trifle of glycerine or of a gelatine solution.

This mixture must have the consistency of a thin pulp when applied to the glass or tin with a soft camel’s-hair brush.

When dry, the artist may engrave into this coat of plaster of Paris, by means of a lithographic engraving needle, any design or picture with the greatest ease; the plate or glass is thereby laid bare, and design or picture appears black through the plaster of Paris coating. Mistakes or errors are easily remedied by filling in the plaster of Paris preparation.

With the regular printers’ roller composition a stereotype is now made of the picture or design on the glass or plate, in the usual way; some bichromate of ammonia solution should be added to the roller composition, to make the stereotype hard enough for the type press, and it will be as durable as any electrotype, and answer the same purpose.--Am. Lith. and Printer.

Stereoscopic Photography.--Of late, there is quite a revival in this branch of our art-science, several English and many foreign amateurs having been working with twin lenses during the last and present seasons. The Belgian Bulletin has an article on the subject, and the last technical meeting of the Photographic Society was devoted to it. Although Wheatstone announced the instrument in 1838, it was not until photography had come to his aid by furnishing satisfactory diagrams, and Brewster had popularized the matter by the invention of the lenticular stereoscope, that much progress was made; then Wheatstone gave his Bakerian lecture on January 15th, 1852, to put the finishing touch to this important branch of scientific work. The earlier attempts failed by reason of employing too wide an angle.