GLTPHOGRAPHY. A method of ex tending pictorial illustrations, invented by Mr. E. Palmer, of London, England. It is an process, which can tiles the artist to become the engraver of his own work. The drawing being made upon a copper plate, upon which a suita ble ground has been laid, with points of the proper forms to produce the various species of line required to bring out the desired effect. The work is then deep ened by a rolling process : by allowing rollers to lay on parts of the plate a com position of Lithargc and turpentine : re peated layers are put on until the required depth is gained. It is now placed in a solution of sulphate of copper in connex ion with a galvanic battery. Metallic copper is by this means deposited in the lines cut through the grounding of the plates by the drawing pointe, and these becoming gradually filled up, the copper spreads over the whole surface of the composition, forming aplate of nny re quired thickness. The face of this new
plate is, of course, when separated, found to be an exact counterpart of the drawing, and when mounted upon a suitable block to raise it to the proper height, may be used to print froth along with type-matter, as if it were a wood engraving. To make the proper grounding, the plate is stained black with snlphuret of potassium ; it is then warmed, and over it is spread a very thin layer of Burgundy pitch, white wax, resin, spermaceti and sulphate of lead, previously fused together. This white composition is uniformly spread over the plates to one-thirtieth of an inch thick ness. The drawing points of the artist remove the white composition, wherever they arepassed, whereby the blackened surface of the plate is exposed, forming a striking contrast with the surrounding white ground, so that the artist sees his effect at once.