Senefelder is a name inseparably connected with lithography, as it was he who, after a continuous and laborious research, discovered the remarkable properties of the Solenhofen limestone, who thoroughly worked out the conditions under which printing with fatty inks could be carried out, and so thorough and conclusive were whose researches that the process as now practised may be said to be actually identical with those of the discoverer. He was by inclination a dramatic author, but failing to find a publisher for the productions of his brain, he conceived the idea of publishing his own works. At a printer’s he acquired the necessary knowledge to perform the work, but lacked the funds to purchase press or type. He then turned his attention to copperplate, made many unsuccessful attempts with an old one he possessed, and when that was unfit for further experiment, extended his operations to the pewter plates of his mother’s dining service, but still without success. By accident, his next experiments were made upon a stone procured from Cellheim (Solenhofen), and which up to the present had served him as a slab for his ink. For want of paper and ink to write a domestic account for his mother, he casually used the surface of this stone in lieu of paper, using as an ink a mixture of soap, wax, and soot, with the intention of copying upon paper later on. When about to clean the slab, the thought flashed across his mind why not etch the stone with a dilute solution of nitric acid? The experiment was tried, and succeeded beyond expectation. Upon this simple accident has been built up the whole process of lithography. It was only in 1799, after a prolonged and severe struggle, that he was granted protection for his art in Bavaria. The acid etches away a very thin layer of the unprotected stone, while the writing is not attacked, but left slightly in relief. Senefelder—first with a dabber, and later with a piece of wood covered with cloth—inked in the writing, and so produced impressions, the earliest of which were sheets of music. The etching of a lithographic stone bearing a drawing or transfer in lithographic ink has a twofold action, each of which facilitates the printing. In addition to the slight relief already mentioned, as resulting from the application of the acid, the latter forms upon the surface of the stone, where attacked, nitrate of calcium, which resists and refuses the fatty ink upon the surface of the roller, and if the surface of the stone be kept constantly damp it becomes possible to roll up the drawing, to which alone the ink adheres.