Oxalic Acid in Lithography.—

From time to time the use of oxalic acid to polish stones is highly recommended as a new and valuable discovery. The American Lithographer and Printer, replying to an inquirer on this subject, says: « Polishing the stone with oxalic acid for engraving is obsolete. It was resorted to in former times to print cards on glazed cardboard. Polishing by means of oxalic acid gives the stone a high gloss; and this perfect smoothness and gloss preserve the glaze of the cardboard. »