Send for Catalogue of useful novelties and mention this paper. ---------------------------------------------------------------------- EMERY AND CORUNDUM WHEELS, for Grinding and Surfacing Metals and other materials. By ARTHUR H. BATEMAN, F. C. S. A paper read before the Society of Arts, London. Files, Chisels, Grindstones, Composition of Emery, where found, Quality, Specific Gravity, and Hardness, Manufacture of the wheels, Emery Powder, Buffing, Polishing, Cutting Power, Corundum. The Magnesian or Union Wheel, the Tanite, the Northampton, the Vulcanite, the Climax, the Vitrified, a porous wheel with central water supply. Fifty uses enumerated to which the wheels are put, for Metals, Stone, Teeth, Millboard, Wood, Agate, and Brick. How to mount a wheel. How to hold the work, and directions for various classes of work. Discussion and questions proposed and answered. Contained in SCIENTIFIC AMERICAN SUPPLEMENT, NO. =125=. Price 10 cents. To be had at this office and of all newsdealers. ---------------------------------------------------------------------- =THE BIGELOW= =Steam Engine.= BOTH PORTABLE AND STATIONARY. =The CHEAPEST AND BEST in the market. Send for descriptive circular and price list.= =H. B. BIGELOW & CO., New Haven, Conn.= ---------------------------------------------------------------------- [Illustration: Diamonds and Carbon] Shaped or Crude, furnished and set for Boring Rocks, Dressing Mill Burrs, Emery Wheels, Grindstones, Hardened Steel, Calender Rollers, and for Sawing Turning, or Working Stone and other hard substances: also Glaziers' Diamonds. J. DICKINSON, 64 Nassau St., N. Y. ---------------------------------------------------------------------- =SECOND-HAND ENGINES,= Portable and Stationary, at Low Prices. HARRIS IRON WORKS, TITUSVILLE, PA. ---------------------------------------------------------------------- HOW TO MAKE A PHONOGRAPH.