17. MEDALLION PORTRAITS OF DISTINGUISHED AMERICAN INVENTORS, with biography in brief and engravings of their inventions, viz.: Franklin, Fulton, Whitney, Wood, McCormick, Blanchard, Winans, Morse, Goodyear, Howe, Lyle, Eads. 18. ENGRAVINGS of Capitol, Washington, with brief history, dimensions, cost, etc.; United States Patent Office, interior and exterior views, dimensions, and description; Scientific American Buildings, N. Y. and Washington. 19. MISCELLANEOUS INFORMATION.-Force of Expansion by Heat; Small Steam-boats, proper dimensions of Engines, Boilers, Propellers. Boats; Incubation, Temperature of; To Make Tracing Paper; Constituents of various substances; Friction, how produced, and Rules for Calculation; Specific Heat Explained; Specific Gravity of Liquids, Solids, Air, and Gases; Gunpowder--Pressure, Heat, and Horse-Power of; Copying Ink, to Make; Heat, its mechanical equivalent explained; Molecules of Matter, size and motion explained; Lightning and Lightning Rods--valuable information; Value of Drainage Explained; Amount of Power at present yielded from Coal by best Engines; Sound--its velocity and action; Liquid Glues, Recipes; Value of Brains; Properties of Charcoal; Height of Waves; Speed of Electric Spark, etc.; Plain Directions, with Engravings, showing how any person can make Electro-Magnets and Electric Batteries at a cost of a few cents; Valuable Recipes. _The Scientific American Reference Book,_ price only 25 cents, may be had of News Agents in all parts of the country, and of the undersigned. Sent by mail on receipt of the price. Address MUNN & CO., 37 Park Row, New York, THE SECOND GREAT SALE OF PATENTS AT AUCTION Will take place at the Auction Rooms of GEO. W. KEELER, 53 Liberty St., N. Y., on July 16, at 12 o'clock. Models now on exhibition. Send for Catalogue. WOOD & LIGHT MACHINE CO. WORCESTER, Mass. Manufacture of all kinds of IRON-WORKING MANCHINERY, including many novelties. Shafting, Pulleys, &c. Send for Circulars. [Illustration] $95 A month and expenses. SALESMAN WANTED to sell to DEALERS. SAMPLES FREE. CANDY & NOVELTIES LETTERS must have enclosed return postage. H. SMITH & CO., CONFECTIONERS, Cincinnati, O. POND'S TOOLS ENGINE LATHES, PLANERS, DRILLS, &c. Send for Catalogue. DAVID W. POND, Successor to LUCIUS W. POND. WORCESTER, MASS. STEAM PUMPS. FIRST PRIZES, CENTENNIAL, PHILA., VIENNA, PARIS, NEW YORK, BALTIMORE, BOSTON. Send for circular of recent patented improvements, THE NORWALK IRON WORKS CO., South Norwalk, Conn. Prices Reduced. N. F. BURNHAM'S 1874 WATER WHEEL Is declared the "STANDARD TURBINE," by OVER 600 persons who bought and use them with PART and FULL GATE open. Pamphlets Free. N. F. BURNHAM, YORK, PA. OTIS' SAFETY HOISTING MACHINERY OTIS BROS. & CO., No. 348 Broadway, New York. $55 TO $77 a week to Agents. $10 _Outfit Free_. P. O. VICKERY, Augusta Maine.