Media of Different Densities, Devices by Means of Buoyancy Through, 151 Mercurial Pneumatic Device (See Cunningham, George). Mercury, Inclined Glass Tube and Ball, 68 Momentum, Defined, Explained and Distinguished from Energy, 201 Momentum and Energy, Account and Explanation of Perpetual Motion Devices by Means of, 205 Momentum and Energy, Distinguished and Considered; Attempted Devices for Perpetual Motion by Means of (See Table of Contents), 5 Munro, R., Comments on Mackintosh's Experiment, 169 Newcomb, Simeon, Notice of, 15 Newton, Sir Isaac, Mention of, 135, 220 Letter to from Prof. 's Gravesande, 236 Nicholson, William, Notice of, 315 His Article Against the Possibility of Perpetual Motion, 316 Orchard's Vacuum Engine, 137 Orffyreus, Jean Ernest Eli Bessler (Councillor), His Perpetual Motion Labors (See Table of Contents), 5 Remarks of Author Concerning Claims of, 252 Papin, Dr., Argument by Against the Possibility of Perpetual Motion, 275 Pasley, T. H., Article by, 347 "Pamphleteer, The," Article Published in, 349 Paradox, Hydrostatical, 118 Patents, U. S. (See U. S. Patents); Patents, British (See British Patents). "Peasant Boy Philosopher" (See Ferguson, James). Pendulum, Gallileo's Experiment with, 268 Perpetual Motion Defined, 11 Perpetual Pump, 109 Perpetual Motion, Its Possibility Considered with Reference to Conservation of Energy, 269 Perpetual Motion, Consideration of Its Possibility, 270 Arguments Against Its Possibility--Article by Dr. Papin, 275 Article by Rev. John Wilkins, 281 Article Based on Paradoxical Hydrostatical Balance, 305 Article by P. Gregorio Fontana, 306 Article by William Nicholson, 316 Article Published in "The Artisan," 329 Article Published in "Mechanic's Magazine," 278