[20] By means of this instrument very minute forces can be accurately measured, such as electrostatic or magnetic attraction and repulsion, by the torsion (turning or twisting) of a wire or filament, the angle of torsion being proportional to the amount of force exerted. [21] Merz, Henry, “History of European Thought in the Nineteenth Century,” Vol. I, Page 362. [22] For a recent work on modern electrical theory, see Starling, Sydney G., (head of the department of physics in the West Ham Municipal College, London), “Electricity,” London, 1922. For the pioneer work of Ampère, see his “_Theorie des Phenomenes Electrodynamiques_,” 1826. CHAPTER 5 MODERN MAGNETIC THEORY We have already shown how the magnetism of a magnet is converted into electricity, by means of rotating coils cutting the lines of magnetic force in the “field.” The energy used to drive the machinery may, of course, be derived either from water-power or by steam. Gravity gives energy to falling water; chemical energy produced by the oxidation of coal becomes heat energy, which in turn causes the expansion of steam, which produces energy of motion in a piston; and this motion, transmitted to the parts of an engine to a dynamo, produces electrical energy. When the electric current from the dynamo has been conducted to any desired point by cables, another motor, acting in the opposite sense, causes the electricity to change back again into the original mechanical energy, less the loss due to imperfections in the operation. Here we have, then a clear picture of what is meant by the phrase, _transformation of energy_. But another question naturally arises at this point. We know that with a finite quantity of magnetism we can produce an unlimited quantity of electricity. Yet we add no new material, no source of supply, to the dynamo. Let the rotating coils continue to cut the lines of magnetic force in the magnetic field, and the magnetism of the magnet will be transformed into current electricity—furnishing a literally exhaustless supply from the great storehouse of nature. For us the energy of the universe is infinite in quantity. The reservoir of energy is exhaustless, and the dynamo is man’s open sesame. But just here the very interesting question arises: Is the inexhaustible supply of electric current with the expenditure of a limited quantity of magnetism fully explained by saying that it is due to the rotational movement of the coil? Can the mere rotation of a metal in a magnetic field actually _create_ an endless supply of available energy? Not likely! As Dr. Gustave Le Bon well says: “Such a metamorphosis would be as marvelous as transformation of lead into gold by simply shaking it in a bottle. Another interpretation must be sought for the phenomenon.”