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acid action alternate currents angle apparatus armature arrangement attraction axis ball battery binding-screws called carbon cells centre charge circle circuit coil condenser conductor connected consists copper cylinder deflection denote density diamagnetic difference of potential disc discharge distance dynamo earth effect electro-magnet electromotive force electroscope employed energy equal experiment flow flux force due galvanometer glass gutta-percha heat Hence horizontal increase induction inner coating instrument insulated intensity inversely junction knob length Leyden jar lines of force liquid machine magnetic force magnetic meridian metal motion movable needle north-seeking observed obtained Ohm's law opposite direction parallel passes perpendicular plane plate poles portion produced quantity of electricity repelled repulsion resistance rotation round shell shellac side soft iron spark strength surface suspended temperature terminals terrestrial magnetism thermo-electric Thomson effect tion tricity tubes of force unit velocity vertical Wheatstone's Bridge wire zero zinc
Página 334 - Our Place among Infinities: A Series of Essays contrasting our Little Abode in Space and Time with the Infinities Around us. Crown 8vo, cloth extra, 6s. The Expanse of Heaven : A Series of Essays on the Wonders of the Firmament.
Página 324 - Newton generalized the law of attraction into a statement that every particle of matter in the universe attracts every other particle with a force which varies directly as the product of their masses and inversely as the square of the distance between them; and he thence deduced the law of attraction for spherical shells of constant density.
Página 114 - Observations of magnetic force are made either by counting the number of vibrations executed in a given time, or by statical measurements. If a magnet executes small horizontal vibrations under the influence of the earth's magnetism, the square of the number...
Página 334 - ANTHONY PROCTOR. With Illustrations, some colored. I2mo. Cloth, $1.75. CONTENTS.— Introduction. — What the Earth teaches us.— What we learn from the Sun. — The Inferior. Planets. — Mars, the Miniature of our Earth. — Jupiter, the Giant of the Solar System. — Saturn, the Ringed World. — Uranus and Neptune, the Arctic Planets.— The Moon and other Satellites.— Meteors and Comets : their Office in the Solar System.— Other Suns than Ours.— Of Minor Stars, and of the Distribution...
Página 287 - ", large number of persons at one time by throwing an image of the heated points upon a screen, with the aid of a lens. On watching the image for a few minutes, incandescent particles will be observed traversing the length of the arc, sometimes in one direction and sometimes in the other, the prevailing direction being, however, that of the positive current. This circumstance, which appears to be connected with the higher temperature of the positive terminal, explains the difference between the forms...
Página 124 - ... for then the tendency of the indicating cube or sphere was to move outwards, in the direction of the magnetic lines of force. The appearance was remarkably like a case of weak electric repulsion. 2269. The cause of the pointing of the bar, or any oblong arrangement of the heavy glass, is now evident. It is merely a result of the tendency of the particles to move outwards, or into the positions of weakest magnetic action. The joint exertion of the action of all the particles brings the mass into...
Página 128 - Bismuth is a brittle metal, and can readily be reduced to a fine powder in a mortar. Let a tea-spoonful of the powdered metal be wetted with gum-water, kneaded into a paste, and made into a little roll, say an inch long and a quarter of an inch across. Hung between the excited poles, it will set itself like a little bar of bismuth — equatorial. Place the roll, protected by bits of pasteboard, within the jaws of a vice, squeeze it flat, and suspend the plate thus formed between the poles. On exciting...
Página 289 - The current enters at the binding-screw C, traverses the coil of the electro-magnet E, and passes through the wheel-work to the rack D, which carries the positive carbon. From the positive carbon it passes through the voltaic arc to the negative carbon, and thence, through the support H, to the binding-screw connected with the negative pole of the battery. When the armature F descends...
Página 23 - I went into the cube and lived in it, and using lighted candles, electrometers, and all other tests of electrical states, I could not find the least influence upon them, or indication of anything particular given by them, though all the time the outside of the cube was powerfully charged, and large sparks and brushes were darting off from every part of its outer surface.