Lectures on ElectricitySherwood, Gilbert, and Piper, 1842 - 240 páginas |
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attached becomes bells brass arm brass ball brass wire centre chain charged circuit clouds coating condenser connected consequently copper degree of intensity discharging rod display distance divergency ductor elec electric action electric cloud electric condition electric fluid electric forces electrized body electro-negative electro-polar electro-positive electrometer electrophorus electroscope employ excited glass tube experiment extremity glass cylinder glass handle glass pillar glass plate gold leaves horizontal illustration inches inner surface instrument insulated kite latter lecture lever Leyden jar light lower luminous machine mahogany means metallic arm motion needle negatively electrical observe operations pass phenomena piece of apparatus pith balls plate of air pointed wire polarization polarizing body portion present prime conductor produced quantity of fluid ratus represented by Fig repulsion resinous cake rubbing scudo series of sparks side silk spangles sphere stick of sealing-wax tion uninsulated upper vitrious whilst whole WILLIAM STURGEON zinc
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Página 193 - ... of those edifices upright rods of iron made sharp as a needle, and gilt to prevent rusting, and from the foot of those rods a wire down the outside of the building into the ground, or down round one of the shrouds of a ship, and down her side till it reaches the water?
Página 174 - ... or 30 feet, pointed very sharp at the end. If the electrical stand be kept clean and dry, a man standing on it when such clouds are passing low, might be electrified and afford sparks, the rod drawing fire to him from a cloud.
Página 174 - If any danger to the man should be apprehended (though I think there would be none) let him stand on the floor of his box, and now and then bring near to the rod the loop of a wire that has one end fastened to the leads, he holding it by a wax handle : so the sparks, if the rod is electrified, will strike from the rod to the wire, and not affect him.
Página 15 - I call vitreous electricity, and the other resinous electricity. The first is that of glass, rock-crystal, precious stones, hair of animals, wool, and many other bodies; the second is that of amber, copal, gum-lack, silk, thread, paper, and a vast number of other substances.
Página 17 - ... share, or than that quantity which it is capable of retaining by its own attraction, — it does not discover itself to our senses by any effect. The action of the rubber upon an electric disturbs this equilibrium, occasioning a deficiency of the fluid in one place and a redundancy of it in another. This equilibrium being forcibly disturbed, the mutual repulsion of the particles of the fluid is necessarily exerted to restore it.
Página 173 - ... in time there may be found out a way to collect a greater quantity of the electric fire...
Página 193 - ... prevent rusting, and from the foot of those rods a wire down the outside of the building into the ground, or down round one of the shrouds of a ship, and down her side till it reaches the water? Would not these pointed rods probably draw the electrical fire silently out of a cloud before it came nigh enough to strike, and thereby secure us from that most sudden and terrible mischief...
Página 173 - To determine the question, whether the clouds that contain lightning are electrified or not, I would propose an experiment to be tried where it may be done conveniently. On the top of some high tower or steeple, place a kind of sentry-box, . . . big enough to contain a man and an electrical stand.
Página 15 - has thrown in my way another principle more universal and remarkable than the preceding one, and which casts a new light upon the subject of electricity. The principle is, that there are two distinct kinds of electricity, very different from one another; one of which I call vitreous, the other resinous, electricity.
Página 193 - The rod may be fastened to the wall, chimney, &c. with staples of iron. The lightning will not leave the rod (a good conductor) to pass into the wall (a bad conductor) through those staples. It would rather, if any where in the wall, pass out of it into the rod, to get more readily by that conductor into the earth.