It is, moreover, capable of division into positive and negative, and when concentrated or disturbed in one body, it tends to create a similar disturbance or division in a contiguous mass. To this action of electricity, the term static induction is applied. Thus, a positively electrified body _induces_ a division of the electricity in a contiguous body, if both are insulated or surrounded by a non-conducting medium; the negative electricity of the contiguous body being attracted by, and tending to pass to, the positive of the adjoining body, and the positive being repelled to the opposite side. That, in its turn, if sufficiently powerful, tends to disturb the electricity of its neighbor, and attract away its negative electricity; or, if the body which contains it is free to move, to attract that. Thus, by the conflicting action of a positive atmosphere, and a negative earth, and perhaps counter-trade, influenced by magnetism and the solar rays, the currents and winds of the atmosphere are produced, the atmosphere moving with exceeding ease and rapidity. Electricity, excited into currents, or obtained and discharged in either of the methods enumerated, is identical in character, and produces certain well-known effects: 1st. Physiological.--Shocking and convulsing the animal system; producing a peculiar sensation on the tongue, and a flash before the eyes, and in sufficient quantity destroying life. 2d. Magnetic.--_Deflecting the needle_, and, by a suitable arrangement of wire into helices, _conferring magnetic power_, or constituting magnets. 3d. Luminous.--Producing light--by a spark, as it does in natural phenomena--by the glow, the brush discharge, the ball of flame, the flash, or the chain of lightning, and probably the aurora. 4th. Evolving heat.--Melting metallic substances by concentration, with a great intensity of heat--as the wire of the galvanic apparatus, and as is sometimes seen in the effects of lightning in fusing metals on persons stricken; and setting combustibles on fire. 5th. Attraction and repulsion.--Attraction, when the currents flow parallel with each other, or are of opposite natures, and repelling when of like character. 6th. Induction.--Inducing attendant circular or other secondary currents, such as may be seen in the atmosphere during its most violent displays of active energy. 7th. Capable of being dissipated by heated air, or carried off by moisture, although isolated by dry air, of ordinary temperature, which is a bad conductor.