ISBN: 9781130767742

RareBooksClub. Paperback. New. This item is printed on demand. Paperback. 168 pages. Dimensions: 9.7in. x 7.4in. x 0.4in.This historic book may have numerous typos and missing text. Pur… Altro …

RareBooksClub. Paperback. New. This item is printed on demand. Paperback. 168 pages. Dimensions: 9.7in. x 7.4in. x 0.4in.This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1854 Excerpt: . . . of torsion or twist of the fibre which suspends it, the reaction of which measures the force which turns the needle. The thread is fixed at the top to a small windlass t, by which the needle can be raised or lowered, and the whole is included in a glass cage, to preserve the apparatus from the disturbance of the air. Upon this glass cage, which is cylindrical, is a graduated circle d d, which measures the angle through which the needle is deflected. In the cover of the cage an aperture o is made, through which may be introduced the electrified body whose force it is desired to indicate and measure by the apparatus. 1757. Quadrant electrometer. --This instrument, which is gener ally used as an indicator on the conductors of electrical machines consists of a pillar A b, fig. 496. , of any conducting substance, terminated at the lower extremity by a ball B. A rod, also a conductor, of about half the length, terminated by a small pith ball D, plays on a centre c in a vertical plane, having behind it an ivory semicircle graduated. When the ball B is charged with electricity, it repels the pith ball D, and the angle of repulsion measured on the graduated arc supplies a rough estimate of the intensity of the electricity. Fig. 496. 1758. Gold leaf electroscope. --A glass eylinder A B c D, fig. 497. , is connected to a brass stand E, and closed at the top by a circular plate A B. The brass top G is connected by a metallic rod with two slips of gold leaf f, two or three inches in length, and half an inch in breadth. In their natural state they hang in contact, but when electricity is imparted to the plate G, the leaves becoming charged with it indicate its presence, and in some degree its intensity, by their divergence. On the sides of the glass cylinder opposite the g. . . This item ships from La Vergne,TN., RareBooksClub<