Pamphlets on Biology (Volume 3227); Kofoid Collection

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.1837 Excerpt: ... firmly in its position by a nut, but movable, so that the armatures may be removed at pleasure. d, is a strong brass pillar for supporting the axis, which turns on centres, secured and adjusted Fig. 1. by nuts and milled head screws. There is a similar pillar at the other end of the axis, on the opposite side, but concealed from view by the body of the machine. The magnetic batteries are also secured to the frame by strong brass clamps, and adjusted by milled head screws. e, is the pulley wheel, and /, the multiplying wheel. g, the top board, is secured to the frame by screws, and answers as a convenient table for experiment. The magnets are sixteen inches long, the armatures ten inches, so that the whole machine occupies but little room. The alternating currents, from the semi-revolutions of the armatures, are converted into a current of the same direction, by the application of my pole changer. This simple contrivance, beautifully applicable to the magneto-electric, as well as to the electro-magnetic machine, will be found fully described in Vol. xxxiii. No. 1. p. 190, of this Journal. It consists merely of two insulated, metallic, cylindrical segments, secured on the shaft, and two stationary metallic tangent springs for conductors. Silver, about the purity of coin, answers best. The wires from each of the armatures, pass through holes in the brass straps, and through openings in the sides of the machine, to be attached to the pole changers, one of which is seen at h. One pole changer would suffice for both armatures, but by using two, the experiments may be considerably varied, as the separate coils may be combined, to form a simple or compound battery. i i, are the tangent springs of copper, but tipped with silver where they rest upon the silver pole c...