File:The fireside university of modern invention, discovery, industry and art for home circle study and entertainment (1902) (14592267049).jpg

Identifier: firesideuniversi01mcgo (find matches)
Title: The fireside university of modern invention, discovery, industry and art for home circle study and entertainment
Year: 1902 (1900s)
Authors: McGovern, John. (from old catalog)
Subjects: Science
Publisher: Chicago, Union pub. house
Contributing Library: The Library of Congress
Digitizing Sponsor: The Library of Congress

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,it could be seen at Milwaukee, and people at Aurora, west ofChicago, read by the aid of its beams. The shaft passed throughthe air overhead, much like the tail of a great comet. A smallerlight on Mount Washington, makes objects visible that are 100miles away, and the Search-Lights now in New York harbor areseen fifty miles away. Signals are flashed on the clouds. TheSiemens-Halske Projector at the Worlds Fair was also an ex-ample of the triumph of modern optical science, in the economi-cal use and concentration of light-rays. Are there electrical meters like gas meters?Yes. We illustrate Maxims Meter, and there are countlessforms and patents. (Fig. 26.) What is a Solenoid? A solenoid is defined as an electro-dynamic spiral, having theconjunctive wire turned back along its axis, so as to neutralizethat component of the effect of the current which is due to thelength of the spiral, and reduce the whole effect to that of a se-ries of equal and parallel circular currents. ELECTRICITY. 63
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Fig. 26. MAXIMS METER Fig. 26 represents an Electro-meter constructed by Maxim. The solenoid B is in-serted in the main circuit L. L. n n is a branch circuit in which the Electro-MagnetT is inserted. The latter keeps the pendulum Q Q in constant motion in the followingmanner: When a current passes through the coils of the Electro-Magnet; the armatureQ of the Electro-Magnet is attracted; the pendulum therefore, will move towards theleft, taking with it the spring R. which breaks contact with S; the circuit is thus brokenand T is then without current. The pendulum Q falls back again, making contactbetween R and S, and causing a current again to pass through the Electro-Magnet. Themotion of the pendulum is transmitted to the wheel m by means of Q Q and a toothedwheel P fastened upon the axis of Q not shown in the figure. The shaft DM of thewheel m carries the cone L which, when moving, touches the cone L causing it tomove also. The axis of L has a movable weight El and is connected by me

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