. The Ontario high school physics. Fia. 261.—Balance wheelof watch. •Strictly speaking-, it is a point called the centre of oscillation (which nearly coincides withthe centre of gravity) whose distance from the point of suspension should be kept constant. 220 EXPANSION THROUGH HEAT in Fig. 261. The outer metal is the more expansible, and theeffect of its expansion is to turn the free ends of the riminwards, and thus to lessen the effective diameter of thewheel. 251. Thermostats. The fact that a bar composed of twometals having unequal expansion tends to curl up withincreased temperature finds
. The Ontario high school physics. Fia. 261.—Balance wheelof watch. •Strictly speaking-, it is a point called the centre of oscillation (which nearly coincides withthe centre of gravity) whose distance from the point of suspension should be kept constant. 220 EXPANSION THROUGH HEAT in Fig. 261. The outer metal is the more expansible, and theeffect of its expansion is to turn the free ends of the riminwards, and thus to lessen the effective diameter of thewheel. 251. Thermostats. The fact that a bar composed of twometals having unequal expansion tends to curl up withincreased temperature finds practical application also in theconstruction of thermostats. Thermostats are used mainly for controlling the temperaturein buildings heated by hot-air furnaces or boilers. In mostsystems of control, dampersor steam valves are openedand closed by electricity orcompressed air. The objectof the thermostat is to setfree the current of elec-tricity or the compressedair to close the valves ordampers when the tempera-ture reaches a
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Keywords: ., bookcentury1900, bookdecade1910, bookpublishe, booksubjectphysics
