. The Ontario high school physics. Fio. 257. —Expan-sion of liquids Fio. 258.—Expansionof gas by heat. CHRONOMETER BALANCE WHEEL 219 slower tlie beat; and tlie sliorter, the faster. Changes intemperature will therefore cause irregularitiesin the running of the clock, unless some pro-vision is made for keeping the pendulum con-stant in length through varying changes intemperature. Two forms of com- I pensation are in common use. TheGraham pendulum (Fig. 259) is pro-vided with a bob consisting of a jarof mercury. Expansion in the rodlowers the centre of gravity of thebob, while expansio
. The Ontario high school physics. Fio. 257. —Expan-sion of liquids Fio. 258.—Expansionof gas by heat. CHRONOMETER BALANCE WHEEL 219 slower tlie beat; and tlie sliorter, the faster. Changes intemperature will therefore cause irregularitiesin the running of the clock, unless some pro-vision is made for keeping the pendulum con-stant in length through varying changes intemperature. Two forms of com- I pensation are in common use. TheGraham pendulum (Fig. 259) is pro-vided with a bob consisting of a jarof mercury. Expansion in the rodlowers the centre of gravity of thebob, while expansion in the mercuryraises it. The quantity of mercury Fig. is SO adjusted as to keep the centreof gravity* always at tlie same level. In the Harrison, or gridiron pendulum (Fig. 260)the bob hangs from a framework of brass and steelrods, so connected that an increase in length of thesteel rods (dark in the figure), tends to lower thebob, while an increase in the length of the brass onestends to raise it. The lengths of the two sets are ^son^penduimTadjusted to k
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Keywords: ., bookcentury1900, bookdecade1910, bookpublishe, booksubjectphysics
