. Practical physics. te p. 32). He used for his barometer a•water column the top of which passed throughthe roof of his hovise. A wooden image which floated on the upper surface of the water appeared above the housetopin fair weather but retired from sight in foul, a circumstance whichled his neighbors to charge him with being in league with Satan. 43, The aneroid barometer. Since the mercurial Ijarometer is some-what long and inconvenient to carry, geological and surveying parties Fig. 28. The Fortinbarometer 32 PEESSURE IX AIR commoiily use an instrument called the aneroid barometer. It cons
. Practical physics. te p. 32). He used for his barometer a•water column the top of which passed throughthe roof of his hovise. A wooden image which floated on the upper surface of the water appeared above the housetopin fair weather but retired from sight in foul, a circumstance whichled his neighbors to charge him with being in league with Satan. 43, The aneroid barometer. Since the mercurial Ijarometer is some-what long and inconvenient to carry, geological and surveying parties Fig. 28. The Fortinbarometer 32 PEESSURE IX AIR commoiily use an instrument called the aneroid barometer. It consistsessentially of an air-tight cylindrical box the top of which is a metallicdiaphragm which bends slightly under the influence of change in theatmospheric pressure. This motion of the top of the box is multipliedby a delicate sjstem of levers and communicated to a hand which movesover a dial whose readings are made to correspond to the readings of amercurv liarometer. These instruments are made so sensitive as to. Fi. U. The aneroid barometer indicate a change in pressure when they are moved no farther than froma tal)le to the floor. In the self-recording aneroid barometer, or baro-graph, used by the United States \\eather Bureau (Fig. 29), several of theair-tight boxes are superposed for greater sensitiveness, and the jiressuresare i-ecorded in ink upon pajier wound about a drum. Chackwork insidethe drum inakes it revolve once a week. A somewhat different form ofthe instrument is used bv aviators to record altitude. QUESTIONS AND PROBLEMS 1. Why does not the ink run out of a pneiuuatic inkstand like thatshown in Fig. 30? 2. If a tumbler is filled, or partly filled, with water, and a jiiece ofwriting pajier is placed over the top, it may be inverted, as in Fig. M,without spilling the water. Explain. What is the function of the paper?
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectphysics, bookyear1922