. Time and its measurement . escapement and others giv-ing a free pendulum action would re-quire too much space here, so we mustbe satisfied with the few successfulones shown out of hundreds of inven-tions, dozens of them patented. Thepen_dulum stands at the top as a timemeasurer and was known to the an-cients for measuring short periods oftime just as musicians now use themetronome to get regular beats. Gal-ileo is credited with noticing its regularbeats, but did not apply it to clocks,although his son made a partially suc-cessful attempt. The first mathemati-cal investigation of the pendulum
. Time and its measurement . escapement and others giv-ing a free pendulum action would re-quire too much space here, so we mustbe satisfied with the few successfulones shown out of hundreds of inven-tions, dozens of them patented. Thepen_dulum stands at the top as a timemeasurer and was known to the an-cients for measuring short periods oftime just as musicians now use themetronome to get regular beats. Gal-ileo is credited with noticing its regularbeats, but did not apply it to clocks,although his son made a partially suc-cessful attempt. The first mathemati-cal investigation of the pendulum wasmade by Hu3ghens about 1670, and heis generally credited with applying itto clocks, so there is a Huyghensclock with a pendulum instead of thefoliot of Dc Vicks. Mathematically,the longer and ]iea\ier the pendulum. the better is the time-keeping, butnature does not permit us to carry any-thing to the extreme; so the difficulty TIME AND ITS MEASUREMENT 41 of finding a tower high enough andstead} enough, the cumbersomeness ofweight, the elasticity of the rod, andmany other difficulties render verylong and heav}- pendulums impractic-able beyond about 13 ft. which beatsonce in two seconds. Big Ben ofWestminster, London, has one of thislength weighing TOO lb. and measuring,over all, 15 ft. It runs with an error under onesecond a week. This is surpassed onlyby some of the astronomical clockswhich run sometimes two monthswithin a second. This wonderful time-keeping is done with seconds pendu-lums of about 39 in., so the theoreticaladvantage of long pendulums is lostin the difficulties of constructing themFractions are left out of these lengthsas they would only confuse the ex-planations. At the Naval observatotyin Washington, D. C, the standaidclocks have seconds pendulums, therods of which are nickel
Size: 1400px × 1785px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., boo, bookcentury1900, bookdecade1900, booksubjectclocksandwatches
