HOW MINUTE DISTANCES ARE MEASURED

Taranaki Daily News, Volume LI, Issue 275, 14 November 1908, Page 3

HOW MINUTE DISTANCES ARE MEASURED

Tire sensitiveness of the human at-! gitnbiu is gross indeed compared wilHI Hint of the marvellous nuiehines nun! has made. A photographic,plate coupled with n telescope discovers millions of slats whose light the letiaa of the eye does not appreciate; the microphone makes the inaudible tread of a ily sound like the tramp of cavalrymen. The human heat sense eannot reali-e a difference of temperature beyond oneliitli of a degree; luit the barometer, an instrument. 20(1,001) times as sensitive as the skin, notes a dilVerenee of a millionth of a degree. A galvanometer ilexes its linger at a current generated by simplv deforming a. drop of mercury si) as to' press it out of a spherical shape into that of an p««. 'l'lic amount of work don" hy the wink of an eye equals ino.ooo.noil,ooo of the wink* niarketl 011 tile sealc of a delicate instrument; hut even this performance is surpassed by the "coherers'' of Braiiley of 'Paris, by which the Her:/, waves of wireless telegraphy are taught in their .pulsings through space. The range of impressions which vc tret from lifting an object is exceccliiig'v small', an ordinary chemist's balance is some million times as sensitive a" 1 weights Hown the 200 th part, of a milli„vani. Without such instruments as these we should know far less about the world Until thev place within our lea li. 1 They make it evident that, our sense 01nans give us reports of but a compava--1 tivclv small number of comparatively gross stimuli-