, did not think of those ofthe balance with the spiral spring. And it was not until the closeof the year 1750 that Pierre Le Roy and Ferdinand Berthoudstudied the conditions of isochronism pertaining to the spiral. AN INVENTION THAT CREATED MUCH ENTHUSIASM. However that may be, this magnificent… … Fig. 160 Fig. 161 possible ; a new highway was thus opened to the searchers. Thewater clocks (clepsydrae) and the hour glasses disappeared com-pletely, and the timepieces which had till then only marked thehours, having been perfected up to the point of keeping more exacttime, were graced with the…
Clocks and watches
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