Isochronism (3): As a Keyword of Japanese Mechanical Horology

Abstract

  As a history of the calculation of the force from the outer end fixed hairspring and the calculation of the influence to the motion of the hairspring were done formerly by Prof. Hasunuma (The University of Tokyo, Former President of The Horological Institute of Japan) around 1949.

  In this lecture, the new calculation is explained along these histories and also how these lectures are fit with actual experimental result.

  Including the last lecture there must be used long pages for the introduction for these fundamental equations explanations mainly for the horizontal isochronism. It will be allowed for the main explanation of the regulating system of mechanical watches.

  There are some unconfident points, such as the differences of the actual experimental results and the classical theory. These are appointed out here.

  Thus it must be said there are so many unsolved points in the theoretical region of mechanical watches.