Note 332 — THE CONCLUSION: COMPREHENDING A RETROSPECT OF THE LIFE OF DAVID RITTENHOUSE,

This desideratum in astronomical science had long engaged Dr. Rittenhouse’s attention; and it is confidently said by one of his intimate friends, that, in the latter part of his life, he had actually written much on the subject of Pendulums; intended, probably, for publication. But, unfortunately, the manuscript-book, which contained what he had thus written, can not now be found.

In the paper mentioned in the text, he remarks, that “the invention and construction of time-keepers may be reckoned among the most successful exertions of human genius. Pendulum-clocks especially,” says he, “have been made to measure time with astonishing accuracy; and, if there are still some causes of inequality in their motions, the united efforts of mechanism, philosophy and mathematics, will probably, in time, remove them.”

Indeed no man has done more, none perhaps so much, towards removing the imperfections in chronometers, to which he alludes, as this great mechanician himself. His admirable time-piece, now in the possession of the Philosophical Society at Philadelphia, constructed by him, on an improved plan of his own, affords ample proof of the “astonishing accuracy” (as he expresses it) to which the pendulum-chronometer may be brought. A description of the mechanism of this extremely accurate time-piece, as well as of the principles on which its superior correctness depends, is inserted in the Appendix.