Mechanical Analysis of the Trevelyan Rocker

Abstract

ALMOST every physical cabinet possesses one of Trevelyan's rockers, and yet it is rare to find one which always works well and gives complete satisfaction. Some two years ago having experienced this difficulty in New York, where I was then Professor of Physics, I requested Mr. Robert Spice, F.C.S., of 230, Bridge Street, Brooklyn, U.S., a very skilful constructor of acoustic instruments, and a thorough physicist, to make for me several of these rockers and ascertain, if possible, the conditions of success. After many experiments with rockers of different sizes and angles, Mr. Spice obtained a formula by which a perfectly satisfactory rocker can be constructed, as several trials since then, both in America and Europe, have convinced me. Believing that there are many other professors who feel interested In this matter I communicate to the readers of NATURE, at Mr. Spice's request, his analysis of the rocker.