HAVING read with much interest Mr. Hubert Airy's communication to NATURE (NO. 94), on “Pendulum Autographs,” I wish to say a word on the compound pendulum long ago devised, I believe for the first ...

IT may interest some of your readers to know that they can for themselves observe in the most accurate manner the motion of the compound pendulum described by Mr H. Airy * by merely attaching the ends ...