Excerpt from The Correlation of Physical Forces It has happened with this subject as with many others, that similar ideas have independently pre sented themselves to different minds about the same period. In 'leibig and Wohler's Annalen' for May a paper appeared by M. Mayer which I had not read when my third edition was published, but which I have now read in the translation by Mr. Youmans of New York. It deduces very much the same conclusions to which I had been led, the author starting partly from (e priori reasoning and partly from an experiment by which water was heated by agitation, and from another, which had, however, previously been made by Davy, viz. That ice can be melted by friction, though kept in a medium which is below the freezing point of water. In 1843 a paper by Mr. Joule on the mechanical equivalent of heat appeared, which, though not in terms touching on the mutual and necessary dependence of all the Physical Forces, yet bears most importantly upon the doctrine. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.