Let us now go back ten years and see how this verdict was arrived at.
When Professor Tyndall was preparing his work on heat, he desired to acquaint himself with all that Mayer had done upon this subject. He accordingly wrote to two eminent Germans, authorities upon this question, for information. Both responded, and one of them, Professor Clausius, procured Mayer's publications to send to Tyndall. In his first letter he said he thought Professor Tyndall would not find anything very important in Mayer's writings. But before forwarding the memoirs he read them himself, and then wrote to Tyndall: "I must here retract the statement, in my last letter, that you would not find much matter of importance in Mayer's writings; I am astonished at the multitude of beautiful and correct thoughts which they contain." He then went on to point out various important subjects in the treatment of which Mayer had anticipated other eminent writers. Professor Tyndall perfectly agreed with Clausius, and resolved to do his share toward making so able and original a man better known in England. Accordingly, on June 6, 1862, he gave a most interesting lecture at the Royal Institution, full of new views and novel experiments, on the subject of "Force." At its close he remarked: "To whom, then, are we indebted for the striking generalizations of this evening's discourse? All that I have laid before you is the work of a man of whom you have scarcely ever heard. All that I have brought before you has been taken from the labors of a German physician, named Mayer. Without external stimulus, and pursuing his profession as town physician in Heilbronn, this man was the first to raise the conception of the interaction of natural forces to clearness in his own mind. And yet he is scarcely ever heard of in scientific lectures, and even for scientific men his merits are but partially known. Led by his own beautiful researches, and quite independent of Mayer, Mr. Joule published his
