The "Appendix" here referred to is from the pen of Prof. Henry, the chairman of the board, and details elaborate experiments on sound in relation to fog-signaling, as pursued in the service of the United States Lighthouse Board since the year 1855. Brought to book by this "Appendix," Prof. Tyndall asks his readers, in the preface of the present edition of his volume, to bear in mind that "the Washington Appendix was published nearly a year after his [my] report to the Trinity House." But in so writing it seems to have escaped his notice that in a subsequent part of this same preface he has confessed that he was "quite aware in a general way" that labors like his own had been conducted in the United States, and that "this knowledge was not without influence on his conduct." And in so writing he forgets, too, that he was an interested listener to the paper read by Prof. Henry on this subject in his hearing while he was in the United States, and before he had turned any attention at all to the phenomena of sound in connection with fog-signals. He states in the body of his book, as already mentioned, that his inquiry under this head began on May 19, 1873, several months after his "general" and his special knowledge of what had been accomplished in this country. And yet, in the face of all these facts and acknowledgments he has allowed his "summary of existing knowledge" on the subject to stand without any recognition of American science in the premises—a suppression which does as little credit to his scientific generosity as to his literary art, for he can be convicted of delinquency in respect of the former by the inconsistency of statement into which he has fallen through a want of dexterity in the latter.
We may, therefore, safely leave the acknowledged record to substantiate the claims of the United States Lighthouse Board when they represent that their researches, running through many years, "are much more extensive on this subject than those of the Trinity House." It remains for us only to consider the second branch of their representation—namely, that the latter (the Trinity House) "has established no facts of practical importance which had not been previously observed and used by the former (the United States Lighthouse Board)." In support of this statement we may point to the fact that Prof. Tyndall nowhere pretends to have established by his researches any improvements whatsoever on the methods or instru-