48 o THE POPULAR SCIENCE MONTHLY. 



Trinity House Board on fog-signals. Now, although this account is interesting 

 in itself to the public generally, yet, being addressed to the Lighthouse Board 

 of the United States, it would tend to convey the idea that the facts which it 

 states were new to the board, and that the latter had obtained no results of a 

 similar kind ; while a reference to the Appendix to this report will show that the 

 researches of our Lighthouse Board have been much more extensive on this sub- 

 ject than those of the Trinity House, and that the latter has established no facts 

 of practical importance which had not previously been observed and used by the 

 former.'''' 



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 pref- 

 ace of the jjresent edition of his volume, to bear in mind that " the 

 Washington Appendix was published nearly a year after his [my] re- 

 2)ort to the Trinity House." But in so writing it seems to have es- 

 caped 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 " tJds 

 knowledge was not tolthout influence on his conduct.''^ And in so writ- 

 ing 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, 18V3, 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 litei'ary art, for he can be convicted of delinquency in re- 

 spect 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 sub; 

 stantiate 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 importatice which had not been pre- 

 viously observed and used by the former (the United States Light- 

 house 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- 



