THE CONTROVERSY ON ACOUSTICAL RESEARCH. 479 



edges, without influence on his conduct in giving direction to his 

 researches, it will naturally occur to ordinary minds that this knowl- 

 edge should also have been " not without influence " on his pen when 

 he was professing to give a summary of the existing state of science 

 on this subject. And when to this statement of the case, as acknowl- 

 edged by himself, Ave add that he was made acquainted with the 

 nature and purport of Prof Henry's explorations on this question, not 

 only " in a general way," but also in a very special way, it becomes 

 still more inexplicable that, in defining " the blank " which he claims 

 to have filled by his recent inquiry, he should have disregarded the 

 labors and results of American science, and that, too, while profiting 

 by the instruments and methods of that science in the very conduct 

 of his investigations. The reader will understand the force of our 

 remark that Prof. Tyndall was acquainted with the researches of Prof. 

 Henry, not only " in a general way," but also in a special way, when 

 we state that a paper by the latter on the abnormal phenomena of 

 sound in relation to fog-signaling was read by its author in the 

 hearing of Prof. Tyndall at a meeting of the Washington Philosophi- 

 cal Society, called for the purpose of doing honor to the British sa- 

 vant wliile he was sojourning in the national capital. And the force 

 of our remark that he has ignored the results of American science in 

 magnifying " the blank" which he describes, while profiting by the in- 

 struments and methods of that science in conducting his inquiry, will 

 be understood wiien we say that the researches of Prof. Tyndall Avere 

 prosecuted with the help of a steam-siren, gratuitously lent to him by 

 the Lighthouse Board at Washington, constructed and patented by 

 a citizen of Mew York, and introduced by Prof. Henry into the light- 

 house system of the United States. 



We are now prepared for the next stage of this review. It so 

 happened that while Prof. Tyndall was conducting his researches on 

 sound in relation to fog-signaling, an officer of the United States Corps 

 of Engineers, Major Elliot, had been deputed by the Lighthouse 

 Board at Washington to make a tour of inspection in Europe, with 

 instructions to report upon matters relative to lighthouse apparatus 

 and the management of lighthouse systems. Major Elliot reached 

 London a few days before Prof. Tyndall began his experiments at 

 Dover, and was courteously invited to be present, but for want of 

 time was compelled to forego the privilege. The results of the Eng- 

 lish experiments were, however, subsequently communicated to Major 

 Elliot by Sir Frederick Arrow, the Deputy Master of Trinity House 

 (who, we are sorry to say, has since deceased), and were embodied in 

 his report on the " European Lighthouse Systems," as recently pub- 

 lished. The publication of Major Elliot's report was accompanied, in 

 the annual report of the United States Lighthouse Board for the 

 year 1874, with the following observations : 



*' Major Elliot gives a detailed account of a late sei'ies of experinients by the 



