49 



THE POPULAR SCIENCE MONTHLY. 



contains observations, but contradictory 

 observations ; while, as regards the es- 

 tablishment of any principle which 

 should reconcile the conflicting results, 

 it leaves our condition unimproved." 



A distinction is here drawn, and 

 again recognized in his letter, that 

 goes to the root of the subject; the dis- 

 tinction, namely, between experiments 

 on fog-signals made for direct purposes 

 of utility, and similar experiments con- 

 ducted with a view to the establishment 

 of scientific principles. This discrimi- 

 nation is all-important. It is no doubt 

 possible to have both objects more or 

 less in view in such an inquiry ; but it is 

 also possible that either may so predom- 

 inate as to characterize the respective 

 courses of investigation, and yield very 

 dissimilar results. Elaborate experi- 

 ments may promote practical ends, and 

 contribute little or nothing to science ; or 

 they may advance scientific knowledge 

 without any immediate influence upon 

 practice. It was claimed by Prof. Henry, 

 in his Appendix to the report of the 

 Lighthouse Board for 1874, that the 

 researches of the board had been more 

 extensive on this subject than those in 

 England, as well as prior to them ; but 

 the question remains, To what purpose 

 were they carried on? The answer to 

 this question, defining the character and 

 object of the inquiries, is immediately 

 given in the statement that the Ameri- 

 can re.=ults of "practical importance" 

 are in advance of the English. The 

 writer in the Nation speaks of " Amer- 

 ican science " as bearing Baconian fruit, 

 such as Daboll's trumpet and Brown's 

 steam -siren. These devices and con- 

 struction are, no doubt, highly impor- 

 tant, but there is certainly a wide differ- 

 ence between the invention of whistles 

 and systematic inquiries into the causes 

 of acoustical phenomena. No one doubts 

 the immense value to the country and 

 to civilization of the labors directed 

 by Prof. Henry, as chairman of the 

 Lighthouse Board ; but he has him- 

 self declared their practical character, 



and how broadly true is this character- 

 ization appears from a passage in a let- 

 ter which he wrote to the Secretary of 

 the Treasury, dated February 22, 1875, 

 defending the Washington board against 

 an attack made upon it in Congress. It 

 is noteworthy, also, as showing that, 

 when Prof. Henry wishes to protect 

 himself from adverse criticism, he falls 

 back upon the verdict pronounced by 

 Prof. Tyndall in this very matter of 

 fog-signals. Prof. Henry said : " The 

 board has a standing committee on 

 experiments which has accepted and 

 sought to test every invention that 

 could be supposed to aid the mariner. 

 Many illuminants, various devices in 

 engineering, expedients for floating aids, 

 plans, and theories of all kinds, have 

 received its attention. To this accusa- 

 tion can be opposed on behalf of the 

 board the verdict of foreign nations, 

 the tributes of scientific associations, 

 and the contented judgment of mari- 

 time and commercial men from whom 

 no complaints are received. Its buoys 

 are excellent in their construction ; its 

 buoy-service is well performed ; its 

 light-ships are equal to any in the world ; 

 its lights are entirely satisfactory to the 

 commercial and nautical men for whose 

 interest they are maintained; and its 

 fog-signals surpass, in the finding of 

 Prof. Tyndall, who conducted a series 

 of experiments for the Trinity House 

 Board, those of all other nations, and 

 have been adopted for England." But 

 it is claimed that Prof. Henry's inves- 

 tigations constitute also an important 

 contribution to "American science," in 

 relation to fog-signaling. Prof. Tyndall 

 denies that they have at all advanced 

 our scientific knowledge upon the sub- 

 ject, and the writer in the Nation had 

 this denial before him when he wrote. 

 It was his plain business, then, to dis- 

 prove it if he could, and give the evi- 

 dence that Prof. Tyndall was in error. 



The simple question is, What new 

 scientific principles have been estab- 

 lished, or what causes elucidated by 



