PHILOSOPHICAL SOCIETY OP WASHINGTON. 317 



ioil was at once introduced into actual use in the years 1865 and 

 1866, in all the light-houses of the United States; with an 

 economy of at least one dollar on every gallon of the hundred 

 thousand in annual use ; that is of 100,000 dollars per annum. 



During the progress of these useful labors, no less important 

 investigations were commenced, on the most efficient forms of 

 apparatus for acoustic signalling, as the substitutes for light 

 signals during the prevalence of sea-board fogs. " Among the 

 impediments to navigation, none are perhaps more to be dreaded 

 than those which arise from fogs. . . . The only means at 

 present known for obviating the difficulty, is that of employing 

 powerful sounding instruments which may be heard at a suffi- 

 cient distance through the fog, to give timely vrarning of impend- 

 ing danger."* 



Gun signals were early abandoned, as inefficient, dangerous, 

 and expensive : inefficient, because of both " the length of the 

 intervals between the successive explosions, and the brief dura- 

 tion of the sound, which renders it difficult to determine with 

 accuracy its direction." Innumerable projects eagerly pressed 

 upon the Board by visionary inventors (some of them being 

 rattles, gongs, or organ pipes operated by manual cranks, many 

 of them being varieties of automatic horn or whistle operated 

 by the Avinds or the waves) were impartially tested, and uni- 

 formly rejected as wholly insufficient : very few of their projec- 

 tors having the slightest practical idea of the requirements of 

 the service. Experiments on steam-whistles of large size and 

 on horns with vibrating steel tongues or reeds, sounded by steam- 

 power, or by hot-air engines, varied and continued for several 

 years under wide changes of conditions, finally determined their 

 most efficient size and character.! 



In 186Y, comparative trials were made at Sandy Hook (on 

 the Jersey shore, at the entrance to Raritan Bay, and to New 

 York Bay,) with three powerful instruments ; a large steam 

 whistle whose cup was 8 inches in diameter, and made adjust- 

 able in pitch ; a large reed trumpet IT feet long and 38 inches 

 in diameter at its flaring mouth, whose steel tongue was 10 inches 

 long, 2| inches wide, and half an inch thick at its smaller vibrat- 

 ing end, and was blown by a hot air engine ; and lastly a large 



* Report of L. H. Board ioY 1874, p. 83. 



t An enterprising inventor had secured a patent for a metallic com- 

 pound or alloy for steam-whistles, especially adapted to increase greatly 

 their power as fog-signals. In vain was he assured that his "improve- 

 ment" was a fallacy ; that the cylindrical cup of the whistle was not a 

 bell, but only a resonant chamber ; and that its material was compara- 

 tively unimportant. He was only with difficulty convinced, when Henry 

 had his whistle formally tested, with a stout cord wound tightly around 

 its cylindrical surface : when its tone under steam escape was proved to 

 be as full, as loud, and as penetrating, as with the cord removed. 



91 



