DISCOURSE OF W. B. TAYLOR. 349 



distinctly heard at the distance of six miles or more, and with 

 increasing distinctness as the steamer advanced, was suddenly lost 

 at about three miles, and was not recovered until within a quarter 

 of a mile from the station ; the wind at the time being approxi- 

 mately adverse to the sound. A six-inch steam whistle on board 

 the steamer was meanwhile distinctly heard at the station during 

 the whole time of inaudibility of the larger ten-inch whistle, which 

 had also been sounded without any interruption. This remarkable 

 phenomenon implied a compound flexure of the sound-beams, and 

 accorded with previous observations made at the same points by 

 General Duane the engineer in charge of the first and second Light- 

 House Districts. 



In 1873 observations were again made at Whitehead station, and 

 at Cape Elizabeth light station, both on the coast of Massachusetts. 

 At Whitehead the steam whistle was heard through a distance of 

 1 5 miles, with a light adverse wind. At Cape Elizabeth, with a 

 stronger adverse wind, the siren was heard only about nine miles. 



In 1874, observations were made at Little Gull island, (off the 

 coast of Connecticut;) at Block island, (off the coast of Rhode 

 Island;) and at Sandy Hook, (New Jersey.) At Little Gull island 

 the sound of a siren was heard against a moderate wind, only three 

 and a half miles. At Block island the siren was reported to have 

 been heard under favoring conditions of wind through a distance 

 of more than 25 miles. While it was frequently heard at Point 

 Judith station, and the siren at the latter point was as frequently 

 heard at Block Island, (the distance between the two points being 

 17 miles,) it was shown on comparison of records, that the two 

 instruments had not been heard simultaneously; the wind when 

 favorable to the one being unfavorable to the other. 



At Sandy Hook, for the purpose of making simultaneous obser- 

 vations in different directions, three steamers ( the tenders of differ- 

 ent light-houses) were employed,- with steam whistles specially 

 adjusted to the same tone and power. The latter quality having 

 been carefully tested by the phonometer, the three vessels steamed 

 out abreast on trial ; and their whistles sounding in regular succes- 

 sion " became inaudible all very nearly at the same moment/ 7 One 

 of the vessels being then anchored at a distance from land, the two 



