28 



BULLETIN OF THE 



Table C. 



OLscrvations at Little Gull Island, Long Island Sound, yuly ij, 1881, com- 

 mencing at 6.30 A. M. Thermometer, jg° Fahr. Barometer, 2Q. 80. Wind, 

 W.N.W., force 3, hauling to the westward and increasing gradually. 



On August 3d, I had an opportunity to bear this fog-signal myself, 

 and to note its audibility. The wind was from the south and very 

 light ; the air was damp, smoky, hazy, and, as the sailors say, hung 

 low; the barometer stood at 29-90; the tide was about flood. Our 

 steamer was run for six miles jn the axis of the siren's trumpet, 

 which was sounded for our benefit at its full force. Note was made 

 every third minute in a scale of ten of the intensity of the sound, 

 and it was found that the audition decreased normally with the 

 distance for the first two miles; at 2i miles it had fallen off one- 

 half; at 3 miles it had fallen to one-tenth its power; at 3k miles 

 away we could hear but a faint murmur, and when 4 miles distant, 

 we had lost it completely ; and yet there seemed to be no reason 

 why we should not have heard it clearly at three times that distance. 



The next morning was calm, but heavy with white fog ; yet we 

 heard the Little Gull siren distinctly though it was 10J miles off, as 

 we lay at our dock in New London. The steamer ran out of the 



