34 BULLETIN OF THE 



" With a view to the protection of life and property at sea, yi the years 1873 

 and 1874, this subject received an exhaustive examination, observational and ex- 

 perimental. The investigation was conducted at the expense of the Government, 

 and under the auspices of the Elder Brethren of the Trinity House [the govern- 

 ing body of the British Light-House Establishment.] 



" The most conflicting results were at first obtained. On the 19th of May, 

 1873, tne sound range was 3^ miles; on the 20th it was 5^ miles ; on the 2d 

 of June 6 miles; on the 3d more than 9 miles ; on the 10th 9 miles; on the 

 25th 6 miles; on the 26th 9% miles; on the 1st of July 12%" miles; on the 2d 

 4 miles, while on the 3d, with a clear, calm atmosphere and smooth sea, it was 

 less than 3 miles." * 



The officer who made the reports, as to the fog-signals at Beaver 

 Tail and Little Gull, after the accidents to the steamers Rhode 

 Island and Galatea heretofore mentioned, was the Assistant Inspector 

 of the Third Light-House District, Lieut. Oomd'r F. E. Chadwick, 

 U. S. N.; and it was he who had charge of the Light- House steamer 

 while the foregoing observations were being made, after Capt. George 

 Brown, U. S. N., the Inspector — to whom I am indebted for many 

 courtesies on this trip — was called elsewhere by other official duties. 

 Mr. Chadwick brought to this work an unbiased mind, trained in 

 the severest schools of scientific investigation. His object in all his 

 experiments was simply to ascertain the exact truth for practical 

 official purposes. He had not proposed, even to himself, to make 

 any generalizations from his observations. But he kindly answered 

 certain of my questions as to the opinions which had forced them- 

 selves upon him, and his answers are here set down for the con- 

 sideration of those who use these fog-signals overmuch as a guide 

 for their ships. 



" It seems to me" he said " that navigators should understand that when at- 

 tempting to pick up a fog-signal attention must be given to the direction of the 

 wind, and that if they are to windward, (in a moderate breeze,) the chances are 

 very largely against hearing it, unless close to ; that there is nearly always a sector 

 of about 120 to windward of the signal in which it either cannot be heard at all, 

 or in which it is but faintly heard. Thus, with the wind E. S. E., so long as 

 they are bearing from the signal between N. E. and South, there is a large 

 chance that the signal will not be audible until it is very close. 



" As they bring the signal to bear at right angles with the wind, the sound will 

 almost certainly in the case of light wind increase, and it will soon assume its 

 normal volume — being heard almost without fail in the leeward semicircle. 



" Fog, to my mind, and so far as my experience goes, is not a factor of any con- 

 sequence whatever in the question of sound. Signals may be heard at great dis- 



* Sound, by Tyndall, 3d Edition English, page 324. 



