432 WRITINGS OF JOSEPH HENRY. [1874 



There is moreover at this station a bell, operated by a 

 Stevens clock, not at present used. It is placed on a high, 

 wooden frame structure, on which one of the ancient bell 

 striking machines was originally erected. The most proper 

 position for the fog-signal is on the ground occupied by this 

 bell-tower, but as this was not removed at the time of the 

 erection of the trumpets, they were placed in such positions 

 as to have the line of sound interrupted to the north-eastward 

 by the bell and light towers. It was therefore thought prob- 

 able that this was the cause of the deficiency of sound in 

 this direction. To test this, the vessel was caused to traverse 

 the arcs of several concentric circles, in the portion of the 

 horizon where the sound was most required as a signal. The 

 first arc traversed was about one and one-half miles from 

 the signal. The vessel on this crossed the axis where 

 the sound was quite loud, and proceeded northward until 

 the sight of the trumpet was obscured by the before-men- 

 tioned towers, when the sound became almost inaudible. 

 The vessel next returned across the axis, on a circle of about 

 three miles radius, with similar results; but after crossing 

 the axis the sound on the southern side continued to be but 

 little diminished in intensity along an arc of two and a 

 half miles, or as far as the land would allow the vessel to 

 go. The vessel was next put upon an arc of which the 

 radius was one and a half miles, and on the south side of the 

 axis, and sailed to the northward until the axis was reached; 

 it was then turned and run for the entrance of the harbor, 

 hugging the southern shore, keeping as far from the signal 

 as possible. Throughout this passage the sound was clear 

 and loud, showing very little — if any diminution of power 

 as the several positions deviated more and more from the 

 direction of the axis, until the vessel was at right angles 

 with the axis, the land not permitting any greater distance. 

 The vessel approached to within three-quarters of a mile of 

 the signal and then continued still farther around, until 

 nearly in the rear of it, the sound still continuing clear and 

 loud. The vessel next proceeded up the harbor, nearly in 

 the line of the axis of the trumpet prolonged in the rear 



