effect gradually diminished. The actual effective range of the bell sound,
whatever the bell size, is comparatively short, and, like the gong, it is
used only where it needs to be heard for short distances. Mr. Cunningham,
Secretary of the Scottish Lighthouse Establishment, in a paper on fog
signals, read in February, 1863, says the bell at Howth, weighing 2¼ tons,
struck four times a minute by a 60 pound hammer falling ten inches, has
been heard only one mile to windward against a light breeze during fog;
and that a similar bell at Kingston, struck eight times a minute, had been
so heard three miles away as to enable the steamer to make her harbor from
that distance. Mr. Beaseley, C.E., in a lecture on coast-fog signals, May
24, 1872, speaks of these bells as unusually large, saying that they and
the one at Ballycottin are the largest on their coasts, the only others
which compare with them being those at Stark Point and South Stack, which
weigh 31¾ cwt. and 41½ cwt. respectively. Cunningham, speaking of the
fog-bells at Bell Rock and Skerryvore lighthouses, says he doubts if
either bell has been the means of saving a single vessel from wreck during
fog, and he does not recall an instance of a vessel reporting that she was
warned to put about in the fog, or that she ascertained her position in
any respect by hearing the sound of the bell in either place. Gen. Duane,
U.S.A., says a bell, whether operated by hand or machinery, cannot be
considered an efficient fog signal on the sea-coast. In calm weather it
cannot be heard half the time at a greater distance than one mile, while
in rough weather the noise of the surf will drown its sound to seaward
altogether. The use of bells is required, by the International Code, on
ships of all nations, at regular intervals during fog. But Turkish ships
are allowed to substitute the gong or gun, as the use of bells is
forbidden to the followers of Mohammed.

[Illustration: FIG. 1.--COURTENAY'S WHISTLING BUOY.]