The morning call., 1893-11-05


of sound show conclusively that the object
IS being neaTed. nor decreasing that one
IS Teceding from danger. A naval officer
commenting upon Pilot job ns0n's remark
few days ago said:
= ''In a dense fog one night we heard s
whistle clearly. but as we had our bearings
correctly we kept on. The sound grew
less and less and in, half an hour wa!
hardly audible. The captain was al a los
TO understand. He was convinced that ht
was nearing the shore, not steaming away
$50 he dropped anchor. and when the 70!
: lifted three hours later we found that WI
=*1Sete within two miles of the beach. The
:: W histle had sounded the loudest when WE
Were ten miles away. Had he been guided
by the sound alone our ship would have
!. .Geen high on the rocks as the New OrB
:ib*to-day.
IRON another occasion, when in blind
Sing snowstOrm and quite gale blowing
:. from the northeast, we heard fog whistle
:: more distinctly when it was to leeward of
us than when to Windward. One would
slRpGse that the wind would carry the
sound along when The signal station was
"]n. the direction the gale came from, but it
:. did not"
The wreck of the steamer Rhode Island
:: en- Bonnet Point, IN Narragansett Bay,
w fiich happened on November 6, $780, was
caused, 1t was said, by tie failure of a fog
: 5 gnal to give warning. The Lighthouse
::Beard made an investigation, which
showed that the fog signal was in full
toperatiCu when the wreck occurred, but it
ALSO brought out the fact that, while
.there was no lack of volume in the sound
.,.,, sd fr-Nl 81 oft n
:decided lack in the addition Of that sound.
: So much so that it would not be heard at
the intensity expected. nor at the place
expected; that it could not he heard at all
: at some points, and then it could be heard
better some distance away than near Dy
thai it could be heard and lost, and heard
and lost again, all within reasonable ear
shot and all this while the signal was IN
~fail blast aud sounding continuously.
: The subject Of fog signals was treated
at length az the session OF the Pan-Amerl-
can Congress. and in paper read before
that body a. B. johnson, chief clerk Of the
Iighthouse Board, spoke of the dangers
that exist because of the alterations OF
audibility OF these signals. In this paper
: he says:
=: LAST summer CS91) l had an opportu-
nifty while on a lighthouse steamer to eX-
:perience something of the variations in
!: the addition of the Beaver Tail fog-signal.
.=Mhen- the steamer left the lighthouse
:landing the fOg-signal was TO sound for a
given time, and TO commence when the
e. steamer had reached given point half a
mile distant. When that point was reached
I'VE could see by the steam-puffS COMM z
from the escape pipe that the signal was
: being blown, but we could not hear its
Sound, nor did We as we continued on our
. course, running away from the light sta
=: ton for the EeXt FIVE minutes. When less
d. h-o, mi nd hal 10 foa m 1pT
was stopped and we all listened intently.
~Fhe expert naval officers thought they
heard trace of the fog-signal, but my un-
trained ears failed to differentiate it from
the moan Of the whistling-buoy close to US.
: i ct the blasts of the ten-inch steam
. whistle, for which we were listening, can
often be heard at distance OF ten miles. "
- On the night of May u, 1881. the Gala
tea, a propeller of over 1900 tons burden.
:. with full load Of passengers and freight,
: bound through Long Island Sound from
providence 10 New York. grounded in a
dead calm and dense fog on Little Gull
:" Island, about an eighth of mile from and
behind the fog signal. 1t was alleged that
the fog signal, steam siren at Little Gull
light, was not in operation at the time OF
the accident and an investigation was
ordered. The nava. officer who carried on
the inquiry took the sworn evidence of the
-lightk eepers at Little Gull and other light
keepers within hearing distance, of other
3. Government officers who were for the time
being SD located that they might have
knowledge of the facts, and of the officers
OF vessels that were within earshot, in
= cluding those of the Galatea. and reached
the conclusion that the log signal was
sounding at the time of the accident, and
that although the fog signal was heard at
Mystic fifteen miles distant in another
direction. and although it was heard ou a
-':c.o mi 10 hpUOn6 (TalatpH maj
it was heard family. if at oil. on that yes
sci, though the Galatea was but an elghth
of a mile from the source Of the sound.
;. Scores Of similar cases have been lnves-
tigated and exhaustive reports on The
subject are in the possesslon Oh the Light
: house Board. Professor Henry. account
ing for these alterations, says: AS the
heat of the sun increases during the hrsi
= part of the day the temperature OF the land
rises above that of the sea. and this excess
:: of the temperature produces upward cur
rents OF air. disturbing the general hoW OF
WIND both at the surface Of the sea and al
an elevation above"
Other conditions cause like phenomena,
. ahQ the Lighthouse Board has made some
: In terestng experiments with kites along
Inc SboTe line, which demonstrated that
ar currents are at times very Irregular.
: anu oI course at such times the sound
= waves cannot be relied oa.
= mariner therefore should not assume
:that because he tails TO hear the sound of
10Y sighal ne is out of hearing distance.
And when he hears the signal he should
take IL TO mean only that danger is near.
and not try to navigate his ship by 1t. The
accompanying diagrams are the result of
actual experiments made, and show ho W
deceptive the signals may prove.
:. AS. San Francisco harbor is often ap-
preached and left during heavy fogs the
pilots should be familiar with the vain hie
Government rules upon the subject of
! alteration of sound, and should be care
fully examined on them before receiving
license. Were this SO. the excuse offered