The Dolores star., 1923-08-24
.I4YEaAuGs5cO AlHw NESSEZ WO>O

In order to avoid the likelihood of confusion be-
tween lights, endeavOr Is made to give the lights
distinct characteristics. As much of the coast was
lighted before the introduction of modern light
house apparatus, the original lights were as a rule
fixed but at the more important of these stations
apparatus has been Installed to make the
lights flashing occulting. This effect is produced
in the case of flashing lights by revolving all or a
part Of the lens which is specially constructed with
panels of prism for concentrating the rays into
beams-!n the of occulting lights by some
form Of travelling screen shutter which ohscures
the light at intervals. In either the motion Is
regulated by n clockwork with the necessary gov
erning mechanism to cause light and dark periods
in accurate sequence. The terms flashing" and
"occuting' refer to the relative durations OF light
and darkness, flash being an interval shorter than
the duration of an eclipse while occultation Is
shorter than. or equal to, the duration of light.
The first fog signal in the United States was
cannon, Installed Boston light In l7l9 which was
fired when necessary to the signals of ships
In thick weather. Guns of various types were used
at other lighthouses, but have now been generally
abandoned. Bells were introduced at n compora.
lively early date. Trumpes were the next i'm
provement, and steam whistles came into use In
1857. Experiments were made with sirens In 1867
and the first service installation was at SANDY
HOOK East beacon in 1868. This apparatus has heen
houilieu ana improved until the present automatic
siren, using compressed air instead of steam wos
evolved Practically all fog signals as nov in
timing the strokes or blasts This usuoIlv cons,t
OF cl"ckw0rk whereby the cycle is ranao,ad
every minute IN order to facilitate identification
submarine signals, which have been introdp,ed
III recent years, nave as a rule more effectve and
constant range Of audibility than signals sounded
IN air. Such a signal consists essentIau,, % =
specially designed bell, submerged sufoi'.,
avoid wave disturbances. with some form of s,,,
ing attachment On light vessels the bell is usr
any SWUNG over the ships side a chain nj
tached to a davIt, and the striking davico T.. -
rated pneumaically to ring certain SET of LI,,
at prescribed intervals '"S
Al Hght stations the bell is usually s,,n,,or.oa
on tripod placed on the sea bottom. n sb,,r, AZ
lance away from the light and the strII;in,
mechanism operated electrically through n c,bIe
with characteristic number of blows ot rag,,,s ~
terVals. When attached TO buoys swinrin, yona
Is provided which is forced up and dny,n '',ie .i
Ouoy sufges In the sea. The motion of tha y,,
causes spring to stretch and when # hos r.ocrI
sulncent tension it Is released the artion ,,
Ing Il blow to be struck on the bell rha 80
are OF equal Intensity, this being due To rho ar.
'ioh q the spring, although the interval b.t,.a,
them varies with the condition of tho seo , =" ="
regular code of blows is therefore prnctIc.hI
In orCer to obtain the best resu,tu ,I,t
marine bells, receiving apparatus soreybn. ,I
lar to telephone. has been devised for ot,achu,
10 Vessei. Inc sound may be heard also nm ,,
sells not equipped with receiving Dprorotn,
observers below the water line, and portIcrIai ~
iron steel ships Al
Since 1885 systematic records have hoo, ,.o-
OF the number of hours of fog or thick weatbsr ~
served each year at the different foysIpnoI s,n
lions. these figures present interesting stati,ttos
ana are OF considerable value In approrim.,in
the prevalence OF fogs at various localities vben
proposed new signals are under consideration rrha
aoSo'uie maximum record Of fog was at seguIn