The Baltimore County union. [volume] (Towsontown, Md.) 1865-1909, 1909-03-20
OUR COAST BEACONs.

mousse DOar0 OF tnlS country is StIlVlDg
is continuous chain of lights COM
pletely encircling the United States
and possessions and in the case of rivers
and inland seas bounding the waters
on all sides, so that ship may never
leave the area of a light thrown by
one lighthouse before entering the
circle of the light of another. AS
fast as Congress will appropriate the
money the gaps are being filled.
But what makes the light? When
the curiousinquirer is told kerosene"
he naturally wonders why his own
student lamp does not give better
light if the same oil in the lighthouse
sends its beams from five to twenty
FIVE miles.
Various methods of lighting were
in use until 184o, when new system
was introduced of employing nearly
true paraboloid refectors and better
glass lenses. In some cases these re-
hectors gave light which is not sur
passed even today, except when han
died with intelligent care. In 1852,
when the present lighthouse board
was instituted, the Fresnal system of
lenticular glasses was introduced from
France and still remains. The first
cost is great, but by the saving of oil
over the reflector system this is soon
reduced. With any reasonable care
fine light always results, and it is i'm
possible for keeper to maintain a
poor light with this apparatus with
out fragrant disobedience Of instruc'
tions.
Even with such an apparatus no
common lamp can supply the light.
First order lamps have five wicks, one
inside the other, and are fed with oil
by a pump and pipe system. The oil
is fed to the wicks so that it reaches
the ends where the fame is in the
right time and in the right quantity.
It is difficult to look at it, so intense
is the light. In the lenses rather
than in the lamp is the secret, for they
pick up and utilize nearly all the rays
of light which ordinarily go astray.
The Fresnel apparatus collects almost
all of this waste light and reflects and
refracts it out il one great broad beam
of light. parallel to the surface of the
sea, where it is needed.
The flames which come from the
lamps are largely transparent. So, of
course, are all other similar flames. If
flames were not transparent there
could be no advantage in having one
flame inside another and third in
side the first two, etc. The lights
from the inner flames could not get
out and would do no good.
In some lighthouses usually the
range light purposes, the light is all
to be concentrated in one beam. This
is done by concentric rings of prisms
and central bullseye and reflector.
Vessels getting such light in range,
either by itself or with another light
and running down the beam, are safe
from distractions which may be near
by, the range lights or beams of light
marking out the channel to be fol-
lowed.
1t is frequently asked of lighthouse
keepers why electricity is not used in
place of mineral oil. An electric light
is expensive to install and difficult and
expensive to maintain. There is al
ways difficulty in keeping the arc ex-
actly in the focal point of the lenses,
the carbons never burning twice alike
and constant watching being necessa'
ry. Failure to have the light source
exactly in the focal point of the lens
results in sending the light rays up or
down instead of straight out, where
they are wanted. Electricity, while
superior in penetrative power in fog,
has no advantage over a powerful OIL
lantern in clear weather. Mineral
oil, colza oil or lard oil lights of the
first order could be seen hundred
miles were it not for the curvature OF
the earth; and as long as the light is
visible long before the coast is all
purposes are served.
1t is only within recent years that
mineral oil has been in use. Lard oil
succeeded COLA oil and was used ex-
clusively up to 1880 and with mineral
oil up to 1889. Since the latter year
mineral oil has been used entirely,
except where electricity has been ex-
perimented with, or coal or acetylene
gas. So far coal oil, for power, effi-
cheney, cleanliness, ease of operation
and cheapness, holds its own against
all other means of light making.
Electricity, if it can be successfully
installed, is the best light, but through
expense of maintenance and in the in.
ability to get skilled attendants for
such a light for the price set en- keep
ers' services it makes slow headway.
The traveller who cruises up the
coasts and who sinks one light before
picking up another must know thai
somewhere in the dark circle is spot
picked for the foundation of a light
which will be erected as soon as fund:
and time allow.-IScienti1fc Amerzcan
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