Maryland independent. [volume] (Port Tobacco, Md.) 1874-current, 1913-01-24


II lights the Aestylene Beaeons as Il
Sets at Night and Extinsuishes Them
as It Rises In the Morning.
The sun is the most Trustworthy OF
lighthouse keepers The sun or the
heat from it lights many hundreds Of
beacons along our COASTS aud water.
ways evening after evening and ex.
tinguishes them punctually every morn
ing. They are guides on land and sea
that are never touched by human hands
from one months end to another The
way in which the United States gov.
ernment, through its lighthouse board,
has utilized the services OF the sun and
nade that great lamp Of heaven a
faithful and unerring servant is most
interesting
The discovery of acetylene gas was
the first step toward retiring the lonely
keepers OF the little lights In faroif
places Modern magic was not slow
In recognizing the fact that by the ap
plication of certain well known scien-
,iiic principles the lighting Of the great
chains of lpieons that glrdle the coasts
Of the two seats aud the guilt and cover
the great mkes and every navlgable
stream in our huge country could be
much sinnlided
The tluted States did not become in
:erested IN the avetylene light and Its
automatically generating gus buoy until
about the year 1906 and did not adopt
it until 1918 Then the engineers Of
the lighthouse bonrd devised some
wonderful improvements. among them
the utilization Of the sun
The self lighting and self extinguish-
ing acetylene beacon Is n very simple
thing. bul il depends almost entirely
on the ''sun valve which is one Of the
most wonderful bat least complex of
the achievements Of modern science
In the first place. the source Of light
for these lone beacons is dissolved
acetylene. which Is stored under pres
sure in steel cylinders One of these
cylinders can be charged with enough
gas to last small hencon three years
Usually. however, in the case Of float
ing buoys. six months supply is all
that is necessary. as such buoys are
oyerhauled sai painted twice year
Knowing the size of the flame and its
hourly consumption Of gas, ii is very
easy to compute how long u cylinderful
will last and how often It will need to
be visited. That is all the care the
light will need The sun valve does
the rest
The scientific principle upon which |
the sun valve depends is that Hight |
waves become transformed in different |
degrees, according to the nature OF the |
intercepting body. Sunlight upon dark I
surfaces is converted Into heat, and
heat produces expansion. This expan-
sion is especially perceptible In certain !
metals
In carefully sealed and substantial |
ly mounted glass jar nearly foot |
high and about one-fourth that In. d. |
ameter thick black rod is placed per |
pendieularly through the center. 1t is
supported by three sleuderer rods of |
highly polished copper. The big black |
rod is of copper also and is coated with |
Iampblack to make it absorb light to
the greatest possible degree Tie sup
porting rods reflect light without abb
sorbing 1t and do not expand or con
tract to the same extent as the largest |
rod
The thick black piece of copper In
the ecnter of the jar Is extremely SEN
sitiye to light and heat AS the sun
appears and the atmosphere grows
warmer In the morning this rod length
ems. 1t pushes down into the metal
chamber in which the glass jar rests
and touches the end of lever. It
presses down on this lever, which is
controlled by spring and cuts of the
flow of the gas to the lamp
When the sun disappears from view
In the evening and the temperature Of
the air falls the process is reversed
The rod contracts and releases its pres
sure on the lever. allowing the gas to
dow upward to the lamp. The gas is
ignited by little pilot fame thet Is
never extinguished. Thus the beacon
is lighted at the proper time and Is put
out when it is no longer needed, al
though along desolate coasts it may
never gladden. the human eye for
months at a time.
The engineers Of the lighthouse board
say that the precision Of this device Is
almost incredible. 1t can be used with
equal certainty in equatorial heat and
In polar cold, for 1t responds with the
utmost accuracy to small variations in
temperature. 1t is used on lonely Is
lands in the Pacific. There are nearly
hundred of these sun valve beaeons
in Alaska. In summer they are aids
to navigation. and in winter they guide |
the travellers on dog sledges over the
frozen wastes Harper's Weekly.