New Ulm review., 1912-12-18
The uNERRINC sun
& Is Uncle Sans Most Reliable
Lighthouse Keeper.
NEVER FALTERs IN ITS WORK.

~ the Aid Of the Wonderful Sun valv
Il Lights the Aestyisne esaeons a.
SETS at Night and Ext;nsu;shss Then
- u Rises In the Morning.
The sun is the most trustworthy o
lighthouse keepers. The sun or tn
heat from it lights many hundreds o
beacons along our coasts and water
ways evening after evening and ex
tinguishes them punctually every morn
ing. They are guides on land and set
that are never touched by human hands
nom one months end to another. Tht
way In which the United States gov
eminent, through its lighthouse board
has utilized the services Of the sun and
made that great lamp OF heaven q
faithful and unerring servant Is most
Interesting.
The discovery OF acetyiene gas was
the first step toward retiring the lonely
keepers of the little lights in faron
places. Modern magic was not slow
In recognizing the fact that by the ap-
plication Of certain we'll known scien-
ti6c principles the lighting Of the great
chains Of beacons that girdlc the coasts
Of the two seas and the gulf and cover
the great lakes and every navigable
stream in our huge country could be
much simplifed.
The United States did not become in
terested in the acetylene light and its
automatically generating gas buoy until
about the year 1906 and did not adopt
it until 1908. Then the engineers of
the lighthouse board devised some
wonderful improvements. among them
the utilization of the sun
The self lighting and self extinguish-
ing acetylene beacon is a very simple
thing, but it depends almost entirely
ON the "sun valve" which is one Of the
most wonderful but 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 a small beacon three years.
Usually. however, in the case Of float
ing buOys. six months supply Is all
that is necessary, as such buoys are
overhauled and painted twice year.
Knowing the size of the flame and it's
hourly consumption of gas, it is very
easy to compute how long a cylinderful
will last and how often it will need to
be visited. That is all the care the
Sight will need. The sun valve does
abe rest
The scientific principle upon which
the sun valve depends is that light
waves become transformed in different
degrees, according to the nature of the
antercepting body. Sunlight upon dark |
surfaces is converted into heat. and
heat produces expansion. This expan-
sion is especially perceptible in certain |
metals
In carefully sealed and substantial |
fv mounted glass jar nearly foot
high and about one-fourth that in di- !
ameter thick black rod is placed per- |
gsendiculariy through the center. 1t is
supported by three slenderer rods OF
highly polished copper. The big black
rod is Of copper also and is coated with |
lampblack to make it absorb light to |
the greatest possible degree. The sup |
porting rods reflect light without alb !
ssorbing it and do not expand or con-
tract to the same extent as the largest |
rod
The thick black piece Of copper in |
the center Of the jar is extremely sen |
sitive 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 a lever. 1t |
presses down on this lever. which is
'"''Ut~ui"' i'v 4 spring and cnts off the ,
finw "t lli. .,as 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 |
flow upward to the lamp The gas is
1gnited by little pilot flame that is
never eXtinguished. Thus the beacon
is lighted at the proper time and is put
out when 1t is no longer needed. al |
though along desolate coasts it may
never. gladden. the human eye for
months at 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 it responds with the
utmost accuracy to small variations in
temperature. 1t is used on lonely is
lands in the Pacific. There are nearly |
a hundred of these sun valve bcacons
in Alaska. In summer they are aids /
to navigation, and in winter they guide
the travellers on dog sledges over the
frozen wastes.-Harpers Weekly.
Deadly.
81 understand that number Of wo-