Weekly national intelligencer. [volume] (Washington [D.C.]) 1841-1869, 1854-02-11
FOR THE NATIONAL INTELLIGHNCRR.
PRACTICAL RESULTS FROM THE DISCOVERY AND
STUDY OF PoLARIZEDLIGHT.
BIZ PRor. c. G. PAas.

When isolated principle truth in any branch Of
science is discovered the question is Immediately asked
bono? quid ute? Of what is it! Franklin answer
ed this question for all time by asking another, VIZ
What is the use of new born babe? OF what or
Importance to man was it that in 1910, NJ Malus dis
covered that the different sides Of ray of light pos
sessed of different properties in relation to the plane OF
its incdence This is one of the most obscure OF all
scientific propositions and yet shall soon see how ti
umphantly the caver is slenced and how literally even
this little fountain has poured its treasures into the lap
Of art.
Without entering into the elucidaon Of the facts we
will briefly enumerate them as they to US.
When glass is properly annealed and Of good quality
it exhibits no change of coors when examined by polar
lied light II the glass has not been properly anneaed,
poarscope instantly detects the defect by the display
Of coors The anneang Of glass is expensive, and the
often sights this part of his work Glass
tumbers pitchers decanters, tubes &C., not we'll
nealed break often upon the slightest scratch or upon
the sudden application Of heat cold Glass tumbers
will often crack when piece Of ice is left in them and
frequently break when set away by themselves owing to
slight scratch which they might have received
4 week previous. ~, .@s,a*
larized light few little plates Of glass, what is bet
ter NcoPs prism and piece of glass blackened on one
SIDE will show the purchaser whether he is buying
neaed glass or not. The Ncos prism eye-piece is
simple apparatus costing from ten dollars and
small that may be carried in the vest pocket without
inconvenience.
If piece of annealed glass be pressed bent the
Of its particles becomes disturbed but this dis
turbance does manifest itself to the eye TO the
powerful magnfer. But, when viewed by poarized
light the whole internal commoton reveals itself in the
most beautiful manner and while the pressure is in
creasing disruption inevitable though all the while
the naked eye sign of fracture change is appa
rent beautiful feature in this experiment is, that
it shows exactly in what direction fracture would take
place If the pressure sufficiently increased. Taking
advantage Of this property, model bridges and other
structures have been made of glass and when submitted
to strain or pressure poarized ray dscloses to the
architect what neither the unassisted eye calculation
could discover
The quality gems for jewelry is determined by po
arzed light The quality of sugars and of many articles
of commerce and Of fabrics suspected of adultera
tion may be proved by polarzed light When you enter
picture gallery you often cheated of good view OF
some painting by the strong reflection of light from the
varnsh and you may not be able to select suitable po
sition Look the picture through Ncols eyepiece,
and oil this reflected at obterated, and You
have a good position any where. 1t is the same when
specular reflections interfere with the sight in viewing
landscape or any distant objects.
Last and least the mariner often detects, even at
great distance hoa sunken rocks by the color
Of the water but if the is shining and the reflection
from the is before him, he nothing to
able him to judge and reef under such circum-
stances might be slightly above the water without his
being able to see it. The Nicos eye-piece exngushss
all this reflected light and gives him clear view Of what
is before him To hunters and anglers this property OF
the eye piece is often very valuable.
For true spendor and variety the phenomena of po
arized light surpass all others in the whole range OF
science without enumeratng all the advantages result
ing from the discovery Of Malus think have an
swered cu tonos this subject to his satisfaction