El Paso herald. (El Paso, Tex.) 1901-1931, 1913-02-20


the 1nfra-red rays Of light is to combine
a sheet Of the densest blue cobalt glass
with solution Of bichromate Of potash
or some suitable orange dye. Here is
which the sky is black. and vet the
vegetation and the grass appear to be
snow white-slthOugh the picture
comes from sunny italy. The shadows
IN this picture are intensity black
since the camera with the filter on f.
percelves only the direct light Of the
sun and does not catch the indirect
light Of the sky. This is said to be
the way things would look to the
human eye on the moon, where there
IS no atmosphere to form a luminous
sky
Metallic Silver Needed
Quite a different impression would
We nave OF our surroundings if the eve
were sensitive only 70 ultraviolet ravs
70 see now things would look with
Ihem We have to avoid glass, for glass
Is as Opaque to them as a black slate
IS 10 the eye. Quartz, however. is
transparent to them, and when we find
some substance that they can get
tnrougn and which viii yet refuse to
recognize the visible rays, we will
nave solved the problem. Metallic
SILVER Is the substance we need and il
IS the only substance known that fully
recognizes every ultraviolet ray and
arrows out every visible ray A very
thin film Of IL must be deposited over
the surface OF the quartz. With this
pictures that seem like views of fairy
land may be taken. Chinese white
appears as black as the ace of shades
in this light. White flowers in the
garden become almost black. and a
NUMBER OF striking contrasts result
Ultraviolet Rays XIII Germs
buI the most remarkable property
OF ultraviolet light is not the effect
II has upon the Photographic plate.
but its germicidal qualities We have
long known that the suns rays tenn
TO XIII germs, but it was not until re-
Gently that the discovery was made
that is was the ultraviolet light that
they contain that does the work The
suns rays are comparatively Door in
ultraviolet light for but little of it
IS aDle 70 struggle through the en-
engagements OF our atmosphere. There
lore, we must look mainly to artificial
sources for our ultraviolet ligh+ for
germicidal use The mercury vapOr
light with a quartz tube is the best
source
Ultraviolet rays Of small wave
length are very nOcuous to all living
cells, and therefore the MISUNDERSTANDING.
lamps have to be used with great care.
Inc quartz mercury-vaDOr lamD is
led by a continuous electrical current.
Its running is regulated by q sentinel
lamp in the same circuit or by noting
Its own state OF luminosity. To light
IL the operator simply shakes the
80 ~ ---~- 10y AAAAAA int Two poles
are connected. Then the lamp is set
IN normal position. the thread Of mer-
curry is broken, but the electric current
continues to pass through the luminous
vapor indefinitely
Purify City Water
Several French inventors have per-
fected a little lamp of this kind which
may be used to sterilize potable water
IN hotels hospitals, private houses.
ana the like. With it they have been
aoLe 10 Kill as many as a billion colon
Dacliu per cubic centimeter-a million
tlmes as many as are found in the most
impure drinking water. They simply
pass the water through a tube con-
tanning the light. and it does the rest.
Not only does it kill the germs them
selves, but II is equally fatal to spores. |
IN water polluted with 12S, OO0. 600 ba-
GILL TO the quart, these bacilh having
spores which could resist boiling for
several hours, not a single spOre es-
capped alive when the water was run
ming through the tube containing the
mercury lamp at the rate of
fourteen gallons an hour.
BY the application of this system
city water supplies can be made as
pure as though they came from the
unsDlhed SHOWS of high mountain
peaks Large merCury-Vapor lamps
need only to be immersed in the water
that flows through a city's mains, and [
as 1t passes within the neighborhoOd Z
OF the burning lamp untold millions ]
or germs are elcctrOcuted every in !
slant by a fluid more subtitle and more /
than electricity itself
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