The Virginia enterprise. [volume] (Virginia, St. Louis County, Minn.) 1893-19??, 1903-08-21
SIGHT DEL U Us


Color blindness is a queer failing. and
the whole human race: is subject to it
to- an extent. 1t has been discovered
that an ordinary cannon, II covered all
over with blotches of red, blue and yell
low paint, becomes to all intents and
purposes invisible, at least at any con-
siderable distance, says the Philadelphia
Press. S s SIS s .. "a. IA - : 81
Six guns and their limberB so painted
and streaked with the three primary
colors, as they are called, were placed
on the Fox Hills at Aldershot, and a
number of artillery officers invited ito
locate them. p : ,.
The distance was only 5000 yardsrf
mere trifle in actual warfare and the
officers were armed with. the best of field
glasses. -.
But so perfectly did the painted guns
harmonic with the natural background
that no one was able to pick them out.
Some horse artillery sent forward to
engage the guns never saw them at all
until they had reached a point barely
1000 yards away.
Many animals Of all kinds take ad-
vantage Of the way in which sight, es-
pecially human sight, confuses colors..
The leopard, living in low thickets,
where the sunlight, broken by leaves,
falls in patches on the soil beneath has
skin blotched with black spots, maxi
ing the creature practically invisible
except at very close quarters. r
Among fish, insects, reptiles and
snakes, hundreds of species are known
Of which their markings render them
practically invisible in their natural
surroundings.
Recent researches have shown that a
far greater number OF people are at
least partially color blind than was
formerly imagined.
The commonest case is a deficient per-
ception of red, blue and violet Often
partially color blind persons name these
quite correctly. But they are unable
! to distinguish between rose red and
blush green.
A few years ago the color perception
of 1000 railway officials was examined
and it was found that SO were quite col
| or blind, and a number more partially
| so. .:>
Women, It may be mentioned, are
hardly ever color blind, but why this is
! so no one pretends to explain.
After any severe nervous shock you
will be very likely to find that you
have become temporarily color blind
Your perception of green light has
probably gone, at least partially. White
objects will then appear to you of a
reddish purple, and green objects to be
very much duller in hue than ordinarily.
Anyone can make him or herself tenn
| porarily color blind by wearing pair
of ruby-red glasses.
The prolonged action of red light on
the eyes ends by firing out the nerves
which receive red light. Consequently,
when the glasses are at last removed,
q rainbow appears to have only two
tcolors, yellow and blue. s-ts=z1-5A9s II
| Many people have found it difficult to
believe in the possibility of the extraor-
binary attitudes assumed by galloping
horses or other creatures in rapid mo-
| ton, as shown in instantaneous photog-
raphy. =.
Here we have another instance Of
sights which we-that is, our eyes-are
unable to grasp.
The fact is that though the eye seizes
| view with extraordinary rapidity,
that view does not pass atvay at once
I from the retina. - =
What scientists call the positive i'm
age persists for a perceptible period of
time, and after it is gone it is replaced
| by negative image, that is the same
view, but in colors complementary to
| the positive image. I
Thus, if the sight seen was regiment
of scarlet-clad soldiers, the negative
image would show those soldiers in q
greenish blue hue -
So the impression we get when look
| ing at anything is actually made up of
a number of different views of the OBJ
ject, whereas the instantaneous photo
graphic plate gives US only one of these
views, Audience looks to us unnatural.
/ A small and simple experiment can be
tried which will go far to convince
| him or her what debt we owe to color,
and what good thing it is we have
/ sunlight, which enables our eyes to
| take advantage of the beautiful hues
| Of nature. :.
( Make a room quite dark, and then
burn some carbonate of soda i'm the
i flame of Bunsen gas burner
/ It will burn with an orange yellow
flight sufficiently strong to illuminate
Everything in the room, but you will
realize with sudden shock that, bright
/ though the light is, all distinctions of
/ color have vanished. Only light and
i shade remain.
I A crimson carnation, blue violet, q
red tabIecloth, a yellow blind-all look
gray or black, or white. The faces of
those present look positively repulsive,
for all natural color has disappeared. !
No other experiment will SO we'll con-
vince those who have witnessed it how
great loss would be that Of our sense
| for color
A Cows Queer Act.
1