Indian chieftain. [volume] (Vinita, Indian Territory [Okla.]) 1882-1902, 1888-10-11

fctive.
We have in what Is called Gloom
ing" an Illusion depending on the
effects Of thickened air A sailor win
toll you that ship really looks larger
when she looms through fog than when
the air is clear. But II her distance is
known and her apparent size measured
with sextant or other suitable instru-
ment, It will be found that she looks
no lnrger than she should look,
whether the air be clear or thick The
mind is simply deceived into thinking
the ship is farther away than she
really is, and SO judges that she looks
larger.
The illusion OF deeply arched in
stead OF nearly FIAT sky is occasion
ally broken. Probably but a small pro-
portion Of those who read these lines
have ever noticed the sky surface look
ing Fat. have observed the appear
ance myself three or four times during
my life, but then have been always
on the lookout for IL, this particular
Illusion having long had great interest
for me. The occasions when the fiat
ness Of the under surface OF the cloud
sky can be recognized are those when
the clouds lie (actually) in long paral-
lei beds OF tolerably uniform breadth
and separated from each other by toll
erably equal distances and lying in the
same general level-the sun being near
the horizon, so as to illuminate the
cloud-bands underneath. At such
times, as also whom instead of uniform
bands kind Of network Of clouds COW
ers the sky towards the place Of the
horizon sun, an effect OF foreshortening
is produced'which brings out the hori-
zontality OF the cloud surface-that Is,
not of the surface of individual clouds,
but Of the general layer.
] remember one occasion when / was
travelling across the Western prairies,
towards the time of sunset that as the
sun in his descending motion passed
from above TO below a layer Of clouds
uniformly reticulated, thegolden tinge
along an edge OF each OF the cloud
streaks so distinctly indicated the rela-
tive positions Of the different parts Of
the network OF clouds, that the true
hatness Of the surface was as strongly
forced on me as usually the incorrect
arched form is impressed on the mind.
For the first and only time in my life |
was not only able (as on three or four
other occasions) but actually forced TO
feel what an immense globe this earth
world OF ours Is. For there was the
widely-spanning surface Of cloud look
ing perfectly fiat though really part
Of the inner surface of an immense
spherical shell.
There Is q converse allusion familiar
only TO balloonists, which is TO be ex-
planned In the same way. Rising high
above the earth's surface in n balloon.
we see the surface OF the earth be-
meath arched into the form Of an i'm
mense bowl or basin. The mind re-
fuses to admit the thought that the eX-
ceedingly minute depression Of the Wis
ible horizon corresponds 10 the seem
ingly immense depth Immediately be-
low the aeronaut Or one may say
(though in reality it is saying the same
thing) that the mind can not admit the
thought OF the immensity Of the dis
tance of the horizon. From a height
OF half a mile the horizon is some
forty miles away, or eighty times
further than the earth's surface below,
but the mind sets the horizon only
three or four miles away Cat least if
the air is clear), and consequently the
surface, which (regarded as whole)
is really slightly convex below the OBJ
server, appears to be markedly con-
cave.
Among illusions affecting color some
OF the most important and interesting
are those which painters have TO take
into account in producing with Opaque
tints, the effects Of sunlight or NOON
light, the CLEAN of metals and kindred
illusions. A painter who should strive
TO represent sun-illumined lily by
simply using the strongest white tints
at his command would fail utterly.
By using dark tints he obtains the
effect Of brightness, where by using
bright tints he only obtains a dirty
looking white. So with metallic effects,
which are often admirably caught in
paintings,
II Is related OF the French painter
Delaroche that he had tried again and
again 10 produce fair imitation OF
cleaning gold in one Of his historical
paintings. Giving up the attempt in
despair, he sent for facre to take
him TO the gallery Of Luxembourg.
whore were some paintings in which
the desired effect had been obtained,
that he might learn the secret. But
lol as lie came down the doorsteps the
yellow wheels OF the hacre glowed in
the sunlight with the very effect ho
wanted; they looked like wheels OF
gold for the nonce. though colored only
with the coarse yellow used by coach
painters Whence tho Illusion? Del
arOche caught the idea in moment,
dismissed the iacre and returned TO
his studio 10 work out successfully the
effect which for days he had been vain
ly striving TO attain. The yellow OF
the hacre wheels was picked out with
bright purple, by contrast with which
the bright but coarse yellow seemed
10 shine with a golden CLEAN. This
was the whole secret which Delaroche
would have learned from the paintings
OF the old masters.
False effects in regard 10 contour
are also common and strangely
enough deceive the Observant more
readily than the unobservant. Look
at a medal under ordinary conditions
and the eye at once recognizes the
elevations and deuressiOns for what