The sun., 1917-09-09
At THE EXTREME. TIE RUINED WINDMILL IS 4
CONCRETE GERMAN OBSERVATION POST FRteaofrelA psoa
Science of Deceit by Paint Developed
to High Point on Land and Sea
With Bizarre Effect

pointers telescopio dsht o. osaSeheo
the broad waste Of the opon - ~
far of ships knows how trying to the
eye such concentration II under the
most favorable Of conditions. mdee0
about ten years ago British army OF
deer gave this subject a good deal Of
attention and prepared an instructive
paper upon the visual fatigue OF gun
layers. As ne summed II up, AFTER
about two minutes continuous follow.
ing Of q target the accuracy Of . sps.
cialized gun layer becomes temporarily
impaired, and he should be maAo Q
casualty and replaced by q fresh Num-
ber from the gun detachment. The
layer should be removed. not % much
because he 10 Sott1ng moro and more
prone to lay incorrectly as because his
| laying Is becoming erratic, requiring
nrst . positive correction to meet II
and Immediately afterward a negative
ono"
The gun laysrS Or gun pdlHfaS
task Is comparatively easy when ooA-
trasted with that of the man watching
through the periscope Of a suhmaT1nA
who must determine the range and the
probable speed Of his moving targse.
Under favorable circumstances. With
the light falling In the right direction.
an effective range OF vision Of much
tingent upon the state Of the sea
Therefore anything that hampers
him in determining either tho true
height or the angle Of approach Of his
quarry will affect accordingly his
Judgment OF distance and speed and
will initiate against his aiming hts tor
pedo so that 1t will strike the target.
Mr.. Mackay has sought to bewildef
the U-boat observer by presenting to
his Vision an indefinite form and in
this way Fastening visual fatigue and
promoting error in range finding.
There are certain things that guide
the man at the periscope. The field of
his instrument bears n number of
graduated lines. some vertical, others
horizontal
The tops OF masts and the tins Of
smokesiacKs of different classes Of ves-
sells have approximately given heights,
and these. as they are measured be-
tween the horizontal lines. from the
waters edge upward give reason
ably accurate idea OF distance, while
the vertical lines, the length Of the
snip and her movement past these I'D
right divisions in prescribed interval
establish fairly well her speed
PeriscOpe Man Bewilderea
ii Manifestly these measurements ~
distance and speed are not SO hard IN
make when the observed craft. because
!. or her uniform coloring, stands out
more or less sharply against the back
. ground of sky. but the tables are ouits
reversed when me vessels contour,
, are made indefinite by mottled color
ing which largely obliterates shadows,
: eonceals familiar forms and ouicklv
tires the eye searching for telltale de-
tails. out and out invisibllty is not
the aim of this order of camoufiage.
Z because II is next to impossible to
, achieve that in broad da aylight, but Mr..
Mackay and Lieut. Commander Fisher
= have proved that il Is practicable to
, bewilder the enemy Observer looking
: through his pcriscope and trying to
, determine where To aim and when to
fire his torpedo
y MIR. Mackay says; 1T is an Old story
I that the leopard cannot change his
spots. but we have found ont that a
r ship can he so painted that her identi-
, fy'nG marks or textures vii seem, in
I the eyes of the observer, to shift from
, moment tn moment Indeed, the bright
I points actually appear to vibrate and
. visual confusion follows with amazing
rapidity
, zone reason for this is that the eye
, does not focus alike for different
: colors, and because the field is
q splotchei with many Colors tho very
4 effort to take them all IN and to get
+, "A picture of the ships entire form
tires the eye ana induces error.
"It must bc evident that ship thus
painted 50 that the atmosphere turns
her to gray or blue can blend more
: perfectly with the prevailing aeria
d background and therefore he better
s able to escape detection than one
r coated with any single tone,
Y "Of course / cannot dvulce the
Il colors employed OF just how they are
e applied, because fully realize the
Il cunning and resourcefulnoss of ouI
$ foe, but the public 1t our principal
h Eastern seaports Will he able ere long
@ to see craft so painted and then prob
t ably will marvel whe,e the gain comes
II IN. lnat tnere - "A ulSlntt gam II
t now established, ana Just a. the >rr'
= hides the bird of brilliant plumage, St
It does distance cloak our parrot ships,
y My part in this work has been ex'
q tremey absorbing to me because
II have felt all along that my lahor'
It would he well rewarded II this nautica
y camouflage should help to make itpcs
sihle to get men and supplies acro@
n the Atlantic"