The Topeka state journal. [volume] (Topeka, Kansas) 1892-1980, 1917-06-11
Washington, June 1.-THE federal

have proved that each nation which
makes war must be prepared to sup
ply itself with every essential of war
fare. The bureau of standards has
brought it's work to a point where
America can meet the cXacting re-
quirements of the army for optical
glass.
The whole system of modern war
fare may be said to be based on the
accuracy of the results obtained by
the use of optical instruments. 1t has
been said that this war goes back to
the methods of primitive times-to the
LIQUID fire of the Greeks and the mana
to hand cold-steel combats of the days
of chiyalry This is only partly true;
at best. only a superficial view of the
question Basically this war is war
of cold science. The infantry charge
is the elimination of an artillery IRE
from hidden guns shooting at targets
MANY miles distant which the Sunners
cannot see. The accuracy of this IRE
is based entirely on the accuracy OF
observations made by various optical
instruments-by field glasses, range
finders, and aeroplane cameras
Nowhere is the remarkable de-
velopment of finely made glass lenses
more beautifully shown than in the
aeroplane cameras. These cameras
are literally the eyes of the army;
Every foot of the battle-ground ana
graphed rccres of times a day. These
photographs are made by men fl2ing
| five and ten thousand feet above the
ground level at speed OF elShty
miles an hour or more, and they are
as clear end distinct as che CABINET
photo of ten years ago.
Only an expert in optical ins-ru-
ments can appreciate the triumph OF
science by the lenses of these cam
eras. A simple lens which will make
7 n Of art
than five separate and distinct factors
of error, and would show nothing but
a blur if used under conditions much
| less trying thar those of aeroPlane
photography. In order to overcome
the sources of error it is necessary
to combine glasses of different chem
| iCal composition in such way hat
| each glass exactly neutraliZes the
error of the others. The composition
| of such glasses must be calculated to
the minutest fraction. The gle sses
must be cooled, annealed, ground and
polished until they are accurate down
| to the finest point that human in
struments can measure.
| Some of the great military cameras
in use on the western front make
PICTURES IT inches by 90. Such cam
eras have lenses with THAT is known
rs 36-inch focal length-tnat is, the
lens is paced a yard distant from
| the sensitive plate. This is necessary
in order that objects en- the ground
may stand out as large as possible.
| The longer the distance from lines to
plate, the more useful are he photo
graphs from the military point of
view. But in -Ief to combine this
| long focus with speed, It is necessary
/ for the lens to be very large, and
each increase in size of the lens in
creases many times the difficulty of
/ casting and grinding it accurately.
| The lens on such camera may be a s
/ a SiX n
must be so perfectly made that this
great block of glass, combined of diff
| ferent elements, casts a sharp clear
image of the scene below on every
part of thc Photographic plate.
Most of the aeroplane cameras are
smaller in size than this, on account
of the difficulty in handling the big
| plates. These smaller cameras take
pictures OF such a sharpness that they
may be enlarged without loss of de-
| tail. The weight is also a factor. 1t
is said that some of the larger cam
eTas weigh as much as 200 pounds.
| This limits considerably the height
to which the aeroplane can rise, and
from shell-fire. Specially constructed
aeroplanes are being used to carry
these big cameras equipped with de-
vices to eliminate vibration.
An army photographer may make
800 pictures in a single aeroplane
flight, and there are hundreds of pho
tographers attached to the aeroplane
divisions of each army. Thus thous-
ands of pictures are brought back
daily from over the enemys lines.
These pictures, along with what this
observer sees thru his field glasses,
are the real basis for military op-
| erations.
Many positives are made from each
negative. Along important sections
of the front, not only are such photo
graphs given to general officers and
staff members, but they go to regi-
mental commanders. and even TO low
er officers The officers in the fight
ing line thus get a clear idea OF the
conditions opposite their positions,
By a STUDY of the photographs, the
staff attempts to determine wha-
movements the enemy has under way.
and military maps are corrected from
day to day
The signal corps of the American
army faces an unusually difficult prob
lem in war photography in laying its
plans for possible defence of Ameri-
can territory. This is due to the lack
of military maps of American soil. II
is compare lively easy for a staff off
Ger who has a large scale and detailed
, military map of given region to take
a number of photographs of that region
and bring the situation up to date
from day to day. Lacking the large
scale military map, the problem be-
, comes more difficult. In such a case
the map must literally he drawn from
Photographic data. It is said thai
our signal corps and engineer officers
recognizing this problem, have work
ed out a most efficient system for map
ping new region entirely from aero.
plane photographs. Details of this sys.
{ tenn are of course not available but i
is said that new apparatus of grea-
. value has been invented and con.
structed by American experts.
One result of the use of wholesale
: photography has been to introduce thu
new element of deceptive scenery anC
dummy gun positions into warfare
Such false positions are built exactl,