Richmond times-dispatch. [volume] (Richmond, Va.) 1914-current, 1918-10-05
NOW TIT SUBMARINES
WITH TWO PERIsCOPEs
While Third Is Being Installed BY
: Germans to Scan Sky for
A1rplancs.
THE EYES OF sUBMERs1BLEs
Interesting Story Of the Develop
ment Of Device From Crude In
strumcnts Made Use of by French
Haif-Ccntury Ago.
ny CLAI, PRICE.

October 4.-Submarines of the type now
employed in the war zone are fitted
with two pcriscopes. one coming below
into the central operating compart-
ment and the other into the after bat
terry compartment. They are so placed
in order that, should one compartment
become. filled with the sea. the steel
door in its transverse bulkhcad may
be logged down and the other compart-
ment may remain.
The installation of two makes it
possible for one pcriscope to be used
exclusively by the hclmsman. who is
looking ahead more or less continu-
ously. while the captain is able to use
the other to examine the horizon in
all directions.
Some of the larger German subma-
two of the ordinary sort and the third
a zenith periscope. for making vertical
ohT ser to detect ;,ts aircram
six inches in diameter. and about TWEEN
ty-ive feet long. This length allows
perstracture deck. the captains peri
scope usual extending few inches
der to give him an mnobstr r1 sweep
of the entire horizon, and the zenith
periseope. when there is one, being the
end, the periscope is reduced in diam
eter from six inches TO. two. or even
one and ree-quarters inches, for the
the sea: For it is not the periscope
which 4, Is picked up by the lookouts
err the periscopc makes in the sea. and
II is obvions that the smaller the ncri-
sec, scope: the ,, S smaller the "feather" it
creased by the speed OF the submarine
which never exceeds four or five knots
Stsnk is uIn s by ,he
lifting and lowering OF the periscope
the. submarine lis able to deliver an at
tack with absolutely nothing in evil
den denec above the water for the greater
periscope may be lifted for few sec
o onds In b order to allow the captain to
cred again Almost at once.
HOW TWO PERISCOPES
MAY SAVE THE DAY
or course. in an attack. the helms
mans ms p of Is not used the nayi
captain. However should the cap
sans Rerisso2s he shot away there
helmsmans periscope.
The first. periscopes. as introduced
into French submarines about fifty
years ago, consisted OF an arrangement
of two mirrors in IA simple tube, each
inclined at forty-tive degrees after the
manner OF trench pcriscope. Later
ment were improved by the instaIla-
tion of two triangular ,prisms instead
=
lenses to focus the view in tho eye
piece. When periscopes came into more
general an use abb about 1900; dtiieuity
vt was found that the introduction
additional lenses in the periscore
tube inverted the image. so that the
sea Was found in that part Of the
image Tin which one expected to find
the sky. and any skip In sight hung
Installation of a correcting Tense which
failed. however, to give any sense of
direction and which compelled the cap
TO ascertain his bearing relative to the
object which he desired to attack. The
periscopes now, generally in use. how
ever. revolve bodily, and the captain
using the eyepiece. goes round with
his instrument. obtaining thereby with
out consulting any indicator. an ac-
curate notion of mis- bearing.
NOW USE MAGNIFiING LENS
TO PICK Up SMALL OBJECTS
Many periscores, n W in use are BIZ
focal. and BY the shift OF small wheel.
maEnifies, in some Subma rines as high
as six times. BY this. signals may be
read and other small objects picked.
perlscopes is worthy of note. When
some time. the lair iii the periscopes OBJ
riously becomes Of the same tempcra-
ture AS the outer air. When the peri
scopes are submerged then the air in
the periscope tupeS IL reduced in tenn
perature TO the temperature OF the sea.
a reduction which would condcnse the
moisture in the pcriScope tubes and
produce a haze o.er the lenses which
would entirely obscure the image. For
dried beforehand by passing II through
calcium chloride and then Theoretically
sealing the periScope 80 that il will
remain dry. In this way. tho periscope
Is mace TO keep it's clearness of image
despite the sudden changes in tempera-
lure which II must undergo.
nj tor ,ct
the outer lens of the periscope has not
been found to interfere materially with
piete MIN OF water is usually formed
over the entire surface OF the glass
Rain is more troublesome than sea
water in this respect. but raindrops
can be washed off the top lens by low
ering the periscopc into the for
an instant.
ton OF rangc-tnder on submarine
as well as the function of the sub
marines marin, eyes The lower eyepiece is
hair-like lines. which, by their coin
cidence with the bow and stern. to-
gether with the vertical lines of the
/. ship under observation, such as the
height of the stack or Of the masts,
gives the range OF the ship. This is
where marine camoufage, as applied TO
allied merchantmen, is Intended to do
it's protective work. BY ohscuring the
length Of ship and the height of its
stack and masts. by breaking up the
straight lines Of ship on which the
enemy periscope seeks to range, il is
intended TO interfere with enemy sub
marines.
OF course. the rangc-fnding fac,li-
ties which the periscope affords to Il
submarine are exceedingly crude as
compared with the range finding APP
paratus of modern battleship, but ac-
curacy of range is very much less
important factor in torpedo warfare
than in warfare with big guns. There
is practically no chance OF torpAdoes
going under, and none whatever Of
their going over their target, so that a
submarine Is only concerned with ind-
ing it's range in a horizontal pane
Moreover battlcship may open fire
at q range OF 10000 yards, while most
submarine attacks are made from a
range probably within 600 yards.
PERISCOPE PROVES
GREAT STRAIN ON EYE
American submarine captains see
need for further improvement in peri
scopes in the grinding Of periscope
lenses to remove the blush, spectrum
like appearance WHICH. lenses. not so
well ground az they might be. give to
the periscope's image. When the image
has whitish look. the eyes view il
with less strain. For such. a strain
J. does the ordinary periscope inf'ict on
the eye that Deriscope watch at sea
Is, usually no more than an hour long.
Too long time at the periscopc swells