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2 “,
v ERE you ever in a telephone exchange?
Did you ever stand behind a busy switch-
board and watch the operators, as with magic
swiftness they shuttle to and fro the myriad
- conversations of a big city? In one of.the
accompanying photographs you are looking
at the busiest switchboard in the world, - It.
is the Cortlandt Exchange in New York City.
- The “A board is shown here, but on the
- opposite side of the room. is another ‘of equal
size known as the “DL board.” As you stand
of this tons board between 10
» the busiest hour of the day, a
wonderful sight greets your view. Cease-
alessly back and forth like the branches of a
“he edgerow driven by the wind, yet with mar-
*yelous ‘skill.’ move-the waving arms of the
‘operators,
.seconds “each, -they answer the calls of this
-mighty metropolis., In all the exchanges of
the city, 450,000 completed ‘conversations are
“handled In this single hour.
+ But come with me,-and you shall see how
“these switchboards operate. “Let us take our
“position behind one ofthe operators at the
A poard. -Each operator attends about
‘forty aeinevibers, On horizontal shelf
_you will notice a double row of cords, a pair
jfor each subscriber. | In front of these Is a
“double, row’ of” small electric lamps, one each
for the calling subscriber and the subscriber
“ealled, Still in front of these is a row of
-listening keys, followed by'a row of buttons
for rewistering ach call that is.made. Just .
-at, the, left of: the: operator's position is a
group of circuit calling keys, by which she
.May place herself temporarily, in, communica-
‘tion with any other exchange of the city..,
Now let us see what is on the upright pan-
“h At the hottem you + “will notice several
vs of subscribers’: ja jacks. A Jack a
cInetaltie” socket, into which the’ operator
plugs when she wishes to make a connection
-with a subscriber's Hne, Beneath each: jack
js a tiny electric lamp. “Above the subscrib-
ers’ Jacks. are rows.of trunk line jacks, one
row for each of the other exchanges of the.
city.
Bot before we observe the actual opera-
tions.of the “’” panel, we must step over
to the “B”™ board.oen the opposite side! of
the room, At this board there are as many
operators as there are other exchanges in
the city. One operator attends. to all of the
“¢ally from ‘some other one exchange of the
city to the subseribers of this particular ex-
change in which she works, If, therefore,
as in New York City, there are about 100
exchanges, each subscriber's line coming to
an exchange must be * fanned out” into 100
branches, one for each “LB operator. On
the upright panel fo front of each “B”™
operator will be as many jacks as there are
subscribers to that exchange. . In one New
York exchange there are.10,199. So closely
packed are these. Jacks that an operator
without leaving her chair. can connect with
each one of them. On the horizontal shelf
in front of the “B” operator is a row of
cords with a tiny electric lamp in front of
each. Let us stppose that we are in the
Cortlandt exchange and standing” behind ‘the
“B” operator who attends the calls from
“At an-average~speed of twenty~*”
‘Cdlatély
ss THE Boys’
WORLD.
In a Telephone Exchange
By FLOYD L. DARROW ‘
5S BE
rw
eRe
.the Spring exchange. ‘There will ‘be about
‘forty of these cords, and each one Ieads back
“to a‘trunk line Jack at the panel ot every
“A operator in the Spring exchange. This
-means ‘that, if there are 100 “A” operators
iat the Spring exchange, vach
2eord will be divided up into
2100 branches,
p are ready “to go
“back to the * board and
“see what happens. You
“serve: a> tiny “lamp ‘ just -
neath: some subscriber's
¢
i responding to the subscriber's
mp, and plugs into- his
k. The. lamp goes
e@ operator presses the lis-;~
key and says
6.) Snppoese
swer ig Snoring 1812.
_which
“ator at the Spring exchange,
cand gives the number. The
2“ 33" operator ‘glances at her
Srow of trunk’ Tine. cords and
lassigns.. an idle _ one,
thirty, At the ‘same ©
tshe picks ae this cord and tues into jack
1812,. As -“ BY operator does this, the
AT the Cort}andt ex-
thi
operator back. at
change picks up the
ont. cord cor-
responding to ‘the
calling © subscriber's.
~line and plugs into
line jack
“By
. operator makes her
~ eonnretion. the bell
_ of the called) sub-
seriber rings. At the
same time one of
the
lamps at the “A”
board in the Cort-
t- exchange
lights, and thé * A"
operator knows that
the connection has
been made. When
the called subserib-
er takes his receiver
off
3
a
this
1
BUD
scriber hangs up his
e the
her of _these two |
Httle Iamps‘~ light.
When both light, the
erator
that the
conversation is com-
» pleted, and she dis-
connects, them by
.removing the cords
. from the jacks.” If?
either. of -the sub-
scribers ~ wishes - to
+ call _ the - operator.
~ before. the “conver-
sation is completed,”
or because he fails
to get his connec-
tlon, he moves his
“B" Board.
The
‘ . receiver hook up
cin- her. receivers.
tiny. electric ow
seriber’s, . meter.”
0
* account,
“ext Invention of the
so ‘The Central Office in the Year 1881,
apd down. This flashes on and off the little
lamp and calls the operator's attention. When
the “A”
‘ers,’ the
operator disconnects the subserib-
little Iamp in front. of © “B.
‘operator in the Spring exchange Bents, and
. i The Busiest Switchboard in the World.
1812, The disconnection’ js
\ .
she removes the trunk line cord from jack
now
© ousplete
~ and the lines are free for “other. ealls.
But suppose Spring 1812 js busy.
‘when >the -* B-".
line cord to this jack,
ofthe pzoel.
, fends the busy signal to the
and the calling subseriber.
> When a ‘call 's completed, the
ator = presses -
registration - vutton
AY
If 80,
operator touches the. trunk
she will .hear a click
In that case: she: immedi-
;ately plugs futo a busy:jack at’ the bottom
This connection automatically
“A operator
oper-
AveusT 12, 1922,
‘
The Polariscope,
HE chemist in a sugar mill is a veritable
wizard. By the aid of one little instru-
ment he is able to determine whether. the
cane. from a certain ‘field is sufficiently rich
, In sugar, whether the mill is. extracting a
proper percentage. of juice from the crushed
enne, whether the juice iis yielding up a
proper share of first grade sugar, whether any
available sugar remains in the ‘blackstrap
mol:
aR
en h to meet the importer’s: tests,
This instrument, that presides over every
operation in the manufacture of suxar, an
is the”court of last ‘resort, the final, judge,
in the sugar, industry,. is. called the polari-
scope. Thé name.is derived from. the -fact
that it uses polarized light in testing the
various solutions. Its mechanism consists of
a peculiar grouping of lenses, mirrors, and
prisms. S
To understand this ‘mazic instrument, one
must remember that light is vibrations, whic
come-at every-angle. It_is the function of
the polariscope to strain out all of the criss-
cross vibrations, and retain only those from
a.given direction, which are termed polarized
light. When these single direction rays are
passed through certain materials. they have
their direction turned. to either the right or
the. left. Sugar turns them'to the left. >
Thus having passed through the first prism
nd the sugar\solution, the’ polarized rays
are unable; to pass through a ‘second prism
because of. this deflection.
. tet its axis ‘is parallel to the rays of light,
and the shadow disappears. »The distance
“that he turns ;
, Mine exactly how pure or jmpure the, sugar
, Solution is.—[A. L. Grego
—.+—_
A Balloon Used for an Engitie. .
JIE balloon has been put to many-strange
uses, perhaps the oddest of which is its
‘employment’ for an engine. “A railroad ‘on
“which the motive power ‘is: supplied by ‘a
balloon is certainly a novelty.” Sach a rail-
yYread has been constructed in the Alps. Its
2 object is to carry passengers up and down
Ifochstaufen Mountain at Bad Reichenhall,
‘a watering place in the Alps.-- The - top of
“this mountain affords a splendid view, but the
“climb to the summit is tedious and’ unin-
~ teresting. > Accordingly it was:decided that
ithe tourists who’ visit the-place would ap-
! preciate’ the labors of the captive’ balloon,
+ devised to convey them tothe summ
The balloon was made to run slong a
“track built at-the side of the roadbed, A
trailer with many wheels clasps ‘this wooden
“1ail, or track, and the ‘passenger car. Is fas-
tened to thé trailer. | The operator sits in
«the ‘car with a cord swinging between him
;and the balloon by which he ean . regulate
“the supply of gas. Safety devices .are. at
hand in case of accident. Before the car
_Starts.up the mountain the balloon is charged
“with sufficient gas to enable it to ascend to
‘the summit, and when’ the top. is: reached
“and-all is ready for the- rerun journey, some
cof the gas is. permitted to es pe, whereupon
the car starts down hill, ‘te speed . being
:ehecked by the retarding effect of the gas
“still left in the baNoon.
It was not until the most rigid “investi-
| gation had been made and the’ coniparative
safety of this method of journeying demon-
strated, that permission was en to build
; the railroad. —UM: P. Chapm
records , the
meters work
sperdlometers,
and each month
their readings - are
photographed .by @
camera that takes
», These.
‘like
seventy of them at
a time. The differ-
ence | between — the
reading one month
and. that of the
previous
gives the number of
calls to be charged
the subseriber's _
And now we have
automatic ex-.~
which does
the
change
xirk”
beyond. de- *
this new-
plicated
scription,
telephone art seems
endowed with» hw
man + Intelligence...
Mechanically per-
fect, It never makes
a mistake, © never
pever
getx ‘Impatient, and
16 always on the job.
“At
