E are accustomed to the
idea that in an electrical
conductor there are elec-

trons or ions in a state of random
motion which has partly to do with
the temperature of the conductor.
We have had less occasion to consider
that this motion may result in a spon-
taneous fluctuation of potential be-
tween points in the conductor. This
thermal agitation, this motion of elec-
tric charges, this potential fluctuation,
does exist and can be measured under
suitable conditions.

The effect is most readily detected
in a conductor having high electrical
resistance. It is characterized by a
continually changing or fluctuating
voltage generated by the resistance
itself, unconnected to any other
sources of potential. An alternating
current instrument is therefore re-
quired to measure the effect, an in-
strument which reads the root-mean-
square or effective voltage.

If an ordinary voltmeter is con-
nected to a resistance as shown in Fig.
1, of course, nothing happens. The
effect is far too feeble to be thus de-
tected. A vacuum-tube amplifier ca-

pable of multiplying the voltage by
about one million must be inserted,
between the resistance and the meter,
as shown in Fig. 2. The amplifier and
the meter, which may be formed by
the combination of a thermo-couple
and galvanometer, then constitute a
sensitive voltmeter which can be used
for accurate measurements.

With such a system measurements
have been made on resistances com-
posed of a wide range of materials,
including advance wire, carbon fila-
ment, metallic films, and various elec-
trolytes. In all cases a mean-square-
voltage, proportional to the resist-
ance, was observed. In all the mate-
rials the ratio of this mean-square
voltage to the value of the resistance
was the same and was independent
of the shape or dimensions of the re-
sistance.

This voltage effect might be caused
by the thermal agitation of the elec-
trical constituents of the material or
it might arise from some property of
the amplifier whereby its own noise
is increased when resistance is con-
nected to its input. In order to settle
this point a measurement was made

on the resistance at liquid-air temper-
ature, and the ratio of mean-square
voltage to resistance was found to be
less than that at room temperature
in the proportion of the absolute tem-
peratures. This relation held accu-
rately in the case of advance-wire re-
sistances over, the temperature range
from liquid oxygen to boiling water.

The same satisfactory agreement was
obtained with other resistances, in-
cluding electrolytes. There can there-
fore be no question about the fluctua-
tion originating in the resistance and
not in the amplifier.

When a different amplifier is used
a different value is obtained for the
ratio of mean-square voltage to re-
sistance. For the purpose of deter-
mining the value of this ratio the fre-
quency characteristic only of the am-
plifier must be known. This means its
amplification squared must have been
measured at a sufficient number of fre-
quencies to plot a complete character-
istic curve. The mean-square output-
current, induced in the thermocouple
of Figure 2 by the voltage fluctuations
in the input resistance, is then propor-
tional to the area under the frequen-
cy characteristic. Since there is pro-
portionality also to the resistance and
the absolute temperature, the empir-
ically derived expression for the
mean-square output-current is propor-

tional to the product of these factors.
The introduction of a fourth factor
—a numerical multiplier which turns
out to be closely connected with Boltz-
mann’s gas constant and with the en-
ergy of a gas molecule at a given tem-
perature—completes the expression.
A knowledge, therefore, of the resist-
ance in the input and of the frequency
characteristic of the amplifier is all
that is necessary for predicting, in any
particular case, how much current will
be induced in the output branch by
the resistance in the input of an am-
plifier.

This thermal agitation of elec-
tricity in a conductor has certain very
practical aspects. When a telephone
is connected to the output of a sensi-
tive amplifier a characteristic sound
may be heard—the “‘sh-sh-sh’’, com-
monly called ‘‘tube noise’. At least
a part of this is the spontaneous noise
arising from the input resistance
itself. In fact, if the input resistance
is high and the tubes are of the best,
the noise due to thermal agitation in
the resistance is so large as entirely

to mask the noise contributed by the
tubes. To the smallness of the volt-
age which can be successfully ampli-
fied, there is then set a limit by the
very nature of the substance of which
electrical circuits are built.

In order to give the exact magni-
tude of the effect both the resistance
and the amplifier would have to be

specified in the terms described above.
Approximate figures may be given,
however, for a usual type of circuit,
with which comparisons can then be
made. Such a circuit is an amplifier
which covers the voice-frequency
range, to the input of which a resist-
ance of one-half megohm is connect-
ed. There then appears to exist across
the resistance a root-mean-square
voltage of the order of a few micro-
volts. This is equivalent to a “power
level” of about —140 T. U., and
this power level is independent of
the resistance. The smallest power
which can be usefully amplified by
this system depends upon the amount
of distortion and superimposed noise
which can be tolerated, but it cannot
be much less than the power of the
noise itself. It is possible, of course,

to handle smaller powers in propor-
tion as the frequency range of the
amplifier can be made narrower; that
is, to have a smaller area under its
frequency characteristic.

Returning to the physical facts in-
volved, these can now be summarized:
Every resistance is a source of ran-
dom voltage fluctuations, the effects
of which can be heard or measured
with suitable amplifying apparatus.
Experiments at different temperatures
prove conclusively that in an ampli-
fier a component of ‘‘noise” comes
from the resistance in addition to that
from the vacuum tube or other ele-
ments. The discovery of this phe-
nomenon, in our laboratories, there-
fore, is not only of scientific interest
but finds an application in the prac-
tical problems with which we deal.

AU CLAIRE STEVE! JOINT
ORTSMOUTH
? PBUFFALO \ ALBAN? WORGE BOSTON
70 L WEST UNITY EVEL HD
OT TA: BOGART eRISTOWN 3
| CHESTERTON | » IEW CASTLE
| CUYRHOGA FALLS A
SPEORIA YWATSEKA | i ALTO iN
TERRE HAUTE /

G¢ ISTEN to the band, marching
up the street,’ as a song of
the Gay Nineties advised: a
curious effect is noticeable. As the
band approaches and its music grows
louder the bass notes come out most
strongly. The same band, the same
music, but there is a different empha-
sis to the notes when the band is near
and the music loud than there is when
it sounds faintly from far away. The
explanation of this and other anoma-
lies of hearing is to be found in some
recent measurements of loudness
which have been conducted in our
Laboratories.

Loudness is a psychological phe-
nomenon depending upon the struc-
ture and action of the human ear.
Physically, behind the impression
which a listener receives is the alter-
nating pressure of the train of sound
waves upon the ear drum. Loudness
does not inhere in the sound waves;
they transmit energy and exert on the
ear drum an effective or so-called
“root-mean-square” pressure which
the physicist measures in units of
force (dynes) per square centimeter
of area affected.

How does loudness, which is a sen-
sation, correspond to effective pres-
sure, which is the physical character-
istic of a compressional wave in air?
At first thought it might appear that
the two should be directly propor-
tional, that is, have a linear relation
between them. Not so readily would
one expect that there would be a

linear relationship between loudness
and pitch, since the receptive fibres of
the basilar membrane are not equally
distributed with reference to pitch, as
the “‘piano model” of the ear so plain-
ly illustrates. Having two notes of
different pitches, that is different fre-
quencies, and of equal effective pres-
sures will they produce similar sen-
sations of loudness? Or, in other
words, having two notes of different
frequencies both equally loud, will
their effective pressures be the same?

The experiments answer that, in
general, they will not be; and more
than that, the difference of effective
pressure between notes of two pitches,
which seem equally loud, is not a con-
stant difference but depends upon the
pressure. These somewhat compli-
cated and unexpected relationships
are illustrated in the accompanying
graphs which give the results of com-
parisons of the sensation of loudness
for various pure tones, differing in
pressure and frequency.

The observers listened to pure mu-
sical notes from a telephone receiver
driven by current from a vacuum-tube
oscillator. The listeners compared
different notes, two at a time, as to
the sensation of loudness and by ad-
justment of the current brought them
to perceptibly equal loudness. The
value of current corresponding to any
note, and hence the pressure exerted
by its sound wave, was known from
the setting of the current control.

ment of apparatus for the tests. The
observers listened alternately to notes
on circuits A and B. That on circuit
A was kept constant at a pitch about
‘an octave and a half above Middle C.
Its intensity was set to some value
unknown to the listener who was par-
ticipating in the test. This was con-
veniently done by turning the dial of
the attenuator marked ‘“‘A’’. The note
of circuit B was then set to some
other pitch; and the listener varied its
intensity by turning attenuator B un-
til it seemed just as loud as that of
the comparison note of circuit A. To
make sure that his settings, which
were repeated several times, were un-
influenced except by the sensation of
loudness, the attenuator dial B was
hidden by a loosely fitting screen

The comparison note of “A” was
successively set at nine different inten-
sities; and a family of notes of other
pitches, but of equal loudness, deter-
mined for each listener. There were
as listeners eleven men and an equal
number of women. The average de-
terminations of each listener were
then averaged to obtain the curves of
Figure 2.

All the points on one of these
curves represent in terms of the root-
mean-square pressure the physical
stimuli, corresponding to the indicated
pitches, which acting on the human
ear will give sensations of equal loud-
ness. This follows from the assump-
tion that the old axiom of “things
equal to the same thing are equal to

Fig. 1\—The attenuators which vary the intensity of tone in the receiver. With the
switch in left-hand position, “A” tone is heard; in right-hand, “B’ tone is heard

each other” applies to the sensation
of hearing. Each of the various notes
represented by a curve sounded just
as loud as the comparison note, and
hence was assumed to be equally loud.
As a check of the application of the
axiom in this particular case, one of

not at all equally sensitive to all notes.
At the highest level of loudness which
was studied, however, there is ap-
proximately equal sensitivity over the
entire frequency range.

Fig. 2—Points on one of these curves represent, for the indicated frequencies, the
physical stimuli which, acting on the ear drum, give sensations of equal loudness

the lower tones was directly compared
with one of the higher tones. The re-
sult was found to agree with the de-
termination previously made by com-
paring these same tones through the
medium of the “A” test-tone.

The curves now show why the band
sounds as it does. The loudness of
the low-pitch tones increases more
rapidly than does that of the high-
pitch tones, for equal increments in
pressure ratios. That is, suppose au-
ral observation to start with wave
pressures only just sufficient to give
audibility. As hearing begins the ear is

loud speakers when the volume is in-
creased. Even though the intensities
of all the pitch components of the
music are amplified nearly equally, a
relatively increased effect on the ear
then comes from the bass portion of
the music. The remedy for the con-
dition is the reduction of the volume
until the music, as a whole, is of about
the volume to which the listener is
accustomed for music of its type.
Then the various components do not
give rise to unusual relative sensations
of loudness and hence to an apparent
distortion.

HE single-tube radio re-
ceiver, popular five years ago,
demanded but a modest bat-
tery equipment to supply its filament
and plate circuits. As the art devel-
oped, receiving sets became more
complex; reliable operation on weaker
radio field-strengths and ample vol-
ume on loud speakers became essen-
tial. The number of tubes increased,
and with it the need not only for more
power, but for higher plate-circuit
voltages. While the need can be met,
as originally, by batteries, they re-
quire a certain amount of attention in
the way of inspection, replacement
and recharging. Of this responsibil-
ity most radio listeners would gladly
be relieved, even at some additional
first cost and operating expense. In
effect, they ask for a power supply
which needs no attention other than
to turn the set on and off. As a re-
sult, there have appeared many dif-
ferent forms of “battery eliminators”’
intended to supply suitable power by
conversion from the commercial sup-
ply of 110-volt 60-cycle alternating
current.

In some cases this “conversion” is
the simple one of voltage-reduction
through a transformer. More often
it requires conversion of alternating
current into direct, by means of a rec-
tifying element which will pass cur-
rent in one direction only. The
vacuum-tube is itself a rectifying ele-
ment; through it current can flow only
when the plate is positive to the fila-

ment. When three-element tubes are
used, as for example the 205-D in
the 25-B amplifier, the grid plays no
part in controlling electron-flow and
it is strapped to the plate. No grid is
provided in rectifier tubes, such as the
217-A. The rectified output of a tube
is limited as to current by permissible
heating and by filament-life. It is
limited as to voltage by the potential-
difference which the tube will block
when its plate is negative to its fila-
ment.

Another type of rectifying element
involves an electrolytic cell, in which
one electrode is of an inert material,
frequently lead, and the other is alu-
minum or tantalum. Both of the lat-
ter metals have the property of form-
ing a film of oxide on their surfaces
which blocks current-flow from elec-
trode to electrolyte, but allows cur-
rent to flow in the opposite direction.
With the aluminum electrode, a so-
lution of borax is commonly used;
with the tantalum electrode, a dilute
solution of sulphuric acid. The cur-
rent through either type of cell is
limited by heating, which decreases
the life of the active electrode, and
by excessive loss of water due to elec-
trolysis.

Another limitation to the useful-
ness of the electrolytic rectifier is the
low value of reverse-voltage which it
can be depended on to block. This is
of the order of forty volts for the
aluminum type and sixty-five for the
tantalum type. For higher voltages,

it is necessary to use an appropriate
number of cells in series. When out-
put voltages up to 135 are desired
this is not a serious factor. Much
higher voltages are required for the
power tubes now coming into use; and
for this service the number of elec-
trolytic cells becomes excessive. On
the other hand, a single vacuum tube
may be selected from available types
for use in rectifier circuits delivering
as high as 10,000 volts. As a prac-
tical example in the field of radio re-
ception were an aluminum rectifier to
be used in place of the single 205-D
rectifier tube in the 25-B amplifier, as
many as twenty cells in series might

be required to supply sufficient voltage.
How a rectifier operates is illus-
trated by Fig. 1, which shows a cir-
cuit commonly as “‘half-
wave” since only one half of each
cycle produces current-flow. In cir-
cuits of this type the heating effect of
the current through the rectifier is
equivalent to that of a steady current
twice as great as that which is deliy-
ered to the load. The peak voltage
across the tube during the non-con-
ducting half-cycle is equal to the peak
value of the alternating e.m.f. plus
the voltage of the first filter-con-
denser; the total will approach at
light loads twice the peak voltage.
An alternating com-
ponent in the rectified
current is quite objec-

may be greatly reduced
by inserting one sec-
tion of a simple low-
pass filter as shown in
Fig. 1. The propor-

7 tion of alternating cur-
APPLIED rent which remains in
VATACE the output of the filter

CONDENSER C,
APPLIED the filter constants, but
\ 4.0. VOLTAGE
: its effect on the opera-
j tion of the amplifier
VS can be determined ex-

actly only by expe-
rience or trial. Any
degree of filtering can
be obtained by using

more capacity, more
inductance, or both;
and by using more than
one section of fil-

Fig. 1—A “half wave” rectifier; (a) its circuit; (b, c, d, e)
wave-forms of current and voltage

minimum when that capacity is equal-
ly divided between C, and C,. On the
other hand, the larger is C,, the lower
is the output impedance of the recti-
fier circuit, and the less likely is “‘sing-
ing” when several stages of an ampli-
fier are fed in parallel from a single
rectifier.

Condenser C, may be omitted from
the filter; this has the effect of mak-
ing the wave-form of the rectifier
current much less peaked. In turn
this reduces the heating of the recti-
fier element for the same quantity of
electricity through it,* but the impe-
dance of the filter is increased, so
that a higher alternating voltage
must be impressed. In the case of a
vacuum tube the decrease in heating
may more than compensate for the
increase in reverse voltage to be
blocked, but no advantage is secured

when electrolytic cells are used be-
cause the increase in voltage will re-
quire a proportionate increase in the
number of cells.

In the so-called ‘“‘full-wave”’ recti-
fier both halves of the alternating
current cycle are used, with advan-
tages in both efficiency and lower
noise-level. The most common type
of circuit is shown in Fig. 3; it em-

_ * Total current per cycle is the integral of the
instantaneous current; heating is proportional

ploys a transformer with a mid-tap
on the secondary winding, and two
rectifying elements. To deliver the
same voltage to the load this circuit
requires twice as many turns on the
transformer secondary as in the cir-
cuit of Fig. 1 (a) but the current is
divided between the two rectifying
elements and their associated trans-

former-windings. Hence this circuit
is adapted to use with vacuum tubes
where current-flow is a limiting fac-
tor. While the load can be equally
balanced with tube and tantalum rec-
tifiers, it is difficult to do this if alu-
minum cells are used. This difficulty
is avoided if the circuit of Fig. 4 is
used. No transformer mid-tap, and
only half as many secondary turns,
are needed. At least four rectifying
elements are used, instead of two, but
since two elements are always in se-
ries to oppose the reverse voltage, the
circuit has an advantage when the
breakdown voltage of the rectifying
elements is a consideration. Where
four elements would be required in
the circuit of Fig. 3, they could be
rearranged according to Fig. 4 with a
transformer of half the secondary
voltage to give the same output volt-
age.

Full-wave rectification with two
elements may be effected by the cir-
cuit of Fig. 5. With a transformer
secondary equal to that of Fig. 1 (a),

approximately twice the output volt-
age is secured at no-load; each con-
denser in Fig. 5 is charged in turn to
the voltage of C, in Fig. 1 (a) and
both in series discharge through the
load; each carries full load-current.

cy of the alternating component in
the output is doubled, and to atten-
uate it an equal degree requires a
filter of higher cut-off and therefore
smaller and less expensive. On the
other hand the ear is much more sen-
sitive to the 120-cycle tone resulting
from full-wave rectification than to
the 6o0-cycle tone of half-wave recti-
cation, so that the noise level is about
the same in the two cases. Where a
radio receiving system is quite in-
sensitive to these low-frequencies, no
audible hum may be heard at all in
the loud speaker, yet there may be a
large ripple present in the supply
which under some conditions will be
sufficient to modulate the received
speech or music. This condition may
make itself known by bad quality
or a peculiar fuzziness in the pro-
gram which is being received.

tion, the rectifier is at a considerable
disadvantage as compared to the dry-
cell battery, since its internal resist-
ance is so high that changes in load
produce large changes in output volt-
age. For example, one commercial
rectifier shows a 15 percent drop in
voltage when the output current is
increased from five to twenty-five
milliamperes and another under simi-
lar circumstances gives a drop of 55
percent. Dry cells, on the contrary,
have sufficiently low internal resist-
ance, especially when new, that their
output voltage will change but little
over the range of loads ordinarily
imposed on them.

Electric power for heating the fila-
ments of vacuum tubes is supplied un-
der conditions quite different from
those attending its use in plate cir-
cuits. Impedance of filament circuits
is relatively low: currents are rela-
tively large and voltages small. Un-
der these circumstances disadvantages
of storage batteries are much less
marked. Since most radio outfits have
been designed for this source of fila-
ment power there is a decided appeal

in a device which combines with a
small battery a rectifier whose cur-
rent can be allowed to flow through
the battery continuously when the

radio set is not in use. A battery op-
erated in this manner requires little
attention other than the addition of
water at intervals; it has long life and
gives good service.

Several ‘trickle’ chargers employ
rectifiers of the contact type. One of
these consists of a disc of oxidized
copper held in contact under pressure
with lead or other soft metal. The
cuprous oxide film has a low resist-
ance to voltage in one direction and a
high resistance in the other direction,
thus fulfilling the requirements for a
rectifier. The ordinary crystal detec-
tor is a rectifier of this general type.

A rectifier widely employed in bat-
tery chargers and capable of passing
several amperes is of the hot cathode
type, but the tube, instead of a
vacuum, contains an inert gas which is

STEP-DOWN
TRANSFORM “RECTIFIER
STORAGE-=
BA
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ON o AUXILIARY
SOCKET FOR
‘B’ BATTERY
ELIMINATOR
OF F
DPDI
SW/TCH
VOLT
60~

ionized by the electrons emitted from
the hot filament. When the anode,
which is usually a piece of graphite,
is positive, electrons are drawn from
the filament; these ionize the gas
molecules by collision, so making them
conductive in the direction of anode
to cathode. During the half-cycle
when the anode is negative any elec-

trons emitted from the filament are
repelled and the gas in the tube is not
conductive during that period. The
internal resistance of a tube of this
type is much lower than that of a
vacuum tube and larger currents can
be rectified, but on the other hand the
reverse voltage which can be blocked
is lower.

Fig. 7—Low-pass filter for filament circuits
current is of the order of two am-
peres, as against a few milliamperes
in plate-current supply. This necessi-
tates a costly and unwieldy choke coil
in the filter. Since the impedance of
the load is low, quite large values of
capacity become necessary. Condens-
ers may be replaced by resistances as
shown in Fig. 7, but at a sacrifice of
efficiency. The filter problem is con-
siderably simplified by using so-called
‘“60-mil” tubes with filaments in se-
ries with the plate circuit of the last
audio-frequency stage. This raises
the load impedance to a value which
gives satisfactory filtering, and re-
quires no more current than can be
handled by a choke-coil of moderate
size. In the typical circuit shown in
Fig. 8, the plate and grid voltages of
the 205-D tubes are such as to allow
a current of thirty milliamperes
through each of these tubes, giving

sixty milliamperes through the fila-
ments of the three tubes in preceding
stages.

For the filaments of tubes in cer-
tain stages, sixty-cycle alternating cur-
rent may be employed. This is par-
ticularly true of the last audio stage

in which the filaments usually require
more power than do the other tubes
of the receiver, and where any alter-
nating current hum will not be ampli-
fied by succeeding stages. In the 25-B
amplifier, suitable voltage for this
purpose is given by one of the sec-
ondary windings of the 60-cycle power
transformer. To the midpoint of this
winding are connected the grid and
plate circuits. This balances out to a
considerable degree the effect on the
grid and plate circuits of the alternat-
ing voltage across the filament. The
same end may be achieved by con-
necting a potentiometer of equal re-
sistance across the filament leads.
When necessary, a better balance
can be secured with a variable poten-
tiometer adjusted for minimum noise.

Audio-amplifier tubes of other than
the last stages may also be lighted by
alternating current, but naturally
noise introduced in these tubes will be
amplified by succeeding stages and
may become objectionable. These
noises may be minimized by using
tubes with low-voltage filaments, such
as the 215-A, and carefully adjusted
potentiometers. Radio-frequency am-
plifier tubes may be lighted by alter-
nating current. If the detector tube
is lighted by alternating current a com-
plicated and carefully adjusted circuit
is required, else noise will be excessive.

Both plate and filament circuits re-
quire a supply of power; the grid cir-
cuit, however, requires only a voltage
of proper value. Since no current
flows, and no work is done, it is cus-
tomary to use small dry-cells. Elimi-
nation of these batteries, desirable for
maintenance reasons, may be effected
by using in their place the fall-of-
potential across a resistance in which
direct current is flowing. This cur-
rent may be that required to light
single filaments, as in Fig. 9; or to
light filaments in series as in Fig. 8.
In the latter circuit a potential of 9

Fig. 9—How a grid bias can be supplied
by potential drop in a filament circuit

volts, negative with respect to the
power amplifier filament, is available
at ‘-B’”. Where series filaments are
not used, their place may be taken
by resistance, as is done in the 25-B
amplifier. It should be remembered,

however, that potential thus obtained
for grid bias is deducted from that
available for the plate circuit of the
last tube; and that a certain amount
of power is lost in the resistance.
This method is coming into use be-
cause it eliminates an element whose
replacement is annoying and often
forgotten, and because for large val-
ues of grid-potential as required by
the 25-B amplifier, a resistance takes
up much less space than would the
equivalent number of dry-cells.

Any consideration of the relative
costs of supplying power to a radio
set by various methods involves the
correlation of data as to the load, the
number of hours’ use per day, cost
and life of different kinds of batteries,
cost of electric power, and efficiency
of each piece of apparatus through
which that power must pass. All of
these quantities vary over so wide a

range that data of practical value
would be too bulky for this article.
The “practical value’, even, of data
is doubtful since the annual charge is
probably one of the least important
factors in the selection of power-
sources for radio reception. Far
greater weight is given to such points
as low first-cost, ease of maintenance
by unskilled hands, warning of im-
pending failure, and adaptability to
sets of different types. The annual
charge for power is practically the
only operating expense in connection
with a radio set; compared with the
pleasure of radio reception this ex-
pense is so moderate that it is gener-
ally ignored. After all, what the
user buys is satisfactory reception of
radio programs. Given this, at a
price within his means, and a differ-
ence of a few dollars is counted of
little importance.

Hard-grained scientists seldom make predictions as to develop-
ments likely to occur in their particular field of experiment
and research. At least such has been the rule among responsible
savants. . . . During the past three weeks, however, three venerable
scientists and inventors have voiced predictions which occasioned
no end of excitement. . . . Predictions are romantic and ‘
furnish . . . interesting copy for newspapers . . . Unfortunately
even scientists do not qualify to visualize scientific achievement as
yet unaccomplished.
The policy of the Western Electric Laboratories furnishes an
excellent case in point. Here are employed a great number of
the shrewdest engineers in the world. It is the method of these
laboratories to successfully perfect new inventions, try them out
secretly over a long period of time, and when they are classed as
positive and fool-proof, announce them to the public. In other
words they accomplish first and predict afterward. Such practice
may lack the romance attached to the perfection of a publicly
predicted device, but in the long run it is the best method for the
good of the general public.

N December 15, 1926, the
() long distance cable between
Chicago and St. Louis was
formally opened with ceremonies ap-
propriate to the most western strand
of a cable network which, paralleling
the Atlantic from Portland to Wash-
ington, stretches inland to join most
of the principal cities in the industrial
area of the United States.

The new cable* is 344 miles long,
provides more than 250 telephone
and telegraph circuits and represents,
with its associated apparatus, an out-
lay of about $7,000,000. While this
project will supply circuit facilities
equivalent to ten open-wire pole-lines,

it was undertaken at this time to give
increased protection against storm
damage. Wires grouped into cable,
which is in turn suspended from steel
strand, offer less surface to wind and
sleet and more resistance to loads im-
posed by both. Safe inside a leaden
sheath, their paper covering main-
tains its insulation through good
weather and bad. But the sheath
must be continuous, else rain and
melting ice will find their way inside,
wet the paper and quickly put the
cable out of service. Evaluation of
the ability of cable-sheathing to main-
tain its integrity is a subject of contin-
uous study in these Laboratories.
As a material for cable sheath, lead
and certain of its al-
loys are almost ideal.
They are easily ap-
plied to the cable core;
they have sufficient
flexibility to allow the
completed cable to be
reeled, unreeled and
bent into place; they
are strong enough to
protect the cores, im-
pervious to moisture,
and highly resistant to
corrosion. Consider
now the other side of
the picture; thousands
of miles of cable, aloft

Machine for vibrating short lengths of cable. Cracking of ste ae ee ae
any sheath admits air to a partial vacuum in the samples; t at-
mercury manometer then closes its contact and indicates that ‘ to the jar of pass-

and shrinking as the sun warms them
or the frost chills. Here are forces
tending to open cracks in the lead
sheath through which moisture may
enter. For example, the rate of ex-
pansion with change of temperature
is 60 per cent greater for cable than
for its supporting strand. In a hun-

yield or plastic flow of the metal but
a definite separation of the crystal
grains.

Early sheaths of commercially pure
lead were not sufficiently resistant to
fatigue or to corrosion to give com-
plete satisfaction. A lead alloy con-
taining 3 per cent tin was substituted,

Fatigue-tester with a capacity of fifty-six specimens of sheath material

dred-foot span an unstressed cable,
just the length of the strand at sixty
degrees Fahrenheit, at 120 degrees
would be a half-inch longer than the
strand. This extra length is taken
care of, in part, by actual compres-
sion of the cable. But the cable also
lengthens and shortens in relation to
the strand, and so moves into and out
of a “bow” at each pole because there
the cable is already bent. These slight
but repeated bendings and straighten-
ings with vibration due to wind and
road traffic, combine in tending to “‘fa-
tigue” the lead sheath. Under severe
conditions it may eventually crack
open, with disastrous results, certain-
ly when the next rain falls. Lead al-
loys differ from ferrous metals in fa-
tigue failure in that the fracture
always passes between the crystal
grains. Under stresses producing this
type of failure, lead alloys show no

since it had greater resistance to se-
vere service stresses than had lead
alone. Later due to economic condi-
tions an alloy containing 1 per cent
antimony was used in place of the
lead-tin alloy. This material could
be used because of its still greater re-
sistance to fatigue and because it was
satisfactory in all other respects. Each
of these changes in composition of
sheath was made only after exhaus-
tive laboratory tests in which samples
were exposed to vibrations and to
bending under measurable conditions.

For these tests two different ma-
chines were developed to take sam-
ples of actual cable. In one machine
short specimens are clamped at one
end while their other ends are set
into rapid vibration by motor-driven
cams, In the other a bending test is
given to U-shaped pieces of cable sev-
eral feet long, by vibrating the free

ends toward the clamped ends. These
two types of machines are used in
evaluating the ability of proposed
sheath materials to withstand service
conditions. They were seen to be

bulky and require considerable test
material, so it was thought advisable
to develop a test based on a simpler
form of specimen. Careful studies of
reported field conditions and com-
parative analysis of a large amount
of data have shown that the extreme
service conditions causing failures
may be simulated by stressing at a
reasonably rapid rate a small speci-
men of lead sheath.

This specimen was designed so that
the maximum stress will not occur at
the clamped portion, thus eliminating
the unknown effect of stress due to
clamping. One end of the specimen
is clamped, the other end is inserted
in a phosphor-bronze boot which is
held against a cam by a helical spring.

The machine has a capacity of fifty-
six specimens. It can produce a break
in a specimen of standard sheath ma-
terial in three days whereas it may
take the bending-machine six weeks
to cause a break in a specimen cable.
The high speed and large capacity of
this machine permits the testing of
150 to 200 times as many specimens
as the bending machine.

All of the characteristics of fatigue
failure are exhibited in specimens
tested on this machine. All proposed
alloys and modified sheaths are inves-
tigated also by testing sample lengths
of cable in the vibrating and bending
machines. Decisions are based on con-
current results only. As a further pre-
caution it is customary to make trial

installations of cable under actual
service conditions. Such searching in-
vestigation is necessary in view of the
importance of cables in our communi-
cation system and the investment in
their manufacture and installation.
In addition to meeting the require-
ments for aerial use, all cable must be
able to withstand the mechanical
strain of pulling into conduits, since
it is most economical to employ
the. same type of cable for both
underground and aerial service.

ESEARCH problems some-
times require the measure-
ment of small displacements.

For those approaching the order of
one part in 100,000, simple and di-
rect methods of measurement can no
longer be applied and recourse must
be had to various artifices. In a prob-
lem bearing on the physical nature of
permalloy it was desired, in detecting
changes of length, to extend the lower
limit of measurement to a few parts
in 1,000,000,000. The actual accom-
plishment, measuring to four parts in
a billion, resulted from the develop-
ment of a new method of measuring
increments of length which is more
sensitive and more accurate than any
used heretofore.

Since 1847 it has been known that
magnetic substances change their di-
mensions with magnetization. This
phenomenon, called magnestostric-
tion, was also early recognized as
highly significant in explaining certain
ferromagnetic phenomena. On the
other hand within our Laboratories
experiments on the effect of tension

rods had confirmed the existence of a
critical composition of nickel-iron al-
loy which has no magnetostriction.
This led L. W. McKeehan to formu-
late his atomic theory of magneto-
striction which relates the properties
of permalloy to its magnetostrictive
behavior.*

To test the theory there were re-
quired measurements of magnetostric-
tion, at low magnetizations, in iron,
nickel and permalloy. Relatively
large magnetostrictive effects repre-
sent only exceedingly small changes
in length. To be able, therefore, to
detect such effects in the case of
permalloys where it is very much

smaller there is required a method of
determining, in a centimeter of length,
a change of the order of one-tenth of
the diameter of an atom.

measurements there was the photo-
electric cell. ‘This cell connected to a
sensitive galvanometer forms an ex-
ceedingly accurate and sensitive in-
strument for measuring’ changes in
light intensity. The method first pro-
posed, therefore, was to direct light
by a concave mirror from an illumi-
nated slit onto an unilluminated slit
in such a way that the quantity of
light transmitted through the latter

slit would be proportional to the
angle of tilt of the mirror. If the
mirror was tilted by a change in length
of the specimen under examination
then the change could be sensitively
measured.

That the sensitivity could be much
increased if the single slits were re-
placed by screens with parallel stripes
of equal width, alternately transpar-
ent and opaque, was pointed out by
E. C. Wente.

This idea was embodied in the sys-
tem finally employed. Light from a
lamp was directed by a lens onto a
concave mirror. Between the light
source and the mirror was interposed
a glass screen, with opaque and trans-
parent stripes half a millimeter wide.
The mirror acted to form an image
of the series of slits in the screen. It
was set so as to form this image on
a continuation of the screen, which
projected beyond the original beam
of light and received illumination
only from the reflected beam. When
the bright images of the slits coin-
cided with the opaque stripes of the
screen no light was transmitted. As
the mirror was tilted, transmission
became possible and the amount of
light increased to a maximum and
then decreased to zero when coinci-
dence with the opaque stripes again
occurred. It required but a small tilt
of the mirror to pass from full trans-
mission to complete extinction. The
transmitted light was collected by an-
other lens onto a photo-electric cell.
The changes in photo-electric emis-
sion, as affected by the changes in the
light intensity, were then read on a
galvanometer.

The magnetostriction which was
measured was that occurring in the
middle portion of the specimen under
examination. The specimen was in

the form of a wire and the portion
measured was that between a rigidly
supported upper sleeve and a lower
sleeve which rested upon the short
arm of a lever. The long arm of this
lever actuated another lever which
tilted the mirror.

When magnetostriction changes
the length of the specimen and the
mirror tilts, the galvanometer read-
ing changes. If, for example, at the
start there is no current because the
imzge of the slits coincides with the
opaque stripes of the screen, then the
current and galvanometer reading in-
crease to maximum, and then decrease
to zero when such coincidence again
occurs. As the length continues to
change this cycle repeats; and the ob-
server knows the whole number of
spaces on the screen over which the
mirror image has been shifted from
his count of the number of times the
galvanometer has swung back to its
zero. The fraction of a space is de-
termined by the galvanometer read-
ing; this could be read to one-tenth
of a centimeter on a scale one meter

away from its mirror. And that de-
flection corresponded to a magneto-
strictive displacement of about four
billionths of a centimeter for each of
the ten centimeters of length of speci-
men between the clamping sleeves.

So sensitive a system necessitated
complete protection from building vi-

brations. The apparatus was accord-
ingly mounted on a heavy plank and
the whole was supported upright on a
Julius suspension of damped springs.
Thermal changes were also to be
avoided. These arose from the mag-
netizing winding surrounding the wire.

by jacketing the solenoid with a
vacuum as shown in the accompany-
ing diagram. This, however, did not
result in constant temperature within
the solenoid and an additional non-
magnetizing winding was imbedded
in the upper sleeve. Current was also
supplied to this winding so that the
heating of the specimen was due to
both magnetizing and non-magnetiz-
ing windings. This made the wire
slightly hotter than it would other-
wise have been but its temperature
could be maintained by small adjust-
ments of the current through the aux-

iliary, or heater, winding. The natu-
ral drift in equilibrium temperature
within the solenoid was thus very
closely compensated.

The results of the experiments
demonstrated that permalloy, consist-
ing of approximately 80 percent
nickel and 20 percent iron, has no
magnetostriction for moderate mag-
netizations and expands only slightly
for intense magnetization. Permal-
loys having less than 80 percent
nickel expand with magnetization and
those having greater than 80 percent
nickel contract with magnetization.

telephone engineer this question is an-
swered by curves expressing the nu-
merical’ results of articulation-tests.
But to the public, hearing is believ-
ing: a demonstration to the ear leaves
an impression lasting beyond the
memory of curves and tables. And
sO, in conjunction with technical pa-
pers by R. L. Jones and Harvey
Fletcher, use was made of speech and
music transmitted through a public
address system into which distortion
could be introduced at will. So effec-
tive were those initial demonstrations
that many requests were made that
they be given before other audiences.
On account of the expense and effort
involved in setting up bulky appara-
tus which was required, only a few of
these invitations could be accepted.

To simplify the apparatus problem
through the use of phonograph rec-
ords was a logical step. Cooperation
of the Research group engaged in de-
velopment of electrical recording and
reproducing was enlisted, and a se-
ries of records was made in May,
1925. With these records a demon-
stration required only a phonograph
turntable and reproducer, a suitable
amplifier and a loud speaker; the
whole being readily transported, and
set up in a few minutes. Such an out-
fit was used on a number of occasions,
among them a series of talks to non-
technical audiences in Pittsburgh,
Cincinnati, St. Louis, Chicago and
Cleveland by Paul B. Findley of the
Bureau of Publication.

During these talks it was realized
that certain improvements could be
made in the sound-quality of the rec-
ords and in the selection of material.

Accordingly a new set of records was
cut in the autumn of 1926 which has
been favorably received by technical
and general audiences alike. Its pres-
entation is accompanied by an expla-
nation, couched in terms to suit the
previous experience of the audience.
A brief recapitulation of this mate-
rial will serve here to introduce a de-
scription of the records themselves.

Research efforts in our laboratories
have been devoted for a number of
years to investigations into the char-
acter of speech—a fundamental study
carried on for the American Tele-
phone and Telegraph Company as
basic to its program of improving the
telephone art. To proceed with this
improvement on a systematic basis it
was necessary to know the importance
in speech of its various pitches, and
this is most easily found by determin-
ing the relative degrading effects on
the intelligibility of speech resulting
from the suppression of certain pitch-
ranges. Since electrical filters may be
designed to pass, unhindered, electric
currents corresponding to the sound
vibrations of certain pitches while en-
tirely suppressing those of other
pitches, suitable filters were construct-
ed to suppress any desired range of
pitches. Statistical studies were then
made of the transmission of each of
the characteristic speech sounds
through a telephone system contain-
ing these filters. Since speech is com-
posed of vibrations varying in fre-
quency from 100 to about 8000 cycles
per second, the filters were construct-
ed so that the upper and lower limits
of transmission could be imposed at
will on the various pitches of the
voice range. The transmitted band,
for example, could be set to include
from 60 to 3000 or 60 to 2000 cycles
per second; or some of the lower

tones might be suppressed by adjust-
ing the filter to pass only the region
above, say, 375 cycles per second.
The results of the studies have been
extremely valuable in engineering im-
provements in the telephonic appa-
ratus both for wire and for radio
communication.

Listening to a demonstration of
one of these records, concerned with
speech, we hear part of an essay by
Poe, the speaker’s voice sounding
very natural with the fundamental
tones well rounded out and the higher
pitched endings of the consonants be-
ing in proper proportion. As the rec-
ord progresses the lower tones sud-
denly disappear from the speaker’s
voice and it loses its character al-
though the intelligibility is perfect.
Since no vibrations below 375 cycles
per second were passed through the
filter inserted at this point in the
process of recording, they do not ap-
pear in the sounds of the loud speaker.
Continuing, the record reaches a point
at which the filter was adjusted so
that no sound below 750 cycles per
second was recorded. The voice is
then without character and most un-
natural. The higher tones are, how-
ever, unhindered and without difficul-
ty we interpret the speech by the con-
sonants although the vowels are badly
distorted. The importance of the
consonants for interpretation is thus
emphasized.

The record continues and the lower
tones are restored, but all the vibra-
tions above 2500 cycles per second
are suppressed. The voice sounds
natural but the interpretation is not
so good as before. The consonant
endings are missing and one gets the
impression that the speaker’s mouth
is full of mush. When the record
progresses to the point where nothing

above 1000 cycles per second is trans-
mitted the speaker’s voice has a gut-
tural character, and in the absence of
the consonants it is extremely difh-
cult to interpret the speech. At times
whole phrases are missed. This rec-
ord illustrates well the contribution
of the various regions to the intelli-
gibility of speech.

A second record shows the effects
of the same type of transmission on
piano music. The prelude to the
Waltz from the Ballet “Naila’’ is
heard, first with extremely natural re-
production. We note that the selec-
tion is one which encompasses almost
the entire range of the piano. As the
record reaches the first point at which
the filter was introduced in the process
of recording, the bass notes are sud-
denly stilled. The filter passes only
the vibrations above 375 cycles per
second. This corresponds to F-sharp
above middle C and all the lower
tones are therefore suppressed. The
melody is present but the tonal char-
acter is missing. When the record
progresses to the point at which the
750-cycle filter was introduced, cor-
responding to a pitch an octave still
higher, the music begins to assume a
tinkling character.

The lower tones are then restored
and those above 2500 cycles per sec-
ond are eliminated. The selection as-
sumes a rather dull character; the
brilliance of tone is gone and the mu-
sic becomes almost a thumping noise

as the 1250-cycle point is reached, the
preponderance of the bass and the
absence of the treble causing the re-
production to lack musical character.

A third record shows the effects of
forcing a vacuum tube to carry more
than its rated load. We have often
heard the effects of such over-loading
in radio receiving sets perhaps with-
out knowing its cause. By contrast
with a condition of normal load, we
notice in the over-loaded condition
many harsh extraneous sounds in the
music or the speech, sometimes de-
scribed as “buzzing” or “rattling.”
When the reproduction is further lim-
ited by the transmission of only the
band of frequencies from 375 to 2000
cycles per second we are reminded of
radio sets in the days before much
attention was paid to the quality of
the reproduction, when the receiving
set reproduced only a limited part of
the speech band and the vacuum tubes
were over-loaded in the process.

Due to the simplicity and reliability
of such records for demonstrating the
fundamental ideas as to the transmis-
sion of speech and music, it is prob-
able that the new records will find
many uses. They can serve for
demonstrations to almost any group
which is interested in speech and mu-
sic and their transmission. This month
they are being used for this purpose
in a series of talks which L. S.
O’Roark is giving before A. I. E. E.

DuRING THE MONTH OF FEBRU-
ARY there will be delivered to mem-
bers of the Laboratories on com-
pleted subscriptions, 4,448 shares of
American Telephone and Telegraph
Company stock. This is the largest
number delivered to our staff in any
one month and represents total sav-
ings through salary deductions and
interest of $511,520.

W. A. SHEWHART has been ap-
pointed to represent the American
Physical Society on the Sectional
Committee of the American Society
of Mechanical Engineers, organized

for the standardization of graphic
presentation. The scope of the com-
mittee’s work includes standard meth-
ods for the graphic presentation of
business and other data.

R. D. Gipson AND K. O. THorpP
are in Birmingham, Alabama, making
an investigation of the power-line car-
rier-telephone system of the Alabama
Light and Power Company.

L. B. Cooke is installing for the
Penn Public Service Corporation a
power-line carrier-telephone system
which employs a repeater of recent
design. This system will provide

At the inauguration by the American Telephone and Telegraph Company of commer-
cial telephone service between New York and London. In the foreground, left to
right: President Gifford, B. Gherardi, E. B. Craft, N. T. Guernsey

communication between the follow-
ing cities: Erie, Piney Dam, Seward,
Glory, Johnston and Deep Creek.

R. M. PEASE has joined Henry B.
Arnold in Atlanta, where they are in-
vestigating the power-line carrier-
telephone system of the Georgia Rail-
way and Power Company.

SHEET BRASS for Bell System use
will now conform to specifications
agreed upon at a conference held in
Montreal on December 2 and 3 be-
tween representatives of the Haw-
thorne Works of Western Electric,
American Brass Company, and
Messrs. Fondiller, Van Deusen, Town-
send, and Hayford of the Laborato-
ries. Several months’ work were in-
volved in developing the specifica-
tions; similar work on other non-
ferrous metals is now in progress.

L. J. StviAn of the Laboratories
and H. S. Osborne of A. T. & T. re-
cently returned from five weeks in
London and Paris. While in Paris
they represented the Bell System at
the plenary meeting of the Comité
Consultatif International des Com-
munications Teéléphoniques, which
adopted for its Transmission Refer-
ence Standard a replica of the one de-
veloped in the Laboratories. This
will be built here and installed at the
Conservatoire des Arts et Métiers in
Paris. At this meeting it was also de-
cided to recognize as the admissible
units both the ‘“‘napier”’ and the “‘deci-
mal unit”, which equals ten TU.

ON THE EVENING of December 9,
1926, Mr. Craft spoke on the gen-
eral subject of ‘“‘Research”’ at the an-
nual dinner of the Alumni of Worces-
ter Polytechnic Institute, of which he
is an honorary alumnus. In empha-
sizing the need for research, Mr.
Craft said, ““We cannot make the en-
gineering applications unless we en-

courage research, and research devel-
opments cannot reach their fullest
utilization for public welfare unless
the engineer is interested, sympa-
thetic, and appreciative of their im-
portance.”

Edward Buttner of the Engineering Shop
Department has been forty years with the
Bell System

kilowatt broadcasting equipment for
the Fisher Blend Station of the B. F.
Fisher Flouring Mill in Seattle. Be-
fore leaving the coast he made a sur-
vey for a similar installation at Santa
Barbara, California.

On January 8, D. H. Newman
left New York for Montevideo, Uru-
guay, where he is supervising the in-
stallation of a one-kilowatt broad-
casting equipment for the Republic
of Uruguay.

UNDER THE SUPERVSION OF H. S.
Price the National Life and Accident
Insurance Company of Nashville has
replaced its one-kilowatt broadcast-

P. A. ANDERSON has completed the
installation of a one-kilowatt broad-
casting equipment which replaces the
500-watt set at WBBR, the Staten
Island Station of the People’s Pulpit
Association. In addition this cus-
tomer operates a one-kilowatt equip-
ment at Cleveland, and a five kilo-
watt one at Batavia, Illinois.

Philip C. Rossi of the Patent Drafting
Group has had thirty-five years’ service

at Gibson, Indiana, on January 6 and
7, to observe the operation of the
system recently installed there for
transmitting orders to the engineers
of switching locomotives by radio
telephone.

THE LABORATORIES signified their
advent at Whippany by taking active
part in the Community Christmas
Celebration on December 26. A brief
address was given by L. S. O’Roark
and music for the occasion was sup-

plied by engineers, attached to the
station, who used a Public-Address
System in combination with an elec-
tric phonograph.

ington and Baltimore when the Bal-
timore toll board was changed over
to the C. L. R. method of operation.

THE COMMERCIAL DESIGN of gen-
erators for charging central-office bat-
teries was successfully tested recently
at Reading. Use of this generator is
made possible by the electrolytic con-
denser. The tests were observed by
members of the engineering staffs of
the Telephone Company and the
American Telephone and Telegraph
Company, and by A. E. Petrie, R. L.
Lunsford, and M. A. Froberg of the
Laboratories.

F. F. SreBpert has been at East
Pittsburgh, in connection with tests
on small unit gasoline engines.

TION of the new single-channel car-
rier system are in active progress.
During December K. M. Fetzer, A.
Chaiclin, H. S. Black and A. C. Dick-
ieson visited Watertown and Syracuse
in connection with these tests.

E. W. Hancock Anp W. J. La-
CERTE visited Hartford in connection
with a trial installation of new multi-
level hunting connectors.

W. BENNETT has been at Spring-
field, making tests on the step-by-step
switches which were made in Haw-
thorne.

R. B. BUCHANAN visited Lehigh
Office, Pittsburgh, in connection with
the introduction of straightforward
trunking equipment.

DurinGc DEcEMBER, W. A. Boyd
and H. G. Eddy were in Hawthorne
on regular Survey Conference work.

AT THE ANNUAL MEETING of Ed-
ward J. Hall Chapter, Telephone
Pioneers of America, held on Decem-
ber 16, 1926, the following members
of the Laboratories were elected to
office and as delegates to the next an-
nual convention: J. E. Moravec,
member of Executive Committee; W.
B. Sanford and W. C. F. Farnell,
delegates; G. F. Atwood and G. F.
Morrison, alternates.

‘“RECENT DEVELOPMENTS IN
COMMUNICATION” was the subject of
a talk given by M. B. Long, Educa-
tional Director, on the evenings of
January 10, 11 and 13, before the
Indianapolis, Purdue University and
Armour Institute Sections, A. I. E. E.
Also, Mr. Long informally addressed
the Telephone Luncheon Club at In-
dianapolis on January tenth.

J. F. Newcomb, Assistant Treasurer; H. G. Eddy, Inspection; C. Westerburg, En-
gineering Shop

ECONSTRUCTING the
past from such traces as may
remain is one of the tasks of

the historian. From finds like the
tomb of Tut-ankh-Amen there are
pictured for us the lives and customs
of ancient civilizations. Of times more
remote, the geologist and palaeontolo-
gist draw inferences from the occa-
sional finds of fossils. ‘Their tasks are
frequently most difficult. Is some
particular fossil, for example, the

skull of a primeval man, or the knee-
cap of an elephantine animal? Some-
times sufficient material is found to
permit a rather complete reconstruc-
tion, and in museums of natural his-

The processes of evolution with
which these historians deal were not
only slow but lie obscured in times of
unwritten history. Another type of
evolution occurring in these present
days, when records are easily made
and preserved, is that of science and
its associated arts. The marvelous
evolution of the telephone has all oc-
curred within the brief span of fifty
years.

A historian of the art of telephony
does not lack written material from
which accurately to reconstruct the
past. In our Bell Telephone Histori-
cal Museum there are also many and
interesting exhibits of early appara-
tus or of models of such apparatus
reconstructed on the basis of pictures

and written descriptions. We can
build, for example, actual reproduc-
tions of the instruments with which
Alexander Graham Bell carried on
the first telephone conversation; one
such model was used by him at the
opening ceremonial of the transconti-
nental line in 1915 when he spoke
from New York to Thomas A. Wat-
son in San Francisco.

Another model, also of the first
apparatus of its kind, has recently
been built in our engineering shops
under the advice of W. L. Richards,
Consulting Historian. There was re-
constructed the equipment of the first
commercial telephone-exchange  sys-

hibit it at the New Haven Progress
Exposition from January twenty-
sixth to February fifth.

tures. These were taken while Mr.
Richards, with the assistance of the
writer, was demonstrating this first
central-office system to A. F. Dixon,
Systems Development Engineer.
The eight lines terminated in eight
binding posts at the top of the board.
There were also available, what were
in effect, two cord circuits, each con-
sisting of two rotary levers electri-
cally connected. On a circle, about
the pivot of each lever as a center,
are eight discs or studs. Discs corre-
sponding in position with reference to
the two levers are connected in mul-

tiple to the eight lines. Below the
levers of each cord circuit are the line
switches for the annunciator circuits,
one for each line. And below these,
is a strip to which is connected one

as “Coy’s Chicken’’. It consists of a
large induction coil and a flat steel-
spring which is caused to vibrate by
the hand operation of a lever making
and breaking a local circuit. The cur-

T the annual convention of
A the Institute of Radio Engi-
neers, Dr. Ralph Bown, new-
ly elected president of the Institute,
was presented with the Liebmann
Memorial Prize awarded him by the
Board of Directors of that body “‘for
his researches in ‘Wave Transmission
Phenomena.’ ”

Dr. Bown received his Ph.D. from
Cornell in 1917. He entered the
army in 1917, where he was commis-
sioned as Captain in the Signal Corps.
He was in charge of development of
radio apparatus for the Army at the
Signal Corps Radio Laboratory,
Camp Alfred Vail, until June, 1919.
In August, 1919, Dr. Bown took up
his present work in the American Tel-
ephone and Telegraph Company.

The Morris Liebmann Memorial
Prize, consisting of the sum of five
hundred dollars in cash, is awarded
annually by the Board of Directors
of the Institute in recognition of note-
worthy inventions or other develop-
ments in radio technique.

Dr. Bown well merits this recog-
nition, as he has been an outstanding
exponent of the development of meth-
ods and equipment to place radio
transmission studies on a quantitative
basis. His outstanding researches re-
late particularly to transatlantic radio
telephony and radio broadcast trans-
mission. Dr. Bown has presented
many of the important results of the
work of this organization in technical
papers before the Institute.

was presented by DeLoss K. Martin,
Glenn D. Gillett and Isabel S. Bemis
on the subject, “Some Possibilities
and Limitations in Common-F requen-
cy Broadcasting,” reviewing experi-
mental work done by these engineers
and their associates.

Early in 1926, the Bell Telephone
Laboratories devised and built for the
Information Department of the
American Telephone and Telegraph
Company three portable talking mov-
ing picture outfits for use in connec-

tion with celebrations throughout the
United States commemorating the fif-
tieth anniversary of the birth of the
telephone. The portable equipments
were placed at the disposal of the As-
sociated Companies with engineers

from this company and the Laborato-
ries, to supervise the installation and
operation of the pictures in the field.

Two talking pictures were exhib-
ited—one of Thomas A. Watson, as-
sistant to Professor Alexander Gra-
ham Bell at the time of the invention
of the telephone, and the other a pic-
ture illustrating the development of
the telephone switchboard from the
days of its infancy up to the present
time.

During the year which has just
passed, the two pictures were shown
in twenty-six different cities and towns
over nine hundred times to audiences
totaling over 206,000. This includes
the installation which was made at
the Bell System exhibit at the Sesqui-
centennial, where the pictures were
shown over a period of twenty-three
weeks.

Naturally, the “one-night stand”’
installations throughout the country
introduced many difficult and varying
conditions. In view of this, credit is
due W. W. Sturdy of A. T. & T..,
and to R. E. Kuebler and J. B. Irwin
of the Laboratories for meeting all
the dates:assigned to them, and show-
ing the pictures on schedule time.

1926 one hundred and thirty-four pat-
ents were issued to the following
members of the Department of De.
velopment and Research:

E. H. Colpitts, L. F. Morehouse,
O. B. Blackwell, H. A. Affel, R. S.
Bailey, F. H. Best, W. G. Blauvelt,
R. K. Bonell, L. L. Bouton, R. Brown,
A. Carpe, A. B. Clark, S. I. Cory,
G. Crisson, C.S. Demarest, E. Dietze,
W. H. Edwards, L. Espenschied, H.
A. Etheridge, J. M. Fell, C. H. Fet-
ter, D. K. Gannett, L. L. Glezen, C.
S. Gordon, E. I. Green, I. W. Green,
R. A. Haislip, H. S. Hamilton, J.
Herman, W. H. T. Holden, R. K.
Honoman, R. S. Hoyt, A. E. Hunt,
L. M. Ilgenfritz, A. H. Inglis, E.
Jacobsen, O. H. Loynes, D. K. Mar-
tin, W. H. Martin, A. L. Matte, R.
G. McCurdy, N. D. Newby, H. Ny-
quist, R. S. Ohl, J. T. O’Leary, G.
H. Peterson, K. W. Pfleger, H. E.
Phelps, R. K. Potter, F. W. Rey-
nolds, W. A. Rhodes, F. W. Schramm,
J. T. Schott, S. P. Shackleton, R. B.
Shanck, H. F. Shoffstall, E. St. John,
M. E. Strieby, C. V. Taplin, H. M.
Trueblood, G. S. Vernam, E. Von
Nostitz, J. N. Walters, E. F. Wat-
son, A. Weaver, S. B. Wright, M. K.
Zinn, O. J. Zobel.

The 1927 social season will open
on Thursday evening, February 17,
1927, with the midwinter dance to be
held on the Roof of the Hotel McAl-

This will be the ninth dance given
by the Club since February, 1924,
and we are sure that all of the Club
members and their friends who have
attended these parties have spent
very enjoyable evenings. It has been
the policy of the Club to hold all
dances in New York hotels, and to
have the best music obtainable. The
Committee wishes to announce that
this policy will be followed through-
out 1927.

The sale of tickets for the Febru-
ary dance has been limited to five
hundred by the management of the
Hotel McAlpin and, as only this
number has been printed, we advise
you to purchase your tickets at once
to insure having them. Admission
will be $1.10 each, including tax. No
tickets will be sold at the door. D. R.
McCormack will manage all of our
dances and entertainments for 1927.

1927, the winter session of the Men’s
Bridge Club started in room 269.
These meetings will be held every
Monday at 6:30 p.M.—all men
bridge players are welcome. Prizes
will be given each evening for the
best scores, and also at the end of the
season for the best three all-season
scores. Players must attend seven
nights to be eligible for season prizes.
A weekly fee of fifty cents is charged.

27, 1926
1. H.M.Hagland 6. H.B. Barber
2. A. L. Thuras 7. T.C. Rice
3. D. Wetherell 8. M. N. Smalley
4. E. Rahn g. J. E. Cassidy
5. D.S. Myers 10. A. Zitzman

The church at Stoke Poges—where Thomas Gray wrote his “Elegy in a Country
Churchyard.” First prize, Landscape Class; W. Orvis

picture contest. The Club surely is
proud of its first picture exhibition
and is already looking forward to
making it a yearly event. _

The judges, H. E. Ives and I. B.
Crandall, found before them a rather
dificult task when it came to choos-
ing the best picture, but we feel that
they have succeeded very well in
awarding the prizes to these contest-
ants :

Landscape Class:
First prize, W. Orvis
Second prize, W. Orvis
Third prize, J. Popina
Honorable mention. J. Popina and

Portrait Class:
First prize, J. Popina
Second prize, H. Maude
Third prize, P. D. Hance
Honorable mention, J. Popina, H.
Maude and K. B. Lambert.

Christmas Card Class:
First prize, H. Maude
Second prize, E. Alenius
Third prize, E. Alenius
Honorable mention, E. Alenius,

The prize for the picture showing
the greatest amount of thought when
photographing was most difficult to
judge. These were awarded in this
order:

The prize for the best group of
pictures was awarded to H. Maude,
with J. Popina a very close second.

The Department prizes were
awarded to M. G. Allison in the In-
spection, A. S. Curtis in the Research,
R. H. Mills for the Apparatus De-
velopment, J. Popina for the Com-

The color plates submitted were
especially fine. The prize in this group
was given to A. S. Curtis, while R.
H. Mills received honorable men-
tion. Among the color plates were
some very interesting technical studies
made under the microscope.

The Club is very well pleased with
the response it received and wants to
extend to all the contestants a word
of praise for the good work that was
represented by the pictures sub-
mitted.

In one of the hottest basketball
games ever seen by our friends across
the River, the Bell Laboratories Club
defeated by a score of 34-23 an all-
star team from the Kearny Works of
the Western Electric Company. This
game took place on Wednesday eve-
ning, January 12, in the 4th Regi-
ment Armory in Jersey City.

The Wekearnians fought our men
during every second of play but when
it was all over West Street had
scored its third straight victory over
Kearny in as many years.

At no time during the game was
there a difference of more than two
points, and with two minutes to play
Kearny was leading 23 to 21. A
daring shot by Maurer for a clean
basket brought the score to 23-23,
and with only seconds to play Git-
tenberger dropped a foul almost as
the whistle blew, ending what the
Jersey daily papers referred to as the
best game ever staged on the floor of
the Old 4th Regiment.

While Maurer starred for West
Street our victory was due to very
fine all-around team work. The en-
tire team worked as one man with

This portrait of a young seaman took first prize in the Portrait Class; J. Popina

no thought of individual honors.
The details and line-up of this game
are given below.

Not to be outdone by our star
team, our Juniors met and defeated
the Junior team from the Western
Electric Company, 195 Broadway,
on Friday evening, January 14, in
the gymnasium of the Labor Temple,

This organization of Juniors is
playing in the Club Tournament and
at present is tied for second place.

“What does it cost me in days of labor to satisfy my desires for
the unnecessary things of life?” You will probably be surprised
when you figure out just how hard you are making yourself work
for some of the casual bits of expenses you incur regularly without

Let us say that your income is $2000 per year, and that your
food, shelter, clothing and other actual necessities cost $1600.
Your net income which you can spend for other than necessities
is $400; you have no choice as to how you will spend the $1600,
because this must go to the butcher, grocer, landlord, public service
company and others who are on your payroll.

Therefore, if you feel like spending $10 for something you
could do just as well without—some luxury which must be paid
for out of your net income—you can calculate that this $1o net
income is equivalent to eight days’ work.

THE LABORATORIES were well rep-
resented at the Christmas meeting of
the American Association for the Ad-
vancement of Science held in Phila-
delphia on December 28 and 29. The
following papers were presented:

“Photoelectric Emission as a Func-
tion of Composition in Sodium Po-
tassium Alloys,” by H. E. Ives and
C. R. Stillwell, presented by H. E.
Ives; ‘““Thermal Agitation of Elec-
tricity in Conductors,” by J. B. John-
son; “The Life History of an Ad-
sorbed Atom,” by J. A. Becker; ‘“The
Direct Comparison of Loudness of
Pure Tones,” by B. A. Kingsbury.

ARTHUR W. PAGE assumed on
January first his duties as Vice-Presi-
dent of the American Telephone and
Telegraph Company. Upon gradua-
tion from Harvard in 1905 Mr. Page
entered Doubleday, Page and Com-
pany, of. which he later became Vice-

T. C. Fry is planning to give a se-
ries of lectures at the Massachusetts
Institute of Technology on the engi-
neering application of the theory of
probability, beginning the early part
of February and continuing until the
end of the school term in June.

Joun C. Latuam, until January
first in charge of technical informa-
tion in the Bureau of Publication, was
on that date transferred to A. T.
& T. He recently sailed for Lon-
don to become assistant to H. E.
Shreeve, the technical representative
of the Bell System in Europe.

Field Engineering work of the In-
spection Engineering Department in
the Up-State Territory of the New
York Telephone Company, was held
in Albany on December 8. On De-
cember 16 a conference on similar
work in the territory of the New
England Telephone and Telegraph
Company was held in Boston. In ad-
dition to Telephone Company engi-
neers and representatives of Western
Electric Distributing Houses, R. L.
Jones, G. D. Edwards and R. J.
Nossaman were present at the Al-
bany conference, and G. D. Edwards
and R. J. Nossaman were present at
the Boston conference.

R. B. MILLER spent the gth and
10th, of December in Toledo observ-
ing a trial which the Installation De-
partment of Western Electric Com-
pany was making of a sampling in-
spection plan.

D. A. QuarRtLes and E. G. D. Pat-
ERSON were in West Lynn, Mas-
sachusetts, in connection with a Sur-
vey Conference on telephone power
equipment manufactured by the Gen-
eral Electric Company.

AN ELECTRIC STETHOSCOPE oper-
ated by H. F. Hopkins figured in the
detection of a “crime” as part of a
demonstration before the New York
Electrical Society on December 15.
As each of three volunteer “‘suspects”’
was examined about the affair, the
stethoscope and a loud speaker made
the thumping of his heart plainly au-
dible to a large audience. The quick-
ened beat of the guilty person’s heart
was instantly evident.

Bell Laboratories Record 1927-02: Vol 3 Iss 6