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JNTfUNATlONAl

Ward Leonard Electric Company

Mount Vernon, N. Y.

Printed in U. S. A.

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Ward Leonard/rectric Company

WITHOUT perfect control, light-
ing in the theatre, instead of
being an irresistible means to every end
of dramatic effect, would be continuously
a hindrance and a stumbling block. Of
course, the crux of control in electric
lighting is in the Dimmer System — and
there, perhaps, more than in any other
single department, the Ward Leonard
Electric Company has excelled and does
excell all competitors. I am sure that
without the aid I have received through
their cooperation, during many years,
I could not have achieved many of the
finest, most beautiful effects which it
has been my privilege to set before an
appreciative public.

David Belasco

FOR EWORD

HERE is no art more important in the modern
theatrical production than the skilful use of light.

1 Scenic effects that are realistic and lifelike are
made possible by perfectly controlled lighting of varying
intensity and color; then, too, proper lighting has a psycho-
logical value, causing the audience to absorb the atmos-
phere and feeling of the play without realizing how the
effect is produced.

Eminent theatrical producers have always recognized the
desirability of lighting control. Indeed, most of them even to
the present day have been, and still are, pioneers in the de-
velopment of lighting technique. Especially is this true of
electric lighting. In fact, one of the earliest practical appli-
cations of electric lighting was in the Paris Opera, where it
was first used in 1846.

In looking up the history of theatre lighting we found
no record of a comprehensive assembly of historical facts.
Therefore, we have included a brief outline of the history
of theatre lighting in this book, the prime purpose of which
is to present the development, construction and use of the
Ward Leonard theatre lighting control system.

We believe that many of the facts included in this book
will be of interest to theatrical producers and lighting ex-
perts. If any of our readers find the subject matter worthy
of comment, we shall be glad to receive criticisms and addi-
tional data which may be included in a later edition.

WARD LEONARD ELECTRIC COMPANY

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Figure 1 — One of the earliest references to theatre lighting in literature —
Sciena di Comoedia, 1628, by Joseph Furtenbach.

TRJXJLATIO^

"The stage is like a bridge upon which the play is unfolded. It is described in
my oft mentioned drawing book on page 87. For such a big play, the front
of the stage should be 24 Braza wide, the back of the stage 12 Braza wide, 20
Braza is the length. The side screens or wings which are partly covered by the
curtain are 3 Braza wide for the purpose of preventing the audience from seeing
behind the scenes. Behind these wings there are a number of candles or oil
lamps which light the scenes with great splendor and brilliancy. It also shines
on the clouds and produces an effect that is like bright daylight in the night-
time. In front of the stage there is a 3 Braza high wall which reaches almost
up to a man's eye. Just behind this wall there is a space approximately 1H
Braza wide, in which the musicians are located out of sight of the audience.
On the rear of this wall there is mounted a row of oil lamps concealed from
the audience but throwing a strong light on the stage, giving the effect of
daylight as mentioned above."

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COM F» A.PW Y

TORICAL NOTE

BIRTH OF THE THEATRE

N a circular space at the foot of
a hill, hundreds of years before
the Christian Era, Greek choruses
danced and sang by the light of day
in honor of Dionysus, the God of
Wine. The spectators were accom-
modated on rows of seats rising one
above the other up the slope. In the
center of the ring there stood a
sacrificial table and the leader of the
chorus, following a natural impulse,
would occasionally mount this table so
that he might be more effective. Thus
this table was the beginning of the

Greek stage which at a later date was
built at the back of the circle, or
orchestra, in the form of a narrow
platform.

ROMAN THEATRE

The Romans followed the general
theatre plan of the Greeks, but their
architectural system of arches enabled
them to erect the entire edifice, with
its tiers of seats, from the level ground.
They enlarged the stage, introduced
drop curtains, provided dressing rooms
for the actors, and placed seats in the
orchestra for Senators and other dis-
tinguished persons.

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Figure 2 — Development of the modern theatre from the ancient theatres of Greece and Rome

From The Brickbuilder, December, 1914.

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ORIGIN OF DRAMA
About the middle of the sixth cen-
tury B. C, dramatic exhibitions were
introduced and they soon became
contests in literary and musical skill.
The first tragedy competition is said
to have been won by Thespis in the
year 535 B. C. These spectacles were
usually presented during the festivals
and evidently the populace showed
great interest in them for one theatre
at Athens is said to have accommo-
dated 30,000 persons.

Realistic scenic effects in the modern
sense were unknown. The spectacles
were presented by daylight, and the
dignified architecture of the stage build-
ing itself was the scene of action.

For four hundred years after the
advent of the Christian Era the ancient
dramas flourished, then they seem to
have gradually disappeared and finally
became buried in obscurity.

MIRACLE PLAYS

In the year 1110
we find the first traces
of a long series of
"Miracle Plays", so
termed because they
exhibited events and
mysteries of scripture.
They originated
through a desire to
enlighten the people
in the rudiments of
Christianity. These
scriptural plays were
the earliest dramatic
entertainments in all
parts of Europe. They
were first presented
on rough platforms

n^HE earliest j or m of light
source was the blazing
pine knot. An iron basket
called a "cresset 11 acted as
holder for the flaming wood.
The design here shown was
used in the fifteenth century.

Figure 3 — Admission checks to theatre at Dionysus
Greece. — From The Brickbuilder.

erected within churches or close by.
As their popularity increased, stages
were built in public squares or large

open fields, the audi-
ence or spectators sit-
ting in the open. Vari-
ous forms of construc-
tion were used to ac-
commodate the differ-
ent scenes, which were
really a series of tab-
leaux. In some cases
three stages were ar-
ranged side by side,
inclined at obtuse an-
gles, and the spectators
turned from one to an-
other with each change
of scene. Other stages
were built one above
the other; a structure

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X
X
X
X
X
X
X

Figure 4 — Diagrammatic sketch of the stage described
by Joseph Furtenbach in 1528 (see figure 1).

of nine stories was erected at Metz in

1427.

Portable stages were also in general
use at this time. Mounted on wheels
they resembled a small two-story house
with one side removed. The stage was
on one level, the other being devoted
to dressing rooms. These portable
stages were drawn from place to
place, and thus the theatre as well as
the play was brought to the people in
isolated sections of the country.

STAGE LIGHTING INTRODUCED

The performances of the fifteenth
century were mostly given by daylight,
and it seems probable that the first
artificial lighting was introduced at
this time in the shape of sconces of
candles burned before a shrine. The
literature at this time gives vague
references of the use of flares and
squibs to give local color to the devils,

thus marking the realization of the
value of lighting for its psychological
influence, entirely aside from its use for
illumination.

PROGRESS OF THE DRAMA
A new species of plays called "Moral-
ities' ' became popular about the middle
of the fifteenth century. In these pro-
ductions, vices, virtues, mental attri-
butes and the like were personified by
the various characters. Following the
Morality plays, Comedies and Trage-
dies based on historical events, romance
and many other interesting subjects
made their appearance. About the year
1 59 1 the great luminary of the dramatic
world, "Shakespeare," blazed forth and
produced in quick succession a series
of plays, which have for two centuries
and a half found few if any equals.

BEGINNING OF MODERN THEATRE
In the sixteenth century, although
most theatrical performances took
place on stages set in court-yards,
there were a number of instances where
special buildings were constructed for
the presentation of ^^^^^^^^
plays. Usually these
theatres were circular
in form and open to the
sky, the stage alone
being sheltered from
storms. Theatres of
this kind were con-
structed in England
and on the continent.

Toward the close of
the sixteenth century,
completely enclosed
theatres were erected
in England. Perform-
ances were given in the

Ww*

Figure 5 — Thomas
Wignell, manager
of the John Street
theatre, lighting
President Washing-
ton to his box.
Taken from Horn-
blow's History of
the Theatre in
America.

VV A Ft D

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Figure 6 — Interior of the famous John Street theatre which was built in 1767 and frequently attended by
George Washington. Candles succeeded the open-flame oil lamps in theatre lighting, and the earliest
American theatres including this one were lighted by candles. This illustration was taken from Hornblow's
History of the Theatre in America.

evening. The stage and
interior were illumin-
ated by cressets, lan-
terns and candles.
Stage lighting became
of greater importance,
and the possibilities of
scenic illusions were
soon to claim the at-
tention of theatrical
managers.

At this time the chief
sources of artificial il-
lumination were the
same as they had been
for thousands of years
previous. Torches
made of pine knots,

QPEN-FLAME oil lamps
in which the wick floated
in the oil were used in pre-
historic times. Lamps of this
type are found in ruins dat-
ing back to 7000 and 8000
years B. C.

crude forms of lamps
which burned animal
or vegetable oil, and
candles of wax or tal-
low comprised the com-
plete assortment of
artificial illuminants —
the same smoking in-
efficient means for
producing light that
had been used by the
Greeks, Romans and
early Christians.

FOOTLIGHTS

Although David
Garrick in London is
given credit for intro-

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clucing footlights in 1755 when he
placed a row of candles below and in
front of the stage and masked them
by metal screens, it is a fact that foot-

lights were introduced much earlier
than this. For instance, Joseph Fur-
tenbach in Germany wrote in 1628
giving specifications for a stage which

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Figure 7 — Details of gas lighting equipment taken from Building Neius, October 1894. This illustration shows
construction of batten lights, wing lights and footlights, and indicates layout of control board from which the
dimming and brightening of the lights was manipulated.

. '

"W A R D

L> E O 1VJ A.

ELECTRIC

COMPANY

provided footlights. According to his
description the stage was a platform
inclined toward the audience. In front
of the stage there was a place for the
orchestra, behind which was erected a
wall to screen the musicians from the
spectators. A row of oil lamps on the
stage side of the wall furnished the foot-
lights. There were wings on each side of
the stage — in these wings rows of oil
lamps were hung. The rough sketch
in Figure 4 gives the ideas set forth in
his description which unfortunately was
not illustrated. David Garrick also
used invisible side lights as described
by Furtenbach. These lights are now
known as "borders.' '

Furtenbach speaks of using candles
or oil lamps but seems to prefer oil
lamps. In Garrick's time the entire
stage was lighted by candles,, two or
more groups were hung in the form of
a corona above the stage, footlights
were placed in front and invisible lights
on either side. The
object was simply the
illumination of the
players. The artistic
value of stage lighting
had not vet been
evolved.

The amusing thing
about the descriptions
of theatre lighting sys-
tems from earliest times
is that all writers pro-
claim the lighting sys-
tem as giving brilliant
illumination. Candles
and oil lamps are all
described in the same
glowing terms in the

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ILL

r T J HE tallow candle fol-
lowed the open-flame lamp,
dating from the first century.
In the theatre, candles were
usually protected by shades
which served the double pur-
pose of guarding the flame
from drafts and cutting off
the light that would other-
wise shine in the faces of the
audience.

Figure 8 — Detail of footlight construction showing
reflectors, gas lamps, feed piping and arrangements for
carrying away smoke and products of combustion.

early days of their application.

EARLY AMERICAN STAGE LIGHTING

The early theatres of America used
the same crude methods of lighting
the stage and auditorium that was
then in vogue in Europe. The historic
John Street theatre, erected in 1767,
and New York's leading playhouse for
thirty years, was lighted by candles.

To keep the candles burning brightly
it was necessary to trim the wicks.
One or more attendants were assigned

the task of caring for
the lights. Probably
it was not an unusual
occurrence if a diminu-
tion of lighting neces-
sitated their making a
round of the footlights
during a tense scene
of action upon the
stage.

Somewhat better
systems of oil illumi-
nation gradually de-
veloped. Lamps with
glass chimneys were
devised. More efficient
lighting was obtainable
by the use of cam-

W ^V R. E>

e e o n ^x fs, d

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C O M F» A. N Y

Figure 9 — Apparatus used to represent an artificial
sun in the production of The Prophet' in the Paris
Opera in 1846. An electric arc was located at the
focus of a parabolic mirror and the beam of parallel
rays projected upon a silk screen. This was the earliest
authentic application of electric light on the stage.
This illustration and the six following were taken from
La Lumiere Electrique, by Emile Alglave and J.
Boulard.

phine, kerosene oil and other high-
grade illuminants. These new devel-
opments supplanted candles and other
means of lighting in the theatres.
It was a common sight to see hundreds
of oil lamps burning. They hung in
clusters from the ceilings and projected
from the walls, balconies and boxes.
They were used on the stage as foot-
lights, as sidelights and were suspended
from above. In certain theatres it
was customary to hang oil lamps over
the stage in front of the curtain line.

Despite the number of lamps used,
they threw over the stage only enough
light to make the players recognizable.
The scenery and properties also re-
mained in semi-obscurity. There was
no feasible way of controlling the lights
either in the body of the house or on

the stage. Attempts were made to
show the changes from night to day
and vice versa by the mechanical
interposition of screens. This crude
method was very unsatisfactory but
nothing better was known and the spec-
tators were content. It was not a rare
occurrence for one or more lamp chim-
neys to break in the footlights, or other
parts of the house, and a dense black
cloud of smoke to rise interfering with
vision of the spectators and poisoning
the atmosphere. When critical persons
expressed displeasure, others reminded
them of the tallow candles with which
the theatregoers once had to be satisfied,
and of the nuisance of having snuffers
perform their functions in the midst
of a tense situation.

Figure 10 — The second important development in
electric scenic effects was the representation of a
rainbow by means of the apparatus here shown. This
device was used in the production of "Moses" in the
Paris Opera in 1860. Light from an arc was passed
through an arc-shaped slot, after which the rays were
concentrated by means of a lens and passed through a
prism which produced the spectrum.

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Figure 11 — The scene in the Opera "Moses" in which the rainbow was produced as explained in Figure 10.

GAS LIGHTING

Then a new era dawned in the history
of stage lighting. Gas
developments made
possible scenic effects
that were miracles in
comparison to those of
the daylight, candle
light and oil light
periods.

A method for making
gas in sufficient quanti-
ties to be used for il-
luminating purposes
was devised in 1781,
by Mr, Wm. Murdock,
an English engineer.
In London, in 1803,
Frederick Albert Wind-
sor tried the experi-

A FTER the candle in
'^ domestic lighting, came
the open-fla?ne camphine
burner, which consisted of
one or more round wicks in-
serted into a vessel of clean-
burning camphine oil.

ment of lighting the stage of the
Lyceum theatre with gas. This form

of lighting was
introduced into
America at Philadel-
phia in 1796. where it
was used for purposes
of exterior decoration.
In the year 1816, a
system of gas lighting
was installed in the
Chestnut Street Opera
House, Philadelphia.
There were no munici-
pal gas plants with
large street mains and
radiating feeder pipes
at this time. It was
necessary for theatre
managers, who desired

1^ E O N

E C T Fi I C

COM F»>^ M "V

Figure 72— Realistic lightning was produced in the
Paris Opera in 1860 by means of a so-called magic
mirror, which consisted of a parabolic mirror with an
electric arc at the focus. An electro-magnet operated
by a thumb switch permitted the carbon electrodes of
the arc to be snapped together at will, thus producing
flashes like lightning.

to install illuminating gas, to arrange
for its manufacture on their premises.
At first the methods of manufacture
and control were rough and improvised,

and though gas provided more illumi-
nation than candles or oil lamps it
did not come into general use until
about 1850.

LIGHT CONTROL

The value of gas lighting in the
theatre was due, not so much to its great-
er illuminating power, as to its being
subject to regulation and control. The
new system and its development was a
revelation to the public. Auditoriums

Figure 13 — The first electric spot light was apparently
the one here shown. It was employed in the Paris
Opera in connection with the production of ' "Moses
1860.

Figure 14 — The lamp here shown is a special spot light
intended for lighting a definite point in the scene, but
not for following the movements of the players. It
consists of an arc lamp located at the focus of a para-
bolic mirror.

were darkened during the action of the
play — an improvement heretofore im-
possible. It was found that darkness
and shadow, under control were equally
as important factors as light in pro-
ducing effects.

Elaborate lighting systems were de-
vised. Mains sometimes more than
12 inches in diameter were used and

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Figure IS — Scene in the Opera '"Moses" in which a spot light was used to bring out Moses in his white robes.
This scene was particularly effective as the contrast between Moses and his surroundings appeared little short
of miraculous; electric light being very little known and spotlight never having been previously used.

many thousands of feet
fixed and flexible, were
Lyceum theatre at
London, and the Boston
theatre in America were,
two of the first to be
completely equipped
and so arranged that
the lights were con-
trolled from one point
in the building. A regu-
lator located near the
"prompter" was em-
ployed for the purpose.
Open-flame gas lights
were used at first, and
later glass chimneys
were added to protect
the flame from air
currents. It was the

of feeder pipe, general custom to turn the gas flames
installed. The low in the auditorium rather than out;

because methods that
had been invented for
lighting the gas were
generally so imperfect
that a considerable
amount of gas escaped
and contaminated the
atmosphere before all
the jets would ignite.
However, changes from
"full on" to "dark out"
were occasionally con-
sidered necessary on
the stage itself during
the play, and were
therefore made even
at the risk of fire.

r TTHE kerosene lamp with
an adjustable wick was
invented in 1783 in France.
The glass chimney quickly
followed. It was many years
before it came into general
use.

L E O IV A R. D

ELECTRIC

COM J>A N -y

Figure 16 — Cross-section of electrically lighted theatre constructed in Munich for the International Electro-
Technical Exposition in 1882. This was a remarkable installation which inspired theatrical managers all over
the world. It will be noted that arc lamps are used in the auditorium — the lamps themselves being invisible
and their light transmitted through a skylight — a system of lighting which is still popular. The electrician who
operates the dimmer may be seen at the side, his dimmer being located on the floor below. Footlights, battens,
wing lights and bunch lights are all shown in action. This illustration and the six following, were taken
from La Lumiere Elect rique, August, 1883.

ILLUMINATION BY LIME LIGHTS

During this same period another form
of illumination was developed that was
destined to be of great value in stage
lighting. Henry Drummond in 1816
discovered that by raising a piece of
lime to a high temperature, it became
incandescent and gave out a brilliant
white light. This calcium or lime light,
as it was called, came into general use
for stage illumination about 1860. It
was produced by playing a burning
mixture of oxygen and hydrogen, upon
a block of lime. The light was so con-
centrated and localized that it was soon
adopted for use as a spot light to follow

the hero or some other character about
the stage. It also aided the imagina-
tion in such effects as light shining
through a window, moon light, sun rays
and the like. In some cases lime lights
were used for the general illumination
of the stage, a number of lamps being
set at different points throughout the
body of the house, and their rays direc-
ted upon the stage.

The principle of the lime light once
understood led to the invention and
development of incandescent gas man-
tles, which increased the lighting value
of gas many fold. Such mantle burners
were introduced on the stage for foot-

XV A R. 13

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C O M F»

Figure 17 — Detail of footlights shown in Figure 16.
These lamps were connected with a dimmer for regula-
tion of intensity. Change in color was also provided
by mechanical means, each lamp being fitted with a
revolving screen, one section of which gave the natural
light, the two other sections being blue and red respec-
tively. The change from one color to the next was made
by pulling a cord so connected as to turn the screens.

lights, proscenium lights, border lights
and bunch lights.

COLOR LIGHTING INTRODUCED

Many of the possibilities of effective
stage lighting were realized at the time
gas lighting was in vogue. Much
thought was given to scenic illusions
and colored lights were introduced in
a simple form. Henry Irving, one of the
pioneers in color development, devised
an arrangement for
drawing thin colored
silk or some other trans-
parent material in front
of the lights. Occasion-
all v the bull's-eve of the
lime light was covered
in the same way. Gen-
eral color effects were
produced — one domin-
ating color thrown over
the stage was usually
the limit of the color
scheme.

DISADVANTAGES OF

GAS

While gas lighting

was a great improve-

QPEN-FLAME gas burn-
er was invented in Scot-
land in 1782. This form of
lighting was used wherever
the requirements were suffi-
cient to justify the expense
of a gas generating and dis-
tributing system. One of its
earliest uses was in the
theatre.

Figure 18 — Detail of batten lights shown in Figure 16.
These lamps are controlled in the same way as those
described in Figure 17.

ment over the earlier forms of
illumination, and permitted many
spectacular effects theretofore impos-
sible, it possessed serious disadvan-
tages. Stage lighting equipment took
up almost as much room as the scenery
itself. Rubber tubes trailed in every di-
rection across the stage and wings. The
"rising moon," a gas flame back of a
transparent yellow disk dragged its gas
tube behind as it ascended the scenic
heavens, by means of an ingenious
system of pulleys. The light of the
moon wabbled uncertainly, and the
pulleys creaked, still it was somewhat'
better than earlier representations by

means of a lantern
mounted on the end
of a stick.

Many theatre fires
were caused accidently
while lighting the gas
by the wabbling among
the inflammable scenery
of a blazing spirit wad
on the end of a long cane.
In an article on the
4 'Lighting of Theatres' '
which appeared in the
"Builder" on August
3, 1861, the writer
describes additional
disadvantages of gas
lighting, as follows:

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L E O N A F* D

E C X R I C COMPANY

1 ' The upper
boxes and galleries
are oppressively hot,
the view of the stage
is interfered with,
and whatever there
is of ventilation is
chiefly productive of
a current from the
stage which carries
sound up to the
ventilator instead of
allowing it to pass
to the audience. As
regards the float
(footlights) the dan-
ger for dancers is
consi dera b 1 e as
shown bv sad
accidents. The ob-
struction not only by
the reflectors but also
by the visible smoke
is great, while the
heated air is unfavor-
able in every respect
to the actors and
their efforts, and the
light dazzles their

Figure 19 — Detail of
wing lights shown in
Figure 16. The color
of the light from these
lamps was changed by
hoisting and lowering
color screens. Like all
the other lamps in the
theatre, these also were
connected to a dimmer.

eyes."

PROGRESSIVE DEVELOPMENT IN
STAGE LIGHTING

In 1808 Sir Humphrey Davy ex-
hibited the first electric arc in England.
Some 30 years later the arc came into
limited use for special illuminating
effects. The earliest arcs were operated
with direct current, the arc being
formed between two carbon rods con-
nected in an electric circuit; it was
started by bringing the tips of the
rods together, and then separating
them. The light was emitted by the

positive carbon which became white
hot at the point where the electricity
passed from this carbon to the opposite
one. In operation the carbons were
slowly consumed and in the beginning
frequent adjustment by hand had to
be made.

INTRODUCTION OF ELECTRIC LIGHT
The Paris Opera was the cradle of
electric stage lighting. In 1846 an
astonishing representation of the rising
sun was produced by means of an arc
placed at the focus of a parabolic re-
flector and arranged to cast a beam of
light on a silk screen (see Figure 9).
This device which was used in "The
Prophet" was developed by M. J.
Duboscq who was a co-worker with
Foucault. In 1855, M. Duboscq was

Figure 20— Bunch light for concentrated illumination
for certain points in the scene. Its use is illustrated
in Figure 16.

WARD

L E O M A. R E>

ELECTRIC

COM F»A IS Y

permanently retained by the opera, and
five years later he developed a number
of important contributions to the
art of theatre lighting in connection
with Rossini's Opera "Moses/' Among
these effects were the following: A
perfect rainbow; lightning flashes and

spotlights.

The rainbow was made by passing
light from an electric arc through an
arc-shaped shutter into a concentrating
lens, and from there dispersing the rays
according to the spectrum by means of
a prism as shown in Figure 10.

Lightning was produced by means of
a parabolic mirror at the focus of which
an electric arc was located. The arc
was flashed on and off by snapping the
carbons together. An electro-magnet
was used for operating the carbons as
shown in Figure 1 2.

Two forms of spotlight were em-
ployed; one with the enclosed arc ar-
ranged for manipulation by hand and
equipped with shutters which permitted
the cutting off of the
light at will, and the
other with a parabolic
reflector back of an
arc. The latter was
particularly adapted to
the illumination of
certain spots on the
stage, while the former
was intended for use in
following a performer
as he moved about the
stage. In this case it
was specially intended
to illuminate Moses and
make his white robes
stand out from all the
rest.

'T'HE in candescent mantle
in connection with the
gas burner, invented in Ger-
many in 1890, was an enor-
mous improvement over the
open flame and was quickly-
adopted by the theatre.

Figure 21 — Dimmer rheostat and control board shown
in the foreground of Figure 16. It will be noted that
this dimmer provides individual control for each
rheostat by means of a lever handle. These handles
can also be attached to a longitudinal bar which is
operated by a slow motion wheel from the front. In
this way independent control or interlocked control
was obtained.

A luminous fountain was also pro-
duced at this time.

JABLOCHKOFF CANDLES

Since the earliest arcs were arranged
for hand adjustment of the carbons,

they were adapted only
for use in lamps that
could be personally at-
tended. In 1878 Paul
Jablochkoff caused a
great sensation in the
theatrical world by the
introduction of his
electric candle, which
consisted of two carbon
rods mounted side by
side and separated by
an insulating compound
which would melt
away, once the arc was
started, just fast
enough to permit the
continuous burning of

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L E O N ARD

ECTRIC COMPANY

the arcs across
the upper ends.
In 1 879 the
Bellecour Thea-
tre at Lyons,
France, was
equipped with
52 of these elec-
tric candles, 12
of them being
installed on the
stage.

Electric light-
ing with Jablochkoff candles did not
come into general use and gas lighting
was still the common means of lighting
theatres at this time.

Figure 22 — Circuit diagram
of open-coil type of dimmer
rheostat. From La Lumiere
Electrique, April, 1884.

INCANDESCENT LAMPS

In 1879 when the Jablochkoff candle
was just starting its career in Europe,
Edison in America invented his incan-
descent lamp and this was soon brought
into practical form by the contributions
of various other inventors. Again the
Grand Opera in Paris led the way.
The Director, M. Gamier, reported in
1879 to the Minister of Public Works
that the vapors from the gas were dis-
coloring and destroying the beautiful
paintings of Baudry which hung in the
foyer.

The result of this report was a
series of experiments with various
systems of electric lighting, and these

> :

Figure 23 — The electric lighting and control system used in the Paris Opera and described in IS Illustration,
June, 1887. The insert shows the comparison between electric and gas batten lights and wing lights. The
dimmers are extremely interesting. It will be noted that the rheostats are mounted below the floor, and the
leads brought up to contact buttons, connection to which is manipulated by means of lever arms. These lever
arms can be adjusted independently or locked to a master shaft which is operated from the end by hand.

VV A. R TD

L E O N ARD

ELECTRIC COMPANY

; igun 24 — In the early days of electric lighting in theatres, each theatre provided its own electricity. The
earliest installations employed batteries. Here is shown the power plant of the Paris Opera, as given in the
June, 1887. issue of V Illustration.

tests which were made
in 1880 and 1881 consti-
tuted the first theatrical
in ; illation of incan-
descent lamps.

MANAGERS FAVOR
1 I ECTRIC LIGHT

Theatre lighting by
means of electricity re-
ceived a tremendous
impulse from an exhibit
at the Electro-Techni-
cal Exposition at Mu-
nich in 1882. where a
small theatre complete-
ly lighted by electricity
was erected in the
Crystal Palace. This

A BLOCK of lime heated
to incandescence by an
oxy-hydrogen blow pipe was
used for many years as a
spot light in the theatre.
From this practice the ex-
pression to be in the "lime
light" originated.

theatre, a cross-section
of which is shown in
Figure 1 6, was equipped
with both arc and in-
candescent lamps. A
diffused light was used
here probably for the
first time; a number
of arc lamps being
suspended above the
ceiling and their light
transmitted through
circular panels of glass

ground in ornamental
designs. This method
of lighting was most
effective, since it hid
the unsightly lamps

WAR D

L E O IN

ELECTRIC

COM F» jK. N "Y

Figure 25 — Early Ward Leonard Vitrohm Theatre
Dimmer made up of two vitrohm rectangular plate
units, connected together and mounted on a panel
board which carried a dial switch with an extension
lever to permit convenient adjustment. These dim-
mers were installed in Altmeyer's Theatre, McKeesport,
Pa., in 1892.

and produced a wonderfully soft effect
due to the diffusion of the light. The
walls were illuminated with incandescent
lamps arranged to'form artistic designs.

The stage was lighted entirely with
incandescent electric lamps, arranged
with screens that could be mechanic-
ally operated to change colors from
natural to red or blue. The mechan-
ism by which this was accomplished
is shown in Figure 17.

In September, 1882, a Congress of

Theatrical Managers assembled and
issued a formal report favoring the
lighting of halls and theatres by elec-
tricity, then followed the installation of
electric lighting in the Savoy Theatre
in London in 1882, and the Bijou
Theatre in Boston the same year.
The first New York theatre to install
incandescent lighting was the Peoples
Theatre on the Bowery in 1885.

Henry Irving was a pioneer in the
art of stage lighting. He made exten-
sive use of the spotlight, which had been
first introduced in the Paris Opera, and
he accomplished much in the extension
of the application of electric lighting
to the production of scenic effects. In
his production of Faust, he arranged,
with Mr. Gourand, a system of circuits
for the production of sparks and fire in
the fight between Faust and Valentine.
Connections to the outside circuits
were made through plates on the
actor's shoes.

Figure 26 — Ward Leonard Theatre Dimmer put on the market in 1894. It consisted ol banks of vitrohm
rectangular plates mounted in a frame work above which dial switches were arranged. Connections between the
contact points on the dial switch and corresponding points in the resistor units were made by means of wires.
This was_the first step in decreasing the space occupied by a bank of theatre dimmers.

W A. R. D

L E O N A.

L E C X R I C

C O M F»

CONTROL OF LIGHTING

The real problem in the application
of electric lights to the theatre is not so
much the illumination of the stage and
auditorium as the proper control of the
light. It was not until various devices
for regulating electrical current and
manipulating the various circuits were
invented that electricity was able suc-
cessfully to supersede gas.

Gas lighting permitted graduation of
the illumination of every part of the
stage and auditorium from a single con-
trol station. This was accomplished by
the manipulation of valves in the re-
gulator from which all pipes radiated.
The amount of gas flow was increased
or decreased by opening or closing the
valves, the amount of illumination
being varied accordingly.

At the time electric lighting was in-
troduced into theatres, control similar
to that available with gas was demand-
ed. Fortunately, the new electric sys-
tem offered even great-
er possibilities than the
gas, although these
possibilities were not
immediately realized.
Todav the refinements
of control offer oppor-
tunities for the pro-
duction of scenic effects
that have not been as
vet completely utilized.

With electricity, the
flow may be adj usted by
controlling the resist-
ance of the circuit or by
controlling the pressure
or voltage, of the cir-
cuit. In alternating-

TN 1808 Sir Humphrey
Daw invented the electric
arc. In the jorties it came
into use on the stage and later
superseded the lime light.
The earliest lamps provided
for adjustment oj the carbons
by hand.

Figure 27 — Ward Leonard Dimmers used in the Olym-
pia Theatre in New York in 1896. The small panel
board in the background contains relay circuits for the
remote control of main-line switches located in different
parts of the house. From The Electrical World, March
1896.

current systems the flow may also be
adjusted by controlling the reactance.

In the beginning, the resistance
method alone was used.

A device, the prin-
cipal characteristic of
which is resistance, is
called a "resistor" and
if it is arranged in
such a way that its
resistance can be varied
or adjusted, it is called
a "rheostat". Rheo-
stats are used to vary
the flow of electricity
through a circuit in the
same way that the flow
of gas can be varied by
partially closing or
opening a valve. Rheo-
stats that are used for
dimming the light in

^^mm

MBH^H

L E O IV A F* D

ELECTRIC

COM F» A TV Y

Figure 28 — Ward Leonard Plate Dimmer — 1897.

a theatre, or other public or private
places, are called "dimmers".

THE FIRST ELECTRIC DIMMER

The first dimmers were made by
using water-barrel rheostats to increase
the resistance and thus reduce the flow
of electricity to the lamps. A rheostat
of this kind consisted of a barrel filled
with water in which two plates or
electrodes were immersed. When the
plates were tight together there was
practically no resistance to the flow of
electricity, and the lamps burned with
full brightness. When the plates were
separated from one another, the elec-
tricity was forced to pass through the
water which greatly cut down the flow
and reduced the brightness of the light.
This type of dimmer was short-lived.
Itwas bulky, difficult to keep in working
order, the results were never twice
alike, and when overloaded it produced
vapors which were often disagreeable.

COIL RHEOSTAT DIMMER
The barrel dimmer was followed by
the coil rheostat dimmer which con-
sisted of a number of coils of German
Silver Wire (a metal having a high
resistance) assembled in a rectangular

Figure 29 — Ar-
rangement of
two Ward Leon-
ard dimmer
plates with a
single operating
handle— 1897.

Figure 30 — Bank of Ward Leonard
plate dimmers arranged for individ-
ual control, as well as master
control. The master lever is be-
tween the first and second plates
—1897.

frame with wires leading to a dial
switch, which permitted, as required, a
variation in the number of coils con-
nected in the circuit. The practice was
to install the dimmers in the basement
below the switchboard and run wires
up to contact points on the board. A
rough diagram indicating the principle
of this dimmer is shown in Figure 21.

Reducing the flow of electricity by
introducing resistance into a circuit
uses up the energy by transforming it
into heat. Therefore, dimmers become
hot in use, and their capacity is gov-
erned by the amount of heat they can
dissipate without attaining a dangerous
temperature, and without being injured
in the process. Coil rheostat dimmers
were unsafe because the coils of resist-
ance wire were dangerously exposed
and frequently became red-hot due to
overload.

VITROHM DIMMERS

The coil rheostat dimmer was stand-
ard practice at the time the Ward

WARD

L E O N ARD

ELE C X R I C

C O M F»

TSI

Leonard Vitrohm plate rheostat (Figure
27) with a dial switch was introduced.
This new method of construction great-
ly reduced the space occupied by the
rheostat and eliminated fire risk, inci-
dent to open-coil construction.

The next important step in the de-
velopment of dimmers was the Ward
Leonard Vitrohm dimmer in which the
dial switch and the rheostat proper
were combined in one structure, elimi-
nating leads entirely. The contacts or
buttons on the dial switch were attached
directly to the resistor wire and the
whole structure was supported by an
iron plate, the electrical circuits being
insulated and supported by vitreous
enamel.

Modern Ward Leonard dimmers are
simply refinements of the original ap-
paratus. They are lighter, more com-
pact and easier to operate but the
general principles of construction are
the same.

The practical process of imbedding
the resistance wire in
vitreous enamel and
fusing this enamel to an
iron supporting plate is
covered by Ward Leon-
ard patents, and is de-
noted by the trade-
name ' ' Vitrohm' ' . Ward
Leonard dimmers that
are constructed with
Vitrohm plates are
called "Ward Leonard
Vitrohm Dimmers".

TRANSFORMER
DIMMERS

As was mentioned
on page 24, in a.c.
circuits it is possible

,\u.w

"T^HE first really commer-
cial arc lamp was the
so-called Jablochkqff candle,
which consisted of two carbon
electrodes insulated from each
other by material that was
broken down and consumed
by the arc as the electrodes
wore away from the action of
the arc.

Figure 31 — Ward Leonard remote control dimmer
operated by three push buttons — 1897. This dimmer
is still used in the Waldorf-Astoria auditorium.

to vary the flow of electricity by chang-
ing the voltage of the circuit or by
changing the reactance, both of which
systems accomplish the result with less
dissipation of energy than the resistance
method.

The earliest methods employed trans-
formers in which provision was made
for varying the secondary voltage. In
the nineties a device of this kind was

put into practical use.
One of the earliest ones
employed an auto trans-
former which operated
with a combination of
variable voltage and
variable reactance as
shown in Figure 32. A
pure reactance method
of current variation was
used in the Earl's Court
Exhibition Theatre in
1896. Thedetailsof con-
struction and electrical
connection are shown
in Figures 32 and 33.

The principle objec-
tion to dimmers of the

-w

L E O IV

ELEC TRIC

COM PA. N Y

6 v v v

Figure 32 — Reactance dimmer described by Dr. J. A. Fleming in the Electrical World. November 1890. The
circuit diagram shows how, by moving the core in the coil more or less, voltage is produced across the terminal
of the lamps. With the iron core completely within the section across the lamps, maximum voltage is produced,
and with the core in the section in series with the lamps, maximum reactance and minimum voltage are
produced — the effect of which is to cut down the current through the lamps.

■

transformer type as developed in the
early days was the amount of space
occupied. Ward Leonard Electric Com-
pany have solved the space problem in mmmm
a.c. installations of very large size by
combining the reactance and resistance
methods of dimming in a new type of
dimmer, in which the reactance in the
main circuits is adjusted by means of
standard Ward Leonard Vitrohm Dim-
mers, carrying less than 2 per cent, as
much current as the lighting circuit con-
trolled by the dimmer.

THEATRE LIGHTING CONTROL

Successful producers have always rec-
ognized the importance of suitable
lighting facilities. Furthermore, they
have realized the effects which thev
could obtain are limited only by the
means of control at their disposal.

In 1905 Carl Lautenschlaeger for-
merly stage director at the Royal
Bavarian Court Theatre in Munich,
delivered an address before the Poly-
technic Club in which he appraised the
importance of control equipment. His
opinion of theatre dimmers is set forth
in the following quotation :

"The conductors converge in a so-
called regulator (dimmer) the most

Figure 33 — Circuit diagram of dimmer equipment in
Earl's Court Theatre. The dimmers are called chokers.
Arc lamp mechanism and rheostat used in spot light
is shown in the insert.

ward

LEON

ELECTRIC

COM F» A. N "Y

important apparatus used in stage
illumination. It includes all neces-
sary appliances for graduating the
intensity of the lights, both of the
stage and in the auditorium. It
permits the lighting and extinguish-
ing of temporary lamps, and the
sudden change of darkness to a blaze
of light. As the switches for the
production of color effects are also
collected in the regulator, with a
proper arrangement of apparatus, one
man can produce every needed change
of light and color, thus giving to
the illumination even in difficult
cases a perfect unity and harmony
with the scene which contributes
greatly to the success of the presenta-
tion."

The period of greatest development
in theatre lighting control has been
during the last twenty years, and to-
day the leading producers give to light-
ing more attention than to any other
single element which
goes to make up the
setting of a scene.

David Belasco, gen-
erally recognized as one
of the most successful
producers in this coun-
try, has contributed e-
normously to the de-
velopment of effective
application of lighting
in the theatre. An idea
of the importance which
he attaches to this
phase of his work may
be gathered from a
statement made by
William Winter in his

r ~THE first incandescent
electric lamp was in-
vented by Edison in 1879
and was provided with a
filament made by the car-
bonization of a bamboo fibre.

"Life of David Belasco." He says :

"Readers will perhaps realize the
importance Belasco attaches to the
art of lighting as an adjunct to
acting and the care he lavishes upon
it when they are informed that
the experimental workshop in his
theatre is operated all the year round
and that in many instances the ex-
penses of his light rehearsals alone
have exceeded the total of all other
costs of production."

Ward Leonard dimmers have been
used by Mr. Belasco ever since their
first appearance on the market, and
much of the development in the per-
fectioning of this apparatus is built
around experience gained under the
direction of him and his electrician,
Mr. Louis Hartmann.

PRESENT-DAY PRACTICES

Starting in 1846 in the Paris Opera,
electricity gradually displaced all light-
ing for the theatre,
and as the use of
electricity spread, the
perfection of its control
developed.

Today, practically
every lighting circuit
in the theatre is con-
trolled by dimmers.

In the past five years
the amount of light
used on the stage, and
throughout the thea-
tre, has more than
doubled. Such a vari-
ation in what is now
considered good prac-
tice makes the use of

L E O IV A

E.LE, C T R I C

COM F» A. IV Y

any present-day figures as merely
comparative, and the figures given
below are not intended to be used
in actual application. The experi-
ence gained from numerous recent
installations indicate that where an
auditorium is decorated in silverleaf
and light colors, 10 watts of lighting
in each color should be provided for
each seat. Where gold leaf and warm
or heavy color decorations are adopted,
20 watts in each color should be pro-
vided for each seat to afford "read-
ing" illumination. In urban motion

Figure 34 — An early form of reactance dimmer used in
Earl's Court Exhibition Theatre and described in
London Engineer , November 1896. In this installation
special attention was paid to the switching from one
color to another. As one color decreased in brilliancy,
the succeeding color was simultaneously increased in
brilliancy. The arrangement here shown permits
individual setting of the different circuits and also gives
interlock and operation with a slow-motion worm and
wheel, or by means of a master lever. Detail of master
lever and slow-motion worm and wheel is shown in
upper right-hand corner.

Figure 35 — Spot light using
an electric arc and providing
for color screens, representing
practice in 1898. From The
Electrical World, May 1898.

Figure 36 — Bunch
light made up of in-
candescent lamps in
special bowl reflector
as used in 1898.

picture theatres, where "reading" light
is not required, satisfactory lighting has
been effected with as little as 4 watts,
each color, per seat.

In high-class theatres, using stand-
ard fixtures with matt white reflecting
surfaces the practice is about as follows :

FOOTLIGHTS

In the footlights, two rows of lamps
are used, one row of colored lamps
back of a row of whites.

The footlights may be 4 to 8 feet less
in length than the clear width of the
proscenium arch. From 150 to 200

"W A. R 13

LEON

ELEC t ric

C O M F»

watts should be used in each color, per
lineal foot of border.

STRIP LIGHT
On each side of the proscenium a
"strip light" 12 to 18 feet high is
recessed on the stage side of the arch.
In this strip 100 to 150 watts of Type
C lamps, each color, per lineal foot,

are used.

BORDERS

Borders are generally from 4 to 10
feet less in length than the width of
the proscenium arch. They are spaced
6 to 8 feet apart, and good practice
is to have one work light at each end
of each border. 100 to 125 watts of
Type C lamps in each color are pro-
vided for each lineal foot of border.

Several floor pockets, each with
three 50-ampere receptacles are con-
veniently spaced on each side of stage,
also one at the rear, and one in the
footlight trough.

For each receptacle there should be
a 2,000-watt dimmer with sufficient
ohms resistance to dim
1.000 watts.

The three receptacles
in each pocket on a side
are connected to differ-
ent feeder switches —
one feeder switch con-
trolling the No. 1 recep-
tacles of all pockets, a
second switch control-
ling the No. 2 recepta-
cles and a third feeder
switch controlling the
No. 3 receptacles.

One pocket with
three 60-ampere recep-
tacles is provided on
each side of the "stage

for connection to arc lamps.

A typical stage lighting plan is

shown on page 58.

Due to the perfect control provided
bv suitable dimmers, the incandescent

IfDISON'S incandescent

lamp finally settled down

to a carbon filament as

the results of inventions of

various engineers.

HTHR present-day repre-
sentative oj the incandes-
cent lamp is the tungsten
filament \ or mazda la?np, and
for the high-power units these
lamps are usually filled with
nitrogen.

Figure 37 — Ward Leonard Rheostats
for spot-light control.

lamp is superseding the arc lamp for
use as a spot light. Most spot lights
are equipped with high-power nitrogen
lamps controlled either from the dim-
mer board or bv a
special dimmer on the
stand. Not only has
the effectiveness of
the lamp been greatly
increased, but the fire
risk which was always
an item has been prac-
ticallv eliminated.

Today, arc lights
are used mostly in
moving picture thea-
tres for projection and
spot light work, and in
all cases thev should
be in enclosed fireproof
booths.

"W A. R. D

L E O N AR D

ELEC XR1C

COM F>j\. IS "Y

WARD LEONARD DIMMER

ARD LEONARD dimmers
are made in a variety of sizes
and types to meet all the
requirements of theatres and other
places of public assembly, such as halls,
churches, and clubs. In fact, Ward
Leonard dimmers are used in private
residence installations on the one hand,
and in the largest theatres on the other.
They are adapted to the staging of
theatrical productions in such a way,
that the lighting program can be as
definitely specified as the music and for
the convenience of shows which travel,
dimmer equipment designed for the
production can be provided in portable
form for shipment like all the rest of the
properties of the play.

In general there are two fundamental
types of Ward Leonard dimmers, name-
ly, the type which utilizes resistance
alone and the type which utilizes

reactance controlled by resistance.

The former is recommended for the
smaller installations and the latter for
the largest installations. The two over-
lap in the average size installation and
choice can only be made when proper
consideration is given to the space avail-
able and the value that is placed upon
convenience of operation.

One fundamental principle which
has always been followed in Ward
Leonard practice, is that all dimmers
shall be built for continuous operation
at any point in their range of control.
This is necessary for the safety of the
dimmers themselves, and the installa-
tion as a whole. When dimmers are
constructed with an intermittent duty
rating, they are a liability, as it is
impossible to adhere to an intermit-
tent rating in conditions of actual
operation.

WARD LEONARD VHTROHM DIMMER

VITROHM PLATES

The basis of all Ward Leonard dim-
mers is the Vitrohm plate — a type of
rheostat developed and made com-
mercially practical by H. Ward
Leonard.

The Vitrohm plates are self-contained
rheostats of extremely compact con-
struction. The plate which furnishes
the rigidity of the structure and pro-
vides for the mounting of the parts is a
solid metal disk, on one side of which is
mounted the resistor with its contact
buttons. The resistor is applied to the
plate by a patented Ward Leonard pro-

cess, then covered with a coating of
special vitreous enamel and fired in a
furnace at very high temperature. This

. ■ i •

' x ./ ■

Figure 38 — Ward Leonard Vitrohm Plates which form
the resistor elements of Ward Leonard dimmers.

ELECTRIC C O M F» A !* Y

Figure J g — Resistive conductor ready to be im-
bedded ia the enamel of a Ward Leonard Vitrohm
place.

causes the enamel to penetrate the
surface of the metal and virtually be-
come a part of it. Upon this enamel
surface the resistor proper is mounted,
together with the stationary contacts
which form the tap connections to the
resistor. Enamel is next applied to the
surface in sufficient quantity to imbed
completely the resistive conductor, or
resistance wire, and the base of the con-
tact buttons, and the plates are again
fired so as to fuse the entire mass into
one integral structure.

The close relation of the resistor
element to the metallic base promotes
rapid dissipation of the heat generated
to the whole plate and even to the
supporting frame work.

Therefore the maximum operating
temperature is much lower than in any
other form of construction. At the
same time, vitreous enamel will stand a
higher temperature than any other
material used for embedding and sup-
porting resistor elements.

The temperature at which the firing
takes place is many hundred degrees
higher than will ever be encountered in
practical use — an actual demonstration
of the indestructible nature of Vitrohm
construction.

The vitreous enamel which supports,
insulates and protects the resistive con-
ductor is dense and impervious to mois-
ture. Therefore, it affords protection
against mechanical, electrical and chem-
ical depreciation, and permanently re-
tains the physical and electrical prop-
erties of the resistive conductor which
is the heart of any dimmer.

CONTACTS

One of the important improvements
made by H. Ward Leonard when the
Vitrohm plate was invented was the
elimination of the leads which formerly
were used to connect points along the
resistance wire to contact buttons on
the dial switch. In the Vitrohm plate
the contact buttons are attached direct-

Figure 40 — Contact arm and concacc-arm drive of
Ward Leonard Vitrohm dimmer plate. The contact
shoes are provided with long plungers which permit
them to ride easily over the contacts and maintain a
proper contact pressure under all conditior- The
drive gives a positive, though flexible connection that
operates with little friction.

L E O IV ^V. R. D

LE. C T R 1 C

C O M F»

M -Y

ly to the resistive conductor by a me-
chanical joint between
the two made under
high pressure when the
metals are bright and
clean.

The advantages of this joint are
many. It contains no solder or tin, the
resistive conductor does not have to be
cut to make the joint with the contact
buttons and the union is therefore per-
manent and not dependent on clamps,
bolts or screws. The joint undergoes
the firing process and therefore is not
affected by any temperature it may later
encounter. In short, it is an important
element which helps to make Ward
Leonard plate dimmers fire-proof and
permanent.

The stationary contact buttons are
made of heavy stamped brass so formed
that the joint with the resistive con-
ductor and the supporting base is com-
pletely imbedded in the vitreous enamel
and solidly attached to the plate. The
contact surfaces over which the mov-
able contact (or skate shoe) travels
project well beyond the surface of the
plate, thus preventing the accumulation
of dust and dirt on or between the con-
tacts, which might cause short-circuit
or poor contact.

CONTACT ARM

The adjustment of the resistance of a
Vitrohm plate is accomplished by means
of a pivoted arm called the contact arm,
which bridges two concentric groups
of contacts on the plate and thus per-
mits the variation in small steps of the
amount of resistive conductor included
in the circuit. This arm is rotativelv
mounted on a shaft at the center of the

Figure 41 — Contact arm and contact-arm drive
assembled on Vitrohm dimmer plate.

plate and is provided with self-adjusting
contact shoes, or skates, which auto-
matically take care of any variation in
the height of the contacts.

These shoes are made of self-lubricat-
ing metal and are each provided with two
plungers that extend into corresponding
holes in the contact arm. Therefore, the
shoes are pressed with definite force
against the contact buttons by means of
coil springs operating on the pins. The
electrical circuit is carried from the shoe
to the arm by means of flexible copper

Figure 42 — Small bank of Ward Leonard Vitrohm
dimmers equipped with independent handles and master
handle.

WARD

L E O N A

ELECTRIC

COM F» A TS "Y

Figure 43 — Variety of sizes of Ward Leonard dimmer rheostats for single-plate installations.

leads fastened permanently into the
rear face of the shoe. Figure 40 shows
an arm of this type with the shoe pins
entirely removed from the guiding
holes in the arm.

CONTACT-ARM DRIVE

In the earliest dimmers the handle
manipulated by the electrician swept
through the same arc as was occupied by
the contacts over which the contact arm
played. In the Ward Leonard Vitrohm
Plate Dimmer the contact arm is rotated
through a flexible drive which multiplies
the motion of the hand several times.

The device employed to translate
the straight line motion to a rotary
motion is peculiarly effective. It con-
sists of a cast iron bow equipped with
a brass link chain, which is wrapped
once around the hub of the contact
arm and positively engages it by means
of a single heavy steel pin. The two
ends of the chain are attached to the
bow by means of wing nuts at each
end which provide for accurate ad-
justment of the tension. Moving the
bow backward and forward causes the
contact arm to rotate as the chain winds
on from one side and off from the other.
This mechanism requires no lubrication,

and unlike the rack and pinion which
is the usual method employed for
translating straight line motion to
circular motion, is not sensitive to
wear, or to dirt, and consequently re-
quires much less effort to operate.

DIMMER BANKS

The dimmer as a complete installa-
tion consists of an assembly of Vitrohm
plates. Such an assembly may be made
in a great variety of ways depending
upon local conditions as to space and
lighting requirements. In general, the
plates are assembled in one or more
rows in a structural steel frame, in
front of which the handles are rota-
tively mounted on one or more shafts.
These levers are connected to the
bows by which the contact arms are
rotated, so that by moving the handle
through a comparatively small arc the
corresponding contact arm on the
Vitrohm plate can be rotated through
its full range.

The independent handles are ar-
ranged with a latch device which per-
mits them to be locked to the shaft on
which they are mounted, or to rotate
freely about it. By providing the shaft

WAR D

L E O NARD

ELECTRIC

COM PA N Y

with a lever which is called a master
handle, it is possible to manipulate at
one time as many units as may be
locked to the shaft, and at the same
time any individual unit or group of
units may be released from the shaft
and operated independently. Again,
by shifting the position of the master
handle, it is possible to increase the
resistance of one group of plates
that is locked to the shaft and at the
same time with the same motion de-
crease resistance in another group. In
this way one group of lamps can be
increased in brilliancy, while another
group is decreased. This result is
called "cross interlocking control."

Where several rows of dimmer plates

are required, each row is equipped with
its line of handles mounted on a shaft,
and the various rows are interlocked by
means of master handles which permit
the operation of all or any number of
parallel shafts with their connected
independent handles by a single master
handle. Furthermore, in many cases the
whole dimmer equipment is arranged so
that it can be operated from slow mo-
tion worm and gear connected to a hand
wheel at the front of the dimmer, in
which event all plates which are locked
to their respective shafts and all shafts
which are locked to one another can

be operated from the one point in a
slow smooth fashion.

Figure 44 — The Shubert-Jefferson, leading dramatic theatre in St. Louis, is

equipped with Ward Leonard Vitrohm dimmers.

WARD

L E O IV A Ft

E.LE C T R I C

C O M F» A IN' *Y

Pt,gur« 45" — Floor Type Ward Leonard Dimmer Bank installed in Loew's Theatre, Los Angeles. Space below

the overhanging row of plates at left allows for the installation of switchboard.

ADVANTAGES

The unique design and construction
of Ward Leonard Vitrohm Dimmers
provide many advantages from both
installation and operating standpoints.
Some important ones are:

1. All Vitrohm Dimmers are con-
tinuous duty dimmers.

2. Minimum space required for a
given service.

3. Minimum weight for a given
service.

4. Reliability of operation.

5. Ease of manipulation.

6. Durability of construction.

7. Simplicity of upkeep.

8. Absence of fire risks.

SPACE

Vitrohm plate construction, permit-
ting free heat radiation, together with
the simple mechanism used to rotate
the contact arm, are responsible for the
compactness of construction in Ward
Leonard dimmers. Each unit when as-
sembled into a bank occupies only four
inches of space in the axial direction.

WEIGHT

The light weight of Ward Leonard
Vitrohm Dimmers follows from the high
efficiency attained in the radiation of
heat from Vitrohm plates. Efficient
radiation in electrical apparatus in-
dicates economical use of material.

•Mi

W A. R 13

LEON

e:lelc XRIC

COM F» A M -V

Figure 46 — Floor Type Ward Leonard Dimmer Bank installed in Raymond Theatre, Pasadena, Calif.

CAPACITY

All Ward Leonard Vitrohm Dimmers
will carry their full rated load contin-
uously at any point in their range with-
out undue rise in temperature. This
extraordinary capacity is simply an-
other advantage of the Vitrohm plate
type of construction which insures the
rapid dissipation of heat so necessary
in a rheostat for this service.

RELIABILITY

The resistors in Ward Leonard dim-
mers are made of metals practically un-
affected by temperature changes, and
are absolutely protected by vitreous

enamel from any kind of deterioration.
Therefore, the resistance values will
remain constant under all conditions of
service. Then, too, the flexible-link drive
by which the rheostats are manipulated
gives a positive connection which will
hold a given adjustment indefinitely.

MANIPULATION

The easy riding self-adjusting contact
shoes, as well as the low friction of the
flexible-link drive make the manipula-
tion of the rheostats extremely easy, so
that an operator can control with one
hand a dimmer of twenty and more
plates.

W A R D

L E O N

ELECTRIC

C O M P

M Y

DURABILITY

There are no fragile elements in a
Ward Leonard dimmer. The Vitrohm
plates are made of metal sufficiently
strong and rigid to stand shipment
anywhere and to protect the resistor
from mechanical strain or damage.
The contact buttons, the arm and the
flexible-link drive for rotating the arm,
including the operating levers and other
accessories, are all designed along en-
gineering lines and will never wear out
under ordinary usage.

UPKEEP

By using the flexible-link drive no
lubrication is necessary at points be-
tween the plates. All bearings which

might require oiling are of the simplest
construction and mounted in accessible
position in front of the bank. The con-
tact shoe, which ordinarily is subject to
considerable wear in rheostats of this
kind, in Vitrohm dimmers requires no
attention or adjustment. This type
of shoe has been standard in Ward
Leonard rheostats for twenty years and
installations made in the beginning of
this period are still in operation without
renewals. 4

ABSENCE OF FIRE RISK

There being no material in the active
parts of the dimmer which has not un-
dergone the firing temperature of the
enamel, there is no danger of starting a
fire in any part of this equipment.

DIMMER XOIV
MECHANISM

Dimmer — A controller for adjusting the in-
tensity of light by varying the current in
the lamp circuit.

Dimmer Plate — A rheostat, including base, re-
sistor, stationary contacts, terminals and
contact arm.

Contact Arm — A movable arm which makes
connection with stationarv contacts and
the position of which determines the re-
sistance in the circuit.

Dimmer Handle — A lever which controls the
movement of the contact arm.

Contact Arm Drive-— Mechanism operated by
the dimmer handle to move the contact
arm.

Dimmer Bank — A number of dimmers mounted
as one unit.

Interlocking Dimmer Bank— One in which the
dimmer handles are mounted on a shaft
to which they may be latched or unlatched.

Interlocking Dimmer Handle — One which is pro-
vided with latching mechanism.

Master Handle — One which rotates a shaft to
which interlocking dimmer handles may
be latched.

Interlocking Master Handle — One which is pro-
vided with latching mechanism.

Grand Master Handle — One which controls in-
terlocking master handles.

Slow Motion Wheel — A hand wheel operating
through gears to control interlocking mas-
ter handles.

Cross Control Mechanism is one by which one or
more interlocking master handles may be
simultaneously moved in the same or
opposite direction to others, by the move-
ment of one handle or wheel.

Preset Interlocking Dimmer Handle is one
which may be automatically latched or
unlatched from connection with others, at
a predetermined position.

CONTROL

Interlocking Control — A control which permits
the grouping of dimmers so that the move-
ment of a master handle or master w heel
will control one or more dimmers as a
unit, without interfering with the in-
dependent control of any single dimmer.

Cross Interlocking Control— An interlocking
control which, by the movement of one
handle or wheel, permits the dimming of
any group of lamps while any other is
simultaneously brightened.

-w

L E O IV A

ELECTRIC

COM PA N "V

Ward Leonard Dim-
mer Equipment in
the Belasco Theatre.
Installed years ago
to control the 3,000
amperes ■ lighting
load, here installed,
and still able to give
service which is
highly satisfactory
to Mr. Hartmann,
the Electrician, and
the exacting Mr.
Belasco.

>V A R D

L E O W A R. E>

ELECTRIC

COM F» A. 1SI Y

WARD LEONARD DIMMER INSTALLATION

Perhaps the most effective way of
presenting Ward Leonard dimmers is to
illustrate and describe a series of typical
installations, because a picture of an
actual installation often gives a better
idea of the possibilities in the applica-
tion of the equipment, than a word de-
scription of the elements which are
combined to make a complete in-
stallation.

The majority of dimmer installations
may be divided into three classes as far
as mounting is concerned:

1. Floor mounting.

2. Top-of-board mounting.

3. Portable mounting.

As far as control is concerned, they may

be divided into the following three
classes :

1. Manual lever control.

2. Manual slow-motion control.

3. Remote automatic control.

These various types of equipment are
illustrated throughout the book by re-
productions from photographs of dim-
mer banks and installations. Each is
discussed briefly in the captions. If the
data given is insufficient, additional in-
formation will be gladly furnished upon
application.

The purpose of these pictures is to
show what has been done with Ward
Leonard dimmers and in this way it is
hoped to assist architects, contractors
and others in obtaining the best results.

LAYING OUT DIMMER BANKS

Too much cannot be said in favor of
giving early consideration to dimmer
equipment in planning a theatre or
other structure where dimmer equip-
ment is to be used. Too often this
important element of the plant is
ignored until the structure is built and
all the principal elements which it houses
have been determined and provided.
The dimmer equipment under such
conditions must be put wherever space
can be found, irrespective of conven-
ience. In making plans which allow
for dimmer equipment, the first step
is to determine the capacity of the dim-
mer required. The second step is to
decide upon the location which will be
best suited when considered from all

points. Of the utmost importance is
the location of the dimmer equipment
and switchboard close to the pros-
cenium arch on the "prompt" side of
the stage. In too many instances the
error is made of allowing space only
sufficient for the switchboard, and the
dimmers have to be mounted over the
board with the levers out of reach of
the operator. The third point is the
determination of the amount of space
required to provide the necessary dim-
ming facilities and proper ventilation.

DIMMER CAPACITY
In selecting the dimmer correspond-
ing to the capacity of the circuits to be
controlled, reference should be made to
Table I where the lamp load in watts is

W A R. D

L E O N A

K. C T R I C

COM F> A N "Y

Ward Leonard Dimmer Bank installed in
the State Theatre in Jersey City, N. J.
This dimmer regulates the colored lights
in the elaborate chandelier above the
auditorium, as well as the stage lighting.

Interior of the State Theatre. To the right is
shown the relative location of dimmers and
switchboard.

L E O N A R. D

ELECTRIC

C O M F»

N Y

given for dimmers of different capacities
made up in five standard assemblies.

SPACE REQUIREMENTS
The approximate space requirements
of a dimmer bank depends not only
upon the size of the dimmer but also the
type of assembly. The number of
plates in a dimmer is determined from
Table I and dimension factors, which
when multiplied by the number of
plates will give the length of the
dimmer, are listed in Table 1 1 (opposite
page) together with the overall end
dimensions of each layout.

The values obtained in the foregoing
method of calculating space require-
ments are based on the average width
ordinarily occupied by each individual
plate in a bank of dimmers of the type
in question. Naturally, plates may be
assembled in different arrangements to
meet special requirements and when so
assembled the over-all dimensions will
vary accordingly. It is always best to
consult the manufacturer and obtain
certified dimensional drawings before
final layouts are made.

VENTILATION
The rating of a dimmer is based on its
ability to dissipate heat, and if it is to
be operated successfully at full capac-
ity, there must be no restriction of the
flow of air between the plates from the
bottom to the top. Especially should
the dimmers be open at the top so that
heated air can move rapidly out of the
way and let cold air take its place.
Dimmers should not be installed under-
neath an obstruction.

TABLE I

TYPE RD INTERLOCKING DIMMERS
for 115 volt 2-wire circuits

Lamp Load
in Watts

Style

No. of
Plates

Catalog
Number

500

750

1000

1320
1500
1700

2000
2400
2700

3000
3300

f A
A
A

A
A

A
A
A

RD 15

RD 17
RD 110

RD 112
RD 115
RD 117

RD 120
RD 125
RD 125

RD 130
RD 130

3600
4200
4800

5400
6000

B
B
B

B
B

2
2
2

2
2

RD 134
RD 138
RD 144

RD 150
RD 160

6600
7200
8100
9000

C
C
C
C

3
3
3
3

RD 166
RD 166
RD 174
RD 190

10200
12000

4
4

RD 1000
RD 1200

15000

RD 1500

REMOTE CONTROL
Sometimes installations work out in
such a way that sufficient space for

housing the dimmer is not available at
the point where the control of the light-
ing should be located. In such in-
stances remote control is employed.

In laying out remote-control installa-
tions the engineering department should
be consulted at the very beginning, as
the variety of factors involved in de-
sign is too great to be covered by
general rules.

ARCHITECTS' TYPICAL
SPECIFICATIONS

To assist those who would specify
standard Vitrohm dimmer equipment,
outline specifications have been pre-
pared to cover the principal points that
play an important part in the success of
a dimmer installation. (See page 44.)

E O N ARD

E.LE.CTRIC COMPANY

DIAGRAMS OF AVERAGE SPACE REQUIREMENT

TABLE II

Diagram 1

INTERLOCKING CONTROL
IN SINGLE ROW

To obtain an approximate length of a bank of
this type multiply the number of plates by 4.5
inches.

Diagram 7

INTERLOCKING CONTROL
TWO ROWS HIGH

To obtain an approximate length of a bank of
this type multiply the total number of plates by
3.2 inches.

Diagram 1 1

INTERLOCKING CONTROL

WITH GRAND MASTER
HANDLE TWO ROWS HIGH

To obtain an approximate length for a bank
of this type multiply the number of plates in the
white stage and white house sections by 3 inches.

DIAGRAM 13

CONTROL WITH CROSS INTER-
LOCKING SLOW MOTION
WHEEL TWO ROWS HIGH

To obtain an approximate length of a bank of
this type multiply the number of plates in the
white stage and white house sections by 4.4 inches.

DIAGRAM 14

FLOOR MOUNTING, 3 OR 4 ROWS HIGH,

WITH COLOR MASTER LEVERS AND

SLOW-MOTION CROSS-CONTROL

WHEEL IN CENTER

This is a most advantageous arrangement.

To obtain an approximate length for a bank of
this type, multiply the number of plates in the
white stage and white house sections by 4.25
inches and add 1 5 inches.

"W A. R. D

L E O N ARD

ELEC X R1C

C O M 1>

TYPICAL SPECIFICATION FOR THEATRE DIMMER

(a) On the prompt side of the stage adjacent
to the proscenium arch there shall be installed
the dimmers listed in the lighting schedule.
These dimmers shall be supported in a rigid
angle-iron frame in such a manner that no
operating handle will be nearer the floor than
six inches, nor more than seven feet above the
floor, so that the average operator can reach
them easily.

(b) The dimmers shall be of the plate type
arranged for either individual operation or for
interlocking to a color master lever. They
shall be arranged in color groups with a master
lever for each color in the house and for each
color on the stage. There shall also be pro-
vided a slow motion cross control wheel and
gears with color masters so arranged that color
sections may be operated individually, or they
may be interlocked to the hand wheel mechan-
ism to raise the illumination of one or more
color groups and at the same time dim one or
more other color groups.

(c) All feeders or group circuits of 3000
watts or less and the dimmers for them shall
be two-wire. Feeders carrying a greater load
may be three-wire.

(d) The dimmers shall be the Vitrohm type
suitable for continuous operation at their rated
load and, after carrying this load at any setting
for two hours with natural air circulation, no
part of the dimmer shall attain a temperature
in excess of 250° C. above the surrounding air
and shall not emit smoke, steam or odor.

(e) The resistor for each dimmer shall be
divided into not less than 110 steps, and the
resistor material and contacts shall be attached
to a rigid metal supporting plate. The resistor
material shall be embedded in a non-hygro-

scopic heat-conducting insulating material cap-
able of withstanding a temperature of 400° C.
without calcining, softening or deteriorating.
The movable contacts cutting the resistance in
and out of the circuit shall be the skate shoe
type with minimum friction consistent with
good carrying capacity and long life.

(f) Where the dimmer for a group circuit
or feeder consists of more than one plate it
will be provided with one common buss for
connecting all the plates to the fuse of the
group circuit. The other separate terminals
of each plate shall be connected with a wire of
suitable capacity to separate sections of the
branch circuit buss. The separate plates
making up the dimmer shall be rated for the
capacity of the branch circuits so connected
to them.

(g) The contractor shall submit to the archi-
tect (or engineer) a drawing showing the pro-
posed arrangement of the dimmer and switch-
board which must be approved by him before
construction work is started.

(Insert the following clause in the magazine
panel specification.)

(h) These fuse panels shall be bussed for
connection to the group circuits outlined in the
schedule and where the dimmer for the group
circuit or feeder consists of more than one
plate the buss for this group circuit shall be
divided to distribute the load on the separate
plates.

The Ward Leonard Electric Company have
on their technical staff experts on theatre il-
lumination and lighting control who will be
glad to co-operate with those interested and
furnish them with suggestions.

A TYPICAL LIGHTING SCHEDULE

CIRC.
NO.

LIGHTS CONTROLLED

LAMPS

MAG.

BRANCH

ClROS,

DIMMERS

SWITCHES

NO.

WATTS

TYPE

WATTS

MASTER

POLES

MASTER

White Foots

200

7000

I 1

" Prose. Strips

100

3200

" Border No. 1

400

7200

#i II ii o

400

7200

/ w

/ U)

1 n

CIO

-i ii ii 3

400

7200

ri ii .. ^

400

7200

1 ©

ii ii u 5

400

7200

«, g

400

7200

Incand. Pockets

8-2000

ii ■!

6-2000

Arc

* * » * *

>V A. R D

L E O N ARD

EJUELC XR.IC

COM F> A. T*i Y

The Ward Leonard
Dimmer shown, which
controls the 5,000 am-
peres required for light-
ing effects in the famous
New York Hippo-
drome, was installed
years ago. There is a
total connected load on
this equipment of
10,000 amperes (three-
wire, direct current).

Close-up of the panel
shown in the lower
part of the picture
above.

New York
Hippodrome.

I."

L E O N AR D

EC X R. I C

C O M F» A. TS' Y

The name Vitrohm has been used in
the specifications, because it represents
in a definite and positive way a metal
plate construction in which vitreous

enamel and resistor material are applied
in accordance with experience of more
than thirty years in the manufacture of
this type of apparatus.

Figure 47 — Ward Leonard Dimmers (top of board
type) installed in the National Theatre, New York City.

Figure 48 — Ward Leonard Dimmers installed
Loew's 83rd Street Theatre, New York City.

BASIC FACTORS IX DIMMER INSTALLATION DESIGN

When requesting proposals for dimmer
equipment, the manufacturer should be fur-
nished with the following information:

1. Voltage of lamp circuits.

2. Whether dimmers are to be connected
to two or three-wire circuits.

3. The circuits to be controlled must be
listed and the name of each indicated,
so that the dimmer handles may be
furnished with proper nameplates.

4. The number of watts per dimmer and for
multiple plate dimmer the number of
watts on each plate.

5. The type of dimmer control : inde-
pendent handle interlocking, cross inter-
locking or remote control.

6. If interlocking or cross interlocking
dimmers are to be used, the general

arrangement including the number and
position of master handles should be
indicated by means of a rough sketch.

7. If the dimmers can be arranged in
some standard form such as shown on
page 43, it will be sufficient to indicate
the arrangement by reference to the
respective diagrams.

8. The dimensions of space available for
the dimmer should be given.

9. The lamp load carried by any dimmer
may comprise several sizes of lamps
providing the maximum capacity of the
dimmer is not exceeded.

10. Where equipment is unusual, any re-
quirements in addition to the above
should be fully specified.

The typical floor plan for stage lighting as shown on page 58 may be helpful in considering the general

problem of lighting.

"w >v R. n>

L E O IV ^V

ELEC X R. I C

COMPANY

Interior of chc National Theatre, Brooklyn, N. Y.

At the left are shown the operating handles of the Ward Leonard Dimmers installed in the National Theatre ir
Brooklyn. The plates are on the opposite side of the wall as shown at the right in a separate room with the
motor generator set

LEON

ELECTRIC

COM F> A ISJ Y

COM

PARA1

riVE EFFICI

ENCY

— i

'■j^

RESISTANCE & REACTANCE

D MMERS

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WARD LEONARD ELECTRIC

COM

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LAMP VOLTAGE £OF NORMAL

100

The curve above shows the comparative efficiency of resistance and reactance dimmers
with different voltages at the lamp, while the one below shows the candle-power at different
voltages. From these curves it will be noted that a distinct saving in energy can be effected
by the use of reactance dimmers; also that their use is justified in installations where the
dimmer is in service for long periods.

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L E O N

ELECTRIC COMF»yVT*WY

WARD LEONARD REMOTE -CONTROL DIMMER 1

In large installations the space re-
quired for dimmer equipment is often
not available at a point where the con-
trol board should be situated. One
solution of this space problem is the
motor-driven dimmer located at any
point where the space is available, and
controlled by miniature switches from
the control board.

The original form of remote-control
dimmer employed by the Ward
Leonard Electric Company was motor
driven as shown in Figure 31 repro-
duced from the catalog of the Ward
Leonard Electric Company issued in
1892. Improved forms of the early
motor-driven dimmer are still furnished
where required. In such installations
each plate or group of plates is con-
nected to a separate motor through a
worm reduction gear and controlled by
push-button stations located at the con-
trol board on the stage. Substantial
positive-acting limit switches prevent
over-running in case the operator does
not shut off the motor. The motor
circuits are manipulated by magnetic
switches or contactors mounted on a
panel carried on the dimmer frame.

REACTANCE DIMMER

A better solution of the remote con-
trol problem is provided by the re-
actance dimmer, a recent Ward Leonard
development. This consists of a Vitrohm
plate and a reactor. In this dimmer,
adjustable reactance is utilized to con-
trol the flow of electricity to the lamps —
the reactance being varied by means
of a standard Vitrohm plate handling
a current of less than two per cent, of
that required by the lighting circuits
which it controls.

By this new system a small Vitrohm
plate for each circuit with standard
hand levers and slow-motion control

are the only parts of the dimming plant
which need be installed on the stage.
The reactors which handle the main
circuits to the lamps may be located
wherever space is available. In this
way, the actual control equipment,
which should be located at a point on
the stage where the operator can follow
the action, is reduced to the smallest
possible dimensions, and entirely within
the limits imposed by modern con-
struction.

PRINCIPLE OF THE REACTANCE

DIMMER

The reactor used is of a closed circuit
type having two A. C. coils and a
D. C. coil. By varying the current in
the D. C. coil by means of a small
Vitrohm plate, the voltage at the lamp
is varied from full brilliance to black
out.

The direct current for controlling
these reactors, if not available from
existing sources, may be furnished by
a small motor-generator. The amount
of power required is approximately one
per cent, of that used in the main cir-
cuits. Among the installations of this
character are the two largest dimmer
installations in the world (illustrated
on pages 50, 51 and 52).

The control board of Grauman^s
Metropolitan theatre shown on page
52, is the most compact of any ever
built. While it controls 135 feeder
switches and the dimmers regulate the
lighting load of 650 kw., it is only about
1 3 feet long, and is installed in a recess
of the prompt side of the proscenium
arch. The remote switchboard is in-
stalled directly under the stage in the
basement. At the rear of this board are
mounted the reactors, which are con-
trolled by the Vitrohm plates on the con-
trol board (shown at top of page 52).

W ^V R, D

O >J

EI-ELC TRIC

COMPAN

w ^v Ft r>

L E O IN

ELECTRIC

C O M F*xV IN Y

Bank of Ward Leonard Vitrohm plates, controlling the reactance dimmers shown below. The center picture on
the opposite page shows this pilot dimmer with the pilot switches and steel front added. This is the largest and
finest auditorium in the United States, having a seating capacity of 12,000 persons. The dimmer is the largest
in the world. Total load connected to dimmers, 900 kw. The pilot board shown in the center of opposite page
controls the contactor board in the basement. This was built by the Cleveland Switchboard Company.

The Ward Leonard
Reactance Dimmers
installed at the rear of
the contactor board in
the basement of the
Cleveland Auditorium.
These are controlled
by the bank of Vit-
rohm plates, shown
above, and regulate
the lamps of stage
and house from full
brilliancy to black out.
This is the first instal-
lation of its kind and
has been in operation
for about one year, giv-
ing perfect satisfaction.

WAR D

L E O IW A Ft

E LE C X R I C

C O M F>

IS T Y

Vitrohm plates on the
rear of the pilot board,
shown at bottom of

this page.

Grauman's Metro-
politan Theatre,
Los Angeles, desig-
nated on the coast
as the '* Show
Hou se of the
World.' Holmes
and Sanborn, Con-
sulting Engineers.

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"!• .; .1 H iJ >l

Jil^iiiliL

Pilot dimmer and
switch-board con-
trolling, by means
of Ward Leonard
Reactance Dim-
mers, the largest
lighting load of any
theatre — 650 kw.
The pilot switches
shown control a
Hub Electric Com-
pany Remote
Switchboard in the
basement.

Ward Leonard Reactor.

L E O N A

ELECTRIC

COM f> ^V >I "Y

Granada Theatre. San Francisco. One of the recent installations of Ward Leonard Dimmers on the coa^t .

370 kw. lighting load, controlled by the dimmer equipment shown in the insert picture.

-W Jk. Ft D

L E O N A Ft

ELLE-CTFilC

COM PAN Y

Auditorium of Castles by the Sea Theatre.
Vitrohm dimmer bank and switchboard
shown below.

Castles by the Sea, at Long Beach, L. I., is
one of the many dining, dancing and amuse-
ment palaces where Vitrohm dimmers are
depended upon under all of the conditions
of service usually existing at seaside resorts.

W ^X R. E>

L E O N A

ELECTRIC

C O M F» A N If

Ward Leonard motion picture type
cross-control dimmer in the State
Theatre, Pittsburgh. Each
dimmer is equipped with
two-drive rods so that each
dimmer can be set to dim
brighten independ-
ently of all the others
and all can be oper-
ated as set from the
one slow motion
wheel. This per-
mits the dimming
of any particular
group simultane-
ously with the
brightening of
any other group.
The compact ar-
rangement made
possible in this
construction has
many important ad-
vantages for control
from the projection
booth.

R. D

LEO >«' ^

L e. C T R I C

C O M F" ^V IS' Y

When Mr. George Eastman built
the Eastman Theatre for the people
of Rochester, he built for per-
manence — permanence in service
Hence. Vitrohm Dimmers tor con-
trolling upward? of 200.000 watts
in lamp load were installed in thi^
wonderful institution.

The Vitrohm dimmer installation is
shown at the right. A rear view ot
the dimmer bank i< shown below.

The installation picture at the right
shows the Ward Leonard "pre-set""
a-i used on these dimmers. This
arrangement permits the setting of
the operating lever so that it either
"drops in" or drops out"' at the
preset pos'tion, thus leaving the
predetermined amount of dimmer
resistance in the circuit.

L. E O N A R D

E, !_,

C T R. I C

COM PANY

Nearly all of the prominent theatres on Broad-
way use Vitrohm Dimmer equipment tor lighting
effects. The Winter Garden and Rivoli are no
exception. The partial list of Vitrohm instal-
lations on page 02 gives some idea of their
universal application.

W A. R. D

L E O N A.

ELECTRIC

C O M F» A ]%'

A typical floor plan for stage lighting

Yitrohm Dimmer equipment and switchboard used for
controlling the lighting of the Auditorium of the
Metropolitan Life Insurance Company, New York.

PORTABLE EQUIPMENT

Compactness and light weight of Vitrohm
dimmers are of particular advantage to
travelling or road shows when the desired
lighting effects cannot be secured with the
local equipment. Here and on the opposite
page are shown several equipments pro-
vided for the purpose.

400-ampere Portable Dimmer equipment manufactured
by the New York Calcium Light Company, using 8
standard rectangular Vitrohm plates and 18 slide type
Vitrohm spotlight dimmers.

W AR D

L E. O N A. R E>

ELE.C T RIC

COM F» A. N Y

Portable Dimmer equipment made by
James Pennetather, New York, using
round type Vitrohm plates.

Portable Dimmer equipment made especially
for the spectacular show, "'Mecca, - ' using Vit-
rohm round plates and Ward Leonard control
levers on the switchboard.

Portable Dimmer equipment made by Kliegl
Bros., New York, using Vitrohm round plates.

WAR. E>

L, E O N

n c

RIC

C O >i r»

IS' "V

PROJECTION LAMP CONTROL RHEOSTAT

(For 600 and 900- Watt Lamps)

THE life and efficiency of a projection lamp
depend on maintenance of the current sup-
plied the lamp exactly in accordance with the
rated current on which it was designed to
operate.

To accomplish this a rheostat is required
capable of reducing the line voltage to pre-
cisely the proper voltage needed to permit the
proper amount of current to flow through the

lamp.

The Ward Leonard Lamp Control Rheostat

is especially designed to serve this purpose with
maximum dependability and convenience.

To reduce the line voltage to approximately
that desired for the proper operation of the
lamp a fixed resistance, made up of Ward
Leonard Ribohm Resistor Units, is provided.
These rigid, self-supporting units are made of
metal ribbons, are very light in weight, are
practically unbreakable, and have great capa-
city for heat radiation.

An adjustable resistance element, of Ward
Leonard Vitrohm construction, permits close
regulation of the lamp current. Initial current
inrush is automatically limited sufficiently to
assure slow heating of the lamp filament — a
feature of substantial value in increasing the
life of the lamp.

Ward Leonard Projection Lamp Control
Rheostats can be used on either Direct or
Alternating Current, and can be supplied for
service on line voltages of 32 to 320 volts.

In common with all Ward Leonard apparatus
the workmanship, finish and general appear-
ance of this equipment fully accords with its
superior efficiency in service.

MOTOR RHEOSTATS FOR BLOWER EQUIPMENT

D. C. Motor Starter

D. C. Motor Starter with 16
Points of Field Control

A. C. Singlc-PhaM. Starter

RELIABLE motor starters for the control
.. of motor-driven blowers for ventilating
theatre auditoriums, motion picture projection
booths, spotlight booths, etc., are essential to the
proper operation of this important equipment.
Ward Leonard Motor Starters will be found
perfectly adapted to thisserviceandareavailable
in types and sizes covering all requirements.

Ward Leonard Vitrohm and Ribohm Re-
sistor Units, incorporated in all of these motor

starters, provide a resistance element (the
heart of a motor starter) of great mechanical
strength and heat radiating capacity — far su-
perior to ordinary cast iron grids.

These features, combined with other points
of great practical advantage, such as per-
manently efficient contactors, smooth-working
of moving parts, and dust-proof construction,
assure the easy, positive and dependable oper-
ation of this equipment.

W ^V Fi I>

LEON

F£ O

ELE.C T RIC

C O vf p» ^v W Y

PUSH BUTTON CONTACTOR

(For Organ Blower Motor)

A RELIABLE automatic starter for the re-
mote control of theatre organ blower
motors is a practically indispensable adjunct
to the proper operation of such organs in the
up-to-date theatre.

Ward Leonard Push Button Contactors of
the type here illustrated are standard equip-
ment for this service. Correct design, quality
material, high grade workmanship — heavily
insulated operating coils, liberal contact areas,
dust-proof construction, thorough ventilation
— Vitrohm Resistors. These are elements
which assure the efficient performance of this
highly important equipment.

ARC CONTROL RHEOSTATS

EASY to operate. Dependable. Regulates
closely over wide range. Mechanically
strong. Will give long service under heavy
duty. Low cost.

The perfect rheostat for motion picture, spot-
light or arc control requirements.

Ward Leonard Arc Control Rheostats,
equipped with Ward Leonard Vitrohm and
Ribohm resistor units, weigh but half as much
as ordinary cast iron grid series rheostats,
and are practically trouble-proof. They are
supplied in several special designs, respectively
intended for picture arc control, for con-
trolling spotlight in booth, for spotlight on
stage, or to serve as generator ballast.

This equipment is widely used and recom-
mended for such service in the theatrical field,
and will be found definitely superior in point of
service, first cost, or maintenance expense.

GENERATOR FIELD RHEOSTATS

THE motor generator set which supplies the
energy for the motion picture machines and
spotlights is generally supplied with a rheostat
for field control. Ward Leonard Vitrohm Field
Rheostats will be found exactly adapted to
theatre needs in this service.

The Vitrohm construction of these rheostats
is very similar to that described in connection
with Ward Leonard Dimmer Plates pictured
elsewhere in this book. Fire-proof, moisture-
proof, non-absorbent vitreous enamel com-
pletely and permanently protects the resistance
wire from oxidation or corrosion.

These rheostats are provided in sizes cover-
ing all usual ampere capacities, and in various
types of control arrangement to suit require-
ments.

W A R D

LEON

E LE C X R I C

COMPANY

A Partial List of Ward Leonard Vitrohm Dimmer Installations

ARKANSAS

Little Rock

Little Rock Theatre

CALIFORNIA

Anaheim

Anaheim Theatre
Elks' CJub

Bakersfield

Hippodrome Theatre

Eureka

Eureka Theatre

Fuller ton

Masonic Hall

Clendale

Palace Grand Thea.

Los Angeles

Arlington Theatre
Belvedere Theatre
Chottiner Theatre
Circle Theatre
Edison Club Room
Graff Theatre
Hotel Theatre
Larchmont Theatre
Le Conte, Jr., High

School
Loew's State Thea.
McKinley High

School
McMurray Theatre
Metropolitan Theatre
Moneta Theatre
John Muir High

School
Paramount Theatre
Rivoli Theatre
Sentuons High School
Southout Theatre
Temple Theatre
rivoli Theatre
Tripoli Theatre
Van Nuys Theatre
Writers' Club

Monte Rio

Bohemian Grove

Oakland

Fox-Oakland Theatre
Masonic Temple

Ocean Park
Dome Theatre

Pasadena

Raymond Theatre

Richmond

T & D Theatre

San Francisco
Castro Theatre
Excelsior Theatre
Fox Theatre
Granada Theatre
Palace Hotel
Rial to Theatre

Santa Clara

Santa Clara College

San Pedro

Dodson Theatre

Santa Rosa
Cline Theatre

CONNECTICUT

Bridgeport
Poli Theatre

Hartford

Poli Theatre

Meriden

Community Theatre

New London
Opera House

DELAWARE

Wilmington

Dupont Theatre

FLORIDA

Miami

Masonic Temple

GEORGIA

Savannah

Masonic Temple

ILLINOIS

Champaign

Virginia Theatre

Chicago

Aryan Grotto Temple
Blue Island Masonic

Temple
Central Park Thea.
Chicago Theatre
Columbia Theatre
Cort Theatre
Covent Garden Thea.
Englewood Theatre
Glickmans Palace Th.
Grand Theatre
Hamlin Ave. Thea.
HumboldtParkLodge
813, A. F. & A. M.
HumboldtParkLodge
Commandery No.
79, K. T.
Illinois Theatre
Lawndale Masonic

Temple^
Lawndale Theatre
Lincoln Tavern
Logan Sq. Masonic

Temple
Lomax Theatre
Marzano Dance Hall
Midway Masonic

Temple
Opera Club
Orchestra Hall
Powers Theatre
Rainbo Gardens
Roosevelt Theatre
Roseland-State Thea.
St. Bernard Com-
mandery No. 35,
K. T.
Senate Theatre
Trianon Ball Room
State-Congress Thea.
Tiffin Theatre
Victoria Tbeatre

Evanston

Evanston Theatre

Kewanee

Peerless Theatre

Lincoln

Lincoln Theatre

Oak Park

Oak Park Theatre
Warrington Theatre

Peoria

Orpheum Theatre

INDIANA

La Porte

Indiana Theatre

Michigan City
Tivoli Theatre

South Bend

Palace Theatre

Whiting

Whiting Community
Memorial House

IOWA

Davenport

New Theatre
Des Motnes

Roosevelt High
School

Ottumwa

High School

KENTUCKY

Covington

St. Joseph School

MARYLAND

Baltimore
Johns Hopkins H. S.
Ford Theatre

MASSACHUSETTS

Boston

Fine Arts Theatre.
Hollis St. Theatre
Loews State Thea.
Selwyn Theatre

Somerville

Central Theatre

Springfield
Poli Theatre

MICHIGAN

Det roit

Capitol Theatre
Gayety Theatre

MISSOURI

Joplin

Scottish Rites Cath'l

St. Louis

Shubert-Jefferson
Gayety Theatre

NEW JERSEY

Asbury Park
Main Theatre

Jersey City

Heste Theatre or Ritz
Rivoli Theatre
State Theatre
Twin Theatre

Lakewood

Lakewood Theatre
Palace Theatre

Montclair

Claridge Theatre

Newark

Shubert Rialto
Central Theatre
Rivoli

New Brunswick
Opera House
Reade Theatre
Rivoli Theatre

Pater son

Lyceum Theatre
Paterson Masonic
Lodge

Trenton

Capitol Theatre
Main Theatre

West Hobo ken

Roosevelt Theatre

NEW YORK

Amityville, L. /.
Masonic Lodge

Astoria, L. L
Astoria Theatre

Brooklyn
Bay Ridge Theatre
Bensonhurst Thea.
Capitol Theatre
Commodore Theatre
Glenwood Theatre
Kismet Temple
Meserole Theatre
Midwood Theatre
Miller Theatre
B F. Moss Theatre
National Theatre
Premier Theatre

Babylon. LI.
Capitol Theatre

Buffalo

Gayety Theatre
Shea's Opera House
Statler Hotel
Victoria Theatre

Cedarhurst, L. I
Central Theatre

Dunton, L. /
Masonic Lodge

Forest Htlts, L. I .
Globe Theatre

Freeporl, L. I .

Freeport Social Club

Hempstead, L. I .
Rivoli Theatre

Jamaica, L. /.

Merrick Theatre
Roseland Theatre

Jamestown

Palace Theatre
Masonic Temple

Long Beach, L. I .
Castles by the Sea

Middletown

Middletown Theatre

New Rochelle
High School
Loew's Theatre

New York City
Belasco Theatre
Blue Bird Dancing
Century Theatre
Clover Garden
Cohan & Harris Thea.
Cort Theatre
Daly 63rd St. Theatre
Empire Theatre
Freeman Theatre
14th St. Theatre
Hamilton

Harlem Opera House
Hippodrome
Hotel Plaza
Jefferson Theatre
Keith's Colonial
Keith's Royal
Keith's 8 1st St. Thea.
Liberty Theatre
Loews National
Loew's 83rd St. Thea.
Longacre Theatre
Lyceum Theatre
Marc Klaw Theatre
Maxine Elliott Thea.
New Winter Garden
Palais Royal
Playhouse
Proctor's Theatre
Rainbow Dancing
Punch & Judy Thea.
Regent Theatre
Ritz Theatre
Roosevelt Theatre
Roseland
Shubert Theatre
Strand Theatre
Tivoli Theatre

Niagara Falls

Cataract Theatre
Strand Theatre

Ozone Park, L. I .
Tower Theatre

Peeksktll

Peekskill Theatre

Rochester

Eastman Theatre
Fays Theatre
Temple Theatre

Rockawax Park, L. I .
Park Theatre

Rockvtlle Center, L. I.
Strand Theatre

Sheepshead Bay. L. I.
St. George Theatre

Troy

Proctor's Theatre
Strand Theatre

Uniontown
State Theatre

White Plains
Lynn Theatre

Woodhaven, L /.
Roosevelt Theatre

Yonkers

Metro Theatre
Orpheum Theatre
Strand Theatre

NORTH CAROLINA
High Point

High Point Theatre
Lexington

Lexington Theatre

OHIO
Akron

Pythian Temple
Cleveland

Allen Theatre

Municipal Hall
Dayton

National Theatre
Niles

Niles Theatre

PENNSYLVANIA

Braddock

Capitol Theatre
McKeesport

Columbian Theatre
Philadelphia

Germantown Theatre
Pittsburgh

State Theatre
Sc rant on

Scranton Theatre

SOUTH CAROLINA

Greensburgh

National Theatre

RHODE ISLAND

"Newport

Newport Theatre
Providence

Palace Dance Hall

TENNESSEE

Chattanooga

Central High School

TEXAS

Dallas

Loew's Theatre

VIRGINIA

Winchester

Winchester Theatre
Handley School

WASHINGTON
Seattle

Garfield High School
Hotel Theatre
Holy Rosary School
St. John's Parish
School #

WISCONSIN

Madison

Orpheum Theatre

WYOMING

Cheyenne
Masonic Temple

CANADA

Toronto

Allen Theatre
Univ. of Toronto

Winnipeg
Gayety Theatre

There are hundreds of others (installed throughout the country during the past twenty
years) that are proving Vitrohm Dimmers are truly Continuous Duty Dimmers.

[BLANK PAGE]

CCA

INTERNATIONAL

[BLANK PAGE]

CCA

INTERNATIONAL

Lillibridge 99-3001. 10. ?-23

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