CORNING MADE IN U.S.A. 5 1 2 " D. X . 1 2 " F . I . D . 1935 PURPLE , Synthetic Purple
This lens is called Synthetic Purple.
inner doublet, missing a red metal rimmed roundel that is inserted in the hole of this lens on the stepped side which is 1 5/8 dia. and is chamfered at this widest point to just near 1 1/4 which looks seated ,
Thank you, Steve Cherry. For the opportunity to obtain this lens
for the lens folder.
and Thank you Zachary again for adding your comment
about this odd lens .
cite: paddy fitz for "Synthetic Purple"
Thank you Railroad signals of the U.S. web site.
Had it not been for paddy fitz commenting about my use
of the "C" word, that most non railroaders use to describe
purple.
his mentioning the word "synthetic purple"
led me to the Railroad signals of the U.S. web site
in which the moderator Todd, felt inclined to share his comments of
his run in with another knowledgeable collector . regarding the "incorrect" term, or is it? (cobalt) aka "C" word, is simply a great must read!
which nerves some in the railroad signalling and collector groups .
However all these forums do in fact bring out correct
historical tidbits, its cutting through the white noise
and rooting out the meaty parts that
brought the below information together that discuses
Purple its use and strange alteration concoctions in early electric color light signalling that's not wildly known.
Thanks guys. and yes this is and its variants are rare and the use of this red center purple is not system wide.
other sources state "hot pink"
however Synthetic purple does hit on web searches however
a glitch in google books will not allow you to pin point the discussion about synthetic purple as google targets "primary batteries" story , i nearly read the whole book finally discovering the synthetic purple story days later .
Enjoy the information as i presented it word for word
comma to period from the book verbatim below.
January, 1936
Railway Signalling and communications, Volume 28
Two Parts ----- part two.
"What information is available as to the use of improved types of signal
glasses to provide a more satisfactory purple aspect?"
Red Center Purple
B.J. Schwendt
Assistant signal engineer, New York Central, Cleveland Ohio.
We have solved our difficulty on color-light dwarf signals by using what we call
a Red-centered purple.
With the regular full purple lens, even with the highest transmission,
it was almost necessary to use a 40-watt instead of an 18-watt
lamp to produce a daylight indication of sufficient range
to cover the stopping distance under the permissible speed
at such signals. This complicated the manner of supplying the standby battery
for such signals. After experimenting in 1928, we hit on the idea of the red-centered purple, which not only made it possible for to use the standard electric lamp on these color-light dwarfs, but also increased the range of visibility.
The following information states the details of this "more satisfactory purple lens"
for color-light dwarf signals:
1, The red center 1 15/64 in, in diameter and is applied to the 3 5/8
inner unit of the doublet lens, which is the color unit.
2, This lens gives about 900 ft. daylight indication under the most adverse sunlight
conditions, whereas our regular purple gives about 500 ft.. wattage and other conditions remaining the same.
3, The electric lamp used is the standard for color-light dwarf signal namely 8- volt
18-watt , rebased PS-16 bulb burning at 7.5 volts .
4, Under bright sunlight conditions, this particular lens
Looks like a poor red ; that is, the purple portion looks bluish and is difficult to see.
By night it looks like a real purple at 300 ft , the red becoming more predominant
as the distance from the signal increases. By night the regular purple looks quite blue, the slight red showing up only at greater distances from the signal.
5, Tests were conducted on a similar purple unit with a red center , only
27/32 in , in diameter. This shortened the range slightly as compared with the large red center, reducing it from 910 to 730 ft and reducing the predominance
of the red previously mentioned.
6, on a cloudy day the comparative ranges are as follows.
Large red center purple- 2000 ft.
Small red center purple- 1600 ft .
Our regular all purple- 1100 ft .
Comments of a manufacturer:
W.N. Manuel
Manager Corning Glass Works ,Railroad , Marine & Traffic division, Corning
N.Y.
Purple, as a signal indication, will probably always be restricted to short range
visibility.
With a kerosene light source , purple is distinctive for a short range night
indication but the the glass appears blue when used as a Mazda lamp
burning near normal voltage.
Electric purple of much greater saturation may be successfully used
as a short range night signal indication, but the range is not sufficient for day light
indication.
A synthetic purple, for use of the doublet lens combination, as manufactured for the signal companies, is in use on the New York Central lines west.
an electric purple disk, having a minimum transmission of 30 per cent,
is used in the searchlight type signal,and its performance may also be obtained
from the New York Central Lines east.
The electric purples are included in the A.A.R.
signal section specification 69-35.
The synthetic purple consists of a red and purple glass
combination , of a predetermined ratio of color area to produce the desired color range within its limitation.
This combination offers at present the best solution for improving
the purple indication.
A Combination Satisfactory:
F.C. Stewart
signal engineer, Elgin Joliet and Eastern
Joliet Ill.
pg 438.
We have never been able to secure a satisfactory
purple for night indication for dwarf signals; consequently,
we resorted to the expedient of inserting a 1 1/4 in diameter red glass disk
in the center of the 5 3/8 in diameter purple roundel .
We think this greatly improved our night indications and the enginemen
liked the change.
on our first installation of color-light dwarf signals of the searchlight type,
we found the stop indication to be very unsatisfactory, especially during the very bright daylight.
We asked the manufacturers to provide red disks with 1/4 in horizontal purple glass stripes through the centers.
The disks were mounted so that the 1/4 in would be horizontal when the signals were in the stop position.
This practice greatly improved the stop indications, as the signal gave the appearance of a red light with a purple halo, or a purple light with a red halo.
either type gave a workable indication.
We do not believe that, in the present state of the art , a satisfactory
purple indication be secured and would prefer a dark red for the stop
indication on dwarf signals.
However , they are made much more frequently than the old custom
of periodic night checks.
When the color- light signals are used, it is the practice
to change lamps periodically so that lamps are burned according
to their rated life.
Consequently, a reported "light out" failure rarely occurs.
With the modern color-light signal, means are provided for focusing
the light in the daytime so that we are assured of good daylight and night indications.
**** NOTE! The above information is well cited for source credit and the information on this page is for educational and historical purposes .
CORNING MADE IN U.S.A. 5 1 2 " D. X . 1 2 " F . I . D . 1935 PURPLE , Synthetic Purple
This lens is called Synthetic Purple.
inner doublet, missing a red metal rimmed roundel that is inserted in the hole of this lens on the stepped side which is 1 5/8 dia. and is chamfered at this widest point to just near 1 1/4 which looks seated ,
Thank you, Steve Cherry. For the opportunity to obtain this lens
for the lens folder.
and Thank you Zachary again for adding your comment
about this odd lens .
cite: paddy fitz for "Synthetic Purple"
Thank you Railroad signals of the U.S. web site.
Had it not been for paddy fitz commenting about my use
of the "C" word, that most non railroaders use to describe
purple.
his mentioning the word "synthetic purple"
led me to the Railroad signals of the U.S. web site
in which the moderator Todd, felt inclined to share his comments of
his run in with another knowledgeable collector . regarding the "incorrect" term, or is it? (cobalt) aka "C" word, is simply a great must read!
which nerves some in the railroad signalling and collector groups .
However all these forums do in fact bring out correct
historical tidbits, its cutting through the white noise
and rooting out the meaty parts that
brought the below information together that discuses
Purple its use and strange alteration concoctions in early electric color light signalling that's not wildly known.
Thanks guys. and yes this is and its variants are rare and the use of this red center purple is not system wide.
other sources state "hot pink"
however Synthetic purple does hit on web searches however
a glitch in google books will not allow you to pin point the discussion about synthetic purple as google targets "primary batteries" story , i nearly read the whole book finally discovering the synthetic purple story days later .
Enjoy the information as i presented it word for word
comma to period from the book verbatim below.
January, 1936
Railway Signalling and communications, Volume 28
Two Parts ----- part two.
"What information is available as to the use of improved types of signal
glasses to provide a more satisfactory purple aspect?"
Red Center Purple
B.J. Schwendt
Assistant signal engineer, New York Central, Cleveland Ohio.
We have solved our difficulty on color-light dwarf signals by using what we call
a Red-centered purple.
With the regular full purple lens, even with the highest transmission,
it was almost necessary to use a 40-watt instead of an 18-watt
lamp to produce a daylight indication of sufficient range
to cover the stopping distance under the permissible speed
at such signals. This complicated the manner of supplying the standby battery
for such signals. After experimenting in 1928, we hit on the idea of the red-centered purple, which not only made it possible for to use the standard electric lamp on these color-light dwarfs, but also increased the range of visibility.
The following information states the details of this "more satisfactory purple lens"
for color-light dwarf signals:
1, The red center 1 15/64 in, in diameter and is applied to the 3 5/8
inner unit of the doublet lens, which is the color unit.
2, This lens gives about 900 ft. daylight indication under the most adverse sunlight
conditions, whereas our regular purple gives about 500 ft.. wattage and other conditions remaining the same.
3, The electric lamp used is the standard for color-light dwarf signal namely 8- volt
18-watt , rebased PS-16 bulb burning at 7.5 volts .
4, Under bright sunlight conditions, this particular lens
Looks like a poor red ; that is, the purple portion looks bluish and is difficult to see.
By night it looks like a real purple at 300 ft , the red becoming more predominant
as the distance from the signal increases. By night the regular purple looks quite blue, the slight red showing up only at greater distances from the signal.
5, Tests were conducted on a similar purple unit with a red center , only
27/32 in , in diameter. This shortened the range slightly as compared with the large red center, reducing it from 910 to 730 ft and reducing the predominance
of the red previously mentioned.
6, on a cloudy day the comparative ranges are as follows.
Large red center purple- 2000 ft.
Small red center purple- 1600 ft .
Our regular all purple- 1100 ft .
Comments of a manufacturer:
W.N. Manuel
Manager Corning Glass Works ,Railroad , Marine & Traffic division, Corning
N.Y.
Purple, as a signal indication, will probably always be restricted to short range
visibility.
With a kerosene light source , purple is distinctive for a short range night
indication but the the glass appears blue when used as a Mazda lamp
burning near normal voltage.
Electric purple of much greater saturation may be successfully used
as a short range night signal indication, but the range is not sufficient for day light
indication.
A synthetic purple, for use of the doublet lens combination, as manufactured for the signal companies, is in use on the New York Central lines west.
an electric purple disk, having a minimum transmission of 30 per cent,
is used in the searchlight type signal,and its performance may also be obtained
from the New York Central Lines east.
The electric purples are included in the A.A.R.
signal section specification 69-35.
The synthetic purple consists of a red and purple glass
combination , of a predetermined ratio of color area to produce the desired color range within its limitation.
This combination offers at present the best solution for improving
the purple indication.
A Combination Satisfactory:
F.C. Stewart
signal engineer, Elgin Joliet and Eastern
Joliet Ill.
pg 438.
We have never been able to secure a satisfactory
purple for night indication for dwarf signals; consequently,
we resorted to the expedient of inserting a 1 1/4 in diameter red glass disk
in the center of the 5 3/8 in diameter purple roundel .
We think this greatly improved our night indications and the enginemen
liked the change.
on our first installation of color-light dwarf signals of the searchlight type,
we found the stop indication to be very unsatisfactory, especially during the very bright daylight.
We asked the manufacturers to provide red disks with 1/4 in horizontal purple glass stripes through the centers.
The disks were mounted so that the 1/4 in would be horizontal when the signals were in the stop position.
This practice greatly improved the stop indications, as the signal gave the appearance of a red light with a purple halo, or a purple light with a red halo.
either type gave a workable indication.
We do not believe that, in the present state of the art , a satisfactory
purple indication be secured and would prefer a dark red for the stop
indication on dwarf signals.
However , they are made much more frequently than the old custom
of periodic night checks.
When the color- light signals are used, it is the practice
to change lamps periodically so that lamps are burned according
to their rated life.
Consequently, a reported "light out" failure rarely occurs.
With the modern color-light signal, means are provided for focusing
the light in the daytime so that we are assured of good daylight and night indications.
**** NOTE! The above information is well cited for source credit and the information on this page is for educational and historical purposes .