IMPROVEMENTS SIGNALLING." IN SIGNALS
Year: 1870

page_text: LETTERS PATENT to Thomas Foulkes, of Eastcheap, in the City
of London, for the Invention of "IMPROVEMENTS
SIGNALLING."
IN SIGNALS AND
A communication from abroad by James Gordon,
of San Francisco California.
Sealed the 25th November 1870, and dated the 30th September 1870.
COMPLETE SPECIFICATION filed by the said Thomas Foulkes at the
Office of the Commissioners of Patents, with his Petition and
Declaration, on the 30th September 1870, pursuant to the 9th
Section of the Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
FOULKES, of Eastcheap, in the City of London, send greeting.
WHEREAS I am in possession of an Invention for "IMPROVEMENTS
IN SIGNALS AND SIGNALLING," and have petitioned Her Majesty to grant
unto me, my executors, administrators, and assigns, Her Royal Letters
Patent for the same, and have made solemn Declaration that the

page_text: same has been communicated to me from abroad by James Gordon,
of San Francisco, California.
NOW KNOW YE, that I, the said Thomas Foulkes, do hereby
declare that the following Complete Specification, under my hand and
seal, fully describes and ascertains the nature of the said Invention,
and in what manner the same is to be performed, in and by the
following statement :-
The nature of my Invention consists,-
Firstly. In apparatus for signalling or telegraphing between two or
more points or stations, by the transmission of confined air through a
pipe or pipes so that the amount of air displaced or received at one
station may be replaced at or withdrawn from another and produce a
mechanical movement for working signals or telegraphs as desired.
66
Secondly. In constructing the said apparatus at the operating and
signal or telegraph receiving stations with chambers herein-after called
tanks," for water or liquid surrounding or clothing the vertically
disposed ends of the air pipes and the combination therewith of move-
able vessels, closed at top and sides, and open at bottom, herein-after
called "
gasometers" applied (in the manner of gasometers or gas
holders) over the air pipes and within the tanks, the gasometer at the
operating station when it is by the operator depressed or raised displacing
or receiving air from and through the pipes, and causing a corresponding
addition or withdrawal at the receiving station and consequent raising or
depression of the gasometer situate at such station, and movement or
production of signals or telegraph indications in mechanical communi-
cation therewith.
And, thirdly. In the use of a mixture of alcohol and water as the
liquid for charging the above-mentioned tanks.
Referring to the accompanying illustrative Drawings, Figure 1 repre-
sents the improved apparatus and the method of transmitting railway
signals by the exhibition of colored metallic discs or squares by day, and
colored lights by night. A, A¹, are two tank, cylindrical or otherwise, as
may be found most convenient, one of which A¹ is placed at the point
where it is desired that signals shall be exhibited, and the other A at the
point where the signalman is stationed. The difference of time between
the instant of manipulation of the apparatus at the one end or terminius

page_text: and the corresponding motion of the signals at the other end or terminius
will be about one second if both termini be close together, and about
one second more to every 1100 feet between the termini, being the same
rate at which sound travels. B, B, are small pipes, (say two inches in
diameter or larger if desired) open at both ends and placed vertically
in the centre of and passing through the bottoms of the tanks into the
air chambers D, D, below; they are fixed tightly through the bottoms
of the tanks so as to be water-tight, and are further secured in the
inside at the bottom by stays or by a large boss so as to hold them
firmly in a vertical position. The upper ends of these pipes B, B, reach
within an inch of the top of the tanks A, A¹. D, D, are air chambers
and are merely used to retain any liquid that may accidently find its
way into the pipes B, B, either by condensation of vapour or from any
other cause, and the presence of which in the pipe would interfere with
the operation of signalling. E is an air-tight pipe of the same size as
the pipes B, B, (or nearly so) and of the requisite length to connect the
air chambers D, D, at the two separate apparatus. C, C³, are the
gasometers, hollow, cylindrical, of convenient size and length, and closed
at the upper end only. They should be made of light sheet zinc or
copper so as to obviate the necessity of any counterweights, the cover
or closed end should be of stouter metal to give strength to bear the
affixing of the rods and frame herein-after mentioned. The tanks A, A',
being filled with liquid the gasometers C, C³, are inverted over the
pipes B, B. F, F, are rods (or a frame) attached to the closed end of C₁
and to which can be affixed different colored signals of painted sheet
metal for day use (one above the other) or different colored glasses for
night use, which latter by being placed in front of bright white lights
with reflectors will give the night colored signals required. H, H, are
two screens which may be painted white. I, I, are orifices, one in each
of these screens, through which the signal is shown both up and down
the line of railroad. These screens may be of any required height, say
from the ground to the centre of the orifice twenty feet; they should be
from sixteen to twenty-four inches apart, so as to admit of the reception
of two lamps with reflectors, placed back to back for night use, and
which lamps and reflectors are suspended by an iron rod, from a cross
piece connecting the two screens at the top so as to face the orifices on
either side. The gasometers should be proportionally long, to give the
requisite vertical motion and consequent elevation in operating, and

page_text: In
proportionally large in diameter to raise the weight of the rods and
frame F, F, with the signal discs or colored glasses affixed, say a length
of ten feet to the gasometers and a diameter of from ten to fifteen inches.
The tanks with their enlarged tops must be in proportion or about one
or two inches larger in their diameter, in their smaller part G is a spar
rack affixed to the top of the gasometer C, and worked by a toothed
wheel, by which that cylinder can be raised or depressed to any desired
point. This gasometer acting upon the confined air transmits it through
the pipes B, B, chambers D, D, and pipe E, or exhausts it from
them, thus elevating or depressing the gasometer C¹ at the other point,
and consequently the rods or frame F, F, so as to bring any one of the
colored signals desired opposite to the orifices I, I, in the screens.
the Drawing the gasometer C is shown as depressed to its lowest point,
and the lowest or No. 1 of the signals (which may be green) showing
through the orifices. If the gasometer C were raised eighteen inches
then the No. 1 signal would descend behind the screens and a black
or No. 2 signal would be shown (or by night the light hidden). By
raising the gasometer C eighteen inches higher the No. 3 signal (which
may be red) would be brought opposite the orifices, and red signals
thereby shown. By again further raising gasometer C, eighteen inches,
the No. 4 (which may be white) signal would be placed opposite to the
orifice, thus showing by day a uniform white color over the whole screen
or a bright white light by night. By using gasometers of ten feet
length a vertical action or motion of from 74 to 80 inches is obtained
sufficient for four signals of eighteen inches square or discs of eighteen
inches diameter, by using longer gasometers greater vertical motion can
be easily obtained if required, and any height of vertical motion can
be obtained to rods or frame with but small motion of the gasometer
by attaching a light lever with links and guide by reciprocating motion;
it is better and simpler, however, to have the gasometers of sufficient
length to give the required vertical motion by direct action. The spur
rack G should work through a guide to steady the motion; this guide
should be opposite to the toothed wheel so that the operator can see it
conveniently. Upon the spur rack divisions should be marked which
marks as they show themselves above the guide just referred to will
indicate the precise position of the other gasometer C¹ and consequent
position of the colored signals attached to it, thus enabling him to
make the desired signal at the signal point without its being within the

page_text: scope of his vision (with absolute certainty) and at any distance or any
level. For convenience sake the operating apparatus A can be placed
in a shaft sunk in the ground for the purpose from sixteen to twenty
feet so as to enable the operator to work on the level of the ground.
5 It is to be observed that it is of no matter in what way the pipe E runs,
it may be up, down, horizontal, diagonal, or all of these combined, as
is found to be most convenient. N, N, are orifices in the air chamber
D, D, which are closed with flanged packed screw plugs, which can be
removed to draw off with a syphon any liquid which may accidently
O have got into it by condensation of vapour or other means.
P is a
platform where the operator stands to work the toothed wheel, but
which may be dispensed with if the operating apparatus is placed on a
shaft, as before-mentioned, so that he can work on the level of the
ground. M, M, are guides four or five inches long, situate on the top of
the tank covers, through which the gasometers move, and serving to
keep them steady and vertical in their motion. Figure 2 shows the
screen as seen on approaching it with the orifice I, through which the
No. 1 signal is seen. In the upper part of this screen a break is made
to show the position of the concealed No. 2 and No. 3 signals, when
the No. 1 signal is exhibited at the orifice.
TO PREPARE THE APPARATUS FOR USE.
1st. Fill the tanks A, A', with water or other liquid to about two
inches above the level of the bottom of the enlarged area at the top.
If the weather be frosty so that there be danger of the water freezing,
low proof spirit, say, forty to fifty per cent. alcohol to fifty or sixty
per cent. water should be substituted for the water only, as it requires
an excessively low temperature to freeze it. Upon the top of the liquid
pour olive oil sufficient to give a surface depth of from one-fourth to
three-eighths of an inch. This prevents any loss by evaporation, and
also keeps the gasometers C, C', smoothly lubricated to pass the more
easily past the guides M, M.
2nd. Put the open end of the gasometer C' over the pipe B in the
gasometer A', and let it sink till nearly half immersed, and then
temporarily suspend it by a line.
3rd. Put the open end of the gasometer C over the pipe B in tank A,
and depress it till it is completely down, and fix it temporarily there.

page_text: 4th. Now depress the other gasometer C¹ four inches below the
position in which you now find it, and hold it there for half a minute.
5th. Release both gasometers from any fixing or line before placed on
them, so that they may work freely on their own balance. The apparatus
is now ready for use.
.
Figure 3 shows the method of using the apparatus, or a similar one,
for the purpose of transmitting messages. The gasometers are about
three feet ten inches in length, with a diameter of three inches. The
pipes B, B, and E are of half or three-fourths of an inch in diameter.
This size of gasometer will give a vertical motion of from twenty-six to
thirty inches, and this is sufficient for practical purposes. K, K, are scales
or surfaces on which are marked divisions one and a half inches apart on
the wider or left-hand side of the scale. On these spaces may be marked
numerals (or messages if desired), but these latter would be limited in
number, whereas numerals can be made to telegraph any number of
communications, and are, in fact, without limit. This wider scale I call
the receiving scale, the narrower or right-hand scale I call the sending
scale, and has numbers or messages marked on it the reverse way
vertically, and by placing the index L abreast of any number on the
narrow scale the index of the other gasometer will point to a corre-
sponding number on the wider scale of the apparatus at the other
terminius. Telegrams can be sent both ways with equal facility, using
the divisions on the narrow scale to send messages by, and the
wider one to receive messages or telegrams by. The reason of the use
of the two scales is to enable the wider scale to be equally divided into
spaces for the numerals, whilst the other spaces in the narrow scale
vary somewhat according to the weight of the gasometers, which of
course increase the pressure on the air as they rise above the surface of
the liquid from not being longer water borne or (liquid borne) as they
are when deeper immersed. The rising gasometer therefore does not
rise (after it passes its balance point) quite as much as the other is
depressed for the reason given, and to meet this variation the narrow
scale is adjusted; also by making it in this manner it has a more
uniform appearance than if the numbers were to run up on onc
apparatus and down on the other. L, L, are the indices attached to the
top of the gasometers. S, S, are small tubes with a gas cock in each, they
pass into the air chambers D, D, and are used by opening the cock when

page_text: it is desired to remove the gasometers, instead of opening the orifice N
to admit air; or if there should be a trifling leak in the pipe E, then by
the use of the cock S communication can still be carried on; in this
case the escape of air, if trifling, can be remedied by the following
means-Support both gasometers by placing pins under the indexes
into holes V, V, in the scales (these holes are placed on the division
line dividing 5 from 4), let the apparatus remain thus when not in use.
Either operator desiring to communicate opens the cock at S and raises
his gasometer C or C¹ (by hand, taking hold of the index) up to the top
of the scale at T, holds it there one or two seconds, then closes the cock
at S, and the apparatus is then fully charged with air; he now removes
the pin at V, depresses his gasometer to the lowest point, this raises
the gasometer at the other terminius till it reaches T, which causes it
to touch a spring and rings a bell attached to attract attention there.
The operator at the other end when he hears the bell removes the pin at V
on his apparatus and communication can proceed. The attachment of
the bells at T, T, are not shown in the Drawing as they form no feature of
the Invention. When the communication is ended the pins are replaced
at V, V. T, T, are points at the extreme top of the scales K, K, on
reaching which the moveable indexes attached touch a spring which
rings a bell; V, V, are holes into which pins can be inserted to suspend
the gasometers when out of use in cases where a trifling leak may exist,
T
If for railway signals, are per Figure 1, move the toothed wheel till
the mark on the spur rack showing above the guide shows that the
colored signal required is opposite to the orifice I in the screen H.
IF FOR SENDING TELEGRAMS, AS PER FIGURE 3.
The operator desiring to telegraph depresses his gasometer C or C¹ to
its lowest point, which causes a bell to ring at the other terminius. He
holds it there for about three or four seconds, he has then only to place
his index to the number desired on the narrow scale and hold it there
for a second; the index at the other terminius will mark a corresponding
number upon the wide side of its scale. For correct working the pipes
and whole apparatus should be made perfectly air-tight.

page_text: In conclusion I would remark that I do not limit the Invention to
any particular size of the tanks and gasometers, nor to any particular
shape, in respect of which the tanks and gasometers instead of being
circular in section may be square or of any other convenient form.
In witness whereof, I, the said Thomas Foulkes, have hereunto
set my hand and seal, this Thirtieth day of September, in the
year of our Lord One thousand eight hundred and seventy.
THOS. FOULKES. (L.S.)