IMPROVEMENTS IN SAFETY SIGNALS FOR RAILWAYS
Year: 1875

page_text: LETTERS PATENT to Benjamin Joseph Barnard Mills, of the Firm
of Harris and Mills, of 23, Southampton Buildings, in the County
of Middlesex, Patent Agent, for the Invention of "IMPROVEMENTS
IN SAFETY SIGNALS FOR RAILWAYS."-A communication from abroad by
Henry Flad, of St. Louis, St. Louis County, State of Missouri, in
the United States of America.
PROVISIONAL SPECIFICATION left by the said Benjamin Joseph
Barnard Mills at the Office of the Commissioners of Patents, with
his Petition, on the 12th May 1875.
I, BENJAMIN JOSEPH BARNARD MILLS, of the Firm of Harris and
Mills, of 23, Southampton Buildings, in the County of Middlesex,
Patent Agent, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN SAFETY SIGNALS FOR RAILWAYS," a communication to me
from abroad by Henry Flad, of St. Louis, St. Louis County, State of
Missouri, in the United States of America, to be as follows:—
This Invention consists in supplying a railway with signals placed at

page_text: intervals along its sides, the said signals being so constructed as to be
operated at a distance by a signalman or by the passing train.
.
For a double track (where the trains only run in one direction on each
track) the signal abreast of the train is set to indicate "danger" (to a
train following), and the signals are left standing at "danger" for a
sufficient. distance in the rear of the train, but are set to indicate safety
after the train has proceeded a given distance, by connection with the
same mechanism by which the signals are set to indicate danger; at
least one signal.in condition indicating danger is at all times left to the
rear of the train, the train reversing the second signal to its rear; so
that in case of an accident between signal stations, the train following
would have sufficient warning.
For single track railways (on which the trains run in both directions)
the construction of the signal apparatus is such that upon each side
abreast of the engine the signals are reversed by the passing train, and
simultaneously the signal two stations ahead upon the left side is set to
danger," while upon the right side the signal two stations to the rear
is set to "safety," so that a train either following or meeting the first
will be warned about two stations from the train first mentioned. Thus
it will be understood the train does not act on the signal at the station
next in advance or to the rear, but upon signals more distant, so as to
always leave at least one danger signal in advance, and one to the rear
of the train, and at sufficient distance for warning to another train.
This is denominated the system of "overlapping signals," as the pipes
or other means of communication between the train and distance signals
overlap or run past each other.
Telegraph wires and rope have been used as a medium of communi-
cation between the locomotive and a signal at a distance, and when the
signals are operated by the signalman work well; water or glycerine
may be used in pipes for the same purpose in such case; but when the
signals are set by the train in motion, neither ropes nor wires, nor an
inelastic fluid will work well. Ropes stretch by the force of the blow
given by a fast travelling train, and will not communicate motion to a
signal at a distance either with promptness or regularity. Such ropes or
wires have to be carried upon sheaves and around curves, and require to
be boxed the whole distance, and require particular arrangements to
eliminate the effects of temperature. Tubes filled with liquid such as

page_text: glycerine or water are free from these disadvantages, but on the other
hand they necessitate special appliances to compensate for the effects of
leakage, which latter can hardly be avoided altogether, it is also
necessary that some elastic medium such as air should be interposed to
ease the blow from the train, for if said blow were communicated directly
to the liquid, it would cause the bursting of the pipes.
The movement of the signal may be easily combined with the
sounding of a gong, which would be operated by a vertical pendulum, or
lever, or otherwise. This would serve to indicate to the engineer that
the air pump had operated, and at the same time call his attention to
the signal station. Or the gong might be struck. by an independent
arrangement, say one hundred or two hundred feet from the signal
stations, for the purpose of indicating the approach of the train.
A signal at a distance may be worked by a watchman by means of the
local signal apparatus and connecting air pipes, and to give signals at
several points distant from him he would be provided with a number of
small air pumps with long stroke, and a false bottom or diaphragm with
valve openings would not be required if the signals are in sight, but if
the signals are out of his sight he should have two pumps, a smaller and
a larger one worked simultaneously by the same lever, the small pump
to operate the signal close at hand, which would indicate when the
distant signal or signals were set, the larger pump or pumps operating
the signal or signals at a distance, whose movements would be
synchronous with those of the signal near at hand. The device for
operating the air pump may extend from the locomotive, tender, or
either of the cars.
.
To operate the signals from a car at the rear end of the train would
have the advantage that the whole train would have passed a given
station before the signal of "danger" to stations back would be changed
to "safety," and the signal abreast from " safety" to "danger," and
that if a few cars got separated from the train in motion, the following
train would find the danger signal, thus preventing the last-named train
from running into the detached cars.
Signals under the system known as the "block system" are worked
by men stationed at equidistant points along the line, each man by
means of telegraph or other means signalling the station next behind a
moving train that the track is clear when the train has passed the

page_text: station. But suppose that after a train has passed a station and a signal
been given for a following train to proceed, and the first train breaks
down after passing the station yet far enough to be out of sight of the
signalman, then the second train although finding a signal of "danger"
at the station might not be warned in time to avoid a collision,
whereas with this system of overlapping signals (which is the main
principle of this Invention), this dangerous contingency could not
occur.
The Invention is not limited to the means of communication described
between the train and the distant signal, as this may vary without
essential change in the novel principle evolved in the Invention.
Neither is it limited to the described air pump by which the train acts
on the said means of communication, nor is it limited to the form of
engine herein described by which the signal is directly operated.
The following is a description of the apparatus preferred to be
employedAt the side of or between the railway track are inclined
levers, so placed as to be depressed by a roller or other device secured to
the locomotive or some car in the train; the levers are enclosed in a box
having only sufficient opening at top to admit the roller by which the
levers are depressed; the box preventing the accidental depression of the
levers by a person stepping thereon, or by other means than the said
roller or its equivalent appliance projecting from the train. The levers
are fulcrummed at a suitable point, and beneath them are springs tending
to raise them and hold them in their upper position ready for the impact
of the said depressing device projecting from the locomotive or car. A
cross pin is secured in ears at the end of one of the levers which passes
through a slot in the end of the other lever, the pin working in the slot
as the levers rise and fall. The pin is connected to the plunger of an air
pump, to which the connection may be made by a link. The air pump
· cylinder is provided with a diaphragm supplied with valves opening
downwardly into four separate air chambers. The upper chamber of the
cylinder has valve openings for air supply either through the bottom or
through the plunger. Air pipes communicating with the chambers lead
to the signal apparatus. The signal post may be made the height of the
eyes of the engineer or have a greater elevation. The air pipes extending a
from the air pumps discharge into a chamber forming the lower part of
a cylinder carried by the signal post. The openings into this chamber
are covered by valves connected together and set angularly with each

page_text: other, so that the opening of one by the passage of air will close the
other (the valves oscillating on a central hinge. In the last mentioned
cylinder works a hollow piston open at top and forming a cylinder, in
which is a turning cylindrical block or head, having upon its side a cam
groove, in which work studs carrying antifriction rollers projecting
inward from the inside of the hollow piston. This cam groove has
inclined portions and vertical portions, the latter ending in a short
incline just sufficient to carry the centre of the stud past the corner.
The arrangement is such that at each rise of the hollow piston the signal
spindle shall receive nearly a quarter rotation, which quarter shall be
completed by the passage of the stud over an incline to carry the point
past the centre of the stud so that on the next rise of the hollow piston
the stud may pass up through another part of the cam groove and again
turn the signal spindle in the same direction as before so as to reverse
the signal. This device is to convert the rectilinear motion in the
hollow piston into rotary motion in the signal spindle, and it admits of
various modifications. The signal spindle carries a lantern with two
red lights and two lights of another color placed alternately on the four
sides of the lantern, red opposite red, in the usual manner, so that a
quarter turn reverses the signal. Above the lantern is a target having
two discs at right angles with each other so as to show alternately as
turned red faces to indicate "danger," and faces of another color to
indicate "safety." The hollow piston should not be closely fitting in its
cylinder, as there will be abundant air to work it, and the surplus air
escapes between the piston and the cylinder. After the piston has been
raised, and as the air escapes, it settles down by force of gravity, and is
ready for another stroko.
Any suitable device may be used to prevent the rotation of the hollow
piston.
The following describes a modification of the mechanism through
which the air acts on the signal. This mechanism is applicable where a
double track is used, and the trains run only in one direction on each
track. In this modification the air pipes enter respectively two cylinders,
in which work pistons connected together by a rod having a cross pin
working in a slot in a weighted lever, so that a pressure of air in the one
cylinder pushes over the lever to the right, and on the air being forced
into the other cylinder the lever is carried over to the left. This lever is
supported on a rock shaft, which forms, its fulcrum, and which carries a

page_text: bevel wheel engaging in a similar wheel at the foot of the signal spindle,
so that by the reversal of the weighted lever the lantern and target of
the signal spindle shall receive a quarter rotation so as to reverse the
signals.
The preferred means of carrying out this Invention is described, but
very considerable modification may be made in the said means without
at all affecting the principle of the Invention. For instance, in place of
the air pumps air pipes and air engines, water pumps, pipes, and engines
may be used, and other liquids than water may be used in them; or the
train may act on a lever or other device that will move the signals
through a cable or other mechanical communication between the train
and the signal. Or the communication between the train and signal
may be by electricity, the closing or opening of the circuit setting in.
motion mechanism by which the signals are reversed.
SPECIFICATION in pursuance of the conditions of the Letters Patent, 1
filed by the said Benjamin Joseph Barnard Mills in the Great Seal
Patent Office on the 12th November 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, BENJAMIN
JOSEPH BARNARD MILLS, of the Firm of Harris and Mills, of 23,
Southampton Buildings, in the County of Middlesex, Patent Agent, 2
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twelfth day of May, in the year of
our Lord One thousand eight hundred and seventy-five, in the thirty-
eighth year of Her reign, did, for Herself, Her heirs and successors, 2
give and grant unto me, the said Benjamin Joseph Barnard Mills, Her
special license that I, the said Benjamin Joseph Barnard Mills, my
executors, administrators, and assigns, or such others as I, the said
Benjamin Joseph Barnard Mills, my executors, administrators, and
assigns, should at any time agree with, and no others, from time to 8
time and at all times thereafter during the term therein expressed,
should and lawfully might make, use, exercise, and vend, within the
United Kingdom of Great Britain and Ireland, the Channel Islands,
and Isle of Man, an Invention for "IMPROVEMENTS IN SAFETY, SIGNALS FOR

page_text: BAILWAYS," a communication to me from abroad by Henry Flad, of St.
Louis, St. Louis County, State of Missouri, in the United States of
America, upon the condition, amongst others, that I, the said Benjamin
Joseph Barnard Mills, my executors or administrators, by an instru-
ment in writing under my, or their, or one of their hands and seals,
should particularly describe and ascertain the nature of the said
Invention, and in what manner the same was to be performed, and
cause the same to be filed in the. Great Seal Patent Office within six
calendar months next and immediately after the date of the said Letters
Patent.
NOW KNOW YE, that I, the said Benjamin Joseph Barnard Mills,
do hereby declare the nature of the said Invention, and in what manner
the same is to be performed, to be particularly described and ascer-
tained in and by the following statement thereof, reference being had
to the Drawings hereunto annexed and to the figures and letters marked
thereon, that is to say :——
This Invention consists in supplying a railway with signals placed
at intervals along its sides, the said signals being so constructed as to be ·
operated at a distance by a signal man or by the passing train.
For a double track (where the trains only run in one direction on
each track) the signal abrest of the train is set to indicate danger (to
a train following), and the signals are left standing at danger for a
sufficient distance in the rear of the train, but are set to indicate safety
after the train has proceeded a given distance by connection with the
same mechanism by which the signals are set to indicate danger. At
least one signal in condition indicating danger is at all times left to the
rear of the train, the train reversing the second signal to its rear. So
that in case of an accident between signal stations the train following
would have sufficient warning.
For single track railways (on which the trains run in both directions),
the construction of the signal apparatus is such that upon each side
abreast of the engine the signals are reversed by the passing train, and
simultaneously the signal two stations ahead upon the left side is set to
danger, while upon the right side the signal two stations to the rear is
set to safety, so that a train either following or meeting the first will
be warned about two stations from the train first mentioned. Thus it
will be understood the train does not act on the signal at the station

page_text: next in advance, or to the rear, but upon signals more distant, so as to
always leave at least one danger signal in advance and one to the rear
of the train, and at sufficient distance for warning to another train.
This is denominated the system of overlapping signals, as the pipes
or other means of communication between the train and distance signals
overlap or run past each other.

page_text: B, having only sufficient opening at top to admit the roller by which the
levers are depressed, the box preventing the accidental depression of the
levers by a person stepping thereon or by other means than the said
roller or its equivalent appliance projecting from the train. The levers
are fulcrumed at E, and beneath the levers are springs F tending to
raise them and hold them in their upper position, ready for the impact
of the said depressing device D projecting from the locomotive or car.
G is a cross pin secured in the ears at the end of lever C, and passing
through the slot c' in the end of the lever C³, the pin working in the
slot as the levers rise and fall. The pin G is connected to the plunger
H of an air pump of which K is the cylinder; the connection may be
made by a link H³.
The plunger may have any suitable packing I to render it air-tight;
L is a diaphragm supplied with valves M opening downwardly into
separate air chambers N, O, or N, N, O, O; the upper chamber P has
valve openings Q for air supply, either through the bottom, as shown
in Figure 7, or through the plunger, as shown in Figure 9; R, R¹, are ·
air pipes communicating with the chamber N, N; and S, S', are
pipes communicating with the chambers O, O, these pipes leading to
the signal apparatus.
The devices will be now described, by means of which the air passing
through the pipes R, S, &c., operates the signals, and then will be
described the course of the pipes from the air pumps to the signals;
T is the signal post that may be made the height of the eyes of the
engineer, or have a greater elevation; R, R', S, S¹, are the air pipes
extending from the air pumps H, K. These pipes discharge into the
chamber U forming the lower part of the cylinder W.
The openings into the chamber U are covered by valves V, V, con-
nected together and set angularly with each other as shown, so that the
opening of one by the passage of air will close the other (the valves
oscillating on a central hinge V¹).
In the cylinder W works a hollow piston W'; this piston is open at
top and forms a cylinder in which is a turning cylindrical block or
head X having upon its side a cam groove in which works studs Y
5 (carrying antifriction rollers) projecting inward from the inside of the
piston W. This cam groove has inclined portions d and vertical
portions e, the latter ending in a short incline e¹ just sufficient to carry

page_text: the centre of the stud Y past the corner f. The arrangement is such
that at each rise of the piston W' the signal spindle Z shall receive
nearly one-fourth of a rotation (say 80°), which one-fourth shall be
completed by the passage of the stud Y over the incline e¹ to carry the
point past the centre of the stud, so that on the next rise of the
piston W the stud Y may pass up through the part d of the cam
groove, and again turn the signal spindle Z in the same direction as
before (so as to reverse the signal). This device is to convert the
rectilinear motion in the piston W₁ into rotary motion in the spindle Z.
The device admits of various modifications, for instance, the cam groove
d, e, e, may be cut in the interior of the piston W', and the stud Y
project from the head X, or directly from the spindle Z. The spindle Z
carries a lantern 9 with two red lights, and two lights of another color
placed alternately on the four sides of the lantern (red opposite red)
in the usual manner, so that a one-fourth turn reverses the signal.
Above the lantern is a target h having two discs at right angles with
each other so as to show alternately (as turned) red faces to indicate
danger, and faces of another color to indicate safety, the color
changing with each one-fourth rotation. The piston W₁ should not
be closely fitted in its cylinder, as there will be abundant supply of a
air to work it, and the surplus air escapes between the piston and the
cylinder. After the piston has been raised, and as the air escapes,
it settles down by force of gravity, and is ready for another stroke.
Any suitable device may be used to prevent the rotation of the
piston W¹, so that its action on the turning head X shall be positivo.
2
In Figures 3, 13, and 14 is shown a modification of the local signal
mechanism (that is, the mechanism through which the air acts on the
signal). This mechanism is applicable where a double track is used, in
which case the trains run only in one direction on each track. In this
modification the air pipes R, S, enter respectively cylinders W and W³ 3
in which are pistons W', W³, connected together by a rod i having a
cross pin j working in a slot in the weighted lever k, so that a pressure
of air in the cylinder W pushes over the lever k to the right, and on the
air being forced into the cylinder W³ the lever is carried over to the left.
This lever is supported on a rock shaft which forms its fulcrum, and 3
which carries a bevel wheel m engaging a similar wheel n at the foot
of the spindle or staff Z, so that by the reversal of the lever / the

page_text: lantern g and target of the signal spindle shall receive a one-fourth
rotation so as to reverse the signals.
In Figures 1 and 2 is exhibited the course of the air pipes and the
system of signalling. In these Figures the signals standing in position
indicating safety are marked T, and those indicating danger marked T.
The track is a single track, on which the trains run in both directions.
The engineer is supposed to regard only those signals upon his right
hand. A locomotive A' (or a car in its train) carrying the shifting
roller D (or other device) will depress the air pump in passing over it,
and will force the air through the pipes so as to reverse the signals. On
the train A' arriving at a signal station the air passing through the
pipe R will set the signal at the right side abreast of the train to
"danger;" the air through the pipe S will set the signal two stations
back to "safety;" the air passing through the pipe R¹ will set the
signal to the left abreast of the engine to "safety;" and the air through
pipe S¹ will set the signal two stations ahead on the left side to
"danger." With the engine A' the air through pipe R sets the signal
abreast of the train upon its left side to "safety;" the air through
pipe S will set the signal two stations ahead upon the left side to
"danger;" the air through pipe 'R' will set the signal abreast of the
train upon the right side to danger; and through the pipe S₁ the
signal two stations to the rear upon the right side will be set to
"safety." With this arrangement the engineer upon each of the trains
would see the signals of the approaching train in advance of the same,
and a train following another would see the signals of danger to the rear
of the same.
. In the case of a double track, as upon each track all the trains run in
one direction, it is only necessary that each track should be supplied
with a single set of signals, which would be placed always upon the
same side of the track (say to the right hand), so that the engineer may
know to which side to look for the signals. These signals need be made
only at the rear of the engine, as collisions can only take place from a
fast train running into, the rear of a slower one, and this would be
avoided by the danger signals at the rear of the first train. Thus in a
5 double track those chambers N and O in the air pumps in communi-
cation with pipes R¹ and S', and also the signals on the left side of
cach single track, and in connection with said pipes, can be dispensed
th

page_text: In Figure 4 is shown the system of signals for a railway crossing.
In this as a train passes an air pumk K the air is carried by a pipe R³
into a distributing chamber o; and from this chamber the air passes
through pipes p to the two signals T³ on the cross tracks, so as to indicate
the approach of a train to a train coming in either direction on the
cross track. This system would be entirely independent of the main
system upon the lines, and is intended only to warn trains approching
upon the other or intersecting line.
Telegraph wires and rope have been used as a medium of communi-
cation between the locomotive and a signal at a distance, and when the
signals are operated by the signalman work well. Water or glycerine
may be used in pipes for the same purpose in such case, but when the
signals are set by the train in motion, neither ropes nor wires nor an
inelastic fluid will work well. Ropes stretch by the force of the blow
given by a fast travelling train, and will not communicate motion to a
signal at a distance either with promptness or regularity. Such ropes or
wires have to be carried upon sheaves and around curves, and require to
be boxed the whole distance, and require particular arrangements to
eliminate the effects of temperature. Tubes filled with liquid, such as
glycerine or water, are free from these disadvantages, but on the other
hand they necessitate special appliances to compensate for the effects of
leakage, which latter can hardly be avoided altogether. It is also
necessary that some elastic medium, such as air, should be interposed
to ease the blow from the train, for if said blow were communicated
directly to the liquid it would cause the bursting of the pipes. For
these reasons it is concluded to use air as a medium of communication,
which besides being free from disadvantages present in all non-elastic or
slightly elastic mediums has this special advantage, that it can be taken
in freely at the air pump end and discharged at the signal end, and can
be used in superabundance so as to insure the movement of the signal
(the quantity in excess of that needed being allowed to escape freely
through the joint between the cylinder W and piston W¹ or W³), and
from this last consideration it will be seen that an exact adjustment of
the size of the air pumps to the length of pipe between the signals and
the pumps is not required, neither is necessary any other arrange-
ment to compensate for leakage. The air pumps could be made of
sufficient size to furnish the requisite amount of air to operate the
signal.

page_text: Many forms of air pumps would be suitable for use, the requirement
being that each depression of the levers C, C³, shall furnish the requisite
amount of air (under pressure) to operate the two or the four signals (as
the case may be), and that the compressed air chambers N, N, O, O, in
communication with the two or the four pipes R, S, &c. (leading to the
several signals), should have capacity in proportion to the length of
pipe modified by capacity of the signal cylinder.
-
The tubes or pipes may be placed beneath the surface of the ground
to prevent the freezing of moisture in them.
Small vessels with cocks may be inserted at the lowest points of the
tubes or pipes to allow the escape of condensed moisture.
Although short bends may be made in the tubes yet they should be
avoided as much as possible, as they impede the passage of the air.
The movement of the signal may be easily combined with the
sounding of a gong, which would be operated by the vertical pendulum
or lever k, or otherwise. This would serve to indicate to the engineer
that the air pump had operated, and at the same time call his attention
to the signal station; or the gong might be struck by an independent
arrangement, say, one hundred or two hundred feet from the signal
stations for the purpose of indicating the approach of the train.
A signal at a distance may be worked by a watchman by means of
the local signal apparatus and connecting air pipes, and to give signals
at several points distant from him he would be provided with a number
of small air pumps with long stroke and a false bottom, or diaphragm
with valve openings would not be required if the signals are in sight,
but if the signals are out of his sight he should have two pumps, a
smaller and a larger one, worked simultaneously by the same lever, the
small pump to operate the signal close at hand, which would indicate
when the distant signal or signals were set, the larger pump or pumps
operating the signal or signals at a distance, whose movements would
be synchronous with those of the signal near at hand. The device D
for operating the air pump may extend from the locomotive tender on
either of the cars.
To operate the signals from a car at the rear end of the train would
have the advantages that the whole train would have passed a given
station before the signal of "dancer” to stations back would he changed.

page_text: to "safety," and the signal abreast from safety to "danger," and
that if a few cars got separated from the train in motion the following
train would find the danger signal, thus preventing the last named train
from running into the detached cars.
"
Signals under the system known as the "block system
are worked
by men stationed at equidistant points along the line, each man by
means of telegraph or other means signalling the station next behind a
moving train that the track is clear when the train has passed the
station. But suppose that after a train has passed a station and a signal
been given for a following train- to proceed, and the first train breaks:
down after passing the station, yet far enough to be out of sight of the
signalman, then the second train, although finding a signal of danger
at the station might not be warned in time to avoid a collision, whereas
with this system of overlapping signals (which is the main principle of
this Invention) this dangerous contingency could not occur.
It is evident that each of the pipes R, S, or R, R³, 8, 8¹, may com-
municate with a separate air pump, or the pump might be so simplified
that the pipes would all communicate with the same chamber in the
air pump, but this latter would not give as certain results, and the
former would involve unnecessary duplication and expense.
The Invention is not limited to the means of communication shewn
between the train and the distant signal, as this may vary without
essential change in the novel principle involved in the Invention.
Neither is it limited to the described air pump, by which the train acts
on the said means of communication; nor is it limited to the form of
engine described, in which the signal is directly operated.
The preferred means of carrying out this Invention is described, but
very considerable modifications may be made in the said means without
at all affecting the principle of the Invention. For instance, in place of
the air pumps air pipes and air engines, water pumps, pipes, and engines,
may be used, and other liquids than water may be used in them; or the
train may act on a lever or other device that will move the signals
through a cable or other mechanical communication between the train
and the signal. Or the communication between the train and signal
may be by electricity, the closing or opening of the circuit setting in
motion mechanism by which the signals are reversed.

page_text: Having thus described the nature of the said Invention, and the mode
in which the same is carried into effect, I would have it understood that
what I claim is,―
First. The method herein described of signalling, whereby overlapping
signals at a distance from the train are reversed, while other signals
between the former signals and the train remain at rest, to be reversed
in their turn, all substantially as and for the purpose set forth.
Secondly. The combination of lever C, plunger H, cylinder K,
diaphragm L, pipes R and S, and signals T, T, &c., substantially as and
for the purpose set forth.
Thirdly. In combination with the pipes R, S, and cylinder U, W, the
piston W', spindle Z, head X, cam groove d, e, and stud Y, substantially
as and for the purpose set forth.
Fourthly. In combination with the air pipes R and S, and cylinder
U, W, I claim the angular butterfly valve V², V, substantially as and for
the purpose set forth.
In witness whereof, I, the said Benjamin Joseph Barnard Mills,
have hereunto set my hand and seal, this Ninth day of November,
in the year of our Lord One thousand eight hundred and seventy-
five.