IMPROVEMENTS IN APPARATUS FOR ENABLING OBSERVERS TO READ THERMOMETERS BAROMETERS AND TO FIND [THE] HEIGHT OF LIQUIDS IN CISTERNS, BOILERS, VATS &C AT A DISTANCE FROM THEM AND TO DETERMINE THE POSITION OF A BODY MOTION IN A DEFINITE TRACK SUCH AS A TRAIN BETWEEN TWO STATIONS AND TO ENABLE THE SIGNALMAN AND [THE] DRIVER TO SIGNAL TO ONE ANOTHER.
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by James Enright at the Office of the
Commissioners of Patents on the 4th June 1883.
JAMES ENRIGHT [of] 34 Netherwood Road West Kensington Park. W.
IMPROVEMENTS IN APPARATUS FOR ENABLING OBSERVERS TO READ THERMOMETERS
BAROMETERS AND TO FIND [THE] HEIGHT OF LIQUIDS IN CISTERNS, BOILERS, VATS &C
AT A DISTANCE FROM THEM AND TO DETERMINE THE POSITION OF A BODY
MOTION IN A DEFINITE TRACK SUCH AS A TRAIN BETWEEN TWO STATIONS AND TO
ENABLE THE SIGNALMAN AND [THE] DRIVER TO SIGNAL TO ONE ANOTHER.
IN
The first part of my Invention refers to various kinds of Mercurial Thermometers
and consists in the use of a glass tube of variable bore such as is commonly used in
the manufacture of Thermometers Into this tube I insert transversely short
platinum (or other suitable material) wires at distances to be determined by the
range and the degree of accuracy required of each particular instrument. Hence-
forward I shall call these wires "Tube-wires "Each tube wire enters the bōre go
as to make contact with the mercury when by increase of heat the latter expands
and rises to it or on the other hand to break contact with it when by decrease of
heat in contracts and falls from it. I insert the aforesaid wires in two different
ways-First, I drill holes in the glass Tube transversely at the points where I wish
to insert them I then place the Tube wires in position and seal them in either with
melted glass or cement-Second, I beat the Tube to softness and then drive in each
wire by pressure to the bore when cold I break off any glass which may adhere to
the ends by passing a fine wire longitudinally through the bore.
The "Tube Wires" being thus set air tight the Thermometer is made in the
usual manner, I graduate it by means of a Standard Thermometer-The point of
insertion of each Wire will mark a definite temperature not necessarily in exact
degree but may be fractionally thus, I wire my mark 20' 5° C and the neat
wire 21' 2° C.
The instrument thus made and graduated is fixed to a suitable piece of wood or
metal and the free end of the aforesaid Tube Wires except that one next the
bulb are united by binding screws or otherwise to insulated coils of wire that is to
say the external end of each "Tube Wire" is united to a coil of insulated German
Silver Wire (or other suitable material). The resistance coils thus united to the
platinum wires (Tube Wires) are all of different resistances. The free ends of the
said resistance coils are united together and to a well insulated conductor which I

page_text: "
shall call the "Cable." Or some of the free ends of the resistance coils may be
united to any part of the other resistance coils-Henceforward I shall call the
resistance coils united to the Cable and to one another the Armature. It is of
small bulk and enclosed in any wood or metallic case-Having now described the
mode of making my Thermometer I proceed to describe how to use it-The
instrument is set up at any place the temperature of which is sought-The Tube
wire next to the bulb which I shall henceforward call the "Earth wire is connected
to what Electricians call a good earth and the cable laid in the ordinary manner
of laying insulated conductors to the place where it is convenient to observe the
temperature. Or the earth wire may be connected to a second Cable which I shall
henceforward call the "Return Cable"-In order to find the temperature at the
place where the Thermometer is all that is to be done is to measure the electrical
resistance in the circuit composed of the Cables and that part of the armature and
column of mercury which may be at the time in circuit.
In order to explain this I will state that the Electrical resistance of two wires
united in a parallel circuit is less than that of either. If a third wire be joined in
with the other two in parallel circuit the resistance is further lessened and so on
every new wire thrown into parallel circuit with a system lessens the resistance of
the system according to a known law and the application of this principle for the
purposes above set forth is part of my invention. Suppose the Mercury in the
Thermometer to stand at the level of the "Earth Wire," and also that a galvanic
battery of any kind is joined up with the Cables or with the Earth and the Cable
no current would pass-Now if the temperature rise the mercury soon reaches
the 2nd Tube Wire from the Bulb and the current passes-A definite known
resistance is now in circuit and when this resistance is in circuit it indicates and
marks a definite temperature-Suppose the temperature to rise still further the
mercury will soon reach the third Tube Wire from the Bulb then a Wire (or
resistance) is thrown into parallel circuit with wire number 2 and the resistance is
accordingly lessened-In constructing the "Armature" I arranged by calculation
that this new resistance shall be so different from the former as to leave no doubt
whatever as to the point to which the mercurial column has risen. Suppose again
that the temperature rises and as a consequence the mercurial column rises to tube
wire N° 4 from the bulb-Then another wire is thrown into parallel circuit with
N° 2 and 3 and the total resistance is again lessened
This device of throwing resistance (which I shall henceforward call "sub-
sidiary resistances") into Circuit such that the resulting resistance differs so from
the previous one as to leave no doubt as to the fact of change-I claim as part
of my Invention-Suppose again that the temperature increases and that the
mercurial column reaches "Tube Wire" N° 5 from the bulb-Then another wire of
the Armature is thrown into parallel circuit and the total resistance again lessened
-Hence in order to ascertain to what point the mercurial column has obtained it
is only necessary to measure the resistance in circuit-When the temperature falls
all these events take place in reverse order in fact certain resistances are now
determined to mark certain points to which the mercurial column has arisen or
fallen Changes of resistance of the coils on account of changes of temperature or
other such minor alterations of resistance do not embarrass the Observer because I
construct the Armature so that by the subsidiary resistances I put in at each
successive rise of the column the change of resistance is so great as to swamp and
nullify smaller changes-I now proceed to describe the method of reading the
Thermometer that is to say to ascertain the resistance in circuit for this purpose I
use a simple form of Wheatstone's Bridge-On this Bridge I have a set of resist-
ances respectively equal to the set of resistances which may be successively thrown
into circuit by the rise or fall of the mercurial column
The ratio on the Bridge for each measurement is thus one of equality: a
circumstance which makes the reading easy and certain I do not limit myself to
this mode of reading but may employ the Bridge as ordinarily used or a current-
measuring-galvanometer using a Constant electromotive force. In each case I can
1

page_text: arrange by attending to the weight of the needle of the galvanometer and the
mode of suspending or pivoting it, the strength of the field about it, and the shape
of the coils that surround it automatically register the variations of temperature.
This registration may be effected in two ways. First, by the needle being prolonged
and its point bent downwards and brought into contact with a revolving cylinder
having smoked paper on its surface Second, by reflecting a spot of light from the
needle or its suspending fibre to a moving sheet of sensitized paper in a dark
chamber.
My apparatus described above and whatever is substantially the same may be
employed in the same way to read and register the rise and fall of the mercurial
column of a Barometer either at the open end or the closed end of the instrument.
If the armature be applied to the closed end, the tube wires are to be fixed in, as
already described with reference to the thermometer. If at the open end, it may
be arranged in substantially the same way without piercing the glass
Obviously, iny apparatus, or a simple modification of it, may be employed in
finding the variations of level of fluids in cisterns boilers, vats, electera: and
automatically registering the same; and I claim as my invention the application of
the apparatus as herein described or whatever is substantially the same to these
purposes If the fluid be nonconducting or a bad conductor, a float carrying
conducting substances to make the necessary contacts may be set on the surface of
the fluids and must then rise and fall with it so that the rise & fall of the float.
indicates the rise and fall of the surface of the fluid
My apparatus may be used to indicate and register the position of a body in
motion in a definite track; for instance the position of a train between two
Stations For this purpose I require a well insulated conductor between the two
stations At certain points this insulated conductor approaches one of the rails
to within eighteen or twenty four inches (or any similar distance) on which the
train is supposed to move, and is brought into electrical contact with a fixed bare
bar of zinc or galvanized iron or other metal, which rests on supports of non-
conducting material-One end of the aforesaid cable is connected to a Battery at
the Station which the train is approaching the other end of it terminates on the
insulated bar of zinc (which I shall henceforward call an "electrode ") next the
other station The distances at which the electrodes are fixed is determined by the
degree of accuracy with which the position of the train is required Let us say
they are fixed 300 f* apart
"
I further require that one of the ordinary rails on which the train runs shall be
vertically perforated at points midway between the electrodes above mentioned―
I also require an apparatus for making contact which I shall henceforward call a
"key" This consists of a lever one arm of which is bent at right angles so as to
project through one of the rail perforations aforesaid and the other is connected by
chain or wire ropes or a metal bar working over and under pulleys to a bolt. This
bolt is kept in position by a strong steel spring spiral or otherwise and supports a
metal bar the free end of which is weighted the weight hanging over one of the
electrodes above described-This bar I shall henceforward call the "Contract bar
The other end of it is hinged to a piece of metal of the same material buried in the
earth and in connection with the Rails-When the Engine which passes over the
projecting end of bent lever, depressed it, it causes the chain working over the
pulleys aforesaid to draw back the supporting bolt of the contact bar against the
power of the Spring. The weight at its end brings it firmly down on the electrode
and puts the insulated cable into contact with the earth. A current may thus pass
through the cable and the resistance in circuit marks the electrode with which
contact has been made
Thus the position of the Train is determined
The reading and registration is absolutely the same as complained already with
regard to my Thermoter. Let us suppose that the electrode in the last paragraph
is the first from the Station from which the Train has taken its departure and that
the electrodes are 300 feet apart; then at 300 feet from the first rail perforation is

page_text: the second rail perforation through which the bent end of the second lever exactly
similar to the first protrudes-In connection with this second lever of my "key" is
a chain or wire rope working under and over pullies and which when the projecting
end of the lever above the rail depressed by the Wheel of the Steam Engine lifts
up the contact har aforesaid thus breaking contact between the contact bar and the
earth. The bolt is then drawn or pressed by the Spring already mentioned and
shoots under the contact bar and keeps it away from the electrode. Thus while
the Engine is on the 300 ft of rail referred to just now and known. definite
resistance is in circuit. Through the second rail perforation also protrudes the
bent end of the lever for the next 300 feet so that the "break" of the first interval
is instantaneous with the " make " of the second. Thus each rail perforation except
the first and last between the two stations has two lever ends projecting in circuit
will gradually decrease from the time the train starts from one station until it
reaches the next.. The measurement of these resistances and of the distances they
indicate is made substantially in the same manner as that already described with
regard to my Thermometer-Slight modifications in the weight of needle, strength
of fields &. may be necessary according to circumstances but I do not limit myself
in this way
In this Case my armature is reduced to a Cable with projecting electrodes, but
when the distance between the electrodes is small, the difference of resistance in
circuit as the Train moves from interval to interval may not be great enough to
give well marked indications of the registering Apparatus. I then introduce
between the electrodes subsidiary resistances not necessary to produce a current but
to emphasize the indications
On the other hand if the distance between the electrode be long and therefore
the distances between the resistances in circuit as the Train moves from electrodes
to electrode is so great as to jolt and disturb too much the needle of the indicating
galvanometer, I insert subsidary resistances in parallel circuit or use a thicker
wire between the electrodes.
·
i
This the last part of my Invention is in connection with the last
Having explained how the position of the Train on the line may be ascertained
I now proceed to describe how a signal-man communicates with the driver. For
this purpose I use the ordinary rails as conductors, improving their conductivity
by attaching short galvanized iron plates to their joints, and by connecting certain
joints in them at crossings, where switches, or the connections of the ordinary
signal machinery cross the lines, with well insulated conductors carrying them
under the rails, and so in general improving the conductivity of the rails.
For this part of my invention I further require a shoe of brass or other suitable
metal to which are attached two wheels of the same material on the flat side and
to the other side a curved strong spring. The latter I attach to the guard iron of
the engine directing it backwards & so fixed that when the train is in motion the
wheels shall roll on the rails pressed on them by the springs so as to make good
contact. A similar shoe & spring is attached to the other guard iron. From the
spring on either side an insulated thick copper wire is led to a galvanometer or
electric bell beside the driver. I do not limit myself to ordinary galvanometers or
bells but may devise more delicate apparatus for the purpose. The rails at the
station are connected to a battery which enables the signal man to signal to the
driver. When the conductivity of the rails is not good enough to give strong and
decided signals, I was a relay on the engine and, when a battery is kept on the
engine, the driver may also. signal to the signalman at the station.