IMPROVEMENT THE
Year: 1852

page_text: LETTERS PATENT to Thomas Slater, of Somers Place, New Road,
Saint Pancras, in the County of Middlesex, Optician, and Joseph
John William Watson, of Old Kent Road, in the County of Surrey,
Doctor of Philosophy, for the Invention of "IMPROVEMENTS IN THE
PROVISIONAL SPECIFICATION left by the said Thomas Slater and
Joseph John William Watson at the Office of the Commis.
sioners of Patents, with their Petition, on the 4th October 1852.
We, THOMAS SLATER, of Somers Place, New Road, Saint Pancras,
in the County of Middlesex, Optician, and JOSEPH JOHN WILLIAM
WATSON, of Old Kent Road, in the County of Surrey, Doctor of
Philosophy, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN THE APPLICATION OF ELECTRICITY TO ILLUMINATING
PURPOSES" to be as follows:-

page_text: Our Improvements consist.
Firstly in adjusting the distances between the parts of the electrodes
by means of an induced magnet or magnets or by means of an electric
current inducing magnetism in helices of wire.
S.condly The use of a chemically compounded electrode containing
caustic substances and the introduction of a certain amount of non-
conducting material to check the excess of convection or otherwise
alter the mode in which the same is performed.
Thirdly. The use of a governor or governors for regulating the supply
of electricity to the illuminating apparatus and thereby increasing or
diminishing the intensity of the light.
Fourthly. The use of several electrodes in the same lamp.
Fifthly. The making the support or supports of the electrodes the
armature of an induced maguet or magnets.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Thomas Slater and Joseph John William Watson
in the Great Seal Patent Office, on the 4th April 1853.
TO ALL TO WHOM THESE PRESENTS SHALL COME we
THOMAS SLATER of Somers Place New Road Saint Pancras in the
County of Middlesex Optician and JOSEРя JOHN WILLIAM WATSON
of Old Kent Road in the County of Surrey Doctor of Philosophy
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria by Her
Letters l'atent bearing date the Fourth day of October in the year
of our Lord One thousand eight hundred and fifty-two in the six-
teenth year of Her reign did for Herself Her heirs and successors
give and grant unto us the said Thomas Slater and Joseph John
William Watson Her special license that we the said Thomas Slater
and Joseph John William Watson our executors administrators
and assigns or such others as we the said Thomas Slater and Joseph
John William Watson our executors administrators and assigns
should at any time agree with and no others from time to time and

page_text: 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 THE APPLICATION OF
ELECTRICITY TO ILLUMINATING PURPOSES" upon the condition (amongst
others) that we the said Thomas Slater and Joseph John William
Watson by an instrument in writing under our hands and seals or
under the hand and seal of one of us 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 we the said Thomas Slater and Joseph
John William Watson do hereby declare the nature of our suid
Invention and in what manner the same is to be performed to be
particularly described and ascertained in and by the following state-
ment reference being had to the accompanying Drawings and to the
letters and figures marked thereon that is to say
Our Invention in improvements in the application of electricity to
illuminating purposes consist
First. In improvements in apparatus for employing electricity as an
illuminating agent.
Second. In apparatus for governing electric currentssoas to indicate
the quantity and intensity of electricity and to increase or diminish
the same when passing into any description of electrical illuminating
apparatus.
Third. In a new mode of applying electric currents so as to cause
an equable consumption of the electrodes.
Fourth. The nature and manufacture of the electrodes.
Fifth. The application of electricity to the purposes of signalizing.
Our Invention of improvements in apparatus for employing elec-
tricity as an illuminating agent consists firstly in using horizontal
levers attached rigidly to a piece or pieces of soft iron serving as
the armature of an induced magnet made magnetic by the same cur-
rent which by its rupture in the space between the poles affords. the

page_text: light by which a vertical rod or beam or other contrivance for holding
the electrode is gripped and held in a fixed position but which rod is
free to slide downwards or take any other course obligatory on the
effect of gravity or the elasticity of a spring the said levers serving the
further purpose by their forming the armatures of an induced magnet
of elevatingorgiving other direct motion to the rod when gript by them.
The simplicity of the above arrangement allowing for its modificationin
an infinity of ways. We claim especially as our Invention the use of
levers attached to the armature of an induced magnet or magnets to act
in the manner and for the purposes described. Of the forms advised
by us as the most convenient on the above principle we select the
following and which plan we recommend for all lamps in which the
apparatus is likely to receive rough usage and where ornamental
appearances and beauty of design are not required. The current
enters by the binding screw A Figure 1 on Sheet 1 of our Drawings
and passes up the body of the lamp B through the magnet C. C. which
is secured to a bracket fixed to the pillar B. A wire C¹ is connected
with the rod Din order to ensure better contact-this rod is suspended
at E by the chain F and counterpoise G which works within the
tubular support B but which is by no means necessary for the suc-
cessful working of the lamp. The armatures H. H. are attached to
brass levers H H¹ which are fitted with eyes through which the rod
D passes freely when induction ceases but when the current passes
through the magnet the outer extremities of the compound levers
H'H' are raised and their eyes simultaneously grasp the rod D
which is thus held at a proper elevation but when the current is
broken the levers assume a horizontal position and allow the rod to
drop down which effects a re-establishment of contact between the
electrodes. A series of antifriction pulleys are fitted at I to surround
the rod and allow it to descend freely. The lower portion of the lamp
corresponds to that shewn at Figure 1 Sheet 2 of the Drawings.
Our improvements for employing electricity as an illuminating.agent
embrace also the construction of electric lamps in the manner and on
the principles next described. The lamps constructed as below differ
in form and principle from those described above mainly by the induced

page_text: magnet being situate in the base of the lamp and by connecting the
armature with the electrode carriers by a system of levers. This form
of lamp may be made exceedingly ornamental and will occupy but
little space. A. A. Figure 1 on Sheet 2 of our Drawings is an
electro-magnet which may be constructed in the form herein-after
described and shewn in detail at Figure 2 Sheet 2 fixed in the base of
the lamp and rendered magnetic by the wire which enters at A' the
other end of the magnet being in connection with the base of the lamp.
The armature B of the magnet is attached to the lower extremity of
the rod C. which is attached at its upper end to one extremity of the
lever D. This lever works on the fixed centre E and is terminated
by a fork F shewn more clearly in the plan view of the lever
shewn detached at Figure 3 drawn full size. The helical spring G
serves to keep the end D¹ of the lever elevated when the magnet is
not in action. This fork embraces the collar H which consists of two
semi-cylindrical pieces hinged together at I and made to grasp the
vertical rod J by the action of the ascent of the fork on the conical
sides of the collar. The rod J is fitted with a socket K and tighten-
ing screw for holding the electrode L which should be fixed rigidly to
it. The lower electrode L' is inserted into the socket M. This socket
is fitted on to the top of the main stand N which also carries a binding
screw by which it is connected with the other pole of the battery.
The black portions of the Drawings represents the insulated points of
the apparatus. Two flexible wires o connect the top of the lamp
with the upper end of the rod J to which they are secured by a bind-
ing screw P. As the correct working of the lamp depends on the
adjustment of the arc or striking distance between the poles during
the working of the lamp we introduce an arrangement which is
marked by the letter Q and which consists of a boss capable of turning
round in a grooved ledge encircling the upper portion of the pillar
through which passes the rod attached to the forked lever D and
the armature of the magnet B. The inner portion of the boss is
grooved with a female screw thread into which works a male screw.
The turning of the boss raises the male screw which consists merely
of a tube grooved on the outside and carrying the lever causes the

page_text: armature of the magnet either to recede or approach the poles and
hence decreases or increases the inductive power. Moreover the
portion of the pillar above the boss being slotted to allow of the lever
passing through restrains the play of the lever to certain limits. These
two circumstances combined serve as the required means of adjust-
ment of the striking distance as will be obvious without further
description. The action of the lower pole of the lamp is as follows.
The current which makes the electro-magnet A makes also the electro-
magnet R before it passes to the general body of the lamp. The
electro-magnet R attracts the armature S which is attached to a
curved lever moving horizontally on the axis T but kept from the
magnet during the time induction is not taking place by the spring U.
At the other extremity of the lever is a moveable tooth V but which
after turning the rack wheel X into which it fits by the induction of
the magnet is always made to resume its original position by the bow
spring V-Y is a screw which is made to rise and so elevate W the
electrode holder by means of the rotation of the wheel X. It will be
clear from this discription of the apparatus that the same action which
results from the magnetic operation of A will induce a similar con-
sequence in the action of R with the exception that in the latter case
the motion is a rising one instead of a descending one. Moreover by
the simultaneous action of both poles the great desideratum of pre
serving the light in one place is successfully accomplished. In addition
to the mode just described of raising the lower electrode we claim also
the means of effecting this by an arrangement in which instead of a
screw travelling within a tube we use a long rack into which fits a
.tooth attached to a lever of the same kind and construction as the last
described but working vertically instead of horizontally the induction
of the magnet being downwards instead of laterally-the action of this
arrangement is very simple and consists merely in the keeper at one
end of the lever being attracted and so causing on every such occasion
the opposite and toothed end to raise the rack a tooth when the
inductive action takes place. The action of this lamp is as follows:-
The electric current on its passage through the magnet A causes the
.armature B to be attracted thereby drawing down the end D¹of the

page_text: lever D and consequently raising the collar H and rod J the electrodos
being thus retained at a proper distance asunder so long as a sufficient
amount of attraction exists between the magnet and armature to keep
the latter down. Should any non-conducting material obstruct the
passage of the electricity through the arc the induction of the magnet
instantly ceases and the helical spring G coming into action forces up
the end of the lever D and at the same time the descent of the forked
end of the lever releases the grasp of the collar upon the rod J which
consequently slides down and re-establishes contact between the elec-
trodes the requisite arc being instantly reformed by the attraction
of the armature as herein-before described. If as in other arrange-
ments for producing the electric light the contact be made by two or
more points on the electrode which points are temporarily removed
to admit of the electrode sliding down as it burns away the light
will for such time go out and a spark passing between the point
of the jaws will fuse them and hence in time from the coat of
oxide formed the lamp will cease to be of any use at all since the
principle does not admit of good conduction being always kept up.
The contact in our lamp is always the same and continuous since
the descent of the rod to which the electrode is attached requires
simply a diminution of the friction exercised on the rod by the
lever and collar apparatus herein-before described and this we claim
as the substantive part of our Invention. This action is accompanied
by no diminution of the light. In addition to the forms described we
prefer for public lights and indeed for all cases of illumination where
the light has to be sustained for a long time the use of several
electrodes and also the use of separate lights in the same lamp but in
all such cases we strictly adhere to the same principles and differ only
in the mode of arrangement of the electrodes. In arranging several
electrodes we take great care to preserve them insulated one from the
other and deriving their electricity by separate wires. We occasionally
oppose several small electrodes forming the positive poles to one larger
electrode forming the compound negative pole of the several batteries.
We find that by combining several electrodes or sources of light in the
same lamp that if near together they prevent the chances of flickering

page_text: going out sparks &c. and render the general illuminative effect
constant. Figure 4 on Sheet 2 of the Drawings is a partial section
andelevation of an arrangement for raising the lower electrode A and
Figure 5 is a horizontal section of the same. This is effected by the
screw B which is secured to the pulley C. A traversing nut D works in
a slot in the side of the cylindrical case E being raised or lowered by
the screw B. The electrode A is fitted into a socket in the top of the
nut and passes through the piece E which serves to guide it in its
ascent. This arrangement which must be worked by hand we substi-
tute for the magnetic arrangement in the bottom of the lamp in
Figure 1 in all cases where the lamps are used in situations where
personal attendance is practicable and easily obtainable.
The next portion of our Invention relates to electrical; governors, in-
dicators and alarums and other minor apparatus connected therewith.
Figure 2 on Sheet 1 of our Drawings shews an arrangement for indi-
cating any variation in the current and also to a certain extent a means
of measuring its intensity. We have termed this the electric governor
or indicator. It is shewn half in section and half in elevation. A is
the base of the apparatus to which is attached the single magnet B.
A helical spring C is interposed between the magnet and armature D.
A rack E is attached to the armature and takes into the pinion F' on
the arbor of the indicator G. A wire H connects the armature D
with the arbor of the indicator and another wire I passes thence to the
outer pole of the battery. The action is as follows-The current on
passing through the magnet attracts the armature drawing it down
more or less according to the strength of the current and consequently
turning the pinion and with it the indicator G which shews on the
graduated dial the strength of the current. The belical spring is for
the purpose of raising the armature when the attraction diminishes.
Figure 3 on the same Sheet of our Drawings is an ajarum or means of
indicating at the battery depôt or at any other place through which the
electric mains may pass any sudden or partial cessation in the continuity
of the current. It may be termed generally an alarum. A is an
electro-magnet made by the same current of electricity that supplies
the lamp or other apparatus. B is the armature attached to a

page_text: lever C. which is bent at right angles and carries a tooth detent
at D which fits the teeth of the ratchet wheel E. Attached to the
centre of E as a radial arm is the rod F.-G is a toothed lever
hammer of which the head I plays within the bell H and is
constrained to the position represented in the Drawing by a coil
spring in the axle on which it works. K is a weight attached
to a string passing round a drum attached to the back of the
ratchet wheel E. The action of the alarum is as follows-When
from any failure in the current the armature B ceases to be attracted
by. the electro-magnet then falling from its own weight it relieves
the detent tooth D and the weight descending causes the ratchet
wheel to rotate and so turn the radial arm F which striking the
hammer G rings the bell H. It is easy to see that the re-establish-
ment of the current will instantly arrest the descent of the weight and
therefore the ringing of the alarum by the induction of the keeper of
the magnet to its former and fixed position. In order to increase or
decrease the amount of light in the lamp when the illuminating appa-
ratus is large or in order to adjust a powerful battery to a delicate
lamp we check the current as it enters by causing it to pass through
iron wires of different thicknesses imbedded in pipe clay or alumina
or asbestas the connection being made by means of a handle of peculiar
construction which by sliding on an axis on which it turns over the
top of the pipe clay bed with the surface of which the iron wires are
arranged parallel and flush the current is passed through any one of
the wires at the pleasure of the operator thereby diminishing or
increasing the intensity of the light given off at the points of the
electrodes. Figure 4 is an end view and Figure 5 a corresponding
plan of this apparatus. A is a lever composed of ivory or any other
good non-conducting material working on the fixed centre B and
turned in a horizontal plane by the small handle C. and having a small
metal stud D at the moveable extremity. E. F.G. H. I. are iron wires
of graduated thicknesses resting in a bed of pipe clay J. which is fixed
in the wooden stand K. The terminals of the wires are united by the
cross piece of metal L which is fitted with a set screw M for the at-
tachment of the wire N. The action of the instrument is as follows-

page_text: The lever being turned so as to bring the stud D on to any par-
ticular wire the current passing in at L travels by D along the upper
surface of the lever A which is of brass and thence by the binding
screw forming the fixed centre of the lever to the lamp. Now if the
current be found too strong all that is necessary is to turn the lever so
as to bring the metal stud on to a wire of smaller dimensions and so by
the increased resistance retard the surplus power. As it will be evident
that the power of a battery must after a certain time of action decline
and as such an event would seriously affect what might be taking place
in the apparatus to which the electricity might be passing such as the
lamp, we have overcome the difficulty by using in practice a reserve
battery the power from which we can instantaneously transfer by the
following contrivance shewn in elevation at Figure 6 and in corre-
sponding plan at Figure 7. A is a disc of wood which may be
firmly attached to any suitable support. B. B¹. B". B¹¹¹ are metallic
plates embedded in the disc all on the same level and having at-
tached in the manner shewn binding screws x. x. 11. 1. In the
centre of the disc is a boss G. which is extended above into a
handle F by turning which the two metallic arms E. E' which are
attached to the boss G but insulated from each other by the intro-
duction of a piece of ivory or other good non-conducting material.
On the arms E. E' are two binding screws H. H¹. The action of
the apparatus is very simple and is as follows. The battery in action
and the battery in reserve are attached by wires to the four metallic
plates B. B. B. B₁11 by means of the binding screws;
thus to
B. B' is attached the battery in action which we will term a and to
B B accordingly are turned the metallic arms E. E¹ the current
then passes by wires attached by the binding screws on E. E' direct to
the lamp or other apparatus. Now supposing the power of a to be
declining from the length of time the light has been burning without
causing any cessation in the production of the light all that is necessary
is to turn by means of the handle F the metallic arms E. Et to the
metallic plates B. B. by sliding over and on to which the reserve
battery, which we will call 6, is immediately brought into play, and the
electricity from the fresh source instantaneously applied-The battery

page_text: is then at liberty to be replenished and prepared for taking b's place,
when b shall have been exhausted. By such means the light may be
maintained with sufficient length of electrodes for a week in action
without cessation. It is often desirable suddenly to change the poles
when either from want of homogeniety in the electrodes or from any
accidental cause one electrode has consumed much quicker than the
other. This we effect by what we term the "brake "a small apparatus
consisting of a sliding plate of brass or other metal which being slid
over 4 buttons of brass each button forming the terminal of either
the battery poles or the lamp poles the current is made to proceed
through the negative pole of the lamp or the positive pole as the case
may be. Let A and B Figure 8, be the positive and negative poles
of a galvanic battery and a¹. 61 the poles of the lamp: then let it be
required to change the poles of the lamp-x. al. 11. 111. are metallic
plates well insulated from one another and arranged in a line in a
wooden stand LL' is a slide constructed of wood and with two me-
tallic ends and moved by the handle C. Now when the ends of L. L'
are on the plates x. 11 then the current setting out from the positive
pole of the battery (A) circulates by the wire 1 to the positive pole of
the lamp a' by the wire n and returns by n¹ to x¹¹ and thence by the
wire 2 to the negative pole of the battery (B). To change the poles
of the lamp the slide is slid back to x¹ 111 and then the current
from A circulates by 3. to 2111 thence to b¹ and by 4 back from x¹ to
B by which 6' becomes positive and a negative in other words the
poles of the lamp are reversed. Occasionally we employ electro-mag-
nets of the following description which we form as follows. A copper
band 4 inches broad and about 25 feet long is insulated by coating
with calico. A portion 3 inches long of this piece is then bent back
and between it and the main piece is inserted a plate of soft iron the
band 2 inches of which is next bent back in the opposite direction and
a similar plate of soft iron inserted as before. The rendering of this
dry pile magnetic is effected by passing the current in the direction in-
dicated by the arrows in the Drawing by which double and opposite
poles are obtained in the same plate. In the Drawing Figure 2
Sheet 2. A is a brass plate B. B¹ are the copper plates x, x¹ are

page_text: the wires bringing the current which renders the pile or flat helix
magnetic-the black spaces represent the iron plates. Cis the keeper.
It will be obvious to the practical man that the herein-before described
arrangements are equally applicable to signalising purposes.
Another portion of our Invention relates to the use of two or more.
electrodes in the same or different planes and the arrangement of such
electrodes so as to produce more than one point of illumination in the
same lamp at the same time. Our improvements in the nature and
manufacture of electrodes are as follows. Causing them to be homo-
geneous, moderately hard, of perfect conductability, suffering moderate
and perfectly uniform convection during ignition andnon-absorbtive as
far as possible of moisture. Under this head we have effected our
improvement in the following manner. We have found that by taking
70 parts of finely powdered coke well boiled in nitro-muriatic acid to
remove any metallic or earthy impurities with which it might be
contaminated and afterwards washing it with caustic potash; that by
taking this and mixing it with 20 parts of red charcoal (we prefer it
from the beech) or as it is termed by the French charbon rouge
or animal charcoal and 5 parts of gas pitch with 4 parts of finely
powdered Newcastle baking coal and 1 part of china clay:-that by
thoroughly incorporating the mass the desired end is obtained by
subsequent careful heating in a mould of appropriate construction.
We generally prepare a mass of about 1 foot 6 inches broad and 3 feet
deep at a time; the gases which are produced by distillation being
allowed, to escape by an eduction pipe. The time occupied for the
preparation of the mass we prefer to be nine to twelve hours-The
heat being applied very gradually for the first two hours after which
the mass is tightly compressed by the ends of the mould being made
to approximate by means of a screw. The furnace for heating the
mould may be of any suitable description. After the mass is withdrawn
from the mould and cooled; if the operation has properly been con-
ducted it may be sawn into pieces of the desired size perfectly homo-
geneous in their structure. We have found that good electrodes
giving a steady achromatic light may be prepared by the following
process from well burnt beech charcoal, selected from the small wood or

page_text: as they are technically termed "loppings:"-box wood will doas well.
A piece of the charcoal sawn into required size for the electrodes is
steeped in a solution of caustic lime for about a quarter of an hour, it
is then taken out, dried and placed into a crucible containing powdered
charcoal and a lid being firmly and closely luted on to the crucible it
is exposed to a white heat for about half an hour: it is then taken out
after the crucible has cooled placed into a saturated solution.of alum
and, after having soaked for about half an hour it is dried and again
brought to a white heat as before. It is again removed and plunged
whilst hot into treacle or any thick saccharine or carbonaceous fluid
and finally once more ignited. If the operation have been properly con-
ducted it is now very hard quite free from any traces of lignious structure
a perfect conductor and burns moderately slowly equally and noise-
lessly when forming the terminal of the voltaic arc. The electrodes
which are formed by the first-described process burn at the rate of
about a quarter of an inch an hour on an average so that an electrode a
foot in length would burn between twenty-four and twenty-eight hours.
They consume evenly and are but little affected by the wind. Before
using the electrodes are pointed by a fine file in order that they may
wear equally after being first ignited. For electrodes which are
intended to be used in lamps where the arc will be great and the
current passing very powerful we use instead of alum soluble glass
which is prepared in the following manner. 15 parts of powdered
quartz or very fine sand are fused with 10 parts of potash and 1 part
of charcoal in a crucible. When the fusing is complete the crucible is
uncovered and the mass taken out and treated with cold water by
which the extraneous particles of carbon and foreign salts are removed-
The residue is then treated with hot water and thereby entirely
dissolved. The electrodes are immersed in this from five to ten minutes
whilst the solution is hot. The other operations for preparing the
electrodes are the same as in the preceding case. The object of
adding the non-conducting substances alum china clay soluble glass
and caustic potash is to prevent the excessive convection which the
otherwise great conductability of the carbon would occasion and

page_text: thereby render the continuity and perfection of the light impossible
from the excressences formed about the poles.
Having now described and particularly ascertained the nature of our
said Invention and the manner in which the same is or may be used or
carried into effect we would observe in conclusion that we do not
confine orrestrict ourselves to the precise details or arrangements which
we have had occasion to describe or refer to as many variations may
be made therefrom without deviating from the principles or main
features of our Invention but what we consider to be novel and
original and therefore claim as the Invention secured to us by the
herein-before in part recited Letters Patent is
⚫. First. The general construction and arrangement of electric lamps as
herein-before described.
Second. The application and use of a conical collar constructed of two
semi-conical pieces of metal hinged at one of their extremities and
acting as a grip upon a solid rod carrying the upper electrode of an
electric lamp as herein-before described.
Third. The application and use of a lever forked at one of its
extremities to act upon the conical collar in the manner and for the
purposes herein-before described.
Fourth. The connection with one extremity of the aforesaid lever of
the armature of an induced magnet to act in the manner and for the
purposes herein-before described.
Fifth. The attachment of a spring in the manner herein-before de-
scribed to the aforesaid lever to cause the forked extremity of the lever
to leave the sides of the conical collar during the momentary cessation
of the induction of the magnet in the manner herein-before described.
Sixth.Theregulation of the striking distance bythe slotand travelling
screw boss shewn in Figures 4 and 5 Sheet 2 of the Drawings in the
manner and for the purposes herein-before described.
Seventh. The construction and use of the screw for raising the lower
electrode in the manner and for the purposes herein-before described
and shewn in Figure 1 on Sheet 2 of the Drawings.
Eighth. The useand construction of the horizontal levers forming the

page_text: armature of an induced magnet or magnets for gripping the electrode
holder in the manner and for the purposes herein-before described.
Ninth. The system or mode of raising the lower electrode in the
manner and for the purposes herein-before described and shewn in
Figure 1 on Sheet 2 of the Drawings.
Tenth. Theuse and application of an electro-magnet for turning the
ratchet wheelgiving motion to the travelling screw holding the lower
electrode in the manner herein-before described.
Eleventh. The system or mode of applying electric currents so asto
cause a more equable consumption of the electrodes in the manner and
for the purposes herein-before described.
Twelfth. The makingofthetwoelectro-magnetsinductive at the same
time and by the same current that supplies the light.
Thirteenth. The use of helices of copper or other wire in lieu of
electro-magnets in the manner and for the purposes herein-before
described.
Fourteenth. The application and use of several electrodes in the same
lamp as arranged in the manner herein-before described.
Fifteenth. The constructionofelectro-magnetsin the manner herein.
before described and shewn in Figure 2 on Sheet 2 of the Drawings.
Sixteenth. The construction of the governor and indicator for indi-
cating the variation and strength of the current in the manner herein-
before described and as shewn in Figure 2. Sheet 1 of the Drawings.
Seventeenth. The use and construction of the alarum shewn in
Figure 3 Sheet 1. in the manner and for the
purposes herein-before
described.
Eighteenth. The use and construction of the apparatus for retarding
the passage of the current entering the lamp in the manner and for the
purposes herein-before described and shewn in Figures 4 and 6. on
Sheet 1 of the Drawing.
Nineteenth. The construction and use of the apparatus for changing
the passage of the current passing to the lamp or other apparatus or as
applied in any way practically from one battery to another as herein-
before described and as shewn in Figures 6 and 7. on Sheet 1 of the
Drawings.

page_text: Twentieth. The construction and use of the apparatus called "the
brake" in the manner and for the purposes herein-before.described
and as shewn in Figure 8 on Sheet 1 of the Drawings.
Twenty-first. The formation and use of electrodes of the materials
and in the manner and for the purposes herein-before described.
Twenty-second. The introduction into the electrodes of a certain
amount of non-conducting material to check the excess of convection
and to render the light properly achromatic in the manner herein-before
described.
Twenty-third. Theintroduction intothecompositionoftheelectrodes
of a certain amount of caustic alkali or earth in the manner and for the
purposes herein-before described.
Twenty-fourth. The application and use of the electric light for the-
purpose of signalizing.
In witness whereof we have hereunto set our hands and seals 1
the Fourth day of April One thousand eight hundred and fifty-.
three.
THOMAS SLATER.
(L.S.)
JOSEPH J. W. WATSON. (L.S.)