IMPROVEMENTS IN APPARATUS FOR OBTAINING LIGHT BY ELECTRIC AGENCY
Year: 1849

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME I CHARLES
THOMAS PEARCE of Park Road Regent's Park Esquiro send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria by
Her Royal Letters Patent, under the Great Seal of the United Kingdom of
Great Britain and Ireland bearing date at Westminster the Sixteenth day
of February One thousand eight hundred and forty-nine in the twelfth year of
Her reign did for Herself Her heirs and successors give and grant unto me
the said Charles Thomas Pearce my exors adññors and assigns Her especial
licence full power sole privilege and authority that I the said Charles
Thomas Pearce my exors admors and assigns or such others as I the
said Charles Thomas Pearce my exors adññors or assigns should at any
time agree with and no others from time to time and at all times during
the term of years therein expressed should and lawfully might make use
exercise and vend within England Wales and the Town of Berwick-upon-
Tweed and in the Islands of Guernsey Jersey Alderney Sark and Man
and in all Her said Majesty's Colonies and Plantations abroad my Invention
of "IMPROVEMENTS IN APPARATUS FOR OBTAINING LIGHT BY ELECTRIC AGENCY"
in which said Letters Patent is contained a proviso that I the said Charles
Thomas Pearce shall cause a particular description of the nature of my said
Invention and in what manner the same is to be performed by an instru-
ment in writing under my hand and seal to be enrolled in Her said Majesty's
19878-3.

page_text: High Court of Chancery within six calendar months next and immediately
after the date of the said in part recited Letters Patent as in and by the
same reference being thereunto had will more fully and at large appear.
NOW KNOW YE that in compliance with the said proviso I the
said Charles Thomas Pearce do hereby declare that the nature of my said
Invention and in what manner the same is be performed are fully described
and ascertained in and by the following description thereof reference being
had to the Drawings hereunto annexed and to the figures and letters marked
thercon that is to say.
Figure 1 shews an elevation partly in section Figure 2 shews a plan of
the upper parts and Figure 3 a sectional plan of the lower part of apparatus
arranged according to the first part of my Invention. a a is the framing
which I prefer to be of wood. The lowing part of this framing supports clock-
work movement enclosed in the case (6) On the top of the apparatus arc
scen the electrodes with their supports. (c) is a bar of carbon (forming onc
of the electrodes) the cross section of which may be cylindrical triangular or
other convenient form the projecting edge or surface of which when the
sectional form is other than cylindrical is presented to its fellow electrode (d)
which is circular in form and revolves at the same time that the bar (c) of
carbon is.advancing upwards.
In the Drawing the disc (d) is represented as being placed at an angle
of 45° with respect to, the bar, or rod (c) of carbon. Other angles may be
given to the disc but I prefer the one shewn. (e) is a 'split shcath which
partly encloses and serves as a guide for the bar electrode c seen emerging
from the upper part of the sheath. This sheath e may be of metal but
I prefer glass for, the purpose... To the top of the sheath e is fixed a metal
collar or ring g into which are inserted, three platinum wires furnished at
their upper ends f¹ each with a piece of the metal called iridium which is
fixed on to the platinum wires by bringing then between the terminal wires
of a galvanic battery of sufficient intensity to fuse the irridium. is a binding
screw for making. contact with the battery wire. The collar g may be sup-
ported from the framework or otherwise instead of its being fixed to the
sheath e. The advantage of employing iridium at f' is that the current of
electricity may be supplied to the electrode near to the portion where the light
is evolved. Attached to the arbor of one of the wheels of the clock movement
is a rod of metal or other suitable material i but when metal is employed the
metal should not be continued through the whole length but have a collar of
ivory hard wood or other suitable non-conducting material to insulate it in
the direction of its length as at . This rod i is supported at its upper end in

page_text: the frame and carries a toothed wheel (c) the teeth of which work in a
similar wheel (7) which may be larger or smaller according to the rate of
motion required for the electrode d: The axis' or arbor of this wheel (1) carries
a bevel wheel m which works in a similar wheel n carried by the axis on
which the circular or disc electrode d is mounted. Thus is motion commu-
nicated to the disc d from the clockwork movement 6 through the medium of
the wheels and rods described at the same time that the bar c is caused to rise
through its sheath by the same clock movement as I will presently proceed to
describe. The frame j. at its lower end is formed with dovetail edges by
which it is guided (for the purpose of adjustment) in dovetail guides carried
by the framing. To facilitate this adjustment the lower part of the frame j
carries a nut or collar through which a screw o passes furnished with a
milled head o¹ by turning which to the right hand the disc d may be drawn
back or by turning it to the left hand the disc d may be made to approach
nearer to the bar electrode c. Thus the distance between the electrodes may
be regulated according the length of arc required. p p are two cutters of
iridium attached by means of a metal spring to the framework. These
pressing against the circular electrode d'serve to cut off the redundant
portions of carbon and maintain a good presenting periphery for its next
revolution. The bar electrode c is caused to rise in the following manner
At the lower end of the axis i is affixed a toothed wheel e' which takes into
and drives the toothed wheel e to which is affixed the toothed wheel c³ which
takes into and drives the toothed wheel e" carrying the bevelled wheel e
which gears into the bevelled wheel e on the axis of the barrel e to which is
attached one end of the line or it may be a chain e-which passes up over the
pulley and is connected at the other end to an eye projecting from the lifting
piece e¹ this piece e supports the end of the bar electrode c and slides up
within the sheath e the eye travelling up in the longitudinal groove formed for
that purpose in the sheath c. Thus is motion given to the electrode c.
Another mode of presenting the edge. or side surface or surfaces of
a bar electrode to another electrode is as follows I employ two circular
electrodes in combination with one bar-the bar being placed between the two
circular electrodes or discs. The advantage of this mode of mounting the
electrodes is that if from any cause such as the inequal waste of carbon or
irregularity of its surface the light should be extinguished at one point the
other remains burning until by the further revolution of the disc or 'the
advance of the bar the electrodes are again brought into contact and the
second point or source of light is restored. I have also employed three
circular electrodes in combination with one bar the bar presenting three

page_text: angles or surfaces to the circular disc electrode. Thus an advantage is gained
over apparatuses hitherto employed by presenting three several centres of light
so merged as to appear as one only when used with a reflector or reflectors
and the liability of the light to being extinguished rendered much less.
Reflectors used may be of glass or of metal. I prefer making them of copper
by electro-precipitation on a mould or matrix prepared of the proper form.
By this method an unlimited number of reflectors may be made of the same
exact form and at a less cost than if manufactured in the ordinary way under
the hammer. Having precipitated the copper on matrices with polished sur-
faces I afterwards silver the surfaces by electro-precipitation. The cover of
the glass shade indicated by the blue line q and enclosing the apparatus is
furnished with a syphon tube q' at its upper surface to allow the gascous
products of the combustion of the carbon to escape into a vessel containing
water or other liquid. I would remark that although I prefer to use bar
electrodes with disc electrodes two bar electrodes may be employed in an
apparatus in such manner as to cross each other at an angle and then
by giving a slow progressive motion to each of the bars a continuity of fresh
surfaces of the electrodes will result.
Figure 4 is a front view and Figure 5 a side view of an apparatus in
which the use of clock work is dispensed with. A is a stand or frame of
wood supporting the apparatus in the centre of which is fixed a split sheath B.
Within this sheath is a solid rod C to the lower end of which is attached the
lines D D passing upwards over two pullies E E and descending to the
weights F F. Resting on the solid rod C is a bar electrode G. At the
upper end of the sheath B are iridium supporting conductors such as before
described. To the frame A is fixed an upright H with a slotted opening
therein which receives the stem of a jointed piece I supporting the upper
electrode J and its appendages. KK are two tubes supported by the
uprights L L from the frame A and furnished with joints M M. NNN
are three tubes of brass forming enlarged parts of the tubes K K and P
each containing a spiral spring which by means of rods N¹ N¹ press on the
pieces of carbon OO & J contained in the tubes K K & P forcing them
towards the lower electrode G. To the upper tube P is fixed a carbon holder
composed of metal and pipe clay. Qis a metal collar fixed to the tube P by
means of a screw R and carrying another metal collar Q which is attached
to it by the three wires Q. To this metal collar is attached an earthen
cone S which may be of pipe clay phosphate of lime or other earthy sub-
stance difficult of fusian & hollow within to receive the bar of carbon.
The cone is contracted at its lower end to prevent the bar of carbon from

page_text: being urged onward too rapidly. S¹ S¹ are two holes in the cone S to
metal ring U and admitting
For the springs in the tubes
receive the wires T T connected with the
of their coming in contact with the carbon.
NNN a falling weight may be substituted. The two lateral bars of carbon
contained in the tubes K are non-conducting carbon the upper and lower
bars of carbon are conductive. The battery being connected with the upper
and lower electrodes the current passes through them producing by the
separation of the bars from each other the required light. As the lower
electrode becomes wasted by the action of the current of electricity the
weights urge it upwards until it is checked by the lateral bars of carbon
which press on it near its upper end. Where electrodes are required of con-
siderable length I graft together several pieces of carbon by either of the
following methods. In the ends of each piece I drill a cylindrical or other
shaped hole or cavity into which I insert a piece of carbon of a shape that
will fit firmly into the hole and long enough to project therefrom. This
projecting part fits into a similar piece of carbon and the two being brought
together become firmly united as one piece. Another mode of grafting
or joining together which I sometimes adopt is the following. In the side
of the bars I make a groove longitudinally into which I insert a smaller
bar or slip of carbon which running in two or more bars the whole become as
Another mode of forming electrodes is to combine together two or more
pieces of conducting and non-conducting carbon so that the surface presented
to the action of the current shall be of conducting matter while the rest of the
electrode shall be of non-conducting matter. This I accomplish either by
the insertion of one into the other by a groove or union of surfaces or by any
other efficient mode to secure contact between the parts. What I mean by
non-conducting carbon is ordinary charcoal whilst that which is conductive
has been subjected to a high temperature in a close vessel as is well known
to electricians.
one.
Another the second part of my Invention consists in an apparatus for
restoring contact between the electrodes and thus regulating and ensuring the
continuity of currents of electricity in apparatus used for obtaining light. It
sometimes happens that a current of air suddenly acting upon the light may
blow out the arc of flame as in exposed situations where it is not perfectly
protected by which the current will be interrupted. Now according to this
part of my Invention the apparatus is so regulated as to ensure the current
of electricity being kept up. Figure 6 represents an apparatus for this
purpose. At one end of a lever a is a short metal tube 6 into which is fitted

page_text: a piece of carbon or other suitable conducting material c shaped like a wedge
or of other convenient form. To the other end of the lever a is connected a
soft iron armature d to which is attached a spiral spring e. The lever a is
kept in a fixed position while the current is passing round an electro-magnet f
which holds the soft iron armature in contact. The instant the light is blown
out battery contact being broken thereby the magnet loses its power and the
spiral spring draws up the armature and therewith the end of the lever
allowing the other end to fall bringing the piece of carbon down between the
electrodes. The circuit is by this means restored which as soon as done the
magnet resumes its power and moving the piece of carbon up again the light
is restored.
.
Another the third part of my Invention consists in regulating the duration
of and intervals between the light for signal lights lighthouses and other
purposes where an intermittent light is desired. This I effect in the following
manner. To one of the arbors of a timekeeper I affix a wheel composed of con-
ducting and nonconducting material say brass and ivory alternately as shewn in
Figure 7 where a is a wheel of brass or copper I prefer the latter it being a
better conductor of electricity. 6666 are pieces of ivory or hard wood inserted
in the periphery. c is a broad metallic spring connected with one of the poles
of the battery by means of the binding screw d. The spring c presses against
the surface of the wheel. The metallic portion of the wheel is connected with
the light apparatus. As the wheel is carried round by the clockwork the
insulating portions and the metallic portions are alternatoly brought into
contact with the battery by means of the spring o C. The spaces between the
metallic portions are of a suitable width to the required intervals of time.
Thus should the light be required to be visible for three minutes and to
be extinguished for three minutes the portions occupied by the metallic
and insulating material would be equal and if the wheel occupied one hour
in its revolution there would be twenty such spaces or divisions. Again
if the light be required to be visible for four minutes and to be extinguished
for two minutes the metallic portions would be twice the length or width of
the insulating portions. In applying this regulating principle to apparatus
giving light one of the electrodes is alternately made to approximate to or
recede from the other by means of an electro-magnet which being under the
influence of the same current keeps the electrode in its proper position whilst
the current is passing and the light maintained. The instant contact is broken
by the wheel the maguct loses its power and the electrode recedes from the
other. When contact is again restored by the further movement of the wheel

page_text: the electrode as quickly resumes its proper position by the action of the
magnet.
A like apparatus is used to obtain more uniform action of currents of
electricity by being the means of alternating the times of use of two or more
batteries in such manner that the time of giving light by means of each battery
shall be regulated. Electricians are aware of the disadvantage arising from
keeping a battery in constant action in a closed circuit as it is termed. When a
battery has been kept in action for some time it has been found that the current
fluctuates considerably and the amount of electricity given off is much dimi
nished which is restored by breaking contact of the poles. I do this by the
application of an apparatus similar to that last described in conjunction with
two or more galvanic batteries so that each battery is put out of action for a
time and into action for a time causing it to rest for a longer or shorter time
while another is doing the work. The wheel a Figure 8 is placed in connection
with one electrode of the light apparatus by means of a conducting wire. b is
a piece of ivory forming one half the wheel a. c, c', are two spring conductors
which press firmly against the circumference of the wheel. The manner in
which it acts is as follows As the wheel revolves during half or thereabouts
of its revolution one of the spring conductors c is in metallic connection
while the other c' is in contact with the ivory or insulating portion 6. The two
springs c, c¹, are respectively connected with the two batteries employed.
Thus in the position of the parts shewn c is in metallic contact the current is
therefore passing through it to the tight apparatus and the battery with which
c is in connexion is now in action sustaining the light while the battery with
which c¹ is connected is at rest. Supposing the wheel to be revolving in the
direction indicated by the arrow the metallic portion shortly will come into
contact with c bringing the battery with which it is connected into use when
at the same moment the insulating portion comes into contact with c¹ throwing
the battery with which it is in connexion out of use.
a is a
Another the fourth part of my Invention consists of an apparatus for regu-
lating the currents of electricity applied to the purpose of lighting by means of
magnets or coils. Figure 9 represents an apparatus for this purpose.
temporary bar magnet held in a fixed position surrounded by a coil of insu-
lated copper wire. b is a permanent bar magnet supported over a by a spindle
or axis. On the upper or front side of b is a toothed wheel c fixed thereto.
d is a pinion which is worked by c & transmits motion to another toothed
wheel e.
Over a pulley on the wheel e passes a line or wire f which descends
and is fixed to a plug or rod f¹ in the split sheath g. is a bar of carbon

page_text: serving with an upper one to produce the light. The mode of action is as
follows. The galvanic battery being charged one of its wires is connected
with the wire of the temporary or electro-magnet a the other wire of the
battery being connected with one of the electrodes the other electrode is con-
nected with the other wire of the magnet. The carbon electrodes being
placed in contact and the current passing the magnet b is deflected as shewn
at the same time moving the toothed wheel and through the train moves the
electrode from its fellow electrode to a distance according to the amount of
battery current passing. Instead of the permanent magnet 6 here described an
electro-magnet may be substituted the fixed magnet a being substituted by a
permanent magnet or both may be electro-magnets or a coil of wire trans-
mitting an electro current may be substituted for either magnet.
Another part of my Invention consists in an improved mode of constructing
galvanic batteries by which
Firstly the fluids employed therein are more equally supplied to each
cell and more readily removed as they become unfit for use by continued
action. The trough known as Masse's Perfluent has been long used
and improvements therein have been made and claimed in a recent Patent
by Mr. Staite in all of which there is an objection on account of the
fluid in some of the cells of the battery being of greater strength than in
others in the same battery giving rise to unequal action in the series, and
consequent loss of power.
My improvements under this part of the Invention consist
Secondly of an arrangement by which each set of plates (metallic elements)
may be removed at once instead of every plate singly. And
Figure 12 a
Thirdly of an arrangement by which the diaphragms form part of the
trough instead of being placed singly and separately in the cells.
Figure 10 shews a plan Figure 11 a longitudinal section
transverse section. a a a is an outer trough which may be made of wood
.porcelain or other earthenware. I prefer wood lined with marine glue or
cement. 6 6 6 is the trough which receives the plates and partition c.
dd are the diaphragms or porous partitions separating the two fluids.
ee represent the supply or exit cells running along the sides of the trough
the lower surface or bottom of which is level with the fluids in the battery
and opening into each cell by portions of the corresponding side of the trough
being removed. ff represent the zinc plates and 99 the copper plates.
Where these are used other metallic elements may be employed. h is a
bar of wood to which are secured the copper plates firmly fixed thereto by

page_text: means of pins running through the wood secured by a nut screwed on the
end of the pins i. kk are similar bars of wood to which the zinc plates are
secured as described for the copper. The copper plates are formed by
bending a piece of sheet copper into the form shewn which serves as two
plates when in their respective cells. In the above arrangements the fluids
are supplied to each cell at the same time and instead of the fluids being
admitted at one end and travelling to the other end they are admitted at the
side of each cell directly instead of indirectly from cell to cell. When only
only one fluid is employed as the excitant it is admitted at the upper part of
each cell equally and simultaneously by means of the trough or cell e com-
municating with the battery cells by openings therein. The fluid as it becomes
saturated with the metal employed is made to pass out of the battery on the
opposite side near the bottom through openings / into the outer trough a from
which it passes into a receiver which may be a cask cistern or any other
convenient vessel where two fluids are employed as sulphuric acid in the
zinc cell and sulphate of copper in the negative or copper cell. The acid
solution is supplied above as described for a single flued battery while the
metallic solution is admitted below and rising as its specific gravity is dimi-
nished passes out at the opposite side through the cell or trough e out of which
it again passes into a vessel containing crystals of the salt employed where it is
renewed and passes on to the next battery which is placed at a lower level
than the first. In this way an economy is effected by using the fluid in each
battery in succession in as many batteries as may be employed forming the series.
In order to encrease the surface of the negative metal employed I bend the
ving
presented
same space. In batteries where concentrated acids are employed as the
nitrice or nitro-sulphuric in the Maynooth battery or that of Grove the
diaphragms or porous partitions are necessarily made of porous earthenware.
In other batteries where the fluids employed are less corrosive such as
Daniell's battery I prefer diaphragms made of sycamore wood cut into leaves
or thin plates and boiled in alkaline solution as potash. I prefer for this
purpose muriate of soda on account of its cheapness. The process of boiling
the wood extracts the gum resins and renders it conductive. After being
boiled I soak them in cold water acidulated with sulphuric acid in the pro-
portion of one part acid to thirty water. Other sorts of wood may be
employed for making the diaphragm but I prefer sycamore. In the

page_text: trough above described other fluids may be employed. Thus, where a current
of voltaic electricity is required to be kept up for several days or weeks
consecutively I prefer employing alkaline solution such as the muriates of
ammonia soda or potash or the sulphurets of lime potash or soda. The
advantage of employing alkaline solutions over acids is that the zinc
employed therewith does not require to be amalgamated with mercury as is
the case where acids are employed.
Having thus described the nature of my Invention and the manner in
which the same is to be performed I would remark that I do not confine
myself to the details herein shewn and described so long as the peculiar
character of any part of my Invention be retained but what I claim is
First the so employing bar electrodes that the light shall be developed at
the sides or edges in place of at points at the ends of such electrodes. I also
claim the mode of using bar electrodes when in combination with disc elec-
trodes that the planes of the disc electrodes shall be held at an angle to the
bar electrodes used therewith. I also claim the mode of causing the electric
currents to be conducted near the point of bar electrodes where the light is
developed by employing holders such as are described in respect to fand fi
Figures 12 and Z. I also claim the means herein described for connecting
joining and combining parts of bar electrodes. And I also claim the mode of
employing bar electrodes whereby a constant supply of non-conducting mattor
is kept up to retard the approach of the bar electrodes employed.
Secondly I claim the modes of regulating currents of clectricity in appa-
ratus for producing light whereby in the event of the light going out contact
shall be re-obtained by the introduction of a conducting substance to be
removed by means of an electro-magnet bar or coil.
Thirdly I claim the use of clockwork for regulating the time of the appa-
ratus giving light as herein described and I also claim the use of clockwork
for regulating the times the separate galvanic apparatus shall be the means
of giving light.
Fourthly I claim the mode of regulating currents of electricity produced
by a battery by employing a magnetic bar or coil as described in respect
to Figure 9. And
Fifthly I claim the improvements herein described of perfluent or main-
taining batteries-applicable to the purposes of obtaining light.
In witness whereof I the said Charles Thomas Pearce have hereunto
set my hand and seal this Sixteenth day of August in the year of
our Lord One thousand eight hundred and forty-nine.
CHARLES THOMAS (L.S.) PEARCE.

page_text: AND BE IT REMEMBERED that on the Sixteenth day of August
in the year of our Lord 1849 the aforesaid Charles Thomas Pearce came
before our said Lady the Queen in Her Chancery and acknowledged the
Specification aforesaid and all and every thing therein contained and spe-
cified in form above written. And also the Specification aforesaid was
stamped according to the tenor of the Statute made for that purpose.
Enrolled the Sixteenth day of August in the year of our Lord One
thousand eight hundred and forty-nine.