IMPROVEMENTS IN OBTAINING LIGHT BY ELECTRICITY
Year: 1845

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COMF I EDWARD
AUGUSTIN KING of Warwick Street in the County of Middlesex Gentle-
man Send Greeting.
WHEREAS Her present Most Excellent Majesty Queen Victoria by Her
Royal Letters Patent under the Great Seal of Great Britain bearing date at
Westminster the fourth day of November in the ninth year of Her Reign
did for Herself Her Heirs and Successors give and grant unto me the said
Edward Augustin King my exors admors and assigns Her especial licence
full power sole privilege and authority that I the said Edward Augustin
King my exors admors and assigns or such others as I the said Edward
Augustin King my exors admors 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 the Islands
of Jersey Guernsey Alderney Sark and Man and also within all Her said
Majesty's Colonies and Plantations abroad the "Invention of IMPROVEMENTS
IN OBTAINING LIGHT BY ELECTRICITY" communicated to me by a certain
Foreigner residing abroad In which said Letters Patent is contained a Pro-
viso that I the said Edward Augustin King shall cause a particular descrip-
tion of the nature of the said Invention and in what manner the same is to
be performed to be inrolled in Her said Majesty's 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
Edward Augustin King do hereby declare that the nature of the said Inven.

page_text: tion and the manner in which the same is to 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
thereon (that is to say)-
The nature of the Invention consists in the application of continuous
metallic and carbon conductors intensely heated by the passage of a current
of electricity to the purposes of illumination. The metal found to be the
most advantageous to use for the purpose, is that which, while it requires a
very high temperature for its fusion, has but a feeble affinity for oxygen, and
offers a great resistance to the passage of an electrical current. Platinum
though not so infusible as iridium, has but little affinity for oxygen, and offers
a great resistance to the passage of the current, and as it is abundant and
easily worked into the requisite form, it appears to be preferable to any other
metal. The platinum should be worked into those exceedingly thin Sheets
known as leaf platinum. This may be accomplished by the ordinary process
of the gold beater, but a more accurate method is to place a 'piece of plati-
num foil between two thick plates of rolled Copper and reduce the whole to a
thin sheet by rolling, when on separating the the Copper pieces the platinum
leaf will be found of uniform thickness in every part. In this way it may be
obtained so thin that on holding it before a printed page the letters can be
distinguished through it. A strip is to be cut from one of these Sheets of a
width proportionate to the quantity of the current which with Grove's cells
having the platinum plates three inches long and two inches wide, is about
one fourth of an inch and of a length proportionate to the intensity which
of course varies with the number of cells. Great care must be taken to cut
the platinum strips of an equal width throughout, and with a clean edge, as
if this is not carefully attended to, the strip will be unequally heated and will
be fused in one part before the other parts have obtained a sufficiently high
temperature to produce a brilliant light. The platinum strip is now to be
suspended between two forceps in an Instrument made for the purpose
one form of which is shewn in section in the Drawing hereunto annexed
and marked No. 1, A is a square brass bar fixed into the wooden
stand C having a binding screw F attached to its lower end. The two
arms E D are attached to sockets which slide on this bar so as to admit
of their being placed at different distances from each other. They are both
bent at right angles as seen in the Figure and terminated by broad forceps
tipped with Platinum. These forceps are closed by the milled screws H. I.;
the arm E has a rod N with a screw cut on it passing through it and by
means of the two nuts B. B working on this rod, the arm may be adjusted to

page_text: any required height and the distance between the forceps thus regulated
The rod passes through the stand and is attached to the binding screw G.
The socket Kis lined with Ivory or some other non conducting substance,so as.
to prevent any metallic communication between the arm E, and the bar; S is
the strip of platinum leaf which is first clamped in the upper forceps; the arm
E is now adjusted to any required height, and the lower forceps are closed so
as to clamp the lower end of the strip of platinum. It may now be included
in the battery circuit by attaching one of the wires to the binding screw at F
and the other to that at G. The current should be one of considerable intensity
and the distance between the forces should be sufficient to prevent the platinum
being fused. The distance may be lessened by raising the arm E, and shorten-
ing the strip of platinum until it attains the highest temperature it will bear
without fusing or the same object may be attained by increasing the intensity
of the current. The Glass Shade R which serves to screen the platinum from
currents of air, dust &c. may then be placed over the apparatus as seen in
the Drawing annexed. When Carbon is used it becomes necessary on
account of the affinity the substance has for oxygen at high temperature, to
exclude from it air and moisture. To accomplish this in the most perfect
manner it should be enclosed in a Tooricelieu vacuum. One form of the
apparatus for this purpose is shown in Section in the Drawing annexed and
marked No. 2, a is a Glass Tube similar to those used for Barometers,
except that it has its upper end enlarged into a cylindrical buib, and a stout
platinum wire sealed in at the top. A binding screw is fixed on the top of
the wire, whose lower end screws in the iron piece, d, to this piece the
forceps are attached, and it is connected with a similar piece at h by the
porcelain rod i. The forceps g are attached to 7, and clamp the lower end of
the carbon piece c which has its upper end held by those at f. n is a copper
wire which is fixed into the piece at h and extends to the bottom of the tube,
the tube is filled with Mercury in the same manner as a Barometer, the usual
precautions being taken to expel the air; its length independent of the bulb,
should be about thirty inches, so that when it is inserted in a cup of Mercury,
a vacuum will be formed in the bulb.-The Instrument is included in the
electrical circuit, by connecting one of the wires from the Magnetic or Voltaic
Battery with the binding screw fixed on the wire, e and the other with a wire
which passes into the Mercury in the Cup at the bottom of the tube The
circuit is thus completed by the Column of Mercury, and when it is depressed
in the tube by the formation of vapour of Mercury, the connection is preserved
by the copper wire n; that form of Carbon found on the interior of Coal Gas
Retorts which have long been used, is well suited for this
purpese, and may be
в

page_text: worked into the form of either small pencils or thin plates by the aid of the
Saw and File. As Carbon will bear a very high temperature without fusion
or volatization it may be employed when a very intense light is required.
When an intermitting light for the use of Light-Houses or for other purposes is
required it may be obtained by breaking the Circuit at intervals by Clock work;
to effect this, one of the wires from the magnetic or voltaic battery is con-
nected with a spring which is made to press on the circumference of a metallic
wheel fixed on one of the arbors of the Clock, having certain portions of its
surface cut away so as to break and close the Circuit at any required intervals.
When the apparatus is suitably sealed it may be applied to submarine lighting,
and also to the illumination of places where it is necessary to guard against
the inflammation of highly combustible or explosive Compounds, as in powder
magazines mines &c. When a Current is of sufficient intensity two or more
lights may be made in the same Circuit, care being taken to regulate the
power by increasing or diminishing the number of armatures if a magneto-
electric machine is the source of electricity or the number of cells if a voltaic
battery be used, so that the united resistance of the strips of platinum or
carbon should be sufficient to prevent the passage of such a quantity of elec
tricity as would destroy them.
Claim What is claimed as the Invention is the application of continous
metallic and carbon conductors intensely heated by the passage of a suitably
regulated current of electricity to the purposes of illumination as herein-
before mentioned
In witness whereof I the said Edward Augustus King have hereunto
set my
hand and seal this second day of May in the year of our
Lord One thousand eight hundred and forty six
EDWARD A. (L.s.) KING.
AND BE IT REMEMBERED that on the second day of May in the year
of our Lord 1846 the aforesaid Edward Augustin King came before our said
Lady the Queen in Her Chancery and acknowledged the Specification afore-
said and all and every thing therein contained and specified in form above
written And also the Specification aforesaid was stamped according to the
tenor of the Statute made for that purpose
Enrolled the fourth day of May in the year of our Lord One thousand