Year: 1886

page_text: I, PHILIP MIDDLETON JUSTICE of 55 and 56 Chancery Lane in the County of
Middlesex Fellow of the Institute of Patent Agents do hereby declare the nature
of this, invention (a communication to me from abroad by Alessandro Cruto of
Piossasco in the Kingdom of Italy) and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:
The present invention has for its object certain improvements in and connected
with the manufacture of incandescent electric lamps, which are hereinafter
described reference being made to the accompanying drawings which form part of
this specification.
In a previous specification numbered 1895 of 1882 when speaking of the
manufacture of carbon in the form of wire, I said that taking a very fine metallic
wire I attached its ends to two clips fixed to a stopper of cork caoutchouc which
1 then introduced into a glass tube into which was then passed a carburet of
The metallic wire was
hydrogen say bicarburetted hydrogen.
redness by an electric current which decomposed the gas into protocarburetted
hydrogen and carbon which latter was deposited on the metallic wire to the
desired thickness to form the carbon.
then heated to
a metallic wire but I use a
According to my present invention I still use
Wollaston wire which in consequence of its extreme fineness is easily volatilized.
this being effected immediately the first action of the carbon takes place.
The Wollaston wire which I use is cut to the desired length and fixed to the
electrodes of the stopper A. Fig. 1. being given the shape there shewn after which
by known processes its coating of copper or silver is removed thus increasing its
fineness. Then I expose its extremities to the flame of a petroleum lamp which

page_text: deposits lamp black on it which has the effect of preventing the extremity from
separating from the wire attached to the electrode during the formation of the
carbon wire. As the Wollaston wire becomes covered with carbon the lamp black,
from its refractory nature, hardens and prevents the rupture of the carbon.
Owing to the extreme fineness of the Wollaston wire it is very important to
properly regulate the intensity of the current which is done by means of a suitable
rheostat. Further it should be taken into account that the metallic wire owing to
its extreme fineness is also influenced by terrestial magnetism especially at the
commencement of the operation. It is therefore preferable to see at the commence-
ment of the operation that the current descends on the east side of the filament to
ascend on the west.
About 15 minutes after it is necessary to reverse the current to correct the curve
which the filament will have sustained through the influence of the magnetic
inclination, this reversing of the current is effected by a commutator interposed in
the circuit.
By means of a magnet properly placed the carbon wire may be made to take in
the course of its formation different shapes such as elliptical circular &c.
To effect this it will be sufficient to move a magnet around the carbon while in
course of formation.
A practical form to give the filament is that of a V. This form is obtained by
hanging to the Wollaston wire a weight which makes it take that form.
As soon
as the carbon has obtained a little consistency the weight is made to fall by a slight
shake under the glass vessel in which the carbon is forming. I have also observed
that very often the carbons of incandescent lamps are damaged or even break owing
to the jarring to which they may be subiected especially during transit. In these
cases the fracture is usually at 1-2 millimetres from the point where they are
soldered to the platinum support wire.
I am aware that it has been proposed to so arrange the parts as to prevent the
oscillation the carbon but so far as I am aware the proposed arrangement has
never been made practical and to obviate the inconvenience caused by the breaking
of the carbon I proceed as follows-
When the carbon is completed and after it has been once used but before
detaching the globe from the tube which has served to make the vacuum in the
lamn. I hank or even solder on the apex of the carbon a hook of platinum wire of
which the shank is soldered to the top of the glass globe. I use the carbon
before hanging on the hook because the first incandescence of the carbon causes
if to lengthen.
The carbon will therefore have at its apex a support which will prevent
oscillation and diminish the liability to fracture. This hook 7 (Fig. 3) may. he
fitted either before introducing the carbon into the globe or after the lamp is fixed
on the tube to form a vacuum.. It will be readily understood how the hook 7 may
ho attached to the carbon before introducing it into the globe. I prefer however,.
although more difficult, to place the hook in position after the carbon has been
inserted in the globe and to accomplish this I proceed as follows.
The lamp being ready for the vacuum to be formed (Fig. 2) I take a rod f
(Fig. 3) the end of which has a hole to receive the shank of the hook and
I introduce this into the tube A sufficient to hook it on to the carbon M, where it
will remain suspended, the rod f being withdrawn. A vacuum is then formed and
after the lamp has been once used the lamp is closed care being taken that at the
last closing the shank of the hook 7 remains sealed in the glass globe.
For lamps having two or more carbons the desired number of hooks secured
together by glass and properly distanced are introduced into the base of the globe
before the carbons are inserted with their support. When the latter are in position
the rod f, is inserted in the tube A which is formed with two reduced portions and
the shank of one of the hooks which is purposely left of sufficient length, is sealed
in the glass after the hooks are placed on the carbons.

page_text: To make the carbons more firm 1 further make a uniform enlargement at the
point where they generally break, viz, near their union with the platinum wire.
When the lamp is in use this enlargement will be only feebly incandescent.
The line o. P. 7. of carbon is destined to become luminous and the portions o. s.
and g. r. measuring about 4 millimetres are affected according to the size of the
enlargement which during the time the lamp is in use attains a temperature, of
500-1000°; m, n, are the ordinary solderings to the platinum wire.
The enlarged portions are applicable to carbons for other lamps and may be
produced by the process and by the arrangement which is hereinafter described.
Upon a bed of any insulating material in which are suitably spaced cavities n, n¹,
filled with mercury I arrange at a distance of 34 millimetres from each cavity,
small metallic clamps c, e, in which I fix the support already provided with its
carbon as indicated in Figs. 5 and 6.
The clamps cc, (Fig. 5) are formed of the fixed jaws 0, 0 and the movable
jaws pp, the latter being joined by a piece of insulating material to which is
attached a spring or weight q.. The movable jaws are worked by the rod and
ring which are used to fix the carbon in the clamp. This apparatus is completely
and hermetically closed in a box not indicated on the drawing. The box has two
tubes for the introduction and the exit of the bicarburet of hydrogen.
Before placing the carbon in the apparatus as described I make on its point of
junction with the platinum wire a layer of lamp black by exposing it to the smoke
of a flame of petroleum or any other carburet until the desired thickness is formed.
I then fix the carbon in the clamps e, el, so that its extremities are over the cavities
containing mercury and place upon them a hook of platinum wire a, a', of which
the shank dips in the mercury as shown in Figs. 5 and 6.
The box containing the apparatus is then closed and bicarburet of hydrogen
introduced and at the same time the electric circuit being closed its passage is as
follows.
.
The positive pole being at the cavity the current ascends by the hook a runs
through the portion of carbon between the hook a and the clamp and thence by
the metallic communication (indicated by dotted line in Fig. 6) to the mercury in
the cavity whence it reascends by the hook a, runs through the other part
of the carbon between the hook a¹ and the clamp thence descending to the
mercury in cavity next in order and so on running through all the carbons
which follow one another (so far as the portions which it is desired to enlarge is
concerned) and which are arranged in tension one after the other until the current
emerges by the negative pole at the last cavity.
It results from the foregoing and I wish it particularly noted that the metallic
communication which leads the current is so arranged that the latter runs always
from the hooks to the carbons and then to the clamps and not vice versa. This
is very important so that any transport of matter which there might be consequent
upon defective contact may be in the direction from the hook towards the clamp
and not the other way which would be injurious to the carbon.
.In commencing operations the hooks a, a'. are placed at à distance of 3-4
millimetres from the point where the carbon is soldered to the platinum wire of
the support.
As soon as the current has heated to redness the extremities of the carbons
which are to be enlarged and this has been accomplished and the desired thickness
obtained, the current is cut off without opening the box the hooks are by suitable
external mechanical means made to slide 3-4 millimetres, towards the point of
junction of the carbons and the platinum wire of the support. The circuit is again
closed and by the action of the current the lamp black is hardened and the
enlargement is soldered to the little tubes. r. c and s. c.
From the foregoing it is seen that by the same process I effect besides the
enlargement of the base of the carbons also their soldering to the platinum wires,

page_text: a lampblack soldering as it may be termed which is one of the special points of my
invention.
The enlargement will have a thickness double in section that of the carbon.
It may be observed that when the lamp is lighted this enlargement takes in
appearance the form of an inverted cone, that is having its base towards the
luminous portion of the carbon. The temperature of the enlargement will at the
base of the apparent cone be the same as that of the carbon and will diminish in
the direction of the soldering until it is only a dull red. This enlargement may be
effected on all carbons having circular section.
With Edison carbons it may be made in cutting the vegetable fibre as shown in
Fig. 4 where P. o. will be the luminous portion of the carbon and o, s, the enlarge-
ment which will have an incandescence of 500-1000°, *, m. being the enlargement
for the galvanic soldering.
I may observe that the enlargement for the purpose of preventing the fracture
of the wire near the soldering must not be confounded with the ordinary enlarge-
ment produced by the soldering of the carbon to the platinum wire. A further
improvement relates to the form, the arrangement and the material employed for
supporting the carbons.
The metallic conducting supports are composed partly of platinum wire and
copper wire, that is, the portions a, b, sealed in the glass are of platinum while b, c,
are of copper. These latter are not sealed in the glass stem but at their ends they
are soldered to it by a drop of glass and thence they bend outwards and are
soldered to the small platinum tubes e in which the carbons are fixed and soldered.
The platinum tubes which are also a characteristic of my invention are obtained
in the following manner.
-
In a platinum tube a silver wire is inserted so as to form a core which with the
surrounding platinum is then drawn out to a diameter of millimetres..
This is then cut into lengths of 5-10 millimetres which are immersed in boiling
nitric acid which dissolving the silver, leaves the small platinum tubes in which
the carbon is subsequently fixed, the tube being slightly squeezed, and the enlarge-
ment and soldering being then effected as aforesaid."
"
Further I have observed that the metallic portions which are inside the lamin
and naked give off in course of time a little gas which injures the quality and
duration of the lamp. To obviate this inconvenience I cover the metallic, portions
with glass enamel or vitrifiable colours after having duly heated them by a spirit
lamp, a blow pipe or in a muffle. This operation may be effected either before or
after the carbon is soldered but I prefer doing it after.
The copper wire which I use as the support in the interior of the lamp being
covered with vitrifiable colour or varnish, a perfect adherence to the glass may be
secured.
As vitrifiable colours adhere better to copper than to platinum. I cover the
latter with a slight coating of copper by putting the support in communication
with the negative pole of two Daniell piles and by means of small pincers which
are connected with the positive pole I plunge the platinum into a solution
sulphate of copper and thus effect the copper coating which however may be
otherwise done.
of
Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed. as communicated to
me by my foreign correspondent, I declare that what I claim is:-
1 An incandescent electric lamp the top of the carbon of which is prevented
from oscillation by means of a hook or connection attached thereto and one end
being also sealed in the glass substantially as described.
2nd In the manufacture of incandescent electric lamps in which the carbon is to
be prevented from oscillation by means of a hook or connection as described the

page_text: process hereinbefore set forth for applying and securing said hook or its equivalent
substantially as described.
3rd The process described by which in the manufacture of an incandescent
electric lamp an enlargement at the base of the carbon is effected as also a carbon
for incandescent electric lamps formed with such an enlargement substantially as
and for the purposes set forth.
4th In an incandescent electric lamp covering the metallic conductors which
support the carbon with vitrifiable varnish or colours, enamel or any other
substance having similar properties substantially as and for the purposes.
forth.
set
PHILIP M. JUSTICE.