Year: 1888

page_text: Date of Application, 11th Sept:, 1888
Complete Specification. Left, 15th Dec., 1998.
Complete Specification Accepted. 12th Feb.. 18.9
A
1, ERNST BÖHM of 53 Red Lion Street, Clerkenwell, in the County of Middlesex,
Electrician, do hereby declare the nature of this invention to be as follows:-
My invention relates to incandescent electric lamps chiefly designed for use in
mining and similar operations.
The main object of my said invention, is to obviate the danger attending the
employment of incandescent lamps in mines, by reason of the liability to breakage of
the globe or bulb, and consequent explosion of the combustible gas or gases in the
mine by contact with the incandescent carbon or other filament.
In carrying my said invention into practice I form around the globe or bulb 'con-
taining the carbon or other filament an envelope or outer globe or casing, and
I fill the intermediate spaces between the outer and inner globes with water or
other suitable liquid.
Should the said outer globe become broken, the inner globe, if it still remains intact,
will prevent contact of the combustible gas or gases with the carbon or other filament,
and thus avoid an explosion.
An important advantage afforded by my present invention is, that, by making the
lamp with an outer and inner casing as above described, I.obtain a great increase in
the illuminating power of the lamp with the same strength of current. Moreover, 1
may still further increase the illuminating power of the lamp by increasing the space
between the outer and inner globes. By using coloured liquid between the outer
and inner globes my improved lamps may be advantageously employed for illuminating
purposes.
It is evident that my said invention may be applied in numerous other ways, such
for instance as a lamp for photographic or other purposes to which the incandescent
lamps heretofore made are applicable.
In some cases I may cast upon the outer casing a solid reflecting glass lens for
strengthening the same and for increasing the illuminating power.
נד
11
2
11000
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.

page_text: I, ERNST BOHM of 53 Red Lion Street, Clerkenwell in the County of Middlesex,
Electrician, do hereby declare the nature of this invention and in what manner the same is
to be performed, to be particularly described and ascertained in and by the following
statement:-
My invention relates to incandescent electric lamps chiefly designed for use in
mining and similar operations.
My said invention is mainly designed to provide for increasing the illuminating
power of such lamps, and to obviate the danger attending the employment of
incandescent lamps in mines, by reason of the liability to breakage of the globe
or bulb and consequent ignition of the fire-damp by the incandescent filament.
My said invention comprises various improvements bereinafter set forth.
Figure 1 is a front elevation showing one form of my improved incandescent
electric lamp:
Figure 2 is a similar view, showing a slight modification of my invention herein-
after described.
and
Figure 3 is a side elevation showing another modification of my said invention,
Figures 4 to 7 are different views showing further modifications thereof.
Like letters indicate corresponding parts throughout the drawing.
A is an incandescent electric lamp containing the carbon or other filament.
Around the globe or bulh of the lamp A I arrange an envelope or outer globe or
casing a and I fill the intermediate space between the outer and inner globes with water
or other suitable liquid.
Should the said outer globe or casing a become broken, the inner globe, if it still
remains intact, will prevent contact of the combustible gas or gases with the carbon or
other filament and thus avoid an explosion.
By making the lamp with outer and inner globes or casings and filling the inter-
mediate space with liquid, as above described, I obtain a great increase in the
illuminating power of the said lamp with the same strength of current. Morcover I
may still further increase the illuminating power of the lamp by increasing the space
between the outer and inner globes. I sometimes use coloured liquid between the outer
and inner globes of my improved lamps so that they may be advantageously employed
for decorative purposes.
Figure 2 shows a modification in which I provide the outer globe or casing a with a
socket or cap al upon the removal of which, water or other liquid can be introduced
into the space between the outer and inner globes. By this means when coloured
liquids are employed they can be expeditiously and easily changed so as to vary the
colour of the light.
Figure 3 shows a modification wherein a solid glass lens
formed upon the outer globe or casing a.
The solid glass lens
is cast or otherwise
greatly strengthens

page_text: that part or portion of the bulb or globe which is exposed and therefore most liable to
fracture when the lamp is placed in its casing or holder. Moreover the said lens b
increases the illuminating power of the said lamp and admits of a more powerful light
being obtained without increasing the strength of the current, and permits of a powerful
ray of light being thrown in any desired direction.
Figures 4 and 5 show a modification wherein I dispense with a second or outer
globe or casing a and form the lens & upon the bulb or globe of the lamp A. c is a
reflector preferably formed by silvering or enamelling a portion of the bulb or globe
of the lamp A.
Figures 6 and 7 show a modification wherein 1 employ four lenses b so as to
diffuse or spread the light and thus render the lamp suitable for ordinary lighting
purposes.
It is obvious that I can somewhat modify the construction of my improved incan-
descent electric lamp without departing from the nature of my said invention. For
instance I can form the said lamp with any suitable number of solid glass lenses
formed upon the globe or bulb thereof and I can make the said lenses of any
suitable shape.
When the lens or lenses are placed upon the second or outer globe or casing I
sometimes form the said lens or lenses by blowing them upon the said outer globe or
casing thus forming a hollow or concave lens or lenses which are filled up by the water
or other liquid in the space between the globes.
Moreover it is obvious that my invention may be applied to lamps for numerous
other purposes for which incandescent lamps as heretofore constructed are applicable,
for instance to a lamp for photographic or similar uses, or as a lamp for carriages,
omnibuses, tramcars or the like.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is :-
First. An incandescent electric lamp having the globe or bulb surrounded by an
outer globe or casing so as to form a space for containing water or other liquid
substantially as and for the purpose, set forth.
Second. An incandescent electric lamp having a globe or bulb provided with one
or more lenses, substantially as, and for the purpose set forth.
Third. The improved incandescent electric lamp constructed substantially as
described with reference to Figures 1 and 2, or to Figure 3, or to Figures. 4 and 5
or to Figures 5 and 6 of the accompanying drawing for the purposes above
specified.
Dated this 14th day of December 1888