Magnesium Light Cartridge for Photographic Purposes and Process of Producing same.
Year: 1892

page_text: COMPLETE SPECIFICATION.
Magnesium Light Cartridge for Photographic Purposes and Process
of Producing same.
I, EUGEN HACKH, of Stuttgart, in the Kingdom of Wurttemberg, 31 König.
strasse, Photographer, do hereby declare the nature of this invention and the
manner in which the same is to be performed, to be particularly described and
ascertained in and by the following statement :--
This invention relates to the mixing and producing process of magnesium light,.
which, on account of its exceptional steadiness, and, as it burns an absolute white
light, is very suitable and specially advantageous for photographic purposes.
The method of manufacture is so far essential for the invention, that an oxidation
of the magnesium powder during the mixture of the constituents of the light, as
also during storage, is thereby impossible. For the practical requirements of the
photographic art, the invention has a further and very far reaching import, in that
the magnesium light is made in cartridge form, which enables the steady con-
centration of the light in any direction, or on any object, desired, whereas, by the
use of magnesium-powder as a so-called flash-light, which has hitherto been the
case, this fixed concentration is impossible.
For manufacturing the magnesíum light I use a mixture of metallic magnesium
powder and so-called mealing-powder as used for fire works &c., but which, in
combination with magnesium powder for rapid magnesium light production, has not
hitherto been applied to photographic purposes.
The proportion of ingredients of the mixture varies according to the constituents
of the mealing-powder from 50 to 60 and magnesium powder 50 to 40. These
substances are thoroughly agitated and equally mixed in a revolving drum, and the
disadvantages of oxidation of the magnesium powder during the mixing are
prevented by the introduction of a current of carbonic acid, nitrogen or any other
inert gas in the otherwise hermetically closed drum, and which current not only
purges the oxygen out of the drum itself, but also out of the pores of each particle
of powder, so that the mixture of the powder takes place in an atmosphere which
excludes any possible oxidation of the magnesium-powder.
The extracting from the drum of the mixture of powder thus produced, takes
place without its coming in contact with outside air, by small quantities of the
powder mixture being, put in cartridge form.
Such cartridges consist of a flat disc made of cardboard or any other suitable
material adapted for holding the light powder, and which, by being folded, prevents
the oxidation of the contents by contact with the oxygen of the outside air, or
this cartridge disc is covered with paper or other suitable easily and completely
combustible.
The use of sheet-metal is not recommended for these cartridge plates, not only
on account of the heavy costs of same, but also because they absorb a great
amount of heat, and thus the burning of the light-powder is less perfect.
Cardboard or other nonconducting paper material is on the other hand specially
suitable.
The plate can be of asbestos board which offers still more advantages for the
purpose in question. The plate has a kind of wooden supporting peg in the middle.
which serves for receiving the igniting contrivance for which electric sparks are
used, since, by this, an instantaneous ignition is obtained at any moment desired
without any difficulty.
In order to make these light cartridges burn more rapidly, fibres of asbestos can
be mixed with the constituents of the powder, being there distributed in a very fine

page_text: and equal degree during the process of mixing the powders. This addition of
asbestos fibres varies according to the effect required between 5 and 10.
Fibres of asbestos are specially suitable for this purpose on account of them
being unburnable, and they therefore do not absorb the oxygen of the mealing-
powder which is thus of more profitable effect in the perfect combustion of the
magnesium powder. Again, owing to the asbestos being a non-conductor of heat, no
heat is drawn from the light-powder during its combustion & hence the latter gives
a whiter and stronger light.
As mentioned in the introduction, the closed disc like cartridge form of
magnesium light offers the exceedingly practical advantage of enabling the object
to be illuminated with the most diverse effects, since this light-cartridge can be
moved to all directions and the light concentrated on a certain part of the object
which cannot be done with magnesium light in the form of a loose powder burnt off
on a plane surface as hitherto practiced.
Having now particularly described and ascertained the nature of this inven-
tion and the manner in which the same is to be performed, I declare that what I
claim, is:
1. A magnesium light cartridge substantially consisting of a mixture is held by
a disc like casing consisting of paper, cardboard or other suitable material and is
closed by folding such casing or covering same with a sheet of paper easily and
completely combustible substantially as described.
2. The process of producing magnesium light consisting therein that the
ingredients of such light are mixed in a hermetically closed drum, from which air
is exhausted or substituted by carbonic acid gas nitrogen or another inert gas so
that no oxidation of magnesium can take place substantially as described.
3. The combination with the mixture producing the magnesium light cartridge
the employment of asbestos fibres finely distributed in such powder substantially as
described..
Dated this 7th day of November 1899
E. HACKH,
Per W. H. Beck,
115, Cannon Street, London, E.C., Agent.