IMPROVE- MENTS IN MANUFACTURING AZOTIC COTTON OR PYROXILE FOR PHOTOGRAPHIC AND OTHER PURPOSES
Year: 1857

page_text: LETTERS PATENT to Peter Hippolyte Gustave Bérard, of 323, Rue St.
Denis, Paris, in the Empire France, for the Invention of "IMPROVE-
MENTS IN MANUFACTURING AZOTIC COTTON OR PYROXILE FOR PHOTOGRAPHIC
AND OTHER PURPOSES."
Sealed the 1st January 1858, and dated the 7th July 1857.
PROVISIONAL SPECIFICATION left by the said Peter Hippolyte Gustavo
Bérard at the Office of the Commissioners of Patents, with his Petition,
on the 7th July 1857.
I, PETER HIPPOLYTE GUSTAVE BERARD, of 323, Rue St. Denis, Paris, in the
Empire France, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN MANUFACTURING AZOTIC COTTON OR PYROXILE FOR PHOTOGRAPHIC
AND OTHER PURPOSES," to be as follows:-
I employ shearings of cotton or the shearings of treble-milled cotton
reduced to powder, and mix about half pound of the powdered cotton with
about two & half pounds of nitre or azotate of potash, powdered very dry.
When these ingredients are well mixed on a piece of oilcloth, or a sheet of
paper, the mixture is thrown into a glazed stone jar containing about five &
half pounds concentrated sulphuric acid, & all well stirred together into a
pasty mass from ten to twenty minutes, according to the temperature or
other circumstances.
By this process, the decomposition of the azotate of potash by the sulphuric
acid being effected at the same time the cotton is mixed therewith, the acid
acts more efficiently, & a more regular & more soluble collodion is obtained.
The washing is effected by pouring filtered water into the pan from the time

page_text: the change takes place, stirring it with a rod, then turning the whole into a
larger glazed vessel containing water also filtered. The successive products of
the operations during the day may thus be thrown into the same large vessel.
The cotton deposits itself at the bottom of the vessel, & the liquid is drawn
off by any suitable means, & the washing may be continued till the test paper
will not become red by contact with the liquid.
The drying is then proceeded with, either by pressing the cotton between
the hands or by extending it on cloths, or other suitable means.
For pre-
servation & convenience of transport this azotic cotton may be dissolved in
ether, or in the usual mixtures of ether & alcohol; the solution may be then
evaporated so as to collect the distilled ether, & by continuing the evaporation
I obtain a dry transparent collodion, soluble in ether, & a product applicable
to photographic, surgical, & other operations.
*SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Peter Hippolyte Gustave Bérard in the Great Seal Patent
Office on the 1st January 1858.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, PETER
HIPPOLYTE GUSTAVE BERARD, of 323, Rue St. Denis, Paris, in the Empire of
France, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Seventh day of July, in the year of our Lord One
thousand eight hundred and fifty-seven, in the twenty-first year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Peter Hippolyte Gustave Bérard, Her special licence that I, the said Peter
Hippolyte Gustave Bérard, my executors, administrators, and assigns, or such
others as I, the said Peter Hippolyte Gustave Bérard, my executors, adminis-
trators, and assigns, should at any time agree with, and no others, from time
to time and at all times thercafter during the term therein expressed, should
and lawfully might make, use, exercise, and vend, within the United Kingdom
of Great Britain and Ireland, the Channel Islands, and Isle of Man; an
Invention for "IMPROVEMENTS IN MANUFACTURING AZOTIC COTTON OR PYROXILE
FOR PHOTOGRAPHIC AND OTHER PURPOSES," upon the condition (amongst others)
that I; the said Peter Hippolyte, Gustave Bérard, my executors or adminis-
trators, by an instrument in writing under my, or their, or one of their hands
and seals, should particularly describe. and ascertain the nature of the said
Invention, and in what manner the same was to be performed, and cause the

page_text: same to be filed in the Great Seal Patent Office within six calendar months
next and immediately after the date of the said Letters Patent. ;
NOW KNOW YE, that I, the said Peter Hippolyte Gustave Bérard, do
hereby declare the nature of my said Invention, and in what manner the
same is to be performed, to be particularly described and ascertained in and
by the following statement:
Great difficulties have been hitherto experienced in manufacturing azotic
cotton intended for the preparation of collodion. Even the most skilful
manufacturers of that substance can often obtain but costly, imperfect, and
uncertain products. When put into 'sulphuric ether, in the proportion of
from two to five parts for one hundred of ether, an insoluble deposit is always
formed in the liquid, which deposit amounts sometimes to one-third of the
azotic cotton employed. The difficulty of manufacturing the azotic cotton,
the irregularity and bad quality of the products, depend chiefly on the con-
siderable bulk of the carded cotton made use of, and in the difficulty
experienced in immersing quickly enough this cotton in a rather small bulk
of nitrate of potash (nitre) dissolved in sulphuric acid.
By my improved process all the inconveniences alluded to are avoided;
instead of two to four ounces at most, which it was possible to immerse in a
common earthen pan, now, twice and even thrice as much cotton, if prepared
by my process, can be easily immersed in the same vessel; and at least one-
third of the sulphuric acid and nitrate of potash are saved, so that the cost
price of the pyroxile obtained is thus much reduced.
The cotton which I use for my process is that obtained from the shearing
of swan skins (tontisse de molleton). I mix together half a pound of sheared
cotton with two pounds and six ounces of powdered saltpetre or azotate of
potash, in a very dry state. I proceed in the following manner :-I take two
glass balloons or large bottles, capable of containing from two to two and
a half gallons, five pounds and five ounces of concentrated sulphuric acid
being poured in one of the balloons, the powdered azotate of potash is thrown
into the same balloon, which should be closed at once with its stopper, and
the vessel is shaken for about half a minute, and the liquid is then poured
into the other balloon containing the shearings of cotton; the second balloon
is also directly closed. The mixture forms a thick paste, which is shaken
several times in the course of about six to ten minutes, which is the time
required for completing the operations, according to the degree of temperature.
The washing out of the product is operated by pouring at first filtered water
into the balloon after the five or six minutes required for completing the
operation, as just said; and the whole is then poured into a large glazed

page_text: earthen vessel containing also filtered water. The products obtained from the
several operations performed in a similar manner during the course of a day
are poured into the same vessel; the cotton deposits to the bottom of the said
vessel, the superincumbent liquid is drawn off by means of a stop-cock placed
either above the deposit or near the bottom of the vessel, under a muslin or
hair cloth stretched a short distance above the bottom; the cloth keeps the
cotton back and allows the liquid to flow out; new filtered water is poured in,
and so on, until the washing being completed the blue color of litmus paper
is no longer affected when dipped into the liquid.
When it is in that state the cotton should be dried, and this is effected by
means of an apparatus rotating quickly (uno essorense), which drives out the
greater part of the moisture; the drying is then completed in a chamber
heated by steain pipes.
The azotic cotton made in this way can be dried more easily than when
made with carded cotton.
In order to obtain a greater solubility, ensure its preservation, and avoid the
causes of spontaneous alteration and the danger attending removals, the
azotic cotton is dissolved either in ether or in the usual mixture of ether and
alcohol; it is then left to settle, and the solution being drawn off is evaporated
by means of a still so as to collect the ether which distils over.
The collodion I obtain in the way just described is dry, diaphanous, entirely
soluble in ether and in alcoholic mixtures, and is ready for use either for
surgical or for photographic and other operations.
In a word, my Invention consists in the process before described for
obtaining a new kind of product, and in the product itself, either as powdered
azotic cotton or the said dissolved and dried material, forming a dry collodion
entirely soluble, unalterable, and unexplosive; consequently capable of being
transported anywhere without danger.
In witness whereof I, the said Peter Hippolyte Gustave Bérard, have
hereunto set my hand and scal, this Thirtieth day of December, in the
year of our Lord One thousand eight hundred and fifty-seven.
Signed and sealed in the presence of
J. D'AUBREVILLE, C. E.,
Rue de l'Echiquier, 36.
P. H. G. BERARD. (L.S.)