IMPROVEMENTS IN PRESERVING ORGANIC SUBSTANCES
Year: 1861

page_text: LETTERS PATENT to William Rattray, of Saint Clement's Chemical Works,
Aberdeen, Manufacturing Chemist, for the Invention of "IMPROVEMENTS
IN PRESERVING ORGANIC SUBSTANCES."
Sealed the 21st June 1861, and dated the 8th January 1861.
PROVISIONAL SPECIFICATION left by the said William Rattray at the
Office of the Commissioners of Patents, with his Petition, on the 8th
January 1861.
I, WILLIAM RATTRAY, of Saint Clement's Chemical Works Aberdeen
Manufacturing Chemist, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN PRESERVING ORGANIC SUBSTANCES," to be as follows:-
My said Invention consists, first, of a mode of preserving animal and
vegetable matters by impregnating them with an aqueous solution of sulphurous
acid. For this purpose I plunge the material to be preserved in a quantity of
the solution, or otherwise bring the solution into contact with the surface of
the material for such a length of time as may be requisite to produce the
necessary impregnation. When fresh animal and vegetable matters have been
impregnated with a solution of sulphurous acid in this manner, the effect is to
preserve them from decay for a considerable period.
My said Invention consists, secondly, of the use of the alkaline and earthy
sulphites in packing preserved animal and vegetable matters in cases, and I
Prine &

page_text: introduce these sulphites, either dry or in solution, into a case with the pre-
served matters, for the purpose of assisting more effectually to prevent them
from undergoing decay or injurious change.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said William Rattray in the Great Seal Patent Office on the 8th
July 1861.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
RATTRAY, of Saint Clement's Chemical Works, Aberdeen, Manufacturing
Chemist, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Royal
Letters Patent, bearing date the Eighth day of January, in the year of our Lord
One thousand eight hundred and sixty-one, in the twenty-fourth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said William Rattray, Her special licence that I, the said William Rattray, my
executors, administrators, and assigns, or such others as I, the said William
Rattray, my executors, administrators, and assigns, should at any time
agree with, and no others, from time to time and at all times thereafter
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, my Invention for "IMPROVEMENTS IN
PRESERVING ORGANIC SUBSTANCES," upon the condition (amongst others) that I,
the said William Rattray, my executors or administrators, by an instrument
in writing under my, or their, or one of their hands and seals, should par-
ticularly describe and ascertain the nature of the said Invention, and in what
manner the same was to be performed, and cause the 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 William Rattray, do hereby declare
the nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement, that is to say:-
My Invention consists, first, of a mode of preserving animal and vegetable
matters by impregnating them with an aqueous solution of sulphurous acid.
For this purpose I plunge the material to be preserved in a quantity of the
solution, or otherwise bring the solution into contact with the surface of the
material for such a length of time as may be requisite to produce the necessary

page_text: impregnation. When tresh animal and vegetable matters have been impreg
nated with a solution of sulphurous ad in this manner, the effect is to pre-
serve them from decay for a considerable period.
My said Invention consists, secondly, of the use of the alkaline and earthy
sulphites in packing preserved animal and vegetable matters in vessels or cases,
and I introduce these sulphites, either dry or in solution, into a case with the
preserved matters, for the purpose of assisting more effectually and to prevent
them from undergoing decay or injurious change.
The aqueous solution of sulphurous acid which I employ in carrying out my
Invention may be prepared by any of the methods known to chemists. This
solution may be produced of various strengths, but I prefer to make it of the
strength indicated by six degrees on Twaddell's hydrometer, because I believe
that a solution of that strength keeps better without alteration than a stronger
solution. A solution of greater or less strength may, however, be used, but
for the purpose of mixing it with water and preventing mistakes in the
strengths of the diluted solutions employed in performing my Invention, I find
it convenient to keep and use a concentrated solution of one uniform strength.
I dilute the standard solution which I employ with water, so as to make it of
the strength most proper or convenient for operating upon any particular
material to be preserved.
I find in practice that it is convenient to employ diluted solutions of the
four following strengths, videlicit, a diluted solution of a strength equal to that
produced by a mixture of one part of concentrated sulphurous acid of the
strength of six degrees of Twaddle with 50 parts of water, which may be called
solution No. 1, one other diluted solution of a strength equal to that produced
by a mixture of one part of such concentrated acid with 40 parts of water,
which may be called solution No. 2; one other diluted solution of a strength
equal to that produced by a mixture of one part of such concentrated acid with
thirty parts of water, which may be called solution No. 3; and one other diluted
solution of a strength equal to that produced by a mixture of one part of such
concentrated acid with 20 parts of water, which may be called solution No. 4.
By means of these 4 diluted solutions the operations herein-after described
may be performed.
I suspend the material to be preserved or operated upon in any suitable
water-tight vessel constructed of wood or other suitable material, which I call
curing vessels, observing always that the different pieces of material do not
touch each other or rest on the bottom of the vessel while under treatment.
I have found that a useful plan for securing these conditions is to suspend
each piece in a net. This mode of suspension I have found most useful in the

page_text: treatment of animal matters, such as meat, fowls, fish, &c. In the case of
vegetable matters, potatoes for instance, I have found that there is less need of
this practice being observed as from their more firm consistency, they may be
placed in the curing vessel at random.
The material to be preserved having been introduced into the curing vessel,
a quantity of the solution No. 1 is to be run into it until the materials are
covered with the liquid. The curing vessel is then to be covered and kept
undisturbed from 3 to 5 hours, more or less, according to size or sizes of the
pieces of material to be operated upon. The liquid is then to be run off, and
the materials in the vessel are to be kept undisturbed, and allowed to drain
from 3 to 4 hours. A second solution (No. 2) is then to be run into the curing
vessel in the same way as before, and left to act upon the material for a similar
period as the first solution, after which the solution is to be run off, and the
material allowed to drain as before. A third solution (No. 3) is then to be run
into and kept in the preserving vessel in the same way as the previous solution,
and it is to be afterwards run off, and the preserved substances drained as
before.
In most instances I have found that the agency of three solutions of dilute
acid are sufficient to secure the preservation of most organic substances, and
as general indications of a sufficiency of treatment having been employed I
have observed that after the substances have been submitted to and left to
drain from the acid they are found to retain a somewhat pungent smell of the
acid, and to be in appearance somewhat plump and swelled. If these
characteristics are found not to be sufficiently developed, then a fourth
solution (No. 4) of the acid must be applied in the same manner as the
preceding ones, but for a shorter period. Instead of the solution No. 4, one
of the other diluted solutions may be employed if it shall be deemed sufficient
to produce the desired effect upon the materials to be preserved. At the end
of the process, in every case, the preserved materials are to be well drained.
Sulphurous acid, whether of greater or less strength than the solutions I
have named may be employed for preserving organic substances, but I have
found in many cases that stronger acid acts injuriously upon the substances so
preserved, while the use of weaker solutions of acid than those which I have
mentioned above prolongs the period of treatment, and is productive of results
otherwise unsatisfactory.
The above concludes the description of the mode of carrying out the first
part of my Invention, and the preserved substances are now ready to be sub-
mitted to treatment by the second part of my Invention, which I shall now pro-
ceed to describe.

page_text: The second part of my Invention, which relates to the preservation of
animal and vegetable matters in vessels or cases is more particularly applicable
to the preservation of materials operated upon according to the first part of
my Invention. There are two modes in which I carry out this second part of
my Invention, which I shall respectively call the dry and the liquid modes.
First, the dry mode. The substances having been submitted to the treat-
ment described in the first part of my Invention, I dip them into a solution of
either of the alkaline sulphites or of the earthy sulphites, or concentrated
sulphurous.acid, which I prefer to be somewhat concentrated, I then allow the
substances to drain, and expose them to the air for about two hours in a warm
place, so that the water contained in the solution of the salt remaining on the
surface may evaporate and leave the dry salt on the surface of the preserved
substances. The preserved substances are now ready to be packed in casks,
chests, or other cases, and in doing this the different pieces should be so placed
that in the package they do not come into actual contact. This may be
obviated by rolling the surfaces of the pieces in any of the alkaline or earthy
sulphites reduced to the form of dry powder, and any interstices which may be
left in packing are to be filled with the same powder, and the cases closed up
in as secure a manner as possible to prevent the access of air. A variation in
the dry mode of packing just described consists in this, that instead of rolling
the preserved pieces in the dry powder, 1 envelope each piece in a cover of
linen or of cotton cloth, such cloth having been previously steeped in a
concentrated solution of sulphite of lime, or of sulphite of alumina in sul-
phurous acid and dried. Thus enveloped, the pieces are to be placed in the
packages, and the interstices filled with the dry powder in manner as above
described.
Second, or liquid mode.-I shall now describe this mode of preserving
substances when packed in cases. The substances having been submitted to
the treatment above described as the first part of my Invention, and also
dipped into a solution of the sulphite in manner as I have described in the
dry mode of packing, are, without being dried, to be at once packed in the
intended cases, in such manner as to prevent their rolling about, yet not so
much as to obstruct the liquid to be put along with them from getting into
contact with their surfaces. Upon the cases being filled the interstices or
vacant parts in them are to be filled with a solution in sulphurous acid of any
of the sulphites already named, of strength measuring about 2° on Twaddle's
hydrometer. As described in the dry mode, in this mode also I have found
it advantageous for each of the pieces to be enveloped in covers of linen or
cotton cloth previous to being packed, and the solutions added as above

page_text: described. I prefer the dry mode of preserving materials in packing cases
above described, and I may remark, that whether the dry mode or the liquid
mode of packing be selected, it will be necessary to have the cases selected
for packing of substantial make, and as securely air and water tight as
possible.
In treating raw hides by my Invention, I plunge them or suspend them in
the stronger acid solutions above mentioned, that is to say, No. 4, and I sub-
mit them to only one or two applications of such dilute acid. After draining
I powder them with either of the dry sulphites, but I prefer sulphite of lime,
either alone or mixed with a portion of dry sulphite of alumina. The hides are
then to be compactly folded in bundles, so that the flesh sides may be placed
in the interior.
Having now particularly described and ascertained the nature of my said
Invention, and the manner in which the same is to be performed, I declare
that I claim as of my said Invention,―
First, the preserving of animal and vegetable matters by means of aqueous
solution of sulphurous acid, as above described.
Secondly, the preserving of animal and vegetable substances by means of
alkaline and earthy sulphites when packed in vessels or cases, as above
described.
In witness whereof, I, the said William Rattray, have hereunto set my
hand and seal, this Eighth day of July, in the year of our Lord One
thousand eight hundred and sixty-one.
W. RATTRAY. (L.S.)