IMPROVEMENTS IN THE MANUFACTURE OF SALICILIC ACID AND IN THE APPARATUS EMPLOYED THEREIN
Year: 1876

page_text: in the Empire of Germany, for the Invention of "IMPROVEMENTS IN THE
MANUFACTURE OF SALICILIC ACID AND IN THE APPARATUS EMPLOYED
THEREIN," bearing date the Twenty-fourth day of November, One thousand
eight hundred and seventy-six.
MEMORANDUM OF ALTERATION proposed to be entered and filed by
Herrmann Augustin, the Assignee of the above Letters Patent, to portions of
the Specification of the said Letters Patent, according to the Statutes in that
case made and provided.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HERRMANN
AUGUSTIN, of No. 74, Leipziger Strasse, Berlin, in the Empire of Germany, Chair-
man of the Board of Inspection of the Chemical Joint Stock Factory Company, send
greeting.
WHEREAS Her most Gracious Majesty Queen Victoria, by Her Royal Letters
Patent bearing date the Twenty-fourth day of November, One thousand eight
hundred and seventy-six, did grant unto the above-named Ernst Schering, his
executors, administrators, and assigns, the sole privilege to make, use, excrcise, and
vend the Invention of "IMPROVEMENTS IN THE MANUFACTURE OF SALICILIC ACID
AND IN THE APPARATUS EMPLOYED THEREIN," within the United Kingdom of Great
Britain and Ireland, the Channel Islands, and the Isle of Man, during the term of
fourteen years then next ensuing:
And whereas the said Ernst Schering, on the Fourteenth day of March, One
thousand cight hundred and seventy-seven, within the time prescribed by the said
Letters Patent, caused a Specification in writing under his hand and seal of the said
Invention to be filed in the Great Seal Patent Office:
And whereas by an Indenture of Assignment bearing date the Eighteenth day of
July, One thousand eight hundred and seventy-seven, and made between the said
Ernst Schering of the one part, and me, the said Herrmann Augustin, of the other
part, and duly registered in the Great Seal Patent Office, the said Letters Patent and

page_text: "
Invention were duly assigned to and are now vested in me, the said Herrmann
Augustin (as chairman of and on behalf of the Chemical Joint Stock Factory Com-
pany of Berlin), for all the residue of the said term of fourteen years:
And whereas after the date of the application for the said Letters Patent, and
since the filing of the Specification in pursuance thereof, I have ascertained and
been advised that the description of the said Invention in certain parts does not
give the true chemical terms as to be in accordance with the acknowledged appel-
lations known by chemists:
And in order to render the said Specification more definite, clear, and distinct, I
propose to make the several alterations, crasures, and corrections therein as herein-
after contained.
NOW KNOW YE therefore, that I, the said Herrmann Augustin, by and
with the leave of Her Majesty's Aftorney General, do hereby for the reasons
aforesaid, and in order more clearly to define and limit the true nature of the said
Invention and the means of carrying it into practical effect, make the following
alterations and erasures in the said Specification, that is to say :-
"
I strike out at line 38, page 2 of the said Specification, as printed by Her
Majesty's Printers, the word phenol," and add after the next word "sodium," the
word "carbolate ;" and in line 39 of the same page I strike out the words "salicilic
acid soda," and substitute therefor the words "sodium salicylate."
At line 41 of the same page I strike out the word "of" after the word
commencement"; and at line 42 of the same page I add immediately before the
word "sodium" the word "basic;" and immediately after the word "sodium" the
word "salicylate," striking out the words "salicilic acid soda natron."
At line 50 of the same page of the said Specification, I strike out the word
'phenol" immediately before the word "sodium;" and add immediately after tho
word "sodium" the word "carbolate."
At line 6 on page 3 of the said Specification, I strike out the letter "s from the
word "acids," altering it from the plural to the singular; and at line 9 of the same
page I strike out the second syllable of the word "throughout," reducing it to the
word "through."
At line 15 of page 3 I strike out the words "carbolic acid natron," and substitute
therefor the words "sodium carbolate;" and at line 17 of the same page I inscrt
immediately before the word "sodium the word "basic;" and immediately after
the word "sodium" the word "salicylate," striking out the words "salicilic acid
natron."
נו
I strike out at line 18 of the same page (3) the words "jackets or chests," and
substitute in lieu thereof the word "chambers;" and in the next line (19) of the same
page I strike out the word "chests," and substitute therefor the word "chambers."
I strike out at the end of line 27, and at the beginning of line 28 of the same page,
the words "carbolic acid natron," substituting therefor the words "sodium carbolate;"
and at linc 31 I strike out the letter "i" immediately before the word "opened,"
and substitute therefor the letter "c."
I strike out at line 34 the words "carbolic acid natron," and substitute therefor
the words "sodium carbolate ;" and at line 35 I strike out the word "chests" and
the letter "F" immediately before the Figure "3" and substitute in lieu thereof the
word "chambers" and the letter "J"; and I further strike out in the same line (35)
the letter "F" immediately before the Figure "4," and substitute in lieu thereof
the letter "J."
I strike out at line 43 of the same page (3) the words "chests," and substitute
instead thereof the word "chambers," and in the next line (44) of the same
page (3) I strike out the words carbolic acid matron" and substitute in lieu
thereof the words "sodium carbolate."
"
I strike out at line 45 of the same page (3) the word "chests" and the letter "F"
immediately before the Figure 4, and substitute therefor the word "chambers" aud
the letter "J;" and I further strike out in the same line of the same page (3) the

page_text: letter "F" after the Figuro "4" and immediately before the Figure "5
extreme end of the line, and substitute in lieu thereof the letter "J."
"
at the
I strike out at line 52 of the same page (3) the words "natrium salicilic acid
natron," and substitute in lieu thereof the words "basic sodium salicylate," and at
line 53 of the same page I strike out the letters "ic" in the word "sulphuric" and
substitute in lieu thereof the letters "ous," changing the word "sulphuric " into
"sulphurous," and I further strike out at line 55 of the same page (3) the words
falls down," and substitute therefor the word "precipitated." Also I strike
out at line 56 of the same page the letters "ic" from the word "sulphuric" and
substitute therefor the letters "ous," changing the word "sulphuric" into
"sulphurous."
I strike out at line 2, page 4, of the said Specification, the words "warm spirits
of wine" and substitute therefor the words "hot alcohol;" and at line 16 of the
same page (4) I strike out the word dialisis" and substituto in lieu thereof the
word "dialisation."
"
I further strike out at line 17 of the same page (4) the letter "ic" from the
word "sulphuric" and substitute in lieu thereof the letters "ous," altering the
word from "sulphuric" to "sulphurous."
And, lastly, at line 20 of the same page (4) I strike out the word "cloan" and
substitute in lieu thereof the word ".
'pure."
And I do hereby declare that the said Specification, as amended by the present
Memorandum of Alteration, shall read as follows:-
" SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
"the said Ernst Schering in the Great Seal Patent Office on the 14th March
1877.
"
" ERNST SCHERING, of Berlin, in the Empire of Germany.
IMPROVEMENTS IN
THE MANUFACTURE OF SALICILIC ACID, AND IN THE APPARATUS EMPLOYED
"THEREIN.'
"This Invention has for its object improvements in the manufacture of salicilic
"acid, and in the apparatus, employed therein, and consists in treating the ready-
"formed sodium carbolate (by the action of which on carbonic acids, when heated,
" is formed, as is well known, sodium salicylate) with carbonic acid on a system
"consisting of a combination of heated tubes, when the free phenol on the coin-
"mencement of the action of the carbonic acid on the carbolic acid salts is again
brought into contact with the already formed basic sodium salicylate, and carried
"back in the turn of the reaction.
"
"E
"My Invention consists further in the production of carbolic acid salts by carbonic
acid, not being confined to any particular part, but the unabsorbed carbonic acid
flowing out of one tube may be carried over to the following tube charged
"with phenol salts.
"
th
MyInvention further consists in the use of the carbonic acids at a higher pressure
"than the usual atmospheric pressure, whereby the production is greatly augmented,
"and especially because in my apparatus the sodium carbolate is fully treated, and
"without the formation of other matters.
"The accompanying Drawings show my improved apparatus, and the following
"is a description of such Drawings, and of the manner of using such apparatus.
"Similar letters of reference on such Drawings indicate corresponding parts of the
apparatus.
"In the furnace A, and to be heated at the same time, there are, 1, an iron
"worm B fixed directly over the fire-plates C₁ for the purpose of heating the
"carbonic acid to from 160 to 180° centigrade, which temperature is measured by
"the thermometer in the copper casing M.
"This worm is connected at its entrance into the furnace with an apparatus for
"producing carbonic acid, and carries the heated gas through six cocks, three of
"which only are shown on the Drawings, and marked D', D, D³, to six large iron
"tubes, three of which only are shown, marked respectively F¹, F², F³.

page_text: "
"
of
"2. Such iron tubes are closed respectively at their front ends by means
covers G¹, G³, G³, which covers are furnished with copper jackets or chests J, Jº, J³,
placed at the rear end of the furnace for the reception of the carbolic acid. These
"tubes receive the sodium carbolate, and are heated as before mentioned, and in
"them proceeds the chemical process by conducting to them the carbonic acid,
"which is heated to about 180° C., the finished product being basic sodium salicylate
"in the tubes F, and carbolic acid in the chambers J; then the somewhat volatile
"carbolic acid vapour is conducted to the chambers H so that it may be thoroughly
" condensed, and communication is opened with with these chests by means of suitable
"cocks placed in convenient positions, one of which only is shown on the accom-
"panying Drawings, and marked a.
3. Six tubes bent at each end, two only of which are shown on the accompanying
"Drawings, and marked respectively E¹, E, furnished with cocks K, K², K³, which
place the large tubes F in communication with each other, and thus enables the
apparatus to be worked continuously.
"
"
"
"For the purpose of working the apparatus the tubes F are filled with sodium
"carbolate, and fire made up in the furnace. Then any one of the cocks D' to Do
say D', is opened, with the object of conveying carbonic acid to the tube F¹; the
"cock K³ is closed, and the cocks K 1, 2, 4, 5, 6, opened; against these D 1, 2, 3, 5, 6,
being closed, as also the cocks a, b, d, e, f, at the front plates, and c opened. The
"thermometer L is connected to the tube F4 for the purpose of marking the
temperature. After six hours the cocks K 4 and D 4 are closed, D 5 opened,
" and the tube F 4 emptied and again supplied with sodium carbolate. The two
"front chambers J 3 and J 4 are at the same time emptied of the collected carbolic
"acid. When this has taken placo the cocks K 3 and d are opened and c shut, so
"that now the carbolic acid vapours and the carbonic acid remaining from the.
"reaction commencing at, say, F 5 reach F 4 after passing through the tubes E 5, F 6,
"EG, F1, E1, F 2, E2, F 3, E 3, to be afterwards perfectly condensed in the front
"chest and the cooler H 4 connected therewith. The carbonic acid is enclosed, so
"that it passes through three or four tubes only, whilst the carbolic acid vapours
"reach up to the sixth tube, and to F4, as before mentioned. From this moment
"the apparatus works continuously, one tube and two chambers are hourly emptied,
" and the former again filled with sodium carbolate.
"In the before-mentioned case it would be the tube F 5 and the chambers J4
and J 5. In the next hour the process is carried on by F 6, then F 1, F 2, F 3, &c., 3
80 that in twenty-four hours the apparatus can be filled and emptied four times..
"4. Another essential feature of my Invention is the particular cleansing process
applied on known chemical principles to tho salicilic acid produced in the apparatus
"invented by me.
<
"This part of my Invention consists of the following:
*
a. The basic sodium salicylate formed in the tubes of the furnace I dissolve in
"water and add a mineral acid to the solution, preferably sulphurous acid (S O₂), by
which means the salicilic acid is separated from the alkali or other bases and
precipitated.
"
b. This salicilic acid after being cleaned by means of the sulphurous acid is 4
"dissolved and heated with zinc dust, by which process the perfect discolouration
of the fluid is effected. The so-called amorphous salicilic acid, which becomes
"separated from the fluid when in a cold state, is dissolved with hot alcohol, and
"after the same has become cold is now in the state of beautiful crystals; this is
"the so-called crystallized salicilic acid. Both of these substances however still 5
"retain traces of a heterogeneous resinous substance, with the object of getting
"rid of which I employ the dialisator, of which a Drawing is hercto joined.
"
"The apparatus of combined receiving vessels, for the purpose of dialising the
"salicilic acid, consists of the porcelain rings A, with the attachments B and the
apertures C for filling. These rings are bound over from each side with parch- 5
"ment, and into these latter intermediate spaces, through the aperture C, the
"salicilic acid dissolved in diluted spirits of wine is filled in. These vessels are 18

page_text: in number and attached to a glass rod D; they are hung in a large earthenware
"vessel E, of sufficient size to allow of room for a second apparatus or system of
18 dialisers.
"The earthenware vessel E is filled with distilled water, which is warmed by
means of the steam worm F, made of tin or pewter, lying therein. After the lapse
"of 12 hours the dialisation will have advanced sufficiently to allow of the salicilic
"acid solution being drawn from the earthenware vessel. After adding some
sulphurous acid (SO,) the solution is allowed to cool, upon which the salicilic
"acid becomes crystallized in the form of beautiful needles. These latter are dried,
" and then is obtained an absolute chemical pure salicilic acid, to which I give the
"name of acidium, salicilicum dialisatum.
Having thus described the nature of my said Invention, and in what manner
"the same is or may be used and carried into practical effect, I desire it. to be
"understood that what I claim and desire to secure under the herein-before in part
"recited Letters Patent is,-
"First. The general arrangement, construction, and combination of parts which
together form the apparatus for producing salicilic acid by the process and in
"the manner herein-before described and shown in the accompanying Drawings.
"Second. The method or mode of obtaining salicilic acid as herein-before
"described and shown in the accompanying Drawings, whereby the said acid is
"obtained in a state of far greater purity, and at a greatly reduced cost than has
"hitherto been accomplished.
"Third. The application and use of the cleansing process in the manufacture of
"salicilic acid; together with the dialising process and apparatus which is used for the
purpose of obtaining the salicilic acid in a state of perfect purity, as herein-before
"described and illustrated.
"In witness whercof, I, the said Ernst Schering, have hereunto set my hand
"and scal, this Fourteenth day of March, in the year of our Lord One
"eight hundred and seventy-seven."
" ERNST SCHERING. (L.S.)”
And I, the said Herrmann Augustin, do hereby further and lastly declare that the
above written memorandum of alteration is not, nor is any part thereof respectively
intended to extend the exclusive right granted by the said Letters Patent, and that
these presents shall not extend the said exclusive right in any way whatsoever.
In witness whereof. L. the said Herrmann Augustin. have hereunto set my
" ERNST SCHERING. (L.s.)"
And I, the said Herrmann Augustin, do hereby further and lastly declare that the
above written memorandum of alteration is not, nor is any part thereof respectively
intended to extend the exclusive right granted by the said Letters Patent, and that
these presents shall not extend the said exclusive right in any way whatsoever.
In witness whereof, I, the said Herrmann Augustin, have hereunto set my
hand and seal, this Eighteenth day of October, One thousand eight hundred
and seventy-seven,
I hereby grant my fiat, giving leave to the above-named Hermann Augustin, the
Assignee of the above in part recited Letters Patent which were granted to the
herein-before named Ernst Schering, to file in the Great Seal Patent Office, with
the Specification to which the same relates, the above written Memorandum of

page_text: LETTERS PATENT to Ernst Schering, of Berlin, in the Empire of Germany,
for the Invention of "IMPROVEMENTS IN THE MANUFACTURE OF SALICILIC
ACID, AND IN THE APPARATUS EMPLOYED THEREIN."
Sealed the 20th February 1876, and dated the 24th November 1876
PROVISIONAL SPECIFICATION left by the said Ernst Schering at the Oflico
of the Commissioners of Patents on the 24th November 187 G.
ERNST SCHERING, of Berlin, in the Empire of Germany. "IMPROVEMENTS IN THE
MANUFACTURE OF SALICILIC ACID, AND IN THE APPARATUS EMPLOYED THEREIN."
This Invention has for its object improvements in the manufacture of salicilic
acid, and in the apparatus. employed therein, and consists,-
1. In treating the ready formed phenol sodium (by the action of which on car-
bonic acids when heated is formed, as is well known, salicilic acid soda) with
carbonic acid on a system consisting of a combination of heated tubes, when the
free phenol on the commencement of the action of the carbonic acid on the carbolic
acid salts is again brought into contact with the already formed sodium, salicilic
acid, soda natron, and carried back in the turn of the reaction.
2. My Invention consists further in the production of carbolic acid salts by
carbonic acid, not being confined to any particular part, but the unabsorbed carbonic
acid flowing out of one tube may be carried over to the following tube charged
with phenol salts.
3. My Invention further consists in the use of the carbonic acids at a higher
pressure than the usual atmospheric pressure, whereby the production is greatly
augmented, and especially because in my apparatus the phenol sodium is fully
treated, and without the formation of other matters.
The accompanying Drawings shew my improved apparatus, and the following is
a description of such Drawings, and of the manner of using such apparatus.
Similar letters of reference on such Drawings indicate corresponding parts of the
apparatus.
In the furnace A, Sheet 1, and to be heated at the same time, there are,
1. An iron worm B, Sheets 1 and 2, fixed directly over the fire-plates C', Sheet 1,
for the purpose of heating the carbonic acids to from 160 to 180° Centigrade, which
temperature is measured by the thermometer in the copper casing M, Sheet 1. This
worin is connected at its entrance into the furnace with an apparatus for producing

page_text: carbonic acid, and carries the heated gas through six cocks, three of which only are
shewn on the Drawings, Sheet 2, and marked D1, D2, D3, to six large iron tubes,
three of which only are shewn on Sheet 2, marked respectively F1, F2, F.
2. Such iron tubes are closed respectively at their front ends by means of covers
G1, G2, G3, which covers are furnished with copper jackets or chests 11, 12, 13, Sheet 2,
placed at the rear end of the furnace for the reception of the carbolic acid. These
tubes receive the carbolic acid natron, and are heated as before mentioned, and in
them proceeds the chemical process by conducting to them the carbonic acid, which
is heated to about 180° centigrade, the finished product being sodium, salicilic acid,
natron in the tubes F, and carbolic acid in the jackets or chests I; then the some-
what volatile carbolic acid vapour is conducted to the chests H, so that it may be
thoroughly condensed, and communication is opened with these chests by means of
suitable cocks placed in convenient positions, one of which only is shewn on the
accompanying Drawing, Sheet 1, and marked a.
3. Six tubes bent at each end, two only of which are shewn on the Drawing,
Sheet 2, and marked respectively E, E, furnished with cocks K, K, K³, Sheets 1
and 2, which place the large tubes E in communication with each other enables the
apparatus to be worked continuously.
The advantages of my Invention arc,―
1. That by the use of my improved apparatus, as shewn in the Drawing, salicilic
acid can be produced from ordinary merchantable phenol sodium in far greater
quantities than has hitherto been done by any other process.
2. The decomposition of the phenol sodium being as perfect as by any other
process.
3. The perfect purity of the salicilic acid, both in a crystallized form and
otherwise.
4. That by the means mentioned in paragraphs 1 and 2 I am enabled to produce
salicilic acid at a greatly reduced cost than has hitherto been practicable, and that
by the means described in paragraph 31 can also produce it in far greater purity
than it has hitherto been capable to attain by any other process.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Ernst Schering in the Great Seal Patent Office on the 14th March
1877.
ERNST SCHERING, of Berlin, in the Empire of Germany. " IMPROVEMENTS IN THE
MANUFACTURE OF SALICILIC ACID, AND IN THE APPARATUS EMPLOYED THEREIN."
This Invention has for its object improvements in the manufacture of salicilic
acid, and in the apparatus employed therein, and consists,
In treating the ready formed phenol sodium (by the action of which on carbonic
acids when heated is formed, as is well known, salicilic acid soda) with carbonic
acid on a system consisting of a combination of heated tubes, when the free phenol
on the commencement of of the action of the carbonic acid on the carbolic acid salts
is again brought into contact with the already formed sodium, salicilic acid, soda
natron, and carried back in the turn of the reaction.
2. My Invention consists further in the production of carbolic acid salts by
carbonic acid, not being confined to any particular part, but the unabsorbed carbonic
acid flowing out of one tube may be carried over to the following tube charged with
phenol salts.
3. My Invention further consists in the use of the carbonic acids at a higher
pressure than the usual atmospheric pressure, whereby the production is greatly
augmented, and especially because in my apparatus the phenol sodium is fully
treated, and without the formation of other matters.
The accompanying Drawings shew my improved apparatus, and the following is

page_text: a description of such Drawings, and of the manner of using such apparatus.
Similar letters of reference on such Drawings indicate corresponding parts of the
apparatus.
In the furnace A, and to be heated at the same time, there are,
1. An iron worm B fixed directly over the fire-plates C, for the purpose of
heating the carbonic acids to from 100 to 180° centigrade, which temperature is
measured by the thermometer in the copper casing M. This worm is connected
at its entrance into the furnace with an apparatus for producing carbonic acid, and
carries the heated gas throughout six cocks, three of which only are shewn on the
Drawings, and marked D1, D2, D3, to six large iron tubes, three of which only aro
shewn, marked respectively F1, F², F³.
2. Such iron tubes are closed. respectively at their front ends by means of covers
G1, G2, G3, which covers are furnished with copper jackets or chests J', J, J, placed
at the rear end of the furnace for the reception of the carbolic acid. These tubes
receive the carbolic acid natron, and are heated as before mentioned, and in them
proceeds the chemical process by conducting to them the carbonic acid, which is
heated to about 180° C., the finished product being sodium salicilic acid natron in
the tubes F, and carbolic acid in the jackets or chests J; then the somewhat volatile
carbolic acid vapour is conducted to the chests H, so that it may be thoroughly
condensed, and communication is opened with these chests by means of suitable
cocks placed in convenient positions, one of which only is shewn on the accom-
panying Drawings, and marked a.
3. Six tubes bent at each end, two only of which are shewn on the accompanying
Drawings, and marked respectively E', E, furnished with cocks K', K, K³, which
place the large tubes Fin communication with each other, and thus enables the
apparatus to be worked continuously.
For the purpose of working the apparatus the tubes F are filled with carbolic
acid natron, and fire made up in the furnace. Then any one of the cocks D' to Do
say D', is opened with the object of conveying carbonic acid to the tube F 4; the
cock K³ is closed, and the cocks K 1, 2, 4, 5, 6, opened; against these D 1, 2, 3, 5, 6,
being closed, as also the cocks a, b, d, e, f, at the front plates, and opened. The
thermometer L is connected to the tube F4 for the purpose of marking the tempe-
rature. After six hours the cocks K4 and D 4 are closed, D 5 opened, and tho
tube F4 emptied, and again supplied with carbolic acid natron. The two front
chests F3 and F4 are at the same time emptied of the collected carbolic acid.
When this has taken place the cocks K 3 and d are opened, and c shut, so that now
the carbolic acid vapours and the carbonic acid remaining from the reaction, com-
mencing at, say F 5, reach F 4 after passing through the tubes E 5, F 6, E6, F 1, E1,
F2, E2, F3, E3, to be afterwards perfectly condensed in the front chest, and the
cooler H4 connected therewith. The carbonic acid is enclosed, so that it passes
through three or four tubes only, whilst the carbolic acid vapours reach up to the
sixth tube and to F 4, as before inentioned. From this moment the apparatus works
continuously; one tube and two chests are hourly emptied and the former again
filled with carbolic acid natron
In the before-mentioned case it would be the tube F5 and the chests F 4 and F 5.
In the next hour the process is carried on by F6, then F¹, F, F, &c., so that in
twenty-four hours the apparatus can be filled and emptied four times.
4. Another essential feature of my Invention is the particular cleansing process
applied on known chemical principles to the salicilic acid produced in the apparatus
invented by me.
This part of my Invention consists of the following:-
a. The natrium salicilic acid natron formed in the tubes of the furnace I dissolve
in water, and add a mineral acid to the solution, preferably sulphuric acid (SO 2),
by which means the salicilic acid is separated from the alkali or other bases, and
falls down.
b. This salicilic acid, after being cleaned by means of the sulphuric acid, is dis-
solved, and heated with zinc dust, by which process the perfect discolouration of

page_text: the fluid is effected. The so-called amorphous salicilic acid, which becomes separated
from the fluid when in a cold state, is dissolved with warm spirits of wine, and
after the same has become cold is now in the state of beautiful crystals; this is the
so-called crystallized salicilic acid. Both of these substances however still retain
traces of a heterogeneous resinous substance, with the object of getting rid of
which I employ the dialisator, of which a Drawing is hereto joined.
The apparatus of combined receiving vessels for the purpose of dialising the
salicilic acid consists of the porcelain rings A, with the attachments B and the
apertures C for filling. These rings are bound over from each side with parchment,
and into these latter intermediate spaces through the aperture C the salicilic acid dis-
solved in diluted spirits of wine is filled in. These vessels are 18 in number, and
attached to a glass rod D; they are hung in a large earthenware vessel E of
sufficient size to allow of room for a second apparatus or system of 18 dialisers.
The earthenware vessel E is filled with distilled water, which is warmed by means
of the steam worm F, made of tin or pewter, lying therein. After the lapse of 12
hours the dialisis will have advanced sufficiently to allow of the salicilic acid solu-
tion being drawn from the earthenware vessel.
(SO2) the solution is allowed to cool, upon
crystallized in the form of beautiful needles.
obtained an absolute chemical, clean, salicilic
acidium salicilicum dialisatum.
After adding some sulphuric acid
which the salicilic acid becomes
These latter are dried, and then is
acid, to which I give the name of
Having thus described the nature of my said Invention, and in what manner the
same is or may be used and carried into practical effect, I desire it to be under-
stood that what I claim and desire to secure under the herein-before in part recited
Letters Patent is,―
First. The general arrangement, construction, and combination of parts, which
together forin the apparatus for producing salicilic acid by the process and in the
manner herein-before described and shewn in the accompanying Drawings.
Second. The method or mode of obtaining salicilic acid, as herein-before described
and shewn in the accompanying Drawings, whereby the said acid is obtained in a
state of far greater purity and at a greatly reduced cost than has hitherto been
accomplished.
Third. The application and use of the cleansing process in the manufacture of
salicilic acid, together with the dialising process and apparatus, which is used for
the purpose of obtaining the salicilic acid in a state of perfect purity, as herein-
before described and illustrated.
In witness whereof, I, the said Ernst Schering, have hereunto set my hand
and seal, this Fourteenth day of March, in the year of our Lord One thousand
eight hundred and seventy-seven.
ERNST SCHERING. (L.S.)