IMPROVEMENTS IN EBULLIOSCOPES
Year: 1874

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery Lane,
in the County of Middlesex, Patent Agent, for the Invention of
"IMPROVEMENTS IN EBULLIOSCOPES."-A communication from abroad
by Pierre Marie Edouard Malligand and Marie Euphrésine
Elizabeth Brossard-Vidal. both of Paris, France.
Scaled the 17th November 1874, and dated the 29th May 1874.
PROVISIONAL SPECIFICATION left by the said Alexander Melville
Clark at the Office of the Commissioners of Patents, with his
Petition, on the 29th May 1874.
I, ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County
of Middlesex, Patent Agent, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN EBULLIOSCOPES," to be as follows:-
-
:-
This Invention relates to improvements in instruments known as
"ebullioscopes," or ebullition alcoholometers used for ascertaining the
alcoholic strength of liquids.

page_text: It is well known that the boiling point of pure water, although almost
invariable under a constant barometric pressure, is liable to considerable
variation, rising according to the proportion of matters of organic or
mineral origin held in solution in the water. It was, however, found
by the Abbé Brossard-Vidal that alcohol holding certain bodies in
solution, such as sugar, resins, citric and tartaric acid, acts differently,
these bodies (in moderate quantities) not affecting the boiling point of
the alcohol in which they are dissolved. This fact led to the method
of estimating the alcoholic strength of wines and other alcoholic liquors
by the boiling points of different mixtures of alcohol and water. The
instrument employed for this purpose consisted of a small boiler con-
tained in a perforated metal case and heated by a spirit lamp, said
boiler being fitted with a cover provided with two openings, through
one of which the stem of a themometer bent at a right angle passes,
the other being left unclosed during the boiling of the liquid to be
tested. On the cover is fixed a horizontal scale, serving for use with
the thermometer, together with a small graduated scale indicating the
alcoholic degrees, the latter scale being movable to suit the differences of
barometric pressure.
This bent mercurial thermometer, the bulb of
which was constantly immersed in the liquid to be tested, marked
100 degrees centigrade at the end of the stem, and 86 degrees at about
ths of an inch. from the bend. The graduation of this instrument
known as the "ebullioscope" or ebullition alcoholometer was effected
by the aid of mixtures of water and alcohol whose specific gravity was
first taken by means of the hydrometer, the alcoholic strength being
then precisely noted with the, themometer immersed in this same
mixture when in a state of ebullition.
The present Invention relates to various improvements in this
instrument, which consist,-
1st. In the use of a refrigerator to condense the vapours and so

page_text: cut aslant, the better to prevent the formation of a column of liquid by
condensation.
2ndly. In means for reading off with greater precision the point at
which the mercurial column stops, consisting either of a magnifying
lens sliding on the scale carrying the thermometer stem, or by means
of a lunette with cross wires mounted on a suitable support.
:
3rdly. Of a jointed wood scale in which is fixed a second narrower
scale of metal graduated in half millimetres, serving to verify the
accurate calibration of the themometer.
4lly. In the employment of a mercurial thermometer bent at a
right angle and the horizontal part of whose stem is accurately cali-
brated, in lieu of the old themometer which was not calibrated. It
marks 100° centigrade, or 86 degrees towards the extremity of its stem,
and 86 or 76 at about 3/4ths of an inch from the bend, according as the
themometer is made to indicate the whole of the alcoholometric scale
from 0° to 100°, or a párt only from 0° to 25°.
I also reserve the right to divide the 100 alcoholometric degrees into as
many scales as may be necessary. These themometers will moreover
be provided with small reservoirs or chambers to contain a certain
number of degrees, according to the requirement of the graduation.
5thly. To graduate an ebullioscope of any description I employ simple
mixtures of absolute alcohol and water from 1 to 99 hundredths prepared.
with care at +15, the densities having also being ascertained for the
purpose of comparison with those given by Gay Lussac. This method
of graduation is based on the fact that the millimetric divisions of the
mercurial column comprised between the point at which water ceases
to boil and the boiling point of any alcoholic liquor are variable from
one degree to another, but are constant for each percentage measured
with the same instrument. Moreover these same divisions become from
one instrument to another proportional to the respective divisions of
alcohol at 25 or 100 centesimal degrees, measured in the standard.
ebullioscope, and in that graduated by the aid of the preceding apparatus..
Hence, with a single alcoholic mixture, the 25th degree or the
100th, all the instruments of the same manufacture may be accurately
graduated, for which purpose a simple calculation or the graphic con-
struction of an isosceles triangle and the boiling point of water are

page_text: all that is requisite, provided that only those themometers' which are
accurately calibrated are employed.
6thly. Notwithstanding the improvements above indicated, it is still
impossible to obtain perfect constancy in the boiling point of cach
liquid, or exactly the same result on repeating the operation. These
indispensable conditions are however realized by the following modi-
fication, which consists in causing a circulation in the ebullioscope of the
liquid by heating it in detail instead of applying heat directly to the whole
bulk of the liquid. The boiler used for this for this purpose consists
of a vertical cylinder or a tube of slightly conical form open at its upper
part only, on which is screwed the cover, through which passes the
bent themometer to dip into the boiler, as well as the refrigerating
tube in which the alcoholic vapours become condensed. On this cover
is fixed the horizontal scale, also the small movable scale graduated to
indicate alcoholic degrees. The boiler, whose bottom may be either
flat or concave, has connected to its lower part an annular pipe, one
end of which is at a lower level that the other, so as to form a portion
of a spiral at a. point diametrically opposite the boiler. This tube
traverses a vertical chimney of a length and width calculated to cali-
brate the heating surface by that portion of the tube which is contained
in said chimney. Below the chimney is placed a lamp, whose wick
being composed of cotton of unvariable length cut off flush with a
cylinder of wire gauze contributes to regularize the transmission of
caloric.
The apparatus being arranged as described, it will be readily under-
stood that on the temperature of the small quantity of liquid contained
in that portion of the pipe exposed to the flame being raised, a
circulating movement will ensure, which soon becomes imparted to the
entire bulk of liquid, whose boiling point thus becomes so constant that
it may, in this manner, be maintained for about ten minutes.
7thly. A small fixed or movable deflector or cap is also provided,
resembling a truncated cone, notched at its base, and attached at its
upper end to a collar, the latter being also provided with a circular
opening for inserting the bulb of the themometer to be immersed in
the liquid. This deflector serves when plunged into the boiling liquid
both to prevent the tumefaction of the alcoholic liquids during their
ebullition, which it regulates constantly, and to direct continually the

page_text: hottest liquid to the centre of the boiler, that is to say, towards the
thermometer bulb, while allowing the steam to ascend, at same time
that the slightly cooler liquid passes down the sides of the boiler, and
on reaching the bottom reascends and continues then to circulato
throughout the whole time of boiling.
With the new form of boiler described, in which instead of directly
heating the bulk of liquid a circulation of the liquid is produced
exterioly of the boiler it is not indispensably necessary to use the
deflector above referred to, but it is necessary with the old mode of
heating.
8thly. In order to prevent the composition of the water which serves
to determine the zero of the graduated scalo affecting the result,
instead of immersing the bulk of the themometer in the water
usual, it is surrounded by the steam of the boiling water, and this
constitutes another important feature of improvement in ebullioscopes.
as
The instrument is provided with a stem sliding in a socket or pedestal
weighted sufficiently to steady the instrument.
The instrument may be used for determining the boiling points of
liquids generally, either alcoholic or not, and whether simple or com-
pound, the themometer being plunged in the liquid contained in the
boiler or merely immersed in the steam of said liquid.
In using the apparatus pure water is placed in the boiler until it
reaches the lower ring. The water is then boiled, the boiling point
being noted by bringing the zero of the movable scale opposite the
degree indicated by the mercurial column. The water is then replaced
by the liquid to be tested, care having been taken to rinse out the boiler
with some of the same, so that no water be allowed to remain. The boiler
is then filled up to the upper ring, and cold water supplied to the
refrigerater attached at the top of the instrument. The lamp is then
lighted, and as soon as the mercurial column becomes stationary in the
stem, then by means of the slide on the stem of the themometer the
top of the mercurial column is compared with the alcoholometric division
engraved on the graduated scale.

page_text: SPECIFICATION in pursuance of the conditions of the Letters
filed by the said Alexander Melville Clark in the, Great Seal Patent
Office on the 28th November 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALEXANDER
MELVILLE CLARK, of 53, Chancery Lanc, in the County of Middlesex,
Patent Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-ninth day of May, in the year
of our Lord One thousand eight hundred and seventy-four, in the thirty-
seventh year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Alexander Melville Clark, Her special
licence, that I, the said Alexander Melville Clark, my executors,
administrators, and assigns, or such others as I, the said Alexander
Melville Clark, 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, an In-
vention for "IMPROVEMENTS IN EBULLIOSCOPES," a communication to me
from abroad by Pierre Marie Edouard Malligand and Marie Euphrésinc
Elizabeth Brossard-Vidal, both of Paris, France, upon the condition
(amongst others) that I, the said Alexander Melville Clark, my exe-
cutors or administrators, by an instrument in writing under my, or
their, or one of their hands and scals, should particularly 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 Alexander Melville Clark, do
hereby declare the nature of the said Invention, and in what manner
the same is to be performed, to be particularly described and ascertained
in and by the following statement, that is to say :-
This Invention relates to improvements in instruments known as
ebullioscopes used for ascertaining the proportion of alcohol present in
liquids.

page_text: It is well known that although the boiling point of pure water is
almost invariable under a constant barometric pressure, the boiling
point of water holding matters of organic or mineral origin in solution
is liable to considerable variation, rising more or less according to the
proportion of such matters held in solution therein, a result which may
be easily verified by means of a mercurial thermometer.
It was
however found by the Abbé Brossard-Vidal that alcohol holding certain
matters in solution, such as sugar, resins, citric and tartaric acids, gives
a different result, the presence of these matters in moderate quantities
not affecting the boiling point of the alcohol in which they are dis-
solved. This fact led to the method of estimating the proportion of
alcohol present in wines and other alcoholic liquors by comparison
of their. boiling points with the boiling points of different mixtures of
alcohol and water in known proportions. The instrument employed by
the Abbé Brossard-Vidal for this purpose was of simple construction
and consisted of a small boiler, contained within a perforated metal
casing and heated by a spirit lamp, said boiler being fitted with a
removable cover provided with two openings, through one of which was
passed the stem of a thermometer bent at a right angle, the other being
left unclosed during the boiling of the liquid to be tested. On this
cover was fixed a horizontal bar, to. which the thermometer was
attached, and which also carried a small graduated scale for indicating
the per-centage of alcohol, this latter scale being adjustable. to com-
pensate for the differences of barometric pressure. This bent mercurial
thermometer having its bulb constantly immersed in the liquid to be
tested, marked 100 degrees centigrade at the end of the stem and 86
degrees at about ths of an inch from the bend. The graduation of
this instrument, known as the "ebullioscope," was effected by employing
mixtures of water and alcohol; which were first tested by means of the
areometer, and whose alcoholic strength was then precisely noted by
means of the thermometer immersed in this same mixture when
boiling.
'
The present Invention relates to improvements in the instrument, of
which the foregoing is a brief outline.
These improvements consist in a condenser or cooler to condense the
vapors of the liquid undergoing the test, and so maintain the com-
position of the said liquid constant during the whole time occupied in
testing it, which may be five minutes or more, thus enabling the

page_text: alcoholic strength of the boiling liquid to be determined with perfect
certainty. Amongst the various arrangements which might be devised
for attaining the desired result, it is preferred to use two straight
tubes of glass or metal placed concentrically the one within the other,
and screwing into the unclosed opening of the cover of the boiler above
mentioned. The lower end of the inner tube is cut aslant, the better
to prevent the formation of a column of liquid by condensation.
Means are also provided for enabling the point at which the mercurial
column stops to be read off with greater precision, and consisting either
of a magnifying lens sliding along the scale carrying the thermometer
stem, or a telescope provided with cross wires mounted on a suitable
support.
The instrument is further provided with a jointed bar of wood on
which is fixed a narrower strip of metal divided in haft millimetres,
serving to verify the accurate calibration of the thermometer. The
thermometer now used is very accurately calibrated along the horizontal
part of its stem, in lieu of the old thermometer, which was not cali-
brated. It marks 100° centigrade, or 86° towards the extremity of its
stem, and 86° or 76° at about four-fifths of an inch from the bend of
the stem, according as the thermometer is made to indicate the whole.
of the alcoholometric scale from 0° to 100 degrees, or a part only from
0° to 25°.
I also reserve the right to subdivide the 100 alcoholometric degrees
into as many parts as may be necessary. These thermometers will
moreover be provided with small reservoirs or chambers to contain a
certain number of degrees according to the requirements of the
graduation.
To graduate an ebullioscope of any description I employ simple
mixtures of absolute alcohol and water, from 1 to 99 hundredths, pre-
pared with care at +15° centigrade (59° Fahrenheit), and whose
densities have also been noted for the purpose of comparison with those
given by Gay Lussac. This method of graduation is based on the fact,
ascertained by experiment, that the lengths of the mercurial column
comprised between the boiling point of water and the points of
.different alcoholic liquors are variable from one alcoholic degree to
another, but are constant for cach strength measured with the same
instrument. Moreover, these same lengths are, as between one instru-

page_text: ment and another, proportional to the respective lengths for alcohol at
25 or 100 centesimal degrees, measured in the standard ebullioscope,
and in that graduated by the aid of the preceeding apparatus.
Hence with a single alcoholic mixture (the 25th or the 100th.
degree), all the instruments of the same manufacture may be accurately
graduated, for which purpose a simple calculation, or the graphic con-
struction of an isosceles triangle, and the boiling point of water aro
all that is requisite, provided that only those thermometers which are
accurately calibrated be employed.
Notwithstanding the improvements above indicated, it has still been
found impossible to obtain perfect constancy in the boiling point of
cach liquid, or exactly the same result on repeating the operation.
These indespensable conditions are, however; realized by the following
modifications, which consist in causing a circulation in the ebullioscope
of the liquid by heating it in detail instead of applying heat directly to
the whole bulk of the liquid. The boiler used for this purpose consists
of a vertical cylinder or a tube of slightly conical form, open at its
upper part only, on which is screwed the cover, through which passes
the bent thermometer to dip into the boiler, as well as the condenser
tube in which the alcoholic vapours become condensed.
On this cover
•
"
is fixed the horizontal bar to which the thermometer is attached,
as also the small movable scale graduated to indicate alcoholic. degrees.
The boiler, whose bottom may be either flat or concave, has connected
to its lower part an annular tube, one end of which is at a lower
level than the other, so as to form a portion of a spiral. At a point
diametrically opposite the boiler this tube traverses a vertical chimney
of a certain length and of a width calculated to calibrate the heating
surface by that portion of the tube which is contained in said chimney.
Below the chimney is placed a lamp whose wick being composed of
cotton threads of equal length cut off flush, with a cylinder of wire
gauze, contributes to regularize the transmission of caloric..
The apparatus being arranged as described, it will be readily under-
stood that on the temperature of the small quantity of liquid contained
in that portion of the pipe exposed to the flame being raised, a cir-
culating movement will ensue, which is soon imparted to the entire
bulk of liquid whose boiling point thus becomes so constant that it
may be maintained for about ten minutes.

page_text: A small fixed or movable. deflector is also provided resembling a
truncated cone notched or indented at its larger base and attached by
its smaller base to a collar, the latter being also provided with a.
circular opening to give passage to the bulb of the thermometer to be
immersed in the liquid. This deflector serves, when plunged into the
boiling liquid, both to prevent the tumefaction of the alcoholic liquid
during ebullition, which it regulates constantly, and to direct continually
the hottest liquid to the centre of the boiler, that is to say, towards
the thermometer bulb, while allowing the bubbles of steam to ascend,
at same time that the slightly cooler liquid passes down near the sides
of the boiler and on reaching the bottom reascends and continues then
to circulate throughout the whole time of boiling.
With the new form of boiler described, in which instead of directly
heating the bulk of liquid, a circulation of the liquid is produced in a
tube exteriorly of the boiler; it is not indispensably necessary to use
the deflector above referred to, but it is necessary with the old mode of
heating.
In order to prevent. the composition of the water, which serves to
determine the zero of the graduated scale affecting the result, instead
of immersing the bulb of the thermometer in the water as usual, it is :
surrounded by the steam of the boiling water, and this constitutes
another important feature of improvement in ebullioscopes.
The instrument is provided with a stem sliding in a socket or pedestal
weighted sufficiently to steady the instrument.
The instrument may be used for determining the boiling points of a
liquids generally, either alcoholic or not, and whether simple or com-
pound, the thermometer being immersed in the liquid contained in the
boiler, or merely in the steam of said liquid.
In using tho apparatus, pure water is placed in the boiler until it
reaches the lower ring. The water is then boiled, the boiling point a
being noted by bringing the zero of the movable scale opposite the
degree indicated by the mercurial column. The water is then replaced
by the liquid to be tested, care having been taken to rinse out the
boiler with some of the same, so that no water is allowed to remain.
The boiler is then filled up to the upper ring and cold water supplied
to the condenser attached at the top of the instrument. The lamp is
then lighted, and as soon as the mercurial column becomes stationary.in -

page_text: the stem, then by means of the pointer sliding on the stem of the
thermometer the level of the mercurial column is indicated exactly on
the alcoholometric division engraved on the graduated scale.
Having described the nature of the Invention, and the manner of
performing the same, I declare that what I claim as the Invention to
be protected by the herein-before in part recited Letters Patent is,
-
1st. The improvements in ebullioscopes herein specified, comprising
1st, the condenser or cooler; 2ndly, the method of graduation; '3rdly,
the boiler and mode of heating the same; 4thly, the deflector; and
5thly, the use of steam for determining the zero point, all as herein-
before described.
{}
2ndly. The application of the ebullioscopes improved as herein de-
scribed, for determining the boiling point of alcoholic and other liquids.
generally, either simple or compound, whether the thermometer of said
ebullioscope be immersed in the liquid contained in the boiler, or
merely the steam of said liquid, all as herein-before described.
In witness whereof, I, the said Alexander Melville Clark, have here-
unto set my hand and scal, this Twenty-eighth day of November,
in the year of our Lord One thousand eight hundred and seventy-
four.
0
Witness,
H*. SWALES,
53, Chancery Lane,
London.
A. M. CLARK. (L.S.)
c