THE ART OR METHOD OF MAKING A NEW-INVENTED SPIRITUOUS LIQUOR PROVER, AND OF CERTAIN TABLES AND CALCULATIONS THEREUNTO BELONGING, BY MEANS OF WHICH THE TRUE STRENGTH, &Ca. OF ALL SPIRITUOUS LIQUORS WILL BE MORE CORRECTLY AND POSITIVELY ASCERTAINED THAN BY ANY OTHER INSTRUMENT HITHERTO KNOWN
Year: 1787

page_text: DURAND'S SPECIFICATION.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
NICHOLAS DURAND, of Grocers' Hall Court, in the Poultry, in the City of
London, Merchant, send greeting.
WHEREAS His most Excellent Majesty King George the Third, by His
Letters Patent under the Great Seal of Great Britain, bearing date at West-
minster, the Fifth day of December, in the twenty-eighth year of His reign,
did give and grant unto me, the said John Nicholas Durand, His especial
licence that I, the said John Nicholas Durand, during the term of years
therein expressed, should and lawfully might make, use, exercise, and
vend, within England, Wales, and Town of Berwick-upon-Tweed, and also
in all His Majesty's Colonies and Plantations abroad, my discovery of "THE
ART OR METHOD OF MAKING A NEW-INVENTED SPIRITUOUS LIQUOR PROVER, AND OF
CERTAIN TABLES AND CALCULATIONS THEREUNTO BELONGING, BY MEANS OF WHICH THE
TRUE STRENGTH, &Cª. OF ALL SPIRITUOUS LIQUORS WILL BE MORE CORRECTLY AND
POSITIVELY ASCERTAINED THAN BY ANY OTHER INSTRUMENT HITHERTO KNOWN;" in
which said Letters Patent there is contained a proviso obliging me, the
said John Nicholas Durand, under my hand and seal, to cause a particular
description of the nature of my said discovery, and how the same is to be
performed, to be inrolled in His Majesty's High Court of Chancery within
one calendar month after the date of the said recited Letters Patent, as
in and by the same (relation being thereunto had) may more fully and at
large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
John Nicholas Durand, do hereby declare that my said discovery of a new-
invented spirituous liquor prover, and of certain tables and calculations
thereunto belonging, is described in the Plan, tables, and descriptions thereof,
hereunto annexed.
In witness whereof, 1, the said John Nicholas Durand,
set my hand and seal, this Third day of January, One thousand seven
hundred and eighty-eight.
J. N. DURAND. (L.S.)
SPECIFICATION OF THE NEW-INVENTED BRANDY PROVER, AND OF THE TABLES
THEREUNTO BELONGING.
Of the Areometer or Prover.-The prover A of the annexed Drawing repre-
sents the matrix prover, which serves to model and graduate all other provers
by, and which is completely graduated. The prover B is supposed to be a new
prover, not graduated. 1st, put a leaden weight X on prover B, and which
weight must be augmented or diminished by rolling thin pieces of lead about
the sprigg Y, or cutting or filing the weight according as it is found too heavy
or light, in such manner that the prover B, being put into clear water, may
sink about a couple of lines above the ball, but be careful to rubb the ball
and the tube of the prover with a linen dipped in vinegar to clean them
before you begin, otherwise you may be deceived if they be greasy, and do the
same with the matrix prover. 2dly, make a mixture of brandy and water
exactly of the strength necessary, that the prover A may sink exactly to mark
eight degrees; then put your new prover B into said mixture, and mark
exactly the point on the tube of the new prover where said brandy comes to,
and which point will be the spot where the eighth degree must be on the new
prover. 3dly, make another mixture of strong spirit and brandy, so that the
prover A may sink into it exactly to mark the 24th degree; then put your new
prover B into said brandy, and mark the exact spot on the tube of the new
prover where said brandy comes to, and which point will be the 24th degree
on the new prover. Now, as the two degrees 8 and 24 are thus marked on
the new prover, it is plain that the space comprehended between said degrees
8 and 24 (which the lines M, N, on the figures of the provers A and B repre-
sent) is a scale of 16 degrees; and when a scale of 16 degrees on any prover is
found, all the other degrees are found. by dividing and subdividing said space
I you come to one degree, and by doubling the space M, N, (or 16 degrees)
you'll have the space of 32 degrees. If you divide the space M, N, on Figure
until

page_text: B into two equal parts at S, the distance 8, S, is the space of 8 degrees; and
in taking the space 8, S, between the points of a compass, and bringing it
down to W, 0, 0, the space 08 will be 8 degrees, which, divided into two
equal parts, gives the space of 4 degrees, and subdivided again, gives two
degrees, and again subdivided, gives one degree, which being done, you'll find
the space 0, 8, divided into 8 parts, and thereby you have 1, 2, 3, 4, 5, 6, 7,
and 8 degrees, as appears on Figure B; and in like manner divide and sub-
divide the space 8 to S, and do the same with the space S to 24, and with the
space 24 to 32, and by so doing your areometer B will be properly graduated;
then put on your said areometer B a brass weight, and in a liquor that marks
15 degrees on your prover A emerge your new prover B, and if the weight
be too heavy, file off the excess until your prover B marks likewise 15
degrees exactly, and then, as both the matrix A and your new
prover B mark
in the same liquor exactly 15 degrees, they are both equal at that degree, and
will be also equal at every other degree, if these directions be followed
exactly and done with precision. If both the provers agree at any one degree,
they agree at every other degree; but it is better to regulate them at the
15th degree, because it is about the middle of graduation, and thereby
divides any little difference caused by any trifling inaccuracy. The matrix
prover is arbitrarg. I graduated it so that a brandy of Bordeaux constitution
at bead proof should mark 11 degrees on it at temperate, and my tables were
in consequence calculated for such a graduation, Its shape is also arbitrary.
The first areometer was graduated arbitrarily, and the calculations were made
a posteriori.
DESCRIPTION OF THE TABLES AND THEIR DIFFERENT USES.
There are three tables; viz, the first of these tables is called table of rates
of strengths; the second is called table of reduction; and the third shews
their degrees on the prover that the brandies and spirits that are remarkable
in France should mark at each degree of temperature. The first-mentioned
table of rates of strenghts is explained thus:-At the top of this table each
degree of the thermometer is marked from 2 degrees under ice to 22 degrees
above ice of Reaumur's thermometer. The first column to the right and left of
each page of said tables of rates contains the degree of the areometer or prover,
beginning at the top of the page with 33, and ending at the bottom with 0
degree of the areometer. The proof that I adopted to be the universal stan-
dard (and to which standard all other strenghts are to be compared), is about
the strenght of brandies sold all over Europe by retail in the shops, and which
I shall hereafter name shopkeeper's proof. I was, therefore, obliged to shew

page_text: at (each degree of temperature) the degree on the areometer that a brandy
at shopkeeper's proof should mark, and of consequence this degree of the
areometer in column B is pointed out by the marks Ⓑ Ⓑ, which is for
brandy of Bordeaux constitution, and in the columns C is pointed out by the
marks,, which is for brandy of Champagne-in-St-Onge constitution.
A brandy of Bordeaux constitution, to be at Bordeaux proof, should mark on
the areometer a degree that corresponds to the marks ⒷⒷ in the columns B,
according to the temperature of the brandy; therefore, if the temperature of
the brandy (Bordeaux constitution) be at 2 degrees under ice, said brandy
ought to mark on the areometer 9 degrees, because 9 degrees of the
areometer (on the table of rates) corresponds to the marks ⒷB in the
columns B, that is, under or corresponds to 2 degrees under ice, for 9 degrees
of the areometer is on the same line with or opposite to the marks ⒷⒷ in the
column that corresponds to 2 degrees under ice. A primitive brandy, of the
constitution of Champagne, to be at bead proof, must mark on the areometer
a degree that corresponds to the marks according to the temperatures
of the brandies; and supposing the temperature of the brandies to be 2 degrees
under ice, it should mark 10 degrees on the areometer, because 10 degrees
of the areometer corresponds to the marks C, for 10% degrees of the
areometer correspond or is on the same horizontal line with the marks O
as it appears on the table of rates of strengths in the column C, at 2 degrees
under ice. Observe, that if a primitive brandy of Bordeaux constitution (re-
presented by column B), and suppose it at 2 degrees under ice, I say, that
if said brandy marks more on the areometer than 9 degrees, that it is stronger
than bead proof, and if it mark less than said 9 degrees of the areometer,
it is weaker than bead proof; and observe, also, that if a primitive brandy of
the constitution of Champagne in St Onge (represented by column C on table
of rates of strengths), and at 2 degrees under ice, I say that if it marks more
on the areometer than 10 degrees, that it is above or stronger than bead
proof, and if it marks less than 10 degrees on the areometer, it is under or
weaker than bead proof.
In explaining the two columns B and C of my table of rates of strengths
that corresponds to the temperature of two degrees under ice, it will suffice
for the columns of all other temperatures on said table of rates; therefore, in
explaining the utility of my table of rates of strengths, I shall stand to the
columns B and C of said tables of rates of strengths, and corresponds to the
temperature of 2 degrees under ice. These columns being understood, the
others are also understood, being alike in their nature and utility.
N.B.-The tables of calculations being a most elaborate production, having

page_text: taken up near ten years to complete them, 'tis evident that the best way to
make them is to copy them from the set given in herewith, and which are fully
correct.
You'll perceive my universal standard that I have established and adopted
(which is the bead proof or the bead that brandies do or should bear that are
sold by retail by the shopkeepers in every part of Europe), it is, I say,
to this standard that you must compare the strength of all others superior
or lesser strengths. I think there cannot be a better way of comparing or
appreciating different strengths than the mercantile way of so much per cent.
over or under the standard of bead proof. In consequence, in casting an eye
on column B (which corresponds to 2 degrees under ice), you'll find that 1
corresponds to 9 degrees of the areometer, and as this one is above the marks
⑱ it implies that a primitive brandy of Bordeaux constitution at 9
degrees of the areometer, and at 2 degrees under ice, is 1 per cent. over or
stronger than the adopted standard of bead proof; and you'll also find that a
brandy of Bordeaux constitution, and at said temperature, marking 9 degrees
on the areometer, is 2 per cent. above bead proof (or standard that is calcu-
lated for my tables of rates of strengths), because 9 degrees of the
areometer on said tables of rates corresponds to 2 that you'll find in
column B at 2 degrees under ice. A brandy of aforesaid constitution
and temperature, and that marks 22 degrees on the areometer, would
be 80 per cent. stronger than bead proof, because 80 in column B, at
2 degrees under ice, corresponds to 22 degrees of the areometer. You
must particularly observe, that so much per cent. is taken on the price of the
standard that I adopted for my tables of rates (which is bead proof, therefore
the so much per cent. must be taken on the price of a brandy at bead proof.
Of consequence, if a brandy at bead proof is worth ten shillings per gallon,
another brandy that is 80 per cent. stronger than bead proof should be worth
80 per cent. augmentation, to be taken on said price of bead proof; therefore,
80 per cent. on ten shillings is 8 shillings; so 10 shillings added to 8 shillings
makes 18 shillings per gallon that the brandy (which is 80 per cent. stronger
than bead proof) is worth when a brandy at bead proof is worth 10 shillings
per gallon. A brandy of Bordeaux constitution, at the temperature of 2 degrees
under ice, that marks but 9 degrees on the areometer, is 4 per cent. under bead
proof (or adopted standard), because you'll find 4 in the column B of the table of
rates (corresponding to 2 degrees under ice), and that corresponds to 9 degrees
of the areometer, and also that this 4 is under the marks B B, which denotes
its being under the standard of bead proof; therefore the value of such brandy
is found by substracting from the price of bead proof 4 per cent. on said

page_text: price of bead proof; therefore if the price of 1 gallon of brandy at bead
proof is worth 10 shillings, take 4 per cent. on said 10 shillings, which will
make about 5 pence, and in the subtracting 5 pence from 10 shillings, remains
9 shillings and 7 pence that one gallon is worth of a brandy that is 4 per
cent. weaker than bead proof, when that at bead proof is worth 10 shillings
proof is worth 10 shillings, take 4 per cent. on said 10 shillings, which will
make about 5 pence, and in the subtracting 5 pence from 10 shillings, remains
9 shillings and 7 pence that one gallon is worth of a brandy that is 4 per
cent. weaker than bead proof, when that at bead proof is worth 10 shillings
per gallon
DESCRIPTION AND USE OF THE TABLE OF REDUCTION.
This table does not take in either the constitution nor temperature of the
brandy. Its chief use is to calculate the specific gravity of spirituous liquors,
without any regard to the nature of the phlegm. For example, if you have a
spirit that marks 28 degrees on the areometer, and a brandy that marks 12
degrees on the areometer, and that you would make a mixture that would
mark 18 degrees on the areometer, on the areometer, this table shews how much
of each you must take to make that mixture, and that mixture will mark the
degree of the areometer required when it comes to the degree of temperature
that would be a medium of what each was before mixture; and whether the
temperature of both before mixture was 2 degrees under ice or 22 degrees
above ice, or whether they were of Bordeaux constitution or Champagne, it
makes no difference in the result. For example, suppose we have a spirit that
marks 26 degrees on the areometer, and common water that marks a degree
on the areometer, and it is required to make a mixture that would mark 15
degrees on the areometer, quere, how many parts of the spirit and how many
parts of water should be mixed together to make a mixture that shall mark
the degree required on the areometer? Solution by the table of reduction and
the rule of allegation:-
Which, being mixed together, will mark 15 degrees on the areometer when
they attain the same temperature they both marked ere they were mixed,
because brandy and water mixed together causes an effervency which must 35

page_text: subside ere the mixture marks 15 degrees on the areometer, for the effervency
will make it mark something more.
USE AND DESCRIPTION OF THE TABLE THAT SHEWS THE DEGREES ON THE
PROVER THAT THE BRANDIES AND SPIRITS THAT ARE REMARKABLE IN
FRANCE, AT EACH DEGREE OF Temperature.
Suppose you have a brandy of the London standard, and that you want to
know what degree of the areometer it ought to mark at the temperature
of 2 degrees under ice without trying the brandy with the areometer.
Operation by said table, that shews the degree of the prover that brandies
and spirits which are remarkable in France should mark at each degree of
temperature:-You see on said table, at right and left, the degree of
Reaumeur's thermometer, and you see also a line for every standard of the
brandies that are most remarkable in France, &c.; among them you see
London standard; so follow the line of London standard till you come opposite
2 degrees under ice, where you see 13, which is the degree London standard
should mark on the prover, the temperature being 2 degrees under ice. The
same thing must be done with all the other standards in said table, and
all other temperatures, to find the degrees of the areometer that they should
mark.
AND BE IT REMEMBERED, that on the Fifth day of January, in the
year last above-mentioned, the said John Nicholas Durand came before our said
Lord the King in His Chancery, and acknowledged the Specification aforesaid,
and all and every thing therein contained and specified, in form above men-
tioned. And also Specification aforesaid was stampt according to the tenor
of the Statute in that case made and provided.
Inrolled the Fifth day of January, in the year last above mentioned.