AN IMPROVED APPARATUS FOR DETERMINING THE SPECIFIC GRAVITY OF FLUID BODIES, AND THE RELATION THAT THEIR WEIGHT BEARS TO A GIVEN MEASURE
Year: 1805

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, we, JOHN
ROBERT IRVING, of the City of Edinburgh, Advocate, and ISABELL LOVI, of the
said City, Worker in Glass, send greeting.
WHEREAS His present Majesty King George the Third has been
graciously pleased to grant unto us, the said John Robert Irving and Isabell
Lovi, our heirs, exors, aditors, and assigns, His Royal Letters Patent under the
Great Seal of Great Britain, bearing date at Westminster, the Ninth day of
March, in the forty-fifth year of His reign, and in the year of our Lord One
thousand eight hundred and five, for the sole use and benefit of our Invention
of "AN IMPROVED APPARATUS FOR DETERMINING THE SPECIFIC GRAVITY OF FLUID
BODIES, AND THE RELATION THAT THEIR WEIGHT BEARS TO A GIVEN MEASURE ;" and
the full power, sole priviledge, and authority to make, use, vend, and exercise
the said "Invention, either by ourselves, or by our deputy or deputies, agent or
agents, or any such persons as we might agree with, within that part of the
United Kingdom of Great Britain and Ireland called England, Dominion of
Wales, and Town of Berwick-upon-Tweed, and also in all His Majesty's
Plantations and Colonies abroad, according to the laws in that case made
and provided; in which Letters Patent is contained a proviso, that if we,
or one one of us, should not particularly describe and ascertain the nature of
our said Invention, and in what manner the same is to be performed, by an
instrument in writing under our hands and seals, or under the hand and
seal of one of us, and. cause the same to be inrolled in His Majesty's High
Court of Chancery.. within six calendar months next and immediately after

page_text: the date of the said Letters Patent, that then the said Letters Patent, and
all liberties and advantages whatever thereby granted, should utterly cease and
determine, and become void, anything contained in the said Letters Patent to
the contrary notwithstanding, as will more fully appear in the said Letters
Patent themselves.
NOW KNOW YE, that in compliance with the said proviso, we, the said
John Robert Irving and Isabell Lovi, do hereby declare that the nature of
the said Invention, and the manner. in which the same is performed, is as
follows, that is to say:-
There are four objects of improvements to be attended to in examining the
comparative value of different fluids and mixture of fluids, and ascertaining
the proportion that the valuable part of any mixture bears to that which is of
little or less value, and all of which objects an apparatus calculated to
ascertain with accuracy must be held to embrace. The first is the specific
gravity of any fluid, or the proportion which that fluid bears in weight to an
equal bulk of distilled water (which has been generally assumed as the
standard) at any given temperature. The second is. the quantity of the valuable
fluid that exists in any mixed liquor, which must be done by making accurate
mixtures, and ascertaining their specific gravity at a fixed temperature. The
third is the alteration that different temperatures make on the specific gravity
of such fluids or mixture of fluids, which. must also be ascertained by experi-
ment, and recorded in tables to be referred to in practice, or the bulk of such
tables reduced by using a mechanical contrivance for calculating the changes
that such variations of temperature produce. And the fourth, a mode of
ascertaining correctly the weight (at a given temperature) of any given measure
of any fluid or mixed, fluid) that is or has been used in any country or period,
in English grains, or pounds troy, or avoirdupois, or in weights of any other
nation, of which an accurate standard can be procured.
With regard to the first object, the nature of our Invention and improve-
ment is as follows:-We take a large hollow ball of metal or glass (but glass
is preferable) and chuse it light enough to swim in the lightest non-clastick
fluid in nature, which inuriatic ether is considered to be, and adjust it so, by
either adding or diminishing its weight, that it may float in the middle of the
liquor, at the temperature of sixty of Farenheit's thermometer, or any other
temperature of it, or of any other thermometer that we chuse for a standard. S
(This ball must have been so adjusted with a small bucket of metal or glass
to hold the weights under mentioned) appended to it by a hook at the bottom
of the ball (as may be seen in the Drawing annexed at. the letter D, but.
glass is preferable, and in all cases take care that the. material that. is.used is

page_text: not liable to be acted on by the fluid in which it is immersed.) It must now be
well wiped, and loaded with glass or lead, or any other material on which
sulphuric acid will not act, till it swims in the middle of the strongest sulphuric
acid, and at the same temperature that the former part of the experiment has
been performed. Then, taking the specific gravity of muriatic ether at seven
hundred and thirty, and the strongest sulphuric acid at two thousand one
hundred and twenty-five, (which we determine by experiment,) distilled water
being one thousand, the difference of degrees of specific gravity between such
ether and such acid will be one thousand three hundred and ninety-five. Then
suppose it takes thirteen thousand nine hundred and fifty grains troy, or near
two pounds avoirdupois, to poise the ball in the acid, ten grains will represent
one degree of specific gravity, one grain of a degree, one tenth of a grain
1 of a degree, and one hundred of a grain 1000 of a degree; there aro
therefore weights to be adjusted of a similar proportion with the above and of
the same material that was used in the original experiment, taking care that the
fluids used are not capable of acting on them. Having determined the degreo
or fraction of a degree of the specific gravity that any fluid has by loading the
above bucket till it swims in the middle of the liquor, we proceed to adjust one
of the common glass leads (that are used for spirit proofs) (to swim also in tho
middle liquor) and which has been previously numbered with the degree or
fraction of a degree above mentioned, and so on we can go, upwards or down-
wards, either adjusting the weights to the liquor or the liquor to the weights ;;
and if any change takes place in the liquor by evaporation or otherwise, the
rising or falling of the ball, which we term the regulator, indicates it, and the
fluid can be brought to its original gravity by suitable additions, either to make
it heavier or lighter. During these operations, if glass weights are used, it will
not be necessary to attend to the heat; but if metal used, where great nicety is
required, the heat ought to be the same with the original standard heat at
which the previous experiments have been made. Thus, glass leads, numbered
to represent any given degree or fraction of a degree of specific gravity, and
adjusted to the regulator loaded with the proper weights, will very accurately
indicate the specific gravity of any liquor in which they swim, and it is in the
Invention and use of the regulator that our improvement on this branch of the
subject consists. It must be particularly remarked that when water is used for
weakening the liquors, that its air must be extricated by long boiling or the air
pump, else the air bubbles attached to the sides of the ball and weights will
cause fallacious results.
.
With regard to the second object, so much has been done and so well by
Sir Charles Blagden and Mr. Gilpin with regard to spirits, and by Mr. Kirwan

page_text: with regard to acids, and by other philosophers with regard to other fluids, that
little remains except to follow their footsteps.
'
With regard to the third object, our improvement consists in the mechanical
contrivance for giving the correction for the temperature of the liquor. We
lay down on a part of a circle of wood, metal, ivory, or any material in
general use for sliding rules, and about one-third of its radius distant from
the circuniférence," a number of degrees, dividing the circle equally, and then
subdivided again into any fractions that may be necessary for our purpose.
We number them according to the degrees of specific gravity of the liquor we
wish to adopt the circle to, and on lines nearer the circumference give the
strengths or proportions of the mixtures at such degree of the thermometer as
we fix on as a standard. Having then determined by experiment what encrease
or decrease of heat it takes to raise or lower any mixture or mixtures a certain
number of degrees of specific gravity, we lay down on the circumference of a
smaller circle of a radius about two-thirds of the great one, and concentric
with it, a thermometer scale, extending to the same space with the degrees of
specific gravity, which we find by experiment that quantity of heat will alter the
gravity of the liquor. Thus, if fifty degrees of heat lower the specific gravity
seventeen degrees, the thermometer scale of fifty degrees will take up the
space of seventeen degrees specific gravity. This space must be divided into
five parts. If the number of degrees of heat are betwixt thirty and eighty
of Farenheit, and chusing sixty for the standard heat, place it at each end of
the scale, while 30 is placed at the end of the third division from the left,
and 80 at the end of the second division from the right; then, the other
degrees being filled up, by placing the degree of heat determined by the
thermometer opposite the degree of gravity determined by the beads, and
looking to the right if the heat is above 60, or to the left if below 60; we
find opposite the extremity of the scale the gravity of that mixture. This
may be more particularly understood by the annexed circle, which com-
prehends the strengths of spiritueus mixtures betwixt eight hundred and
ninety and nine hundred and fifty of gravity at the heat of sixty. And our
Invention and improvement particularly consists in this as fluids are some-
times irregularly expanded at different degrees of heat as well as at different
gravities, by making several thermometer scales to the same range instead of
one, as in the common sliding rules, an allowance can be made for that
circumstance, and greater accuracy obtained. The Drawing referred to is
appended to this Specification.
. The last object of our Invention and improvement on the ordinary modes
of determining the value of fluids, consists in a mode of finding to a great.

page_text: nicety the contents of any measure by weight. Suppose that we find that
a cubic inch of distilled water weighs two hundred and fifty-two troy grains
and a half, at the temperature of sixty, we make a vessel as nearly as possiblo
to hold one cubic inch, or any number of cubic inches, and by a screw going
into its neck or a cylinder on the end of a screw (as may be observed in the
accompanying Drawing) the liquor may be forced out through a small pipe,
till the vessel is found, by a nice beam, to hold exactly the weight of distilled
water at the temperature of sixty, corresponding to the number of cubic.inches
intended as its capacity. The head of the screw is divided into degrees, which
come opposite to an index-plate, which shews the number of turns that tho
screw makes or parts of turns. This vessel may be constructed of metal,
glass, or pottery, the screws being always of metal, taking care that tho
material cannot be acted on by the liquor to be examined. The Drawing
referred to, appended to the Specification, consists of two such vessels. of the
cylinder shape, though they may be made of any form if they hold nearly
the quantity intended. A, in each, is the body of the vessel; B is the screw
going down into the neck when entirely-made of metal ;. C, the divided hend
of the screw in both; D³, the screw with. the cylinder at its end where the
vessel is made of glass or pottery. One holding four cubic inches may, be
easily adjusted to hold one thousand grains, and answers perfectly to deter-
mine specific gravities when time can be spared for the purpose. The above
vessel will easily give the weights of any measure of any fluid by previously
knowing the contents of that measure in English cubic inches. Another
important consideration, which deserves to be treated of seperately, is facility
of use, and that is compleated by making the glass. beads above mentioned,
when of a numerous range, differ in their colour at stated intervals from the
others; for instance, at every ten degrees or every five degrees of gravity,
or any odd or even number, or fraction of a number, that may be necessary,
in examining the various fluids in nature, betwixt ether and sulphurous acid.
In witness whereof, we, the said John Robert Irving and Isabell Lovi,
have hereunto set our hands and seals, the Thirty-first day of August,
in the year of our Lord Eighteen hundred and five.

page_text: Robert Lockhart, of the City of Edinburgh, in that part of Great Britain
called Scotland, Writer, maketh oath and saith, that John Robert Irving, of
the City of Edinburgh, in that part of Great Britain called Scotland, Advo-
cate, and Isabel Lovi, of the said City, Worker in Glass, the two persons in
the annexed deed poll or instrument named and described, did sign, seal,
and as their act and deed, in due form of law, deliver, the said annexed deed
poll or instrument in presence of this deponent, and of William Johnston,
Writer to the Signet, the other subscribing witness thereto, and saith, that the
the several names, John Robert Irving and Isabel Lovi, set and subscribed
opposite the respective seals affixed thereto, as the parties executing the same,
and the names Robert Lockhart and William Johnston, thereto also set and
subscribed as witnesses attesting the duo execution thereof by the said John
Robert Irving and the said Isabel Lovi, are of the respective proper bands-
writing of the said John Robert Irving and Isabel Lovi, William Johnston,
and this deponent.