CERTAIN IMPROVEMENTS UPON HYDROMETERS AND SACHAROMETERS
Year: 1822

page_text: BATE'S SPECIFICATION.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ROBERT
BRETTELL BATE, of No. 17, Poultry, in the City of London; Optician, send
greeting...
WHEREAS His present Majesty King George the Fourth, in and by
His Letters Patent under the Great Seal of Great Britain, bearing date at
Westminster, the Twenty-first day of March last past, for Himself, His heirs
and. successors, did give and grant unto me, the said Robert Brettell Bate, my
exors, aduiors, and assigns, His special licence, full power, sole privilege and
authority, that I, the said Robert Brettell Bate, my exors, adñiors, and
assigns, and every of them by myself and themselves, or by my and their
deputy or deputies, servants, or agents, or such others as I, the said Robert.
Brettell Bate, my exors; admiors, or assigns, should at any time agree with,
and no others, from time to time and at all times thereafter during the term:
of fourteen years therein expressed; should and lawfully might make, use,
exercise, and vend, within England; and Wales, and the Town of Berwick-
upon-Tweed, 'my. Invention of "CERTAIN IMPROVEMENTS UPON HYDROMETERS AND
SACHAROMETERS in which said Letters Patent there is contained a proviso..
obliging me, the said Robert Brettell Bate, by an instrument in writing under
my hand and seal, particularly to describe and ascertain the nature of my said.
Invention, and in what manner the same is to be perforined, and to cause
same to be inrolled in His Majesty's High Court of Chancery, within two calen
dar months next and immediately after the date of the said recited Letters Patent,
as.in and by the same, reference being thereto had, will more fully appear..
the
NOW KNOW YE, that in compliance with the said proviso, I, the said
Robert Brettell Bate, do hereby describe and, ascertain the nature of my said

page_text: Invention, and in what manner the same is to be performed, by the Plan or
Drawing in the margin of these Presents, and the description thereof herein-
after mentioned; but previously to giving such description I shall briefly
notice the construction of the hydrometers and saccharometers as usually made,
by doing which my Invention will be rendered the more intelligible.
It is well known that hydrometers and saccharometers may be correctly
made with stems of a length sufficient to include all the necessary variations
in the specific gravity of spirits, worts, or other liquids. But by so making
the instruments they would neither be so portable or convenient in use as those
constructed with shorter stems having a series of weights which sink the
instrument in liquids of increased specific gravity, and which weights being
multiples of the divisions on the stem do (while these divisions consist of
equal parts referring to a table or sliding rule for the strength or specific
gravity) correctly answer all the purposes of a long one; but where the divisions
upon the stem (without such reference) are to express or indicate the specific
gravities of liquids, they require to be of unequal length throughout, and this
circumstance has hitherto been found irreconcileable with accuracy in such an
arrangement. It is indeed attempted to gain a true indication in this manner
by giving the same stem three or more faces, each of which contains a
different set of divisions; but this method still requires a long stem when the
faces are few in number and involves confusion in reading off the different sets:
of divisions where the faces are many, and is therefore in both cases objec->
tionable.
.
:
Now, my Invention consists in constructing a set of poises with certain.
properties (which will be explained hereafter), by the combination of which
with the instrument a true indication of the specific gravity of any liquid will.
be given by the divisions of the stem and the number of the poise employed:
The following observations and also the directions (which for the sake of
-clearness I shall confine to one instrument, of which I have given a Drawing,
viz, the saccharometer are quite adequate to the construction of hydrometers:
or of any other such instruments, the principles being the same, in all, and the
construction only varying according to the specific gravities of the liquids in
which. they are to be immersed.
:
i
It is convenient then, first, to consider and fix upon the utmost range
through which the instrument is required to act, for instance, if in:
spirits from 8 specific gravity in water=1, or in worts from 1 to 1-13,
or 1.14 specifi gravity; and it must next be considered. where the range shall
terminate, so as to be capable of easy division into equal or équidifferent parts.
the first and last of which must constitute the top and bottom divisions of the

page_text: scale of the stem (A, B, Fig. 1), and for any proposed length or distance
between these the number of such ranges must be greater or less accordingly
as greater or less accuracy is required;-thus if the instrument be for water or
for specific gravities greater than that of water, but not exceeding the usual
specific gravities of worts, I adopt 1 to 1-15 for the total range, first, because
it will include all the usual specific gravities of worts, and secondly, because its
decimal may itself be divided by 3 or 5 without any remainder, the former giving
me 5 ranges or repetitions of the scale, and the latter 3. In cases where accuracy
is required, the smallest divisor should be adopted for the decimal 15 which
gives 5 repetitions of the scale, cach ranging through 03 of specific gravity.
and I divide this scale into three principal divisions, each expressing 01 of
specific gravity, and subdivide each of these into 10; these subdivisions there-
fore each express an unit in the third decimal place of figures, or Tooth part
of specific gravity, as 001, 002, &c., being the excess of specific gravity over
I then find it convenient to number:
that of water in To'th parts thereof.
the [first weight or poise upon the instrument 1.000 (a Fig. 1. with which,
weight the instrument is to give the specific gravity of water when it floats at
:0 upon the stem at a given temperature), because if it float at any division
upon the stem below 0, as 001, 002, &c., such division being added to the
number on the weight. or poise will give 1-001, 1.002, &c.; the correct
expression of such specific gravity; or the integer may be altogether omitted,
and the decimal giving the excess of specific gravity over that of water (which
is sometimes called the strength) only be expressed.
Having prepared an instrument, and if for water and denser liquids taken
care that it be of such a figure as is calculated to move with the least possible
resistance in such liquids, and also a set of hollow weights or poises of a similar,
figure, with the poise (a) at the bottom of the instrument, but of different sizes,
larger than (a) as (b, c, d, e, Fig. 4) cach being only a little heavier than the
preceding, (and capable of being fixed upon the lower stem of the instrument,
in like manner with the first poise (a, Fig. I.) by a screw or otherwise,) and
having also prepared a sample of liquid of the specific gravity of the extreme
points of each range, viz., 1, which is water 1·03, 1.06, 109, 112, and
1.15 (supposing 5. ranges to be adopted each at 60°, or any other temperature
which may be fixed upon the instrument (with the lightest. poise (a) screwed.
on and with a mark made near the top of the stem at a convenient place, for
the first point or zero) must be immersed in the first liquid or water in this,
so as to float with the
case, and if found too heavy must be made lighter,
mark rather above the surface of the liquid; then see what weight is. necessary
be put upon the top of the stem to sink, this mark. precisely to the level of
Lo

page_text: the surface, as seen from below, and increase the total weight of the instrument
by making such addition to the weight within the lower stem; then immerse
the instrument in liquid of the next specific gravity, viz., 1.03 in this case;
and observe that on several repetitions it settles at the same point near the
bottom, which mark for the lowest division of the stem; the 'stemi 'being then
divided and engraved, repeat this experiment, and finally regulate the instru
ment, by adding to the weight within the lower-stem, as before.
I then put on the poise or weight (b, Fig. 4), intended for the second-range,
and again immerse the instrument in the liquid of 1-03 'specific gravity; and
if the top division sink below the level of the surface; the weight of the poise
inust be reduced until it float the instrument with that division in or above the
level; and if above note how much weight upon the top will sink it precisely
to the level-as before, and insert this additional weight within the poise; then
immerse the instrument in liquid of 1.06 specific gravity and observe that the
bottom division also rests in the same level; for if it sink below the level, the
Bulk of the poise will be too small (when it should be exchanged for one of
greater bulk and the former experiment repeated); but if the bottom division
do not sink to the level, the bulk of the poise will be too great, and such
weight, as is found necessary to sink the division precisely to the level as before,
will give the excess of bulk in its weight of liquid displaced, viz. 1.06 specific
gravity but by diminishing the bulk accordingly and making up -its total
weight, it will be found that when the instrument is again immersed in
1.03 specific gravity, it will sink lower than before, and will require 'to be.
reduced in weight according to its diminished bulk, which reduction of weight
would again disturb its adjustment to the specific gravity of 1·06. The rule
therefore for this correction is to multiply the weight at top (required to over-
come the excess of bulk) by the specific gravity of the metal, of which the
poise is composed; and to divide the product by the difference in specific
gravity of the two liquids employed, (viz. 1.03 and 106 in this case, or :03)
the quotient will be the true-weight, which taken off the outside of the poise
will correct its bulk; and again immersing the instrument with the corrected:
poise in its lightest density or 1.03, see what weight is thien necessary to
sink it to the top division, as before and add so much to the weight within
the poise for its final adjustment.
"In the manner may all the other poises be adjusted, taking care that the-
several liquids are precisely of the specific gravities described at the given
temperature, viz: 103, 1:06, 1:09, 1.12, and 1.15 in this case.
.
It is also necessary to observe that the divisions of the stem are not to be:
Jaid off in equal parts from the top and bottoni points, but the place of evry:

page_text: 5th or 10th division corresponding to every 005 or 01 of specific gravity
should be carefully ascertained by experiment in liquid of such specific gravity
and the intermediate divisions proportioned accordingly; and' this being once
done correctly serves as a scale of proportion for every succeeding stem
belonging to instruments of the same construction, if the stems are made
parallel throughout, because their divisions' will then bear the sainė proportion
to the total length of the scale; whatever may be its bulk...
:
Fig. 3 represents a section of one of the poises. separated from the lower
stem of the instrument, (f) shows the adjusting weight screwed into the poise
which may be removed and made either heavier or lighter, as occasion may
require; the lower. stem (g.). is likewise made hollow and tapped so as to have
a similar adjusting weight applied. The bulb (h). and stem. (i) are made
hollow in the usual manner and may be of any shape most approved for
saccharometers. I prefer that given in the Drawing as being more mobile than
the spherical form generally adopted for hydrometers.
It will now be seen that the peculiar construction of my poises enables me to
make them act not only as that essential part of the instrument which keeps it
in equilibrio, which part has been usually fixed and permanent, but that I am
enabled to make them answer a further purpose beyond this which is twofold,
because, first, each succeeding poise contains the increase of weight necessary
to sink the instrument in liquid of increased specific gravity, which weight has
been usually a separate addition to the instrument; and, secondly, the same
poise likewise so augments the bulk of the instrument as to make it duly
proportionate to the same scale of the stem for the peculiar range of such
poise. It will further appear evident that when one poise is removed and
another substituted, the complete effect of a new instrument adapted to the
range required is obtained by this simple change.
And, lastly, in order to identify and distinguish my Invention (and thereby
prevent as far as I am able any infringement upon this Patent,) I hereby declare
that it consists solely in the peculiar construction and combination of my
weights or poises by means of which peculiar construction I am enabled to
alter their bulk and weight at pleasure and consequently so as to accommodate
or adjust each poise to the permanent part of my instrument, that when either
is combined with it in the way I have described a true indication will be given
of the specific gravity of any corresponding liquid in which the instrument
shall be immersed by the division of the stem at which it floats and the number
of the poise employed.

page_text: AND BE. IT REMEMBERED, that on the Twentieth day of May, in
the year of our Lord 1822, the aforesaid Robert Brettell Bate 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 written. And also the Specification aforesaid was stamped according
to the tenor of the Statute made for that purpose..
.