Apparatus for Preparing Solutions of Definite Strengths.
Year: 1895

page_text: Date of Application, 25th Nov., 1895
Complete Specification Left, 25th Aug., 1896-Accepted, 17th Oct., 1896
PROVISIONAL SPECIFICATION.
Apparatus for Preparing Solutions of Definite Strengths.
ROBERT PROSSER ROBERTS 13 Church Street, Camberwell London S.E.
Pharmaceutical Chemist do hereby declare the nature of this invention to be as
follows:-
A measure which may take the form of a bottle jug or other vessel so graduated
as to afford a means of making solutions of chemical salts of definite strengths
without the aid of a balance.
The graduations are made nearer or further apart to suit the various chemicals
for which the measure is to be used.
It is used as follows:-
Place the bottle on a level surface and add water up to the first mark; then,
drop in the chemical salt until the mixture rises to the mark which indicates the
strength per pint required, shake, allow the air bubbles to escape, then add more of
the salt until the mixture rises to its former level.
Dated this 25th day of November 1895.
COMPLETE SPECIFICATION.
Apparatus for Preparing Solutions of Definite Strengths.
I, ROBERT PROSSER ROBERTS, of 13 Church Street, Camberwell, in the
County of London, Pharmaceutical Chemist, do hereby declare the nature of this
invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement :—
Hitherto when preparing solutions of definite strengths for use in photography
and for chemical and such like purposes it has been necessary to measure the
requisite quantity of water or other liquid and to weigh up the amount of the
soluble salt or other substance to be added thereto to make the solution of
the required strength. For example, in preparing what is known as the "hypo-
solution" for use for photographic purposes a quantity, say three pints, of water is
placed in a bottle and the thio-sulphite of soda crystals are weighed in a balance ;
if the strength of the solution is to be one ounce weight to the pint, three ounces
of the salt are weighed up and added to the three pints of water; if two ounces
to the pint, six ounces of the salt are added and so on.
The object of my invention is to produce apparatus whereby solutions of definite
strengths can be prepared without the necessity of weighing the soluble salts or
other substances.
My invention consists of a vessel capable of holding the liquid and marked in
any suitable manner so as to indicate measured quantities of the liquid. Above
each of these indications or liquid measures is a graduated scale determining,
according to the increased bulk of the liquid caused by the bulk of the added salt
or other substance, the height to which the liquid should rise to make the solution
of the required strength. Different salts or other substances will, if of different

page_text: specific gravities, give different results for any given liquid so that a vessel
graduated according to my invention for preparing solutions of a definite strength
of any given salt can only be used for that salt and for other substances having
the same specific gravity.
One method of graduating the vessel would be by calculations based on the
specific gravity of the substance to be dissolved therein, but as few such substances
are sold chemically pure, I prefer to graduate the vessel by taking the ascertained
mean height of a number of experiments made by adding the definite weight of the
substance to the proper measure of the liquid.
In the accompanying drawing I have shown a vessel, in the form of a bottle for
making a "hypo-solution," graduated according to this invention. The line a 19
the liquid measure and indicates the height to which the water should be filled in the
bottle, and the lines to i represent the various heights to which the mixture should
rise, by the increased bulk of the liquid caused by the bulk of the added salt or
other substance, to give the definite strength required per pint. For a solution of
one ounce to the pint, the water should be filled to a and the salt added till the
liquid rises to b; for a solution of two ounces to the pint the salt should be added
till the level rises to c and so on. a therefore is the zero of the scale indicating
the level to which the water should rise when put in the bottle, and b to i are the
levels, as required, to which the liquid is raised by the increased bulk thereof
caused by adding the salt. The zero a can be any measure of the liquid, for
example 1 pint, two pints, two and a half piuts and so on, and the scale division
lines b to i correspond to the measure and give the required strength of solution
per pint. More than one of such graduated scales may be shown on one vessel if
desired. For example, a scale for one pint measure, a scale for a two pint measure
and so on according to the capacity of the vessel.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is;-
A vessel for preparing solutions of definite strengths, having marked thereon a
scale or scales graduated according to the increased bulk of the liquid caused by
the bulk of the added solid, the zero of the scale being a measure of the liquid
and the graduations thereof indicating the levels to which the liquid should rise by
the increased bulk thereof caused by the addition of the weight of the substance,
for which the vessel is adapted, required, relatively to the liquid measure, to make
the solution of definite strength, substantially as described.
Dated this 25th day of August 1896.
F. W. GOLBY,
36 Chancery Lane, London, W.C., Patent Agent for the Applicant.