Improvements in Hydrometers, Thermometers, and other similar Instruments.
Year: 1885

page_text: Improvements in Hydrometers, Thermometers, and other
similar Instruments.
I WILLIAM CHADWICK of Mount Vernon Turncroft Lane Stockport in the
County of Chester Salesman do hereby declare the nature of my invention for
"IMPROVEMENTS IN HYDROMETERS, THERMOMETERS, AND OTHER SIMILAR INSTRU-
MENTS and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement :--
"
The object of this invention is to facilitate the reading of the indications upon
the scale of hydrometers and other similar instruments and to enable the exact
indication to be seen at a glance.
On the scales of hydrometers, spirit testers, thermometers, barometers and other
similar instruments as hitherto made, the graduations or divisions are marked on
one single column, and the figures showing their values are only marked upon
every tenth or fifth graduation or division, so that whenever the indication to be
read (at the level of the liquid to be tested in the case of a hydrometer or spirit
tester, or at the level of the mercury or spirit in the case of a thermometer)
chanced to be between any two figures, it has hitherto been necessary to make a
subtraction from, or an addition to, the most adjacent figure, before the exact
indication could be taken.
By means of my invention the necessity for this calculation is entirely dispensed
with, as the scale is so arranged and marked that each graduation or division
bears its own corresponding figure and the indication can thus be read at a single
glance.
The nature of my invention whereby I propose to effect this object will be
readily understood on reference to the annexed drawing and the following
explanation thereof.
The drawing represents for the sake of illustration a hydrometer or spirit tester,
with my invention shown as applied thereto.
The hydrometer is made of glass, in the ordinary form, a, a being the mercury
bulb, b, b the air chamber, and c, c the scale tube, d, d is the thermometer for
ascertaining the temperature of the spirit so as to enable the exact value of the
indication to be ascertained, and I would here remark that I propose sometimes
to make the instrument without this thermometer so that an ordinary or other
031

page_text: detached thermometer may be employed for this purpose, but I prefer to make the
instrument in the combined form shown on the drawing.
The graduated scale e, e inside the tube c, c is shown on the drawing as marked
only up to 20 degrees above proof (P) and 40 degrees below, but I wish it to be
understood that I reserve to myself the right to make higher or lower graduations
if desired.
It will be evident that as these graduated lines are so near to each other when
marked in the ordinary way it would be impossible to provide each line with its
corresponding value in legible figures and hence the custom has always been, to
mark the figure on every fifth or tenth division only, but on referring to the
annexed drawing it will be seen that this problem has been solved by my invention
in the following manner, so that each line has its appropriate figure visibly marked
and the position of the line of flotation due to the greater or lesser immersion of
the instrument, due to the strength or specific gravity of the liquid being tested
can be read at a glance.
For this purpose I divide the scale perpendicularly into two columns by a
central line and I make each alternate line or graduation on opposite sides of the
central dividing line, that is to say, the odd numbers 1. 3. 5 &c on one side, and
the even numbers 2. 4. 6 &c on the other side, and by these means the divisions
are only half as close together as they would otherwise be and thus I obtain room
to place the corresponding numeral above or adjacent to each particular line.
The graduations on the thermometer scale may also be marked in the same
manner if preferred or with the odd numbers on one side of the tube, and the.even
numbers on the other.
I would here observe that in cases where the graduations are too near together
to admit of this being done by means of two columns only I propose to divide the
scale into three vertical columns and to mark the first 1. 4.7 &c the second
2. 5. 8 &c, and the third 3. 6. 9 and so on, and in some cases even more than three
columns might be required, but for ordinary purposes two columns will be found
sufficient.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I wish it to be under-
stood that I do not claim as new the form or construction of the hydrometer
shown on the annexed drawing nor do I claim the combination therewith of a
thermometer as shown, but what I claim is
The combination with a hydrometer, spirit test, thermometer barometer or other
similar instrument, of a scale divided perpendicularly by one or more lines so that
the horizontal graduating lines upon each column can be sufficiently far apart to
admit of the corresponding numeral being placed above or adjacent to each line
substantially in the manner and for the purposes hereinbefore set forth and
illustrated by the drawings annexed.
Dated this 20th day of October 1885
GEORGE DAVIES,
Agent for the Applicant,
4, St. Ann's Square, Manchester.