Improvements in Hygrometers.
Year: 1899

page_text: Date of Application, 30th Dec., 1899
Complete Specification Left, 29th Sept., 1900-Accepted, 10th Nov., 1900
NOYRIONAL DELICATION.
Improvements in Hygrometers.
We, DANIEL HALL and JAMES HENRY KAY, both of Stockport Road, Ashton-
under-Lyne, in the County of Lancaster, Sheet Metal Workers, do hereby
declare the nature of this invention to be as follows:-
The improvements which form the subject of this invention relate to hygro-
meters that are employed for ascertaining the percentage of humidity in the
atmosphere and weight of aqueous vapour. The object of this invention is to
enable said hygrometers which have hitherto only indicated the relative humidity
to indicate also the absolute humidity in the atmosphere and thereby dispense
with the necessity of making calculations in order to ascertain the percentage
of absolute humidity therein. For the purpose of this invention we introduce
by the side of and parallel with each column in the table of figures on the barrel
in the hygrometer which indicates the relative humidity, a second column of
figures which we employ for ascertaining the absolute humidity. The values
of these last named figures are obtained by experiment; the figures in the
relative and absolute columns may be distinguished by distinctive colours as
red and black. In order to ascertain the absolute humidity the difference is
noted in the readings of the dry and wet thermometers that are placed respectively
in the ordinary manner within each side of the case of the hygrometer and which
for the purpose of illustration may be assumed to be 10; reference is made
to the relative and absolute columns of figures that are headed by the number 10,
and the number in the absolute column that is lineable with the degree of
Fahrenheit scale will declare the absolute atmospheric condition: The herein-
before described table is such as would be of considerable assistance in the
textile trade for the purpose of ascertaining the particular humidity of the atmo-
sphere that would be most suitable during the process of spinning certain yarns
or manufacturing certain fabrics. We make the portion of the case containing
the barrel with a false bottom to enable the barrel to be actuated from the
bottom instead of the top. We fit a hinged plate on each side of the case for
placing useful information thereon; said hinged plates may be folded against
the ends of the case and when required may be brought forward so as to be on
the same plane as the front of the case.
Dat T: 001, der of December 1899

page_text: 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-
The improvements which form the subject of this invention relate to hygro-
meters that are employed for ascertaining the percentage of humidity in the
atmosphere and weight of aqueous vapour. The object of this invention is to
enable said hygrometers which have hitherto only indicated the relative humidity,
to indicate also the absolute humidity in the atmosphere, and thereby dispense
with the necessity of making calculations in order to ascertain the percentage
of absolute numidity therein.
In the accompanying drawing Fig. 1 is a front elevation in perspective of our
improved hygrometer and Fig. 2 is a transverse section of the same, on line A-B.
For the purpose of this invention we introduce by the side of and parallel
with each column 6 which in the table of figures on the barrel in the hygro-
meter indicates the relative humidity, a second column of figures which we
employ for ascertaining the absolute humidity; the values of these last named
figures are obtained by experiment; the figures in the relative and absolute
columns may be distinguished by distinctive colours such as red and black, the
column denoting the percentage of relative humidity being indicated by a
distinctive letter as H, and the column denoting the grains of water in a cubic
foot of air or the absolute humidity, by a distinctive letter as G: Numerals as
1, 2, 3, and upwards representing differences in the readings of the dry and wet
bulb thermometers e and y are placed respectively at the top of each pair of
columns and c.
In order to ascertain the absolute humidity, a reading is taken of the dry
thermometer e and the wet thermometer g; the reading of the wet bulb ther-
mometer is substracted from the reading of the dry thermometer. If for example
the reading of the dry bulb is 85 and the wet bulb 75, the difference would be
10. The cylinder or barrel d is revolved by the knob at the bottom of the
instrument until the columns with the Figure 10 at the top are brought opposite
and may be seen through the slot k, when, opposite the figure 85 on the
Fahrenheit scale will be 58 in the column H, being the percentage of relative
humidity, and 7.4 in the column G, being the grains of vapour (water) in a
cubic foot of air, i.e. absolute humidity.
By these means the particular humidity of the atmosphere that would be
most suitable during the process of spinning certain yarns or manufacturing
certain fabrics can be readily ascertained without calculation. We make the
portion of the case containing the barrel d with a false bottom to enable the
said barrel to be more conveniently actuated, the knob j for turning the barrel
being placed at the bottom instead of at the top. We fit either a hinged plate
on each side of the case, or a plate as q to slide within the back of said case,
upon which useful information or memoranda may be placed.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that what
we claim is:-
1. In a hygrometer the combination with the table of figures indicating the
relative humidity in the atmosphere, of a table of figures for indicating at sight
the absolute humidity of the atmosphere at the same temperature, in the manner
as herein before described and as shown.
2. In a hygrometer the indication at sight of the weight of water per cubic
foot of air, and the per centage of humidity at the same temperature, in the
manner substantially as and for the purpose hereinbefore described.
3. In a hygrometer having wet and dry thermometers the combination with
the barrel on which tables of figures are recorded indicating the relative
humidity of the atmosphere, of tables of figures indicating the absolute humidity
of the atmosphere, a false bottom in the centre of the case for supporting the

page_text: barrel, a knob or device for rotating the barrel from the bottom of the case,
and hinged or sliding plate or plates at the side or sides of the case all sub-
stantially as and for the purposes hereinbefore described.
Dated this 28th day of September 1900.
GEO. DAVIES & SON,
Agents for the Applicants, 4, St. Ann's Square, Manchester.