A NOVEL APPARATUS TO BE USED in ASCERTAINING THE VOLUME WHICH GAS MEASURED UNDER ANY ORDINARY CONDITIONS WOULD OCCUPY UNDER STANDARD CONDITIONS."
Year: 1882

page_text: LETTERS PATENT to Augustus George Vernon Harcourt, of Oxford, in the
County of Oxford, for an invention of "A NOVEL APPARATUS TO BE USED in
ASCERTAINING THE VOLUME WHICH GAS MEASURED UNDER ANY ORDINARY
CONDITIONS WOULD OCCUPY UNDER STANDARD CONDITIONS."
PROVISIONAL SPECIFICATION left by the said Angustus George Vernon
Harcourt at the Office of the Commissioners of Patents on the 21st February
1882.
AUGUSTUS GEORGE VERNON HARCOURT of Oxford in the County of Oxford,
"A NOVEL APPARATUS TO BE USED IN ASCERTAINING THE VOLUME WHICH GAS
MEASURED UNDER ANY ORDINARY CONDITIONS WOULD OCCUPY UNDER STANDARD
CONDITIONS."
In measuring gas for scientific purposes the volume is taken under the ordinary
conditions of the temperature and pressure of the atmosphere and the measurement
is then corrected under certain standard conditions.
This correction has been hitherto effected by taking readings from a barometer
and thermometer and, with the assistance of a previously prepared table, making
various more or less difficult and lengthy calculations.
Now the object of this invention is to provide a simple instrument to take the
place of the barometer and thermometer and the prepared table, and by the use
of which the correction of the measurement may be obtained with facility.
The instrument consists of two glass tubes standing side by side, one of which is
open above and may conveniently be contracted and bent over to prevent the
admission of dust; the other terminates in a bulb whose capacity is about four
and a half times that of the tube. These tubes are connected below with a small
flexible reservoir containing mercury which can be contracted by pressure, causing
the mercury to mount in the tubes. This reservoir may conveniently be contained
DC31

page_text: in a small box at the back of which is an upright, supporting the tubes. A screw
passing through the top of the box will serve to apply a regulated pressure to the
reservoir.
The stem of the bulb-tube is graduated and figured, so as to mark the capacity
of the bulb and stem down to each line of graduation.
A small quantity of moist air, or other permanent gas, is passed into the bulb
and stem which are then filled with mercury.
To use the instrument the pressure on the reservoir is increased or relaxed until
the level of the mercury is the same in both tubes. A reading is then made on the
graduated stem and represents the volume occupied at the actual atmospheric
pressure and temperature by a mass of air which under standard conditions occupies
a volume 1000. Any volume of gas measured in a holder or registered by a meter
under the same conditions may be corrected to its true volume under standard
conditions by dividing by the figures read upon the instrument. As a gas under
ordinary conditions is more expanded than under the standard conditions commonly
adopted in chemical and physical laboratories it is convenient in an instrument to
be used for correction to this standard to make the bulb relatively larger.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Augustus George Vernon Harcourt in the Great Seal Patent Office
on the 21st August 1882.
AUGUSTUS GEORGE VERNON-HARCOURT of Oxford in the County of Oxford.
"A NOVEL APPARATUS TO BE USED IN ASCERTAINING THE VOLUME WHICH GAS
MEASURED UNDER ANY ORDINARY CONDITIONS WOULD OCCUPY UNDER STANDARD
CONDITIONS."
In measuring gas the volume is commonly taken at the actual temperature and
pressure of the surrounding air, and the measurement is then corrected to obtain
the volume which the gas would have under certain standard conditions.
This correction has hitherto effected by taking readings from a barometer and
thermometer, by referring (in the ordinary case of a gas measured over water) to
a table giving the tension of aqueous vapour at different temperatures and by a
calculation based upon these readings and the laws of gaseous volume-The use of
a table simplifies the operation, but even thus a reading of a barometer and of a
thermometer and a reference to a table are needed to obtain a figure which by
simple multiplication or division will convert the observed into the corrected
volume.
Now the object of this Invention is to furnish such a figure by the reading of
the single instrument hereinafter described which for this purpose takes the place
of a barometer thermometer, and table.-By its use the correction of the measure-
ment of a gas may be effected with accuracy and facility, the only arithmetical
operation required being a sum in long division.
In the accompanying drawing Fig: 1 shows in front elevation the instrument I
have devised for simplifying the operation of ascertaining the volume which gas
measured under any ordinary conditions would occupy under standard conditions.
Fig: 2 is a sectional plan view of the same, taken in the line 1. 2 of Fig: 1., and
Fig 3 is a vertical section taken in the line 3. 4. of Fig: 2. A is the base of the
instrument, consisting of a box with a removable cover, and B is a backboard
standing up from the hollow base A.-To the face of this backboard two tubes of
glass of equal calibre C. D. are attached the same being set vertically side by side.―
The tube C is open at top and may conveniently be contracted and bent over, as
shown in Fig: 1 to prevent the admission of dust.-The tube D terminates at top
in a bulb whose capacity is about four and a half times that of the tube.-These
tubes extend into the hollow base or box A and are connected by means of flexible
tubes C'. D¹ with a reservoir E containing mercury, and situate in the hollow base
or box A-This reservoir has a loose leathern top and is intended to be contracted
by the application of pressure in order that a column of mercury may be driven
into the vertical tubes.
F is a milled-headed screw passing through a tapped hole in the cover of the
box and furnished at its inner end with a loose button which overlies the flexible
portion of the mercury reservoir.-By turning this screw the button may be
caused to press upon the flexible cover of the reservoir thereby contracting its
capacity.
The stem of the tube D is graduated and the backboard figured to correspond
therewith so as to mark the capacity of the bulb and stem down to each line of
graduation. In order that the instrument may bear accidental inversion during
carriage without injury the flexible tubes C¹ D³ are each provided with a means
for closing the passage through them for the flow of the mercury.-Each tube is
embraced by a U shaped loop of wire c the ends of which are made fast to a
plate c-This plate is furnished with a threaded hole to receive a pressure
screw carrying on its inner end a pressure plate -By turning the screw c
the plate attached to it may be caused to compress the flexible tube between itself
and the loop of wire and thus prevent the loss of any mercury except the small
5 portion remaining in the open tube.

page_text: A convenient size for the instrument is to make the capacity of the bulb a
little less than 31 cubic centimetres (if the standard temperature adopted is
60° Fahrenheit) and that of the graduated portion of the stem 0·7 cubic centimetres.
The bulb and stem are to be charged with a volume of moist air or other permanent
gas occupying under standard conditions 3.3 cubic centimetres, the stem below this
level being filled with mercury. This volume is marked on the instrument as
1000 the unit volume adopted being 500 cubic centimetre. The top line of the
graduation may mark a capacity of 31 cubic centimetres and be figured accordingly
930 this being the smallest volume to which the inclosed air is likely to be
reduced by low temperature and high atmospheric pressure. The maximum
volume to which the enclosed air is likely to be expanded may be taken as
3.8 cubic centimetres and the lowest line of graduation will be marked
accordingly 1140.
To use the instrument the pressure on the reservoir is increased or relaxed until
the level of the mercury is the same in both tubes. A reading is then made on
the graduated stem and represents the volumo occupied at the actual atmospheric
pressure and temperature by a mass of air which under standard conditions
occupies a volume 1000. Any volume of gas measured in a holder or registered
by a meter under the same conditions may be corrected to its true volume under
standard conditions by multiplying by 1000 and dividing by the figures read upon
the instrument; thus, if the rate at which gas is passing through an experimental
meter is 4-7 cubic feet per hour and the reading of the aerorthometer (as it is
proposed to name the new instrument as serving depos óp-Gòûv rò µerpòv) is 980 the
corrected rate is or 4.8 cubic feet per hour.-If the uncorrected illuminating
power of a sample of gas is 15.8 candles the aërorthometer reading being 1050, the
corrected illuminating power (which varies inversely with the volume consumed)
is 15.8 x 1050 or 16.6 candles.
4700
980
Since the Standard conditions commonly adopted in chemical and physical
laboratories are a temperature of 0° centigrade, and a pressure of 760 millimetres
and a gas under ordinary conditions is more expanded than under these conditions,
it is convenient in an instrument to be used for correction to this standard to
make the capacity of the bulb nearly 34 cubic centimetres so that the 1000
graduation may come near the top of the stem. If an instrument is required for
the correction of the measurement of a dry gas the air and mercury with which
it is charged must be carefully dried.
Having now set forth the nature of my Invention of "A novel apparatus to be
used in ascertaining the volume which gas measured under any ordinary conditions
would occupy under standard conditions," and explained the manner of carrying
the same into effect, I wish it to be understood that under the above in part recited
Letters Patent I claim.
The arrangement of apparatus above described consisting of an open tube and a
closed graduated tube of known capacity and holding a known quantity of air in
connection with a reservoir to supply to such tubes mercury or equivalent fluid
substance at varying pressures for facilitating the correction of measured volumes
of gas to standard conditions.
In witness whereof I the said Augustus George Vernon Harcourt have
hereunto set my hand and seal the nineteenth day of August in the year of
our Lord One thousand eight hundred and eighty two.