Improvements in Apparatus for Measuring or Indicating Temperature and Pressure.
Year: 1889

page_text: Date of Application, 6th Aug., 1889
Complete Specification Left. 5th June, 1890 - Accepted, 6th Aug., 1890
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Measuring or Indicating Temperature
and Pressure.
I, WILLIAM LLOYD WISE, of No. 46, Lincoln's Inn Fields, in the County of
Middlesex, Consulting Engineer and Patent Agent, do hereby declare the nature of
this invention (a communication to me from abroad by Peter Roe Bedlington,
of Bilbao, in the Kingdom of Spain, temporarily residing at Fonda Europa, Las
Palmas, Grand Canary, Mining and Mechanical Engineer) to be as follows:―
For
This invention relates to apparatus designed to measure and indicate simultaneously,
temperature and pressure, including also the degree of vacuum within a vessel.
this purpose there are used two boxes or vessels of suitable material such as metal
exactly similar in every respect, placed back to back, and separated from each other
by a rigid metallic plate or diaphragm which forms a bottom or wall, common to
both chambers. In one arrangement each vessel is provided with a single flexible
corrugated top or cover free to yield to pressure, the sole difference between the two
vessels being that one of the corrugated tops or covers is provided with means for
fixing it rigidly at a certain stage during the adjustment of the apparatus. For
convenience of reference this last mentionedvessel is hereinafter calledthe thermometer-
chamber whilst the other vessel whose corrugated cover is always free to act, is
called the barometer-chamber. For the sake of extra sensitiveness, each chamber
may, according to another arrangement, be provided with a corrugated top and
bottom, like the vacuum chamber of an aneroid barometer, the rigid metallic plate
being still interposed between the two chambers, but no longer forming part of them,
and leaving their corrugated surfaces free to act. The casing of each chamber is
formed with a hole by which such chamber is placed in air tight communication
with a corresponding glass tube of rectangular, circular, or other convenient section,
having a bore of suitable size for a mercury column. These glass tubes may be
vertical, inclined, or spirally coiled around the chambers which are enclosed in a
barrel or cylindrical case that may be of metal and the length of which is extended
sufficiently to hold the number of coils required. The cubical capacity of the two
chambers and their corresponding tubes is made exactly similar, and accurately
ascertained, and the air is entirely exhausted from within the apparatus, which is then
filled with mercury or with colored spirits of wine, or other suitable liquid (hereinafter
referred to generally as mercury), to such an extent, that, at the lowest temperature
and pressure which the apparatus is intended to measure or indicate the mercury
shall appear at convenient equal heights in the two tubes.
At this stage of the proceedings, when the outside pressure has produced concavity
of the corrugated covers, the cover (or covers) of the thermometer-chamber is (or
are) fixed by suitable means so that it (or they) shall henceforth be rigid and unable
to yield to pressure. For this purpose an adjusting screw may be used to act on the
cover (or one of the covers) of the thermometer-chamber. The above operation
having been performed, as stated. at the lowest temperature and pressure required to
be measured, if, now, the pressure be maintained constant, whilst the temperature is
allowed to rise, it will be evident that the column of mercury will rise to equal
heights in the two tubes, and will always similarly indicate the temperature; that is
to say, the two chambers will act like two similar thermometers, and the columns
of mercury will come to rest at equal heights in the two tubes connected therewith.
If now the pressure increases whilst the temperature remains constant, it will be
evident that this change will be indicated only by the barometer chamber whose
cover (or covers) is (or are) still free to move and yield. the column of mercury
corresponding to this chamber rising in its tube to a height proportional to the

page_text: increase of pressure whilst the mercury in the other chamber and tube will remain
unaffected by the change of pressure. Thus it will be obvious that the top of the
column of mercury in the tube of the thermometer chamber may be taken as the
base or datum line from which to measure the distance to the top of the movable or
barometric column of mercury. This distance will be a measure of the difference of
pressure, and may be read off by a suitable scale or scales. It is further evident that
this apparatus will always automatically correct itself for temperature, and will be a
correct pressure indicator; and any change of pressure, however slight, may be
measured or indicated with exactness by properly proportioning the diameters of the
chambers and tubes respectively; whilst the apparatus will be entirely free from the
errors which must arise from the use of complicated and delicate mechanism such as
is ordinarily employed to indicate the slight movements in the vacuum chamber of
an aneroid barometer, whose register becomes less reliable in proportion as such slight
motion is more exaggerated or magnified. On reduction of temperature or pressure
the mercury will always find it way back to the normal level by reason of the cohesion
of its particles, the return movement being assisted, if necessary, by giving a slight
inclination, spiral or otherwise, to the glass tubes, as herein before mentioned. The
tubes may be paced back to back, and be provided with a graduated scale or scales,
which, in the case of spiral coils, should also be spiral in form, and may be used to
support the tubes.
W. LLOYD WISE,
Per F. J. B.
.
COMPLETE SPECIFICATION.
Improvements in Apparatus for Measuring or Indicating Temperature
and Pressure.
A communication from abroad by PETER ROE BEDLINGTON, of Bilbao, in the Kingdom
of Spain, temporarily residing at Fonda Europa. Las Palmas, Grand Canary,
Mining and Mechanical Engineer.
I, WILLIAM LLOYD WISE, of No. 46 Lincoln's Inn Fields, in the County of Middlesex
Consulting Engineer and Patent Agent, 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:—
This invention relates to apparatus designed to measure and indicate simultaneously
temperature and pressure, including also the degree of vacuum within a vessel.
For this purpose there are used two vessels or chambers of suitable material, such
as metal, exactly similar and equal in every respect. Tu one arrangement these
chambers are placed back to back and separated from each other by a rigid metallic
plate or diaphragm which forms a wall or partition common to both chambers, each
chamber being, in this case, provided with a single flexible corrugated top cover
or outer side (hereinafter called a cover) free to yield to pressure. Or the two
chambers may be entirely separate and be so placed that the corrugated covers shall
face each other, the rigid plates forming the other sides of the chambers being
outermost. The only difference between the two chambers is that one of the corrugated
covers is provided with a "bridge" or support made with legs or limbs and con-
centric rings holding a series of set screws for the purpose of fixing the cover
rigidly at a certain stage during the operation of adjusting the apparatus.
convenience of reference this last mentioned chamber is hereinafter called the
thermometer-chamber, and its cover the thermometer-cover: whilst the other
chamber whose corrugated cover is always free to act is called the "barometer-
chamber and its cover the "barometer-cover."
..
22
For
For the sake of increased sensitiveness, each chamber may according to another
arrangement, be provided with a corrugated top and bottom, like the vacuum
chamber of an aneroid barometer; the two chambers being placed apart and the

page_text: for
rigid metallic plate being dispensed with to make room for one of the "bridges
the thermometer chamber. Or the two chambers may be brought closer together and
their inner halves may be connected so as to constitute the thermometer chamber;
whilst the two outer halves are connected together so as to constitute the barometer
chamber. In this case there are virtually two apparatus with four chambers which
by means of connecting tubes, are made equivalent to one apparatus with two chambers
each provided with two covers. In this arrangement the bridges are replaced by
fixed tie bolts, the two inner covers being thus maintained immovable and in
equilibrium, whilst the two outer covers are free to yield to variations of
pressure.
1 may be here mentioned that each and all of the arrangements hereinafter
described and illustrated in Figs. 7, 8 and 9 are also adapted to high pressure and
vacuum gauges by encasing the chambers in an outer metallic box or casing that may
be filled with water or other liquid (in the case of a steam gauge) to transmit the
pressure to the flexible covers.
The casing of each chamber is furnished with a hole by which such chamber is
placed in air tight communication with a corresponding glass tube of circular or
other convenient section having a bore of suitable size for a mercury column, whilst
a second hole (hereinafter called the "exhaust" hole) with corresponding metallic
tube is used for exhausting the air from the chambers, after which operation the tube
is hermetically closed. The glass tubes may be horizontal, vertical (in certain cases),
curved or inclined, or spirally coiled round the outside casing which encloses the two
chambers and which casing may conveniently be of metal and is of sufficient length
to hold the required number of coils of glass tube. These coils may be wrapped round
a thin barrel or envelope which fits closely over the said casing and serves, in
conjunction with a spiral scale and screws or bolts, to hold the spiral tubes
securely in place.
The cubical capacity of the two chambers and the sectional area of their corre-
sponding tubes being identical and accurately ascertained, the method of adjusting the
apparatus for use as a mountain barometer (to take a particular application) is as
follows:-
::
*.
As soon as the apparatus is ready to be charged with mercury, it is placed within
a vacuum chamber connected with an air pump capable of producing an almost
perfect vacuum; the chambers are also connected by means of the exhaust" tubes
with the air pump so that an almost perfect vacuum is also obtained within the
apparatus and the covers thus kept in a state of equilibrium. The requisite quantities
of mercury or other suitable liquid (ascertained previously by experiment) are now
admitted in equal portions through the "exhaust" tubes into the two chambers, and
the exhaust tubes are then hermetically soldered. The apparatus is next placed
within a special chamber (hereinafter called the adjustment chamber ) which is
furnished with a standard barometer and thermometer and is connected with an air
pump. Within this chamber is a freezing mixture which maintains the temperature
at 0° Cent. of 32° Fahr. The pressure within the adjustment chamber is now
artificially reduced by means of the air pump to the lowest limit of pressure required
(say 24 inches of mercury) and the mercury falls equally in the two tubes to a point
say about two inches above the lower ends of the tubes. The thermometer tube will
now be marked thus (0° Cent. 32° Fahr.) and the barometer thus (24 inches at 32°F.).
The cover of the thermometer chamber is now rigidly fixed by means of the bridge
substantially in the manner hereinafier described, and the temperature then lowered
below freezing point as much as practicable for the purpose of marking and graduating
the thermometer tube; the graduation being subsequently continued proportionallydown
to the lowest limit required, say-20° C. 4° Fahr. These remarks also apply
to the adjustment of the high pressure gauge and vacuum gauge hereinafter
described except that the temperature of adjustment viz. 32° F. will be the lowest
required to be marked, whilst as to pressure the pressure gauge is adjusted at
atmospheric pressure and the vacuum gauge at an almost perfect vacuum.
-
The temperature being again restored to the freezing point the pressure in the

page_text: adjustment chamber is now raised to 30 inches of mercury, and the barometer tube
subsequently graduated to inches of mercury and fractions thereof. In the ther-
mometer tube the mercury will have risen again to the freezing point; whilst in
the barometer tube it will have risen by expansion to the same amount, plus that
due to the increase of pressure from 24 inches to 30 inches of mercury; the
barometer tube is now marked thus (30) inches at 32° F.). These two points viz.,
32° F., and 30 inches may be called the Datum" points, or points of reference,
by means of which the correctness of the apparatus can at any subsequent time be
easily tested; and the distance between the tops of the two columns of mercury under
the above conditions may, for convenience, be called the "Constant" of the
instrument.
**
The pressure in the adjustment chamber can now be increased to the upper limit
required, say 32 inches of mercury, the barometer tube being again marked and
subsequently graduated up to this higher limit. Finally the temperature may be
raised to its upper limit,say45° Cent. 113° Fahr., the thermometer tube duly marked,
and subsequently graduated from the freezing point upwards.
=
Having thus marked the extreme and intermediate points of temperature and
pressure respectively, the instrument is now removed from the adjustment chamber,
the smaller graduations effected, and finally the barometer tube graduated to feet of
altitude; that is to say starting at
< Datum"
or 30 inches the tube is graduated
upwards for depths below sea level; and downwards to 24 inches, for heights above
sea level, these altitudes being exact only for a temperature corresponding to freezing
point at which the instrument was set.
The instrument is read as follows:--For any temperature T° above 32° Fahr.
subtract from the observed height of the barometer column the length of
range T° 32°, and the result will be the corrected barometric reading; whilst for
any temperature to below freezing point add the length of range 32° -1° to the observed
reading to get the corrected reading and corresponding altitude.
The fixing of the cover or covers of the thermometer chamber may be effected as
follows:-
"
Each cover has secured to it screw studs that extend through the "bridge
furnished with loosely fitting nuts temporarily provided with small and light vanes
and are
suitably attached. As soon
as the thermometer cover (or covers) has (or have)
assumed its (or their) concave form due to the lowest pressure (say 24 inches of
mercury), a jet of air is momentarily directed on to the nuts each in turn so as to
send them spinning down the studs until they rest on the " bridge and thus sustain
the cover or covers in such concave state. The air jet may be directed by means of a
small flexible tube passing through the wall of the adjustment chamber and manipu-
lated by hand from outside; the air, of course rushing in to the partial vacuum.
'As soon as the instrument is removed from the adjustment chamber the nuts may he
finally fixed by soldering. The central adjustment screw may be furnished with a
right and left handed screw thread as hereinafter fully described. by means of
which the central portion of the cover may be slightly raised or depressed and
small adjustments thus effected.
As a further means of adjusting the instrument, should it subsequently become
necessary to do so, the following device can be used. On the rim of each of the
two chambers is cast an extension in which a hole is bored and tapped for the
purpose of admitting a well fitting set screw of suitable diameter and of sufficient
length to ensure its being and remaining permanently air tight.
bore effects communication between the chamber and the set screw; and any small
A hole of smaller
motion of the latter will cause a corresponding increase or diminution of the quantity
of mercury inside the chamber, and so increase or diminish the height of the mercury
column or columns and thus effect the required adjustment. Another device for this
purpose consists in the employment for each chamber of exactly similar secondary
chambers of small diameter (preferably with two flexible covers) each in communi-
cation with its respective chamber. Each secondary chamber is provided with a
central adjusting screw with a right and left handed thread which can cause a pull

page_text: or thrust upon the covers and thus cause a corresponding alteration in the amount of
mercury in the columns; so that the instrument can be adjusted to a standard
barometer and thermometer.
The instrument or apparatus above described may be made as sensitive as desired;
and any alteration of pressure or altitude, however slight, may be measured or
indicated with exactness, by properly proportioning the areas of the corrugated
covers and mercury columns respectively and the apparatus will be entirely free
from the errorswhich usually arise from the use of complicated and delicate mechanism
such as is ordinarily employed to indicate the slight movements of the covers of
the vacuum chamber of an aneroid barometer, whose register becomes less reliable
in proportion as such slight motion is exaggerated or magnified. It is further to be
expected that with the superior magnifying power now available, viz., from 500 to 5000
times and upwards (varying nearly as the areas of the covers and the mercury
columns) the motion of the covers may be kept well within the limits of elasticity
of the material, thereby ensuring the reliability of the instrument afier long use.
In the accompanying drawings
Fig. 1 is a vertical section partly in elevation of an apparatus according to this
invention.
Fig. 2 is a plan partly in section.
Fig. 3 is a side elevation.
Fig. 4 is an elevation of the lower part of the apparatus shewing how the lower
ends of the tubes are secured.
Fig. 5 is a plan of a metal supporting bridge, and chamber to which it is
applied.
Fig. 6 is a side elevation of the bridge, the chamber to which it is applied being in
section.
A and B are the thermometer and barometer chambers respectively with their
corrugated flexible covers a, b, and their common wall or diaphragm e 7. are the
exhaust holes for exhausting the air from the chambers after which they are hermeti-
cally closed; CCC are the legs of a supporting "bridge" hereinafter described, for
the cover of the thermometer chamber and which rest on the casing e forming part of
the chambers; is a central set screw with right and left handed threads, one of
which fits in a nut. g soldered to the cover a. D, D are lugs or brackets cast on the
inside of the outer cylindrical casing E and which, with the long screws ..
serve to secure the upper and lower parts of the said casing at the joint ji, i, i, three
lugs or brackets also cast on the inside of the casing E for supporting, by means of
screws, the inside or chamber casing e provided with corresponding projections / (see
Fig. 2) m, n are the connecting tubes between the thermometer and barometer
chambers and their respective spiral glass tubesF,Gwhich havetheir baseshermetically
embedded in "shoes" H, I. (Fig. 4) cast with a "shoe-piece" which receives the
soldered ends of the connecting tubes m, n, the other ends of which having screw
threads and screw into the tube-piece' K. Brackets L, M support the spiral
thermometer tube F. F and the lower "shoe." N N is a spiral scale that fits between
the glass tubes FF1 and G. G which are secured in place by small screws placed
at intervals and one of which is shewn at o passing through the scale N, N and into a
cylindrical wooden envelope that fits the cylindrical casing E as already mentioned.
G2, is the tube bore with mercury column. Pis a handle supported in bearings pp,
fixed on the upper flange p', of the casing E, and capable of being turned down
into the casing as shewn in Fig. 1. Q. Q' are panes of glass equi-distant from the
covers and held in place between brackets or rings g. q. and removable rings r, rl.
RR are columns that may be used for supporting the apparatus by the bottom
flanges of the casing E above a foundation ring S.
The metal supporting "bridge" comprises three radial legs C. C, C, with
feet C¹. C. C', resting on the chamber casing e, and connected together by concentric
rings T, T, each ring having a series of holes through each of which passes a
screw stud, (see Fig. 6) soldered to the thermometer cover «. Each stud is

page_text: provided with a loosely fitting nut one only of which is shewn, temporarily provided
with light vanes on which a current of air is made to impinge to drive the nut into
place after adjustment of the chamber as herein before described. f is the central
set screw with right and left handed thread, and y is the nut riding loose on the
thread above the cover until the adjustment is completed, when it is brought down
on the cover by hand and soldered thereto, this set screw and nut serving for subsequent
small adjustments by moving the central portion of the cover.
::
::
Fig. 6 is an elevation partly in section, and drawn on an enlarged scale, shewing
another device for tempering up or adjusting the centre of the thermometer cover a.
f is the adjusting screw; the nut soldered to the cover a; and f' a milled nut that
rests free above the bridge during the adjusting process when the screw is free
to move through the central hole of the " bridge." As soon as the adjustment is
effected the nut fi is spun down on to the " bridge "and soldered thereto, the screw
then serves to adjust, by raising or lowering it slightly, the central part of the cover.
Fig. 7 is a vertical section partly in elevation shewing a modified arrangement in
which the two chambers are so arranged that their corrugated covers face each other.
In this case the two chambers A, B; the connecting tubes m, n; and the shoe-
pieces are arranged at a distance apart as shewn to make room for the "bridge.'
This construction admits of the two parts of the casing E being each formed with an
outside flange for connecting them together instead of by the internal lugs D, and
screws shewn in Figs. 1 & 2.1
Fig. S is a vertical section partly in elevation shewing the two chambers A. B.
provided each with two corrugated flexible covers a, a, and respectively, the
thermometer chamber A having in this case two bridges C. C. and C, C, the
latter being placed in the space between the chambers A and B.
Fig.9 is a vertical section partlyin elevation, Fig. 10 a side elevation partlyin section,
and Fig.11 a plan, partly in horizontal section,shewing another arrangement in which
four chambers each with a single corrugated cover, are so connected by a pair of
elastic spiral tubes that the innermost chambers A A¹. are made to constitute the
thermomenter chamber, whilst the outermost chambers B B are made to constitute the
barometer chamber. To allow for the reduction of the intermediate distance when
the thermometer covers become concave under pressure, just before fixing, the
outlets are connected together by the spring tube and both have connection
with the shoe-piece J and tube F by means of the tube
outlets are connected together by the spring tube
with the shoe-piece J' and tube G by means of the tube .
connecting the thermometer covers. f being the central one.
three bolts by means of which the distance of the chambers apart and the concavity
of the covers a, a are fixed as described. The weight of the two sets of chambers
is taken by lugs i.
¹, whilst the other two
and both have connection
are tie bolts rigidly
is one of a sei of
The distance between the innermost chambers A. A being less than that of the outer-
most ones B B the tube should be made a little longer than the other w, so that the
capacity of both may be the same.
Fig. 12 is a vertical section, partly in elevation, and Fig. 13 an elevation,
shewing means for effecting small adjustments of the apparatus to make it agree,
when necessary, with a standard instrument, are screws for adjusting the
capacity of the thermometer and barometer chambers and connected tubes respectively;
they are screwed into tubular extensions Z cast in one with the chamber casing e,
the spaces yy below the screws being in communication with the chambers A
and B through the small holes shewn.
Fig. 14 is a vertical section partly in elevation. and Fig. 15 is a plan. shewing
another device for adjusting the apparatus. XY are two secondary chambers
each furnished with two covers 1, 2. The bottom cover of the chamber Y is
connected to and rests on the casing e by a hollow screw 3, which affords communi-
cation between the chamber Y and the barometer chamber B by means of the
passage y'. The chamber X is in like manner placed in communication with the

page_text: thermometer chamber A. 5 5 are set screws each with right and left handed
screw threads. These screws each work in a nut 4 soldered to the outer cover
of one of the secondary chambers, and in a bracket which is secured to the
casing E by a set screw 7. By turning either set screw 5 to force in or draw
out the small corrugated covers 1, 2, the height of mercury in the corresponding
tube For G, can be adjusted.
Fig. 16 is a vertical section partly in elevation shewing only one of the two
secondary chambers Y, arranged vertically instead of horizontally; the right and
left handed set screw 5 is here shewn screwed through the outer casing E.
Fig. 17 shews the method of graduating the thermometer and barometer iubes
respectively, the former into degrees Centigrade and Fahrenheit, and the latter into
inches and fractions thereof, of mercury, and feet of altitude and depth; the adjust-
ment of the apparatus being effected in the manner hereinbefore described, at
32° Fahr. of temperature and a pressure of 30 inches of mercury, which two points
are the datum points previously referred to.
Fig. 1S is a vertical section partly in elevation and Fig. 19 a plan partly in
horizontal section of the apparatus made of a size adapted to be carried in the
pocket, and being simply a copy of the larger apparatus herein before described but
with coils of less length, and being held by a ring carried by a screw piece ¹,
instead of by the handle I shewn in Figs. 1 and 3.
Fig. 20 is a front elevation, partly in vertical section, of the apparatus applied
as a high pressure gauge.
Fig. 21 is a section of the same in the line X Y (of Fig. 20).
Fig. 22 is a side elevation of a water casing E, shewing the mode of coiling a
pipe, hereinafter referred to, round it.
I is a plate which can be secured in place by screws II. It carries a casing E¹ Eª
secured in place by set screws III and provided with a pane of glass that serves
to protect the thermometer and pressure" tubes F, G respectively, and the scale N.
This scale which in the example shewn is made movable and is graduated to lbs.
per square inch. is provided with two lugs IV that slide in slot V, through the
required range of the thermometer column F'. Pins passing through the lugs IV
serve to keep the scale in place. The scale N carries a rack VI worked by a
pinion VII.
VIII is a pipe to contain water or other liquid, and through which
is transmitted the pressure of the fluid for example steam, to be measured. This
pipe takes one and three fourths of a turn around the casing E which contains
water in the spaces IX, and with which it communicates by the passage X. The
casing E is firmly secured to the plate I by a flange XI and set screws XII so
as to make a water tight joint therewith. This water casing E envelopes the
inner or chamber case c. A is the thermometer chamber; its exhaust hole;
m the outlet tube screwed into the tube piece" K and making communication
between chamber A and the thermometer tube F, the pressure being read off on
the other or pressure tube G.
Fig. 23 shews partly in elevation, and partly in section, the application of the
apparatus to a vacuum gauge. F. G, are the thermometer and vacuum ** tubes
respectively, and N. N¹, movable scales therefor. To read the gauge the plug of a
two-way cock such as that shewn in Figs. 24 to 27 inclusive is turned square with
the pipe for a moment so as to let a jet of air into the gauge and thereby send up the
mercury column to the height of a barometer for the time being. The barometer
scale N is at the same moment moved so that its zero point coincides with the top of
the thermometer column, thus showing the height of the barometer (in the figure 30°
60 in.) and at the same time the zero of the vacuum scale N is placed to coincide
with the top of the barometer column. When the two-way cock is again opened to
the condenser or vacuum vessel, the mercury column sinks and the amount of vacuum
is read off on the scale N (in the figure 270 50 inches).
Fig. 24 shews partly in elevation and partly in section, a two-way plug cock for
use in connection with the vacuum gauge, shewn in Fig. 23 the plug being shewn in

page_text: a position in which it opens communication between the gauge and the condenser or
vacuum vessel.
Fig. 25 is a section along the line A B of Fig. 24.
Fig. 26 is a similar view to Fig. 24 but shewing the communication between the
gauge and condenser closed, and that between the gauge and atmosphere opened.
Fig. 27 is a section of the same partly through main way 13 and partly along the
line C, D, Fig. 26.
S is the handle for turning the plug 9 which is traversed by two ways—eiz., a main
way 10, and a small transverse way 11; 12 12 is the body of the cock having the
passage way 13 13, and the hole 14 which, by turning the plug handle from the
position shewn in Fig. 24 to that shewn in Fig. 26 places the passage 18 in com-
munication with the atmosphere through the way 11 thus admitting a jet of air into
the gauge to mark the atmospheric pressure as described.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed 1 declare that what I
claim is:
1. In apparatus for measuring or indicating temperature and pressure the com-
bination with graduated tubes of small bore, of two similar chambers namely a
thermometer chamber and a barometer chamber each in communication with one of
the tubes and provided with a corrugated flexible cover or covers; the arrangement
being such that the thermometer chamber with its corresponding tube enables the
error due to change of temperature on the internal liquid in the barometer chamber
and tube to be determined by clearly indicating the amount of such changes subsian-
tially as herein before described. with reference to the drawings annexed.
2. In apparatus of the kind referred to in the preceding claim the combination
with the thermometer chamber having a flexible cover or covers, of a bridge or
bridges for rigidly holding the said cover or covers so that the liquid within the said
thermometer chamber shall, after adjustment. be unaffected by changes of external
pressure substantially as hereinbefore described with reference to the drawings
annexed.
3. The improved apparatus herein described and shewn in Figs. 1 to 6 inclusive of
the drawings annexed for the purpose specified.
4. The modified arrangement of apparatus shewn in Fig. 7, wherein the thermo-
meter and barometer chambers, have each a single corrugated flexible cover and
are placed apart with the flexible covers facing each other substantially as
described.
5. The modified arrangement of apparatus shown in Fig. 8, wherein the two
chambers are entirely separate, cach has two corrugated flexible covers and the
covers of the thermometer chamber are provided with two supporting
substantially as described.
<
bridges
:
6. The modified arrangement of apparatus shewn in Figs. 9 to 11 inclusive,
wherein there are two sets constituting four separate chambers, of which the two
inner chambers are connected together to form the thermometer chamber, and the
two outer chambers are connected together to form the barometer chamber, by
means of spiral connecting tubes possessing sufficient elasticity to allow of adjust-
ment and the flexible covers of the thermometer chamber being fixed and held in
equilibrium by a set of tie bolts substantially as described and shown.
7. The modified form of apparatus shown in Figs. 18 and 19 of the drawings
annexed for the purpose specified.
8. A barometer comprising a chamber with flexible corrugated cover or covers,
and a tube, both charged with a suitable liquid, such as mercury. to serve as the
medium for transmitting the slight motion of the corrugated flexible cover or covers
to the liquid in the barometer fube, and thereby magnifying such small motion to
any desired extent substantially as herein described.
9. The construction and application of apparatus of the kind referred to in claim 1

page_text: for use as a high pressure gauge substantially as herein described with reference to
Figs. 20 to 22 inclusive of the drawings annexed.
10. The construction and application of apparatus of the kind referred to in claim 1.
for use as a vacuum gauge substantially as herein described with reference to Fig. 23
of the drawings annexed.
11. The application and use in an apparatus of the kind herein described for
measuring or indicating temperature and pressure of a device substantially such as
either of those hereinabove respectively described with reference to and shown in
Figs. 12 and 13: in Figs. 14 and 15; and in Fig. 16 of the drawings, for adjusting
the said apparatus.
W. LLOYD WISE,
Per F. J. Brougham.