AN, APPARATUS FOR REGULATING TEMPERATUREIN VAPORIZA- TION, DISTILLATION, AND OTHER PROCESSES
Year: 1830

page_text: TO ALL TO WHOM THESE PRESENTS, SHALL COME, I, ANDREW
URE, of Southampton. Row, in the County of Middlesex, M.D., send greeting.
WHEREAS His present most Excellent Majesty King William the Fourth,
by His Letters Patent under the Great Seal of Great Britain, bearing at
Westminster, the Twentieth day of October, in, the first year. of His reign,
did, for Himself, His heirs and successors, give and grant unto me, the
said Andrew Ure, His. especial licence, sole privilege and authority, that
I, the said Andrew Ure, my exors, admors, and, assigns, or such, others as
I, the said Andrew Ure, my exors, admňors, or assigns, should at any time
agree with, and no others, from time to time, and at all times during the
term of years therein mentioned, should and lawfully might make, use,
exercise, and vend, within England, Wales, and the Town of Berwick-upon-
Tweed, and also in all His said Majesty's Colonies and Plantations abroad,
my Invention of "AN, APPARATUS FOR REGULATING TEMPERATUREIN VAPORIZA-
TION, DISTILLATION, AND OTHER PROCESSES;" in which said. Letters. Patent is
contained a proviso that I, the said Andrew Ure, shall cause a particular
description of the nature of my said Invention, and in what manner the same
is, to be performed, to be inrolled in His said Majesty's High Court, of
Chancery within six calendar months next and immediately after the date
of the said in part recited Letters Patent, as in the same, reference being
thereunto had, will more fully and at large appear.
.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Andrew Ure, do hereby declare that the nature of my said Invention, and

page_text: in what the manner the same is to be performed, is particularly described and
ascertained by the following description thereof, reference being had to the
Drawing annexed, and to the figures and letters marked thereon (that is to
say)-
I hereby declare the nature of my said Invention to be an Apparatus for
Regulating Temperature in Vaporization, Distillation, and other Processes,
which apparatus being immersed in the medium whereof the temperature is
to be regulated (and deriving motion by a self action from all alternations of
the temperature of that medium) is applied to modify and adjust the apertures
of moveable valves, stopcocks, and air ventilators or registers, through which
apertures the heating or cooling influences of fluids, elastic or inelastic, are
transmitted or imparted to that medium, in order to raise or lower the
temperature thereof. My said apparatus operates on the well-established
physical principle that when two rulers or flat bars of two different solids,
metals, or metallic alloys, which differ in the rates of their expansibilities by
heat, are firmly united together with their flat faces in contact, and fastened
by rivetts, solder, or other means, a change of temperature in such a com-
pound bar will occasion it to bend laterally, with a sensible movement in
flexure, provided that neither of the two rulers be so thick and rigid as to
resist and counteract the physical force impressed on it by the other. My
said apparatus may be composed of several such compound bars, which are
combined, in order to augment and accumulate their motion in flexure, so as
to operate on moveable valves, stopcocks, air ventilators, or registers, or other
means of opening or closing apertures, in order to regulate the temperature of
the media in which the said combinations of compound bars are immersed ;
and in further compliance with the said proviso, I, the said Andrew Ure, do
hereby describe the manner in which my said Invention is to be performed, by
the following explanation thereof, reference being had to the Drawing annexed,
and to the figures and letters marked thereon (that is to say):-
I take, for example, a bar or ruler of platina, iron, or steel, from a few
inches in length to several feet in length, being one inch or more or less broad,
and one eighth of an inch thick, or more or less, according to its length. I
unite to that bar or ruler, flatwise, by solder or by numerous rivets, a similar
bar of zinc, about twice the thickness of the aforesaid bar; and I.fix one end
or part of this compound bar immoveably to any solid prop or fulcrum, and I
attach the other free end or part of the bar to the arm of a lever or to other
suitable mechanism, which is adapted to transmit the motion in flexure of the
said compound bar to the moveable part of a valve, or of a stopcock, or of an
air ventilator, in such manner that the compound bar. in its flexure, by change

page_text: of temperature, may act by the intervention of the lever or other mechanism
on that valve or stopcock or ventilator, so as to open or shut the aperture
through such valve or stopcock or ventilator, according to the change of tem-
perature in the medium which surrounds the said compound bar. Hence, if
the said medium is to be heated or cooled, by the ingress of any fluid, elastic
or inelastic, into it (or into pipes which traverse through it), the compound
bar may have its moveable part so adjusted to the moveable part of the valve
or other apparatus which admits the said heating or cooling fluid to mix with
the said medium, or to pass through the same in pipes, as that the movement
in flexure of the bar shall effect the exclusion or admission of that fluid, or
cause it to mix with or pass through pipes immersed in the said medium,
accordingly as the temperature thereof exceeds or falls below any assigned or
determinate degree of temperature for which the apparatus has been previously
adjusted. The said. compound bar and apparatus, when thus adjusted, con-
stitutes a self-acting instrument for regulating or controuling temperature,
which I propose to call a heat governor; and it also serves to fix the heat of
a medium at a definite degree amid causes of ever-fluctuating temperature,
for which reason I also propose to call it a thermostat. The compound bar
may be very advantageously made of more than two metals or metallic alloys,
of different expansibilities, provided that they are attached to each other in the
order. of their respective expansibilities, reckoning from one flat side of the
compounded bar to the other, as steel, copper, tin, zinc. Such compound bar
may be either straight or it may be curvilineur, as circular, elliptic, or spiral.
If a single thermostatic bar has its two ends firmly lodged against immoveable
abutments, then, the movement occasioned by the curvature of the bar (from
the lateral flexure which will be produced by any given change of tem-
perature) may be derived from any point in the middle part of the bar; and
if a pair of such bars are placed opposite to each other, having the least
. expansible metals turned towards each other (as the steel side to the steel
side, and the pair of bars being hinged one to another at their ends, as at
F, E, in Fig. 4, then the sum of their respective motions in flexure will be
rendered effective from their middle parts, and may be applied for moving any
valve or stopcock, or other apparatus which has the command or regulation of
temperature. Or a series of compound bars being combined, as shewn in
Fig. 5, must have the first, bar fixed, as at B, to enable them to draw back-
wards as well as push forwards any rod or stem which is attached to or con-
nected with the last bar of the series; thus, the motion of the compound bars,
by flexure may be magnified at pleasure, by multiplying the number of
pairs of bars. It is essential to the exact operation of the thermostat that the
"1

page_text: stationary supports to which the bars are fixed should be rendered as much
as possible independent of any flexure in the shape of the vessel containing
the medium, and therefore I sometimes employ compound bars in the form of
a discontinuous hoop, and I clamp the middle of the curve to a solid fulcrum,
leaving the free ends of the hoop to operate on suitable levers or other
connections, which are capable of modifying, directing, or applying those
motion of the ends which are occasioned by change of temperature to
open or shut valves or stopcocks, as shewn in Fig. 2. Another convenient of
form of the thermostat is to apply two compound bars opposite to each other
face to face, and bolting them firmly together at one of their ends, the other
ends are left free to act by the motions in flexure which they derive from
change of temperature on a valve or stopcock, as is represented in Fig. 3.
When a thermostatic hoop, or a pair of bars bolted together at one of their
ends, is heated, if the more expansible lamina be on the inside faces which
are opposite to each other, then the free ends of the hoop or bars will recede
from each other, but if the less expansible lamina be on the inside faces
which are opposite to each other, then the free ends of the hoop or bars will
approach each other. The general rule for the construction of this thermo-
static apparatus is to fix to an immoveable fulcrum one part, which may be
either an extremity or an intermediate point between the two ends of such
compound bar or bars, and attach the free part, which may be either the end
or ends, or an intermediate point of the same bar or bars, to any such lever,
wheel, rack, pulley, or other mechanism as is best adapted to transmit the
motion of those free points to any moveable valve, stopcock, or ventilating
register, whereof the opening or shutting shall regulate temperature by
effecting the exclusion or admission of heating or cooling fluids (elastic or
inelastic), or permitting the same to mix with the medium or flow through
the medium in pipes. If the temperature of the given medium in which the
thermostat is immersed should tend to deviate from its pre-assigned limit, the
said thermostatic power will consentaneously obstruct or favour the calorific or
frigorific influence, whether that influence proceeds from hot or cold fluids,
elastic or inelastic, mixing with the media or flowing through the same in pipes.
The thermostatic instrument may be made to operate on both the heating and
cooling influences at once, as is particularly shewn in Fig. 1 and in Fig. 5, so as
to regulate the valves or turning air registers of both influences simultaneously;
see explanation of Figures 1 and 5. The applications of the above-described
thermostatic apparatus for regulating temperature in vaporization, distillation,
and other processes, are very numerous. I shall particularize a few instances
in order to illustrate the mode of adjusting the apparatus; but many more

page_text: applications will occur to the philosopher and the mechanician. Suppose,
for certain purposes in pharmacy, dyeing, or other chemical arts, a water bath,
heated by a naked fire, is required to be maintained steadily at a temperature
of 150 degrees of Fahrenheit's thermometer: Let the combined thermostatic
bars E, F, Fig. 4, be placed in the bath between the outer and inner vessel,
A, B, and C, D, and have their moveable part connected by a link with a
lever fixed on the turning plug of the stopcock I, which introduces water
from a cold-water cistern M, through a pipe I, N, into the bottom part of the
bath. The length of the link must be so adjusted that the flexure of the bars
when they are at a temperature of 150 degrees of Fahrenheit will open the
said stopcock, and admit cold water to pass to the bottom of the bath through
the pipe I, N, whereby hot water will be displaced at the top of the bath
thro' an open overflow pipe Q. An oil bath may be regulated on the same
plan; the hot oil overflowing from Q into a refrigeratory worm, from which it is
pumped or lifted back again to the cistern M. A water bath contained in the
outer vessel A, B, which is placed over a naked fire, may also have its
temperature adjusted by admitting cold water to run from the cistern. M
through the tortuous pipe I; N, O, P, in such a quantity as shall be
regulated by the action of the thermostat E, F; on the stopcock I, so as to
carry off the redundant heat of the bath with more or less rapidity.
When a water bath is heated by the distribution of a tortuous steam pipe
thro' it, as I, N, O, P, it will be necessary to connect the link of the
thermostatic bars with the lever of the turning plug of the steam cock, or
of the throttle value I, in order that the said bars by their flexure may
shut or open the steam passage more or less according as the temperature of
the water in the bath shall tend more or less to rise above or fall below the
assigned degree for which the apparatus is previously adjusted. The water of
the condensed steam will pass off from the sloping tortuous pipe I, N, O, P,
through the open orifice P. A saline solution bath has its temperature,
generally speaking, proportional to its degree of concentration; hence the saline
bath may be rendered stationary in its temperature and unchangeable in its
action by connecting the working part of the thermostat to a water stopcock I,
which will admit water to mix with the saline solution whenever by evapora-
tion of water an extra concentration of the solution has taken place, and has
tended to raise too high a temperature in the bath. Water may thus be let
down and distributed into the body of the saline solution in the bath 'through
a row of holes, which are perforated in the pipe I, N, so as to prevent the
boiling temperature of the solution from exceeding the assigned degree.
In Figure 4, a construction of a double boiling pan is shewn for the purpose

page_text: of boiling by a saline solution at an uniform temperature. The space between
the two pans must be about two thirds filled with a solution of chloride of
calcium or muriate of lime; such a pan is excellently adapted for concentrating
cane juice, syrups, vegetable infusions, and all other liquids which are liable to
be injured
boiling them over a naked fire. The space for the saline
solution, between the pans, should communicate by pipes with two cisterns,
one a small water cistern M, having a small pipe from it, furnished with a
thermortatic cock or valve I, to admit the water to flow through the perfora-
tions in the pipe I, N, in order to mix with the saline solution whenever the
concentration and consequent heat of the bath require to be lowered. The other
cistern is a large safety cistern R, communicating with the bath by a large pipe
to receive the overflow of the solution whenever it happens to boil furiously
from too great a dilution with water, or is suddenly subjected to too strong a heat
from the fire. The said thermostatic apparatus may be elegantly employed as
a regulator of the temperature of the air in hothouses, conservatories, theatres;
ball rooms, and apartments which are liable to get over heated or over chilled
by mismanaged ventillation; see explanation of Figures 5, 7, & 8. In a hot-
house warmed by flues or by pipes through which steam or hot water is made
to circulate, or through which flues or pipes warm air is introduced, an
apparatus formed of thermostatie bars may be fitted up of adequate' power
and.sensibility, and the moveable ends of those bars may be so connected with
the moveable parts of the heating or cooling valves and registers as to open
and shut the passages thereof, either together or separately, whenever variation
of the temperature of the air renders such regulation of the apertures neces-
sary. One of the most important applications of the aforesaid thermostat is
to distillation, for this instrument may be made to maintain a uniformity of
temperature in a water bath surrounding a long sloping passage, through
which the spirituous vapours arising from the still are conveyed for the purpose
of undergoing a partial condensation before they enter into the refrigeratory
worm or serpentine, in which the final and total condensation of the said
vapours is to be effected in order to obtain the spirit which is the object of the
distillation. The said long sloping passage may be termed an inter-
mediate condenser, which is adapted to produce a partial condensation of
the most aqueous portion of the spirituous vapours, in consequence of
the regulated temperature of the water bath, the water of which surrounds
the said intermediate condenser externally, and must be kept at such a
temperature that it will not condense any strong alcoholic vapour within
the intermediate condenser, but that it will condense aqueous vapour or a
mixture of vapours in which aqueous vapour greatly predominates; and

page_text: all liquid which may be deposited within the intermediate condenser by such
partial condensation being chiefly water with but little alcohol in it, must not
be allowed to run forwards along with the remaining alcoholic vapour which is
passing onwards to the refrigeratory worm or serpentine, but the said liquid
must be made to run backwards to return into the still, in order that it may be
again vaporised, so as to separate all the alcohol from it; such intermediate
condensers are in common, use in various forms. The essential conditions of
those forms are, that they should consist of a long sloping flattened tube or
other. passage for the conveyance of the spirituous: vapours through the water of
the bath, the form of the passage being such as will expose a thin layer of
vapour to an extensive surface of thin metal plate, the opposite surface of that
thin. metal plate being exposed to the water in the bath; also that the said
surfaces should be inclined to a horizontal plane, in order that the liquid
which is deposited upon them by the partial condensation which is to be
performed by the intermediate condenser may readily drain backwards towards
the still. My thermostatic: apparatus for regulating the temperature. of the
water in the water bath of an intermediate condenser for distillation may be
made as in Figure. 2, and immersed in the upper stratum of the water bath
immediately below the level of its overflow pipe. L, where the excess of heated
water escapes, the compound curved bar being in contact with the thin metal
of the aforesaid long sloping passage thro' which the spirituous vapours are
conducted in their way from the still to the serpentine, worm, or refrigiratory,
that contact being at the highest end of the long sloping passage at the part
thereof where the vapour ceases to be submitted to the action of that partial
condensation which it is the object of the intermediate condenser to effect.
The cold water which is admitted into the bath by my apparatus when
necessary from the cistern I, (Figure 2,) thro' the valve or stopcock F of the
thermostat, may be conveyed by a descending pipe F, K, to the bottom of the
bath, and the admission of cold water at the bottom of the bath will discharge
the hot water at the surface by displacement. The thermostat thus applied
may be made to maintain an uniform temperature in that portion of the water-
bath which immediately surrounds the end of the passage, whereby the
alkoholic vapour enters into the refrigeratory, worm,. or. serpentine, where it is.
to be finally condensed; and that uniformity of temperature. will: give a definite
tension and alcoholic purity to the vapour which is so admitted into the
said serpentine, notwithstanding all the variation of heat which may take
place within the still from variation of the fire in the furnace. By the aid of
this heat regulating apparatus applied. to the water bath of an intermediate
condenser, the distiller may make an exact analysis. and separation of the.

page_text: water, alkohol, and essential oil which are contained in fermented worts, wash,
or wines, and he may draw over at one operation, by the aid of the self-
adjusting instrument and intermediate condenser, an alcoholic spirit of any
desired quality; see the explanation of Figure 2. The draught of a furnace
chimney, and consequently the intensity of the fire, may be regulated by the
action of my apparatus, which in that case may be called a pyrostat. For
example, let a pair of compound bars A, B, A, C, Figure 6, which are bolted
together at one end, be suspended by their ends A, which are bolted together,
so that the bars will hang vertically at a convenient height within the upper
part of the chimney, where they must necessarily be exposed to the draft or
current of heated smoke and gas which is issuing from the chimney, and
let the lower ends B, C, of the two bars be connected by two links B, D,
and E, C, to a turning damper G, H, F, which is made on the plan of
a throttle valve, and applied across the passage of the chimney, being mounted
upon a horizontal axis which extends across the middle of the area of
the passage, and the connecting links B, D, and E, C, from the lower
ends of the two bars being connected with the valve, and at opposite
sides of its axis of motion, the draught of air, and consequently the com-
bustion of the fuel, may be restrained within any desired limits by this appli-
cation of my apparatus, for whenever a more rapid or hotter draft passes up
the chimney the two bars (having their least expansible metals on their
adjacent sides) will close together at their lower ends, and turn the damper
more flatwise across the passage through the chimney so as to retard the draft
therein; or whenever the current becomes less rapid or hot the said bars will
turn the damper more edgeways across the said passage, and allow a more free
draft. Such a self-acting pyrostat may thus remove the great irregularities of
combustion in furnaces which proceed from irregularities in the supply of
fuel and in the draft of chimnies, owing to currents of the wind. Such a
pyrostat may if requisite be enclosed within an iron case which is shaped like
a fan when shut up, and a small rod may be carried thro' a hole in the
lower end of the said case to transmit the motion of flexure in the bars to
the turning damper. If zinc is employed in the construction of such a
pyrostat the whole apparatus should be placed high enough in the chimney to
avoid the chance of melting or injuring that metal. Its oxidizement may bo
prevented by coating it with an incombustible pigment, or wrapping it with a
coil of fine iron wire.
.
I claim as my Invention the aforesaid applications of the movements pro-
duced during the flexure of the aforesaid compounded bars from alternations
of their temperatures, those applications being made for the purpose of regu-

page_text: lating temperature by adjusting the apertures of the passages through any stop-
cocks, turning valves, air ventilators, or registers, or other apparatus, which,
by being more or less opened or shut can have the effect of modifying the
temperature of any flued medium (elastic or inelastic) in which a certain uni-
formity of temperature is advantageous for vaporization, distillation, and other
processes, as herein-before set forth. I do not claim as my Invention the
mere indication of temperature by the flexure of such compound bars, although
I commonly attach to my apparatus (which I propose to call a thermostat or
heat governor) a heat indicator in the form of an index, which is moveable
along a graduated are around the centre of motion of the aforesaid stopcock,
turning valve, air ventilator, or register.
+
EXPLANATION OF THE DRAWING.
Fig. 1, A, B, is a single thermostatic bar, consisting of two or more bars or
rulers of differently expansible solids (of which in certain cases wood may be
one); these bars or rulers are firmly rivitted or soldered together face to face.
One end of the compounded bar is fixed by bolts at A to the interior of the
containing cistern, boiler, or apartment A, L, M, B, whereof the temperature
is to be regulated, and the other end of the compounded bar at B is left free
to move towards C, by the flexure which will take place when its temperature
is raised. The end B is connected by a link B, D, with a lever D, E, which
is moved by the flexure into the dotted position B, G, causing the turning
valve, air ventilator, or register O, N, to turn with a corresponding angular
motion, and during that motion the lever also raises the sluice damper K, I,
(which is suspended by a link from the end E of the lever E, D, into the
position K, H.
This Figure shews how a hothouse or a water bath may
have its temperature regulated. A high pressure steam boiler may be pro-
vided interiorly with an apparatus like Figure 1, placed within the steam to
open a discharge cock, which may act as a safety valve, whereof the action is
derived from the temperature of the high pressure steam independantly of the
elasticity thereof. Figure 2, A, B, C, a thermostatic hoop immersed
beneath the surface of the water bath of a still. The hoop is fixed at A,
and the two ends B, C, are connected by two links B, D, C, D, with a
straight sliding rod D, H, to which the hoop will give an end-way motion
when its temperature is altered.. E is an adjusting screw on the rod
D, H, for setting the lever F, G, which is fixed on the axis of the turning
valve or cock at any desired position, so that the valve may be opened or
shut at any desired temperature corresponding to the widening of the points
B, C, and the consentaneous retraction of the point D towards the circum-

page_text: :
-ference B, C, of the hoop; G, H, is an arc graduated by a thermometer after
.the screw piece E has been adjusted; through a hole at H the guide rod
passes; I, the cold water cistern; I, F, K, the cold water pipe; M, the outside
of the cylinder or tub which contains the bath; L, the overflow pipe at which
the excess of hot water runs off. Fig. 3, a pair of thermostatic bars bolted
fast together at the ends A.. The free ends B, C, are of unequal length so as
to act by the cross links D, E, on the stopcock F. The links are jointed to
the handle of the turning plug of the cock on opposite sides of its centre, and
that plug will be turned round in proportion to the widening of the points
.B, C; H, G, the pipe communicating with the stopcock. Fig. 4, the double
pan for evaporation; between the outer pan A, B, and the inner pan C, D,
the bath is contained. E, F, a pair of thermostatic bars hinged together at
their ends. They are represented in the state of flexure which they acquiro
by heat; they rest against a firm prop at G, and they move the sliding rod H
to and fro endways so as to open the valve or cock I by the action of the
rod H, K, upon the handle of the cock. The rod H, K, passes through a
guide hole at the end of the thermometric arc. L, M, is a cold water cistern.
From the stopcock I the pipe N, O, proceeds into the bath, and may terminate
either at N or at P, according to circumstances. The uses of this double
pan have been already fully described. Fig. 5, a thermostatic apparatus
composed of three pairs of bars D, D, D, which are represented in a state of
flexure by heat; but they are nearly straight and parallel when cold. A, B, C,
is a guide rod fixed at one end by an adjusting screw E. in the strong frame
F, E, having deep guide grooves at the sides M, N. F, G, the working rod
which moves endways when the bars D, D, D, operate by heat or cold. The
-square register plate H, G, may be affixed to the rod F, G, so as to be
. moved backwards and forwards thereby according to the variations of tempe-
.rature. Or the rod F, G, may cause the circular turning air register I to
revolve by rack and wheelwork or by chain and pulley.. The register plate
H, G, or turning register I, are situated at the ceiling or upper part of the
chamber, and serve to let out hot air therefrom. K, a pulley over which a
cord runs to raise or lower the hot air register L, which is situated near
the floor of the apartment or hothouse to admit hot air into the house. The
thermostatic frame and apparatus are supposed to be fixed at or near the
ceiling of the chamber. C, a milled head for adjusting the thermostat by means
of the screw at E, in order that it may regulate the apartment to any
temperature. Fig. 6 represents.a chimney furnished with a pyrostat A, B, C,
acting by the links B, D, E, C, on a damper F, H, G. The more expansible
metal is in the present example supposed to be on the outside. The plane of

page_text: the damper plate will in this case be turned more oblique to the passage
of the draft through the chimney by increase of temperature. Fig. 7
represents a circular turning register, such as is used for a stove or stove
grate, or for ventilating apartments. It is furnished with a series of spiral
thermostatic bars, each bar being fixed fast at the circumference of the
circle B, C, of the fixed plate of the air register, and all the bars act
in concert at the centre A of the turning part of the register by their ends
being inserted between the teeth of a small pinion, or by being jointed to the
central part of the turning plate by small pins. By this arrangement the
thermostatic bars by their flexure will communicate a turning motion to
the moveable part of the air register, and will progressively diminish all
the apertures of the said register as the temperature of the air in
which the bars are immersed rises, and will finally close all the apertures.
When that temperature exceeds the desired degree a turning throttle, valve, or
stopcock being placed in the centre of a circle in place of the said turning
part of the register, may be adapted to any of the thermostatic purposes
berein-before set forth by a series of bars on the same spiral construction
represented in Figure 7, all the spiral compound bars being firmly fixed to the
circumference of the circle, in the centre of which the axis of the turning
valve or cock is situated.
Fig. 8 represents another arrangement of my thermostatic apparatus
applied to a circular turning register like the preceding for ventilating apart-
ments. Two pairs of compounded bars, such as those represented in Figures 4
and 5, are applied to act in concert by means of the links A, C, B, C, on the
opposite ends of a short lever, which is fixed on the central part of the turning
plate of the air register. The two pairs of compounded bars A, B, are
fastened to the circumference of the fixed plate of the turning register by two
sliding rods A, D, B, E, which are furnished with adjusting screws. The
motion or flexure of the two pairs of compounded bars is transmitted by the
links A, C, and B, C, to the turning plate, giving it motion about its centre
for the purpose of shutting or opening the ventilating sectorial apertures more
or less, according to the temperature of the air which surrounds the said
thermostatic turning register. By turning the adjusting screws A, D, and
B, E, the turning register is made to close all its apertures at any
desired degree of temperature; but whenever the air is above that tem-
perature the flexure of the compound bars' will open the apertures. Note,
instead of. a turning register the arrangement of compound bars represented
in Fig. 8 may be applied to give motion to the turning plug of a cock or to

page_text: the spindle of a throttle valve, which is situated in the centre of the circular
frame, as before mentioned of Figure 7.
In witness whereof, I, the said Andrew Ure, have hereunto set my hand
and. seal, this Twentieth day of April, in the year of our Lord One
thousand eight hundred and thirty-one.
DOWDESWELL.
year of our Lord 1831, the aforesaid Andrew Ure came before our said Lord
the King in His Chancery, and acknowledged the Specification aforesaid, and
all and every thing therein contained and specified, in form above written.
And also the Specification aforesaid was stamped according to the tenor of the
Statute made for that purpose
Inrolled the Twentieth day of April, in the year of our Lord One
thousand eight hundred and thirty-one.