IMPROVEMENTS IN APPARATUS FOR PRODUCING COLD BY THE EVAPORATION OF VOLATILE LIQUIDS IN VACUO
Year: 1857

page_text: LETTERS PATENT to James Harrison, of No. 4, Red Lion Square, in the
County of Middlesex, for the Invention of "IMPROVEMENTS IN APPARATUS
FOR PRODUCING COLD BY THE EVAPORATION OF VOLATILE LIQUIDS IN VACUO."
Sealed the 2nd March 1858, and dated the 10th September 1857.
PROVISIONAL SPECIFICATION left by the said James Harrison, at
the Office of the Commissioners of Patents, with his Petition, on the
10th September 1857.
I, JAMES HARRISON, of No. 4, Red Lion Square, in the County of
Middlesex, do hereby declare the nature of the Invention for "IMPROVEMENTS
IN APPARATUS FOR PRODUCING COLD BY THE EVAPORATION OF VOLATILE LIQUIDS IN
VACUO," to be as follows:-
This Invention consists partly in the application of a vessel similar to a
tubular boiler, but having the tubes placed more closely together, for the
purpose of refrigerating by means of the evaporation of volatile liquids in
vacuo. The ether or other volatile liquid occupies the interior spaces between
the lower tubes of this vessel. An exterior current of another liquid is
maintained through the tubes; this liquid is an alkaline or saline solution, or
an alcoholic or other mixture not congealable at the degree of cold required to
be produced. This liquid is cooled during its passage through the tubes, and
it is then conducted into a receptacle, where it is made to pass over the surface
of moulds or other vessels containing the water or other substances which are

page_text: to be cooled or frozen; and it is thence returned and again passed through the
refrigerating tubes. The vessels and moulds are so arranged that the cooled
current shall flow by its own gravity. When it has passed over the surfaces
containing the substances to be cooled, it is then pumped up to the level
whence it primarily flowed. The lower tubes of the refrigerating vessel are
covered by the volatile liquid, and the upper tubes are surrounded by the
vapor, so that the cooling power of the liquid while passing into the aeriform
state, and the low temperature of the vapor after its formation, are both
utilized. The saline or spirituous mixture passes primarily through the upper
tubes, and then through the lower ones.
In small machines, intended for domestic use, the refrigerating vessels are
surrounded or partly surrounded by chambers, which may be made use of as
provision safes, or as cellarets for holding wine, ice, &c.; these chambers, if of
large dimensions, are fitted with tubes for the circulation of cooled liquids.
Worts and other liquids requiring to be cooled are passed directly through
the tubes of the refrigerating vessel at various degrees of velocity, according to
the temperature required, the abstraction of heat being proportioned to the
slowness of the circulation.
For the supply of cool air to houses, hospitals, &c., the air entering from
without is conducted through the tubes of the refrigerating vessel, or through
pipes surrounded by the liquid which has been cooled by the apparatus. For
regulating the temperature of apartments, water which has been cooled in
passing through the refrigerator is conveyed through pipes traversing the
apartments, in a manner similar to that by which buildings are heated by means
of hot water; the circulation of the water may be regulated by a pump or by
fixing the refrigerator at the top of the building, the cooled water will descend
by its own increased gravity.
Another form of refrigerating vessel consists of sheets of copper, each pair
of sheets being separated by half-round gnurled wires at short intervals, fixed
in sloping positions, so that the volatile liquid shall flow from end to end and
over the interior surface of the two sheets of copper, the several pairs of sheets
communicating with a common receptacle for the vapor. When the supply of
volatile liquid is in excess, it flows into a reservoir, whence it is pumped into
the vessel from which the pairs of plates are supplied. By filling the interior
intervals between the sheets with the volatile liquid, and dispensing with the
use of wires except for the purpose of strengthening the vessel, a refrigerating
vessel similar in principle to the tubular refrigerator is produced.
The vapor is compressed into the liquid state in a condenser surrounded by

page_text: water; this condenser consists of spiral tubes communicating with the lower
part of a central vessel in such a manner that should there be a leakage of air
into the apparatus such air will collect in the central vessel, from which it will
be withdrawn by a small pump and forced into a separate vessel, connected
with a condenser, where the vapor with which it may be mixed will be
recovered by the application of a greater degree of cold than that to which it
was exposed in the larger condenser.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said James Harrison in the Great Seal Patent Office on the
10th March 1858. .
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
HARRISON, of No. 4, Red Lion Square, in the County of Middlesex, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Tenth day of September, in the year of our Lord
One thousand eight hundred and fifty-seven, in the twenty-first year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said James Harrison, Her special licence that I, the said James
Harrison, my executors, administrators, and assigns, or such others as 1,
the said James Harrison, my executors, administrators, and assigns, should
at any time agree with, and no others, from time to time and at all times
thereafter during the term therein expressed, should and lawfully might
make, use, exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN APPARATUS FOR PRODUCING COLD BY THE EVAPORATION OF
VOLATILE LIQUIDS IN VACUO," upon the condition (amongst others) that I,
the said James Harrison, my executors or administrators, by an instrument in
writing under my, or their, or one of their hands and seals, should particularly
describe and ascertain the nature of the said Invention, and in what manner
the same was to be performed, and cause the same to be filed in the Great
Seal Patent Office within six calendar months next and immediately after the
date of the said Letters Patent.
NOW KNOW YE, that I, the said James Harrison, do hereby declare
the nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement thereof, that is to say :-

page_text: This Invention consists partly in the application of a vessel similar to a
tubular boiler, but having the tubes placed more closely together, for the
purpose of refrigerating by means of the evaporation of volatile liquids in
vacuo. The ether or other volatile liquid occupies the interior spaces between
the lower tubes of this vessel. An exterior current of another liquid is
maintained through the tubes; this liquid is an alkaline or saline solution, or
an alcoholic or other mixture not congealable at the degree of cold required to
be produced. This liquid is cooled during its passage through the tubes, and
it is then conducted into a receptacle, where it is made to pass over the
surface of moulds or other vessels containing the water or other substances
which are to be cooled or frozen, and is thence returned and again passed
through the refrigerating tubes. The vessels and moulds are so arranged, that
the cooled current shall flow by its own gravity. When it has passed over the
surfaces containing the substances to be cooled, it is then pumped up to the
level whence it primarily flowed. The lower tubes of the refrigerating vessel
are covered by the volatile liquid, and the upper tubes are surrounded by the
vapor, so that the cooling power of the liquid while passing into the aeriform
state, and the low temperature of the vapor after its formation, are both
utilized. The saline or spirituous mixture passes primarily through the upper
tubes, and then through the lower ones.
In small machines intended for domestic use the refrigerating vessels are
surrounded or partly surrounded by chambers, which may be made use of as
provision safes, or as cellarets for holding wine, ice, &c.; these chambers, if of
large dimensions, are fitted with tubes for the circulation of cooled liquids.
Worts and other liquids requiring to be cooled are passed directly through
the tubes of the refrigerating vessel at various degrees of velocity, according to
the temperature required, the abstraction of heat being proportional to the
slowness of the circulation.
For the supply of cool air to houses, hospitals, &c., the air entering from
without is conducted through the tubes of the refrigerating vessel, or through
pipes surrounded by the liquid which has been cooled by the apparatus. For
regulating the temperature of apartments, water which has been cooled in
passing through the refrigerator is conveyed through pipes traversing the
apartments in a manner similar to that in which buildings are heated by
means of hot water. The circulation of the water may be regulated by a
pump or by fixing the refrigerator at the top of the building; the cooled
water will descend by its own increased gravity.
Another form of refrigerating vessel consists of sheets of copper, each pair

page_text: of sheets being separated by half-round gnurled wires at short intervals fixed
in sloping positions, so that the volatile liquid shall flow from end to end and
over the interior surface of the two sheets of copper, the several pairs of sheets
communicating with a common receptacle for the vapour. When the supply
of volatile liquid is in excess, it flows into a reservoir, whence it is pumped
into the vessel from which the pairs of plates are supplied. By filling the
interior intervals between the sheets with the volatile liquid, and dispensing
with the use of wires except for the purpose of strengthening the vessel, a
refrigerating vessel similar in principle to the tubular refrigerator is produced.
The vapor is compressed into the liquid state in a condenser surrounded by
water; this condenser consists of spiral tubes communicating with the lower
part of a central vessel in such a manner that should there be a leakage of air
into the apparatus, such air will collect in the central vessel, from which it
will be withdrawn by a small pump and forced into a separate vessel connected
with a condenser, where the vapor with which it may be mixed will be
recovered by the application of a greater degree of cold than that to which it
was exposed in the larger condenser.
Having thus described the nature of my Invention, I now proceed to
describe, by reference to the Drawings, the manner in which it is performed.
Figure 1 is an elevation in section of an ice-making apparatus requiring a
motive power of ten horses. The pump A is employed in withdrawing the
vapour of ether from the tubular boiler B, and forcing the vapor into the
condensers C, C, where, by means of the pressure, aided by a stream of cool
water, the vapor is reduced into the liquid state, and the resulting liquid
returns through the vessel F into the boiler, where it again undergoes évapo-
ration. The ether in evaporating carries off a large quantity of heat, or in
other words produces a great degree of cold. The cold thus produced is
utilized by means of a stream of saline or alkaline solution passing in the
vessel G round the outside of the boiler and through its tubes, and thence to
the trough H, where it passes along the outer surfaces of the vessels or
moulds containing the pure water intended to be frozen. The solution after-
wards flows into the well of the pump I, by which it is raised to the top of
the boiler whence it again flows by its own gravity through the tubes, &c., as
before. Figure 2 is a section of that portion of the apparatus through
which the solution circulates. The small pump D is employed in making a
vacuum throughout the apparatus, and in case of any leak afterwards occurring
in withdrawing the air which might get into the tubes or vessels, and recover-
ing the ether with which such air would be mixed by passing it through the

page_text: small condenser E under a pressure greater than that to which it had
formerly been subjected. A partial vacuum may be formed by the large
pump A, by removing the cap e², shutting the cock f2, and opening all the
other communications between the vessels, but to complete the vacuum it
will be necessary that a small quantity of ether should be introduced into the
boiler, and the remaining air, mixed with the vapor of the ether, withdrawn
by the small pump D.
After working for a short time it will be found that the whole of the air
has been withdrawn, and that the vessels are occupied by ether vapor only.
The boiler is then to be supplied through the funnel n, with the ether intended
to form the permanent charge. The supply is continued so as to keep the
boiler filled up to the level of the second or third row of tubes from the top
as indicated by the guage m. After the pump A has been at work for a
short time the liquified ether will begin to return into the boiler, and thence-
forward the quantity withdrawn and returned will become self-regulated and
continuous. The inlet valve openings a¹, a², should be made as large as the
ends of the cylinder will admit, because the vapor on entering the cylinder is
much more rarified than when passing through the outlet valves b', 62. All
the valves, but especially the inlet ones, should be nearly balanced, so as to
move with delicacy, as well as certainty, or they may be worked by valve
gearing. The piston c is segmental with as few vacant spaces as possible,
and the stroke is adjusted so that the piston shall work closely to the top
and bottom of the cylinder, in order that the whole of the contained vapor
may be expelled at each stroke. As ether is a solvent of oil, it is necessary
to prevent the oil used in lubricating the piston from reaching those portions
of the apparatus containing the liquid ether, and for this purpose the vessels
g¹, g, are provided. The oil after escaping from the cylinder will flow into
the copper bottles attached to these vessels, and the bottles may be discon-
nected when they are supposed to be full. In replacing these bottles care
must be taken to expel the air from them, and this is accomplished by
placing a small portion of ether in them, and keeping them heated to 100°
while they are being fixed. On the top of these vessels are fixed h¹, h², the
pressure guages. The water required to assist in the condensation of the
ether vapor is first delivered between the casing d', and the cylinder where it
serves to keep the pump cool; the water then flows along a pipe to d², where
it passes downwards, and then rises from below into the space d, containing
the worms i, i, from the top of which it is allowed to escape by overflow
pipes. The quantity of this water will be regulated by the facilities for

page_text: obtaining it. The more cool and the more plentiful it is, the less will be the
power required to work the pump A:
The ether condensed into a liquid state by the internal pressure and the
external supply of water will flow along the pipe j¹ into the chamber F,
where it will raise the float ball Z and be forced up into the boiler, the pres-
sure there being much less than on the condensing side of the apparatus.
As the accumulation of air or vapor in the chamber F would impede the
return of the liquid ether, a return pipe is provided, passing into the
central vessel of the condenser at any convenient point. In the case of
repairs being required, or in order to clean out the boiler, the whole of the
ether contained in the apparatus may be withdrawn in a perfectly pure state,
by closing the stop-cocks ¹, k², and working the pump A until the gauge h¹
shows a nearly complete vacuum, then disconnecting the pipe j¹ at the stop-
cock, and allowing the ether to flow into the vessels prepared for its reception.
Should there be any foulness in the boiler it may be cleansed out with hot
water, and the impurities allowed to flow off by the tube proceeding from the
bottom of the boiler. All the stop-cocks must of couse be accurately fitted;
a leakage through the ways being, however, of less consequence than a leak
between the interior and exterior. The use of india-rubber as washers, or of
white or red lead in securing the flanges must be avoided, as they are acted
upon by ether. Gutta percha may be employed on the cold or rarifying
portion of the apparatus, but for the pump, and the condensation or warm
portion, metallic lead or solder have alone been found to be sufficient. In
order to test the soundness of the whole apparatus before commencing opera-
tions, a few pounds of pressure may be obtained by removing the cap e¹,
shutting the cock f¹, and working the pump for a few strokes, a leak will
thus be more easily detected than if a vacuum, instead of a pressure, had been
first employed. Should the apparatus be perfectly air-tight, the small pump D
will not require to be worked; but in case it cannot be dispensed with, the
ether which collects in the small condenser E must be periodically removed,
and the air outlet may be provided with a loaded valve, so that the quantity
of ether lost may be minimised to any degree. The surface of the boiler and
tubes is equal to 270 square feet, and of the condensers to 260 square feet;
but these surfaces may be varied, bearing in mind the rule that the larger the
surface the less will be the power required. The same proportions will serve
for machines of all sizes. The object of leaving two or more rows of the
tubes in the boiler uncovered, is that the vapor, if charged with any of the
liquid ether caused by its ebullition, may be dried, and that the evaporation

page_text: of the spray from coming in contact with the upper tubes may be utilized in
absorbing heat, as effectually as if the upper tubes were covered with liquid.
If this precaution be not attended to the particles of liquid carried up by the
vapor would become aëriform on their way to or within the pump without
producing useful effect.
The condensers are of great capacity in proportion to their surface, but this
is a necessary precaution in case of any leakage of air into the apparatus.
No air can accumulate on the evaporating side; but the whole would be
carried to the condensers, and if the space were not large a very small
influx of air would materially increase the pressure against which the pump A
would have to work. A tubular condenser similar to the boiler, but placed
perpendicularly, might advantageously be substituted for the coils of pipes,
but a large cylindrical vessel in connection with the lower part of the con-
denser and with the small pump D would still be requisite. The whole of
the vessels and tubes are of copper.
For the purpose of cooling or freezing water, the liquid intended to flow
round the boiler through the tubes, and over the exterior surfaces of the
vessels containing the pure water, may be a nearly saturated solution of
common salt.
For chemical purposes, or where an intense degree of cold is
required, a solution of potash or a mixture of alcohol and water, or alcoliol
alone will be preferable or requisite. The arrangement shown in the Drawing
is for the manufacture of ice. For this purpose the speed of the pump I is
regulated so that the solution shall flow from the vessel G into the trough H,
at a uniform temperature of about 26° Fahrenheit. The freezing trough
must be at a sufficient inclination to allow of the free passage of the solution
onwards, the rapidity of its flow, however, being dependent upon the height or
head in o¹. The overflow partition p² is about an inch lower than p', and the
latter is about the same below the maximum level in o¹. The solution flows
in the course indicated by the arrows in the spaces between the partitions
1, 2, 3, &c. and the ice moulds s¹, s2, s³, &c., until it passes 100 and $100, when
it returns by a pipe to the pump I, when the same course is recommenced.
The solution gradually abstracts heat from the ice moulds as it passes along.
These moulds are of tinned copper, but may be of any other suitable metal;
they are kept in their places by being let into notches at each end of the
intervals between the partitions r, r, r, so that none of the solution can pass
round the ends of the vessels, and that it must proceed regularly up one side
and down the other; the mouths of the ice moulds are raised about an inch
above the level of the current. The moulds are wedge-shaped, so that when

page_text: at the rate of half an inch per hour, required the following degrees of cold :-
Eighth
hour
Ninth
ditto
-
Tenth
ditto
-
Ice
formed.
Total
thickness.
1중
Temperature
below zero.
Eleventh ditto
Twelfth ditto
-
-
Thirteenth ditto ㅎ
-
Fourteenth ditto -
2
2
2
23
2½
20
9°
2°
3°
4°
5°
6°
I here stopped the machine for half an hour in order to observe the process
of the equalization of temperature, and the continued formation of ice from
the surplus cold contained in the mass. The result was that the temperature
of the refrigerating surface rose 13°, and the ice increased one-eighth of an
inch in thickness, or at one-half the rate at which it had been formed, while
the machine was in action. I continued the experiment until the ice was 5
inches thick from each surface or 10 inches in all, at which time the thermo-

page_text: meter indicated 9° below zero. The machine with which I operated was
capable of producing a degree of cold 20° below zero. The ice mould used
was cylindrical in shape, and the freezing process was carried on from the
circumference towards the centre, so that not only was a continually increasing
degree of cold required to produce a diminishing thickness of ice, but the size
of each succeeding concentric ring of ice became less and less.
I have been thus particular in describing this experiment, because upon a
due appreciation of the results depends success in the economical manufacture
of ice. Time and surface instead of increased intensity are requisite. In the
arrangement which I have figured, one hundred vessels, each containing 26 lbs.
of water, are arranged in the trough H. The cakes of ice will be wedges of
the
average thickness of an inch and a half. When the machine is set to
work, the freezing process at first proceeds with considerable rapidity in the
vessels nearest to the head of the stream, and the solution is raised to the
temperature of 32° long before it reaches the lower end of the trough. As
the process proceeds, the slow conducting power of the ice in the first vessels
allows the solution to carry its cooling power lower down, and by the time the
ice is solid in No. 1, the freezing process is going on throughout the whole
range. When one of the vessels of ice is removed, and a vessel of water
substituted, the new vessel for a short time abstracts a larger share of the cold
than its neighbours, until a crust of ice has formed on its inner surface. The
vessels in the upper part of the trough will require much more frequent
removal than those at the lower end, but the ice in the lower vessels will be of
a clearer and more uniform texture; the modifications of which this arrange-
ment is capable are many. If the thickness of the cakes of ice be diminished,
the process will be much quicker and a smaller number of moulds will be
required, but the manual labour of removal will be increased, and the degree
of thinness will be limited by the necessity of having a considerable difference
between the thick and thin edge of the block of ice; if the thickness of the
cakes be increased, the number of moulds would have to be increased also,
while the labour of removal would be diminished. The upper part of the
trough might be filled with moulds of greater thickness than those in the
lower part. The moulds at the lower end might be carried upwards to supply
the places of those removed from the upper, or the moulds might be fixed in
moveable sockets in a framework, made to advance progressively upwards, so
that each mould would be shifted to a colder position in proportion to the
thickness of ice formed within it. The plan which I have figured is that
which is characterised by simplicity and economy. The temperature of the

page_text: solution may be varied, but the nearer it is to 30°, the less will be the power
required to produce a given quantity of ice. The higher the temperature
however, the greater will be the refrigerating surface required in the moulds;
from 24° to 28° will be found to be a desirable medium, the power being the
same, the lower the temperature the slower will be the circulation of the
solution, and the higher the temperature the more rapidly will the pump I
have to be worked. It is not necessary that any given apparatus should be
worked at any fixed rate, because the relation between the parts can always be
adjusted to varying circumstances. Thus, supposing that there should be a loss
of power from any accidental cause, there will then be a surplus of refrigerating
surface; this additional surface can be utilized by increasing the rapidity of
the current of solution, so that a slower formation of ice will take place
throughout the whole length of the trough. And supposing that it is found
desirable to increase the power and to work the pump A at a more rapid rate,
the surplus power may be utilized by lowering the temperature of the solution,
and thus forming the ice more rapidly, especially in the upper portion of the
trough. I have figured an arrangement for causing the solution to traverse
the length of the boiler three times; the object of doing so is to insure a
uniformity, of temperature in the whole mass of solution. It is desirable that
every particle should come in contact with the metallic surface, and if the
current flowed only once through the tubes the centre of each stream might
be warmer than the sides, and could only get cooled by robbing the outside
particles. The number of traverses may be advantageously increased, but
should not be diminished. The whole of the vessels in the refrigerating half
of the apparatus must of course be well surrounded by nonconducting
materials, and the boiler case and trough fitted with double lids divided into
convenient lengths. In a large manufactory a partition should be erected, so
as to divide the condensing from the refrigerating apartment. The trough H
instead of being in one continuous length, may with advantage be divided,
and the lower half made to return so that the last division 100 and $100 may be
close to the pump I, and that the long pipe for the return of the solution may
not be required.
In the construction of small machines for domestic use, the subsidiary pump
D may be dispensed with, so also may the oil traps, the vacuum guage, and
air return pipe; the number of flanges and connections may be diminished,
and for the vessel F with its float valve a simple stop-cock inay be substituted,
and be turned by hand at intervals when the boiler requires replenishing.
Having supplied rules and proportions applicable to machines of all sizes so

page_text: far as relate to the more essential parts of the apparatus, I do not think it
necessary to point out any of the endless variations of detail of which the
subsidiary parts are capable.
For cooling worts, &c. no other modification will be required than the
removal of the trough Hand pump 1. The wort will be allowed to cool down
to 100°, or other convenient temperature in the ordinary coolers, and will then
be conveyed to the top of the boiler at o'; the rapidity of the stream will be
regulated so that it shall flow into the fermenting vessels at 60°, or other
desired temperature. As the ether vapor will pass off at a heat of 50° or
upwards, the power for the pump A will be very much less than that required
in the formation of ice, and the vapor being much more dense, a proportionally
larger amount of cooling effect will be produced by each stroke of the pump.
In the same manner brine intended for the curing of provisions may be cooled
to the temperature requisite for success in the operation of salting.
Where the apparatus is intended for the cooling of air admitted to apart-
ments in hospitals, &c. a very small machine will serve to cool a large
quantity of air; the specific heat of that body as compared with the latent
heat of ether vapor being very low, but the most satisfactory and uniform
results will be obtained by making use of currents of pure water cooled by the
apparatus. As the temperature would never require to be lower than 40°,
the point of greatest density of water, the currents might be made as in the
hot water apparatus to circulate by the gravity of a cold column overcoming
that of a warmer column, but the regulation of the heat would not thus be
sufficiently under control, and the moving power would be so feeble as to
render a stoppage probable. I therefore recommend the use of a pump to
force the cooled water to the top of the house, and by a regulating stop-cock
to allow the return current to fall upon the top of the boiler. Small gutters
would have to be provided where requisite, in order to carry off the moisture
deposited on the cold water pipes:
Figures 4, 5, and 6 are Drawings of another form of refrigerating vessel.
It is composed of flat sheets of copper t, t, t, placed vertically, or nearly
vertically, with similar sheets on the sides and bottom, the whole being soldered
together, so as to be perfectly air-tight. Between the upright plates are
fastened the half round wires u, u, u, these wires have their convex sides
uppermost, and are serrated or notched on the edges of contact, so that the
liquid ether delivered on the top wire will not only run along the slope of the
wires, but will ooze through the indentations: The spaces between the plates
communicate with the nearly cylindrical chambers v, v, where the vapor

page_text: accumulates, and whence it is withdrawn condensed, &c. as already described.
The liquid ether in returning to this refrigerating vessel after passing through
the vessel F is delivered upon the wires by the small tubes a, a, a, these are
of very minute diameter. It then flows by its own gravity along the wires,
and trickles downwards, evaporating as it descends. The liquid which is not
evaporated during this descent is drawn off by the pump y, and forced into
the chamber F, where it mixes with the liquid ether from the condenser. The
stream of ether is thereby so much augmented, that the interior surfaces of
the plates are kept continually moistened with liquid ether, and its volume
may be regulated at pleasure by the stop-cock z. The sloping wires serve not
only to convey and distribute the stream of.ether, but to strengthen the vessel,
and prevent the collapse which would otherwise take place with flat sheets of
copper under the pressure of the atmosphere. The freezing moulds are made
to fit the spaces w, w, w, so that by this refrigerator the ice is formed directly
and rapidly; but it may also be used economically by leaving a space between
the moulds and the flat plates, and passing a stream of saline solution through
this space, and causing it afterwards to flow along a trough similar to H in
Figures 2 and 3. By dispensing with the pump y, and allowing the ether to
fill the space between the plates, a new form of boiler is produced. In this
case the wires would have to be so inclined as not to hinder the flow of vapor
to the chambers v, v. This kind of refrigerator presents some advantages
for adaptation to small machines.
Having described the nature of my Invention, and the manner of performing
it, I now proceed to ascertain the points in which it differs from the more
general description of the process of refrigeration, by the continued evaporation
and condensation of volatile liquids in vacuo, given in the Specification of my
Patent, No. 747, A.D. 1856. I have herein described two new refrigerating
vessels, namely, a tubular boiler, and a series of vertical plates separated by
wires, and two new forms of condensers, namely, a coil of tubes connected
with a central cylindrical vessel, and a vertical tubular condenser combined
with a similar cylindrical vessel.
I am aware that the employment of saline solutions for carrying frigorific
power has been frequently proposed, but the economical use which I make of
this agent is not so much for the mere transmission as for the diffusion of this
power over a large surface, the necessity for which I have ascertained by
original experiments on the conducting powers of ice.
My Invention, as now perfected, consists in the combination of a refri-
gerating process by the continued and self-regulated circulation of a stream of

page_text: ether or other volatile liquid with the continued circulation of a stream of
uncongealable liquid, conveying and diffusing the frigorific effect over large
surfaces, and in rendering the process subservent to the manufacture of ice on
an economical scale, to cooling worts, &c., to regulating the temperature of
apartments, and generally to any process in which a temperature below that
of the season or climate is required.
In witness whereof, I, the said James Harrison, have hereunto set my
hand and seal, this Ninth day of March, in the year of our Lord
One thousand eight hundred and fifty-eight.
Witness,
S. CARPMAEL.
JAMES HARRISON. (L.S.)