NEW METHOD OF PERFORM- ING AND FACILITATING THE BUSINESS OF DIVERS MANUFACTURING AND ECONOMICAL PROCESSES
Year: 1795

page_text: BENTHAM'S SPECIFICATION.
TO ALL TO WHOM THESE PRESENTS SHALL COME, 1, SAMUEL
BENTHAM, of Queen Square Place, Westminster, Esquire, send greeting.
WHEREAS His inost Excellent Majesty King George the Third, by
His Letters Patent under the Great Seal of Great Britain, bearing date at
Westminster, the Twenty-fourth day of January, in the thirty-fifth year of His
reign, give and granted unto me, the said Samuel Bentham, His especial
licence that I, the said Samuel Bentham, during the term of years therein
mentioned, should and lawfully might use, exercise, and vend, within England,
Wales, and the Town of Berwick-upon-Tweed, my "NEW METHOD OF PERFORM-
ING AND FACILITATING THE BUSINESS OF DIVERS MANUFACTURING AND ECONOMICAL
PROCESSES;" in which said Letters Patent there is contained a proviso,
obliging me, the said Samuol Bentham, by an instrument in writing under
my hand and seal to 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 Majesty's High Court of Chancery within six calendar months after
the date of the said recited Letters Patent.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Samuel Bentham, do hereby declare that my said Invention is described in
manner following (that is to say) :-
My Invention consists in the idea of applying to the purposes of art and
manufacture, in the large way the practice that has been so long in use, of
extracting and excluding the air in the way of philosophical experiment. Air,
necessary as it is to the ordinary functions of life, is either known to be or
suspected of being an obstacle to art and manufacture in a great variety of

page_text: ways, whetherwith reference to bodies inken singly,orwith reference to bodies
considered in their application one to another, whether invirtue of its mecha-
nical orite chemical properties, and in both cases, whether in relation to processes
of a mechanical nature, or to processes of a chemical nature; whether in the
capacityof a cause of deterioration, or in that of an obstacle to amelioration and
improvement, whether in relation to colour or in relation to substance; and in
the case of the application of body to body, whether the bodies inquestion bein
the state of solidity, liquidity, or vapour, and if in a solid state whether in
masses or in powders. It may, in short, be considered in the capacity of an
obstacle to preservation, to seperation (as in the way of distillation) to the
effectuation of contact, to intromission, to impregnation, to transmission and
percolation, to mixture or to the regulation of heat by the degree of pressure.
By way of exomplyfying the uses that may be made of this my Invention, I
shall preceed to give particular examples of the several processes included in
the above general denominations, shew in what way the presence of the air
may be an obstacle to the accomplishment of the end in view, and thence in
what ways advantage may be reaped from the extraction and exclusion of it.
1. Preservation in point of substance.-There are few substances but what
when exposed, as in the natural course of things almost every thing is to the
action of the atmospheric air, are subjected to certain alterations, which are
understood to dependingreat measure upon the presence of that element, and
which, so far as that is the case, may be prevented by its extraction and
exclusion; such, for example, are the putrifaction of animal and vegetable
substances in general, the alteration which causes rancidity in oils, the rusting
of metals, &c. The practice of potting solid substances in a substance, which,
like fat, is fluid in the degree of heat at which it is applied, seems to owe its
preserving quality in good measure to the exclusion of the air, by means of the
fat's insinuating itselfinto all the vacuities; whereby an air pump or otherwise
the air can be perfectly extracted from all such vacuities and the subject kept
inclosed in an exhausted chamber, a degree of preservation as perfect as in the
former caso may be expected.
Preservation in point of colour.-Many of the changes, to which bodies
are subject in point of colour, are known to result from the action of
the air. An exhausted chamber affords the means of preserving them from
all such changes for any length of time, care being taken to exclude the light
when the presence of that element also is found to influence the result; thus
tarnishing, fading, and other such injuries may be prevented.
2. Distillation. The greater the quantity of the air in the still the greater
the pressureupon the substance from which the distillation is to be performed

page_text: and the greater the quantity of heat necessary to enable any portion of that
substance, whether it be in a solid or in aliquid state, to assume an elastic state
and so pass into the receiver, extract the air from the whole of the inclosed
space (still and receiver), you subtract in proportion from the pressure, and by
that means from the quantity of heat necessary to the distillation. From the
reduction that may in this way be made in the quantity of heat necessary to
distillation a variety of advantages may be derived.
1. The injuries which various substances are apt to sustain from certain
degrees of heat; the burnt flavor (for example) called empyreuma, in the
distillation of oils and spirits, may be prevented from taking place.
2. Less fowel need be consumed, and a similar saving may be made in the
applying to this purpose the superabundant heat of fewel consumed for other
purposes, and in some cases heat obtained from other sources than that of com-
bustion, as from the rays of the sun, from feimentations, and from chemical
mixtures.
3. Effectuation of contact-The presence of air is an obstruction to many
processes which consist, in the bringing about a uniformly close though simple
contact betwixt body and body, whether junction by cohesion or configuration
be the result intended. Hence, the expulsion of the air may be made to give
facility to the operation of coating the surfaces of metals, stones, glasses,
pottery, wood, horn, ivory, bone, or other hard substances
, melted
or unmelted, of metal or other materials, as in plating, tinning, guilding,silver-
ing, painting,tarnishing, and the like; so likewise to the operations of casting,
whether of metal, glasses, wax, plaister of paris, papier maché, miscellaneous
compositions, or any other materials, simple or compound, capable of being
made fluid or ductile by fusion, solution, or otherwise.
4. Intromissiou into tubular or other cavities maybe regarded as a modifi-
cation of the process of producing simple contact-Hence, the expulsion of the
air maybemade togive facility to suchoperations as thoseof fillingthermometer
and barometer tubes, filling beads for necklaces, hollow globes for mirrors, and
to all other instances of intromission where either the smalluess of the orifice
or the irregularity of the canal oppose difficulties to the expulsion of the air
otherwise than by exhaustion.
5. Impregnation.-By the expulsion of the air this process may be facili-
tated in every instance, whatever be the design of the impregnation, the nature
of the solid to be impregnated, or of the fluid with which it is to be im-
pregnated. This facility maybegiven to theprocess of dyingfilamentous or other
fibrous or porous substances woven or unwoven, where according to the pre-
sent method the presence of the air operates as an impediment to the equal

page_text: other
application of the mordant or the dye to all the surfaces or all the pores; so
likewise to the staining of wood, straw, bone, marble, &c.; so, for example, to
the impregnating of skins with an infusion of tanner's bark, or other astringent
or preservative ingredients, for the purpose of preserving them from putre-
faction; so, for example, to the impregnating any substance with any
substance, whether in a liquid state of vapour, with a view to the preserving
the substance in question by the exclusion ofatinosphericalair; so.torexample,
to the impregnating of meat, fish, and other kind of provisions with salino
solutions, or other anti-putrescent applications, in which instance the laborious.
tedious, imperfect, and uncleanly operation of rubbing may be saved; so, for
example, totheimpregnating of wood or other fibrous and cillulated masses with
any substance for any purpose, for instance, with saline solutions, to preserve
them from putrefaction and combustion, with oleaginous matters to preserve
them from putrefaction, or with poisonous matters to preserve them from cor-
rosion by the sea worm or other insects.
6. Transmission and percolation.-By the saine means the process of por-
colation or filtration may be rendered comparatively instantaneous, whether
the object in view be the purification of the fluid transmitted, or the purification
of the substance through which it was to be transmitted. Thus water, for
example, may be filtered through stone, uatural or artificial, in masses, or
graduated powders, with a small apparatus, in a short time, in quantities
sufficient for large consumtion, as in a ship at sea. Thus also may water or
anyother fluid be driven through skins, for example, to prepare them to receive
the tan, or through wood, to cleanse it from its putrifiable juices. The expe-
dition thus given is attended with further advantage where the liquid if not
speedily transmitted may grow solid by abatement of heat before the process
is compleated, as in the case of portable soups, glues,aud other golantinous
solutions, or run into crystallization, or destroy or injure the filter,as in saline
and other chemical solutions and mixtures.
7. Mixture, viz., of fluid masses with powders or heeps of small sized
bodies. By the same means may this process be accelerated, and in some
instances with the advantage of an increased degree of uniformity and com-
pactness given to the mixt mass. Thus, for example, to operation of mixing
malt or grain with water for the purpose of brewing may be rendered com-
paratively instantaneous; so, for example, the mixture of water with lime or
plaister of paris, and with sand or terras, or other powders, for making mortar,
stucco, or other mortar-like cements, and the mixture of oils with different
powders for the making of glazier's putty and paints.
8. Regulation of heat. By the process of distillation when curried on in

page_text: vacuo a means is afforded of producing a balneum, in which any degree of heat
may be maintained at pleasure and for any length of time from a degree some-
what higher than the lowest at which the liquid can be made to distill in
vacuo up to a degree anything less than that which would cause the vapour of
the liquid (whatever it be) to burst the still. For this purpose, conceiving the
contents of the still (whether the liquid or the vapour or both together) to
constitute the balneum, nothing more is necessary than to stop the passing of
the vapour out of the still into the condensor by a valve, so loaded by deterini-
nate weights or other means as to confine the vapour till it has acquired the
intended degree of heat. By means of the extension thus given to the scale of
temperature by the removal of air, a balneum of regulated heat will be pro.
duced, such as, besides the many chemical purposes to which the existing
expedients for the regulation of heat have been applied, may be applicable
with advantage to a variety of objects, as well of a mechanical as a chemical
kind, hitherto unattempted; for instance, to the preserving motions in mecha-
nism, clock work, for example, from the irregularities to which, under the
ordinary fluctuations of temperature, they stand exposed.
9. Exsiccatiou.-Distillation may be applied likewise, and in some cases
with advantage, to the purpose of seperating fluids from solids, and thereby
drying substances impregnatedwithwater or other fluids. Wood, for example,
may perhaps be dried in this way in a small degree of heat and in a short
space of time. Several of these operations being such for the performance of
which the experimental apparatus that forms the common accompaniment to
a philosophical air pump could not by the mere enlargement of its dimensions
be made to suffice, in the way of instruction to shew how an apparatus of that
sort may be modified for the purpose of adapting it to those purposes, may be
found of use.
1. As to the vacuum chamber receptacle, which is to be exhausted of its
air, and into which the subjects of the several processes are respectively to be
introduced.-The bulk of it will of course be regulated by the scale on which it
is proposed to operate. Like the vessels of a large brewery, it may be of
the size of a large room. In general it should be no larger than necessary,
since the greater the space left unoccupied by the subject in question, the
greater the quantity of air to be extracted. In the same view there may be
an advantage in adapting the form of the chamber in some measure to the
form of the subject to be contained in it. Of course it would not be made of
the same shape for a plank of timber as for a barrel of provisions. Where flat-
ness is not necessary convexity will be preferable,ou account of the advantage
it gives in point of strength. To enable the operator to see the processes as

page_text: they go on, the chamber may have glass windows to it, but it is evident the
glass must be thick, to enable it to resist the pressure of the atmosphere, and
must be fitted in, in the closest manner. Whatever apertures the particular
process in view may require to be made in it, the smaller they are made the
better, the difficulty of close fitting increasing with the size. For the closing
of these apertures the expedients already may suffice. For the accomplish-
ment of such a variety of purposes, a variety of operations may respectively
require to be performed, to some of which a variety of machinery, and
that more or less complicated, may be necessary. As in all or most of these
instances the source of motion will be exposed to the external atmosphere
while the subject to be operated upon will be in the vacuum chamber, the
most commodious means of transmitting the motion from the one of these
situations will on this account be an object of attention. The methods already
in use in the way of experiment, such as the collar of leathers will in general
be found sufficient, however large the scale. A spindle sliding in such
a collar gives rectilinear motion; a spindle turning round on its axis gives
circular motion. From one or other of these twe, or indend from either of
them, any other motions may be produced at pleasure; agitation or pressure
by stampers, rollers, or screws, may serve for examples amongst a thousand
others. The friction that may appear essential to such a mode of communi.
cation will naturally render it advisable that the motion should at that stage of
it be slow, but within the chamber any degree of quickness maybe obtained by
thewell known contrivances of acceleration of the friction; so much asdepends
on the pressure of the external air may be got rid of by substituting to the
pressure of a closefittingcollar like that of leathers,that of a column of mercury,
of a height sufficient to counterballance the greatest weight of a column of the
atmosphere, forming by this means an annular stopple in which the axis
of communication plays. To facilitate the extrication of air from bodies in
different states, different operations may come to be requisite. Where the
substance of the body is of an adhesive nature, the particles of an inferior
stratum of it may come to be forced together by the pressure of the superior
strata in such manner as to form a kind of cells, within which small masses of
air may be peut up. In proportion as a mass is thus disposed to keep air
entangled in it, to extricate the air it becomes necessary to break up the whole
mass in such manner that the boundaries of the several cells may be broken
down. This may be done by making the mass'in its way from the vessel that
contains it to the vacuum chamber pass in a highly divided state; for instance,
through a kind of cullender or sieve, or filtering stone. If the mass is too
viscous to be treated as above, so much as to form, for example, a kind of

page_text: paste, butter, for instance, it may be kneaded by a kind of stampers, or the
whole mass may be forced through slits or holes like vemicelli or macaroni,or
passed between rollers, spreading it out into ribbons of any degree of thinness
From the apparatus thus employed in the comminution, the subject matter at
the close of the operation may fall into the vessel, a cask, for example, in which
it is to be packed. The path of its descent may be inclined, in order to leave
room for a perpendicular descent for the purpose of pressure. This pressure
may be performed, for example, by a kind stamper or piston, so ordered as
that the frequency of its descent shall correspond with the rate at which
the cask is fed as above. When the cask has thus been filled, the cover
being conveyed by a movement from its station within the chamber to the
to the the top of the cask, may then be pressed down upon the cask by the
same apparatus with which the mass is pressed in, leaving the fastening
to be secured at leisure by screws or otherwise after the chamber has been
opened, but before the pressure has been removed. If the subject matter is
in small masses of a yielding nature, for example, in the form of minced meat,
more or less dried, it may be discharged into the cask by tilting; for example
from a vessel of larger content suspended above the cask, the rate of feeding
being regulated as before, in correspondency with the strokes of the pressing
machine. The use of the packing thus close is partly to prevent the air from
insinuating itself into the mass through the vessel, so that an ordinary cask may
suffice, partly to prevent the component parts of the cask from being unequally
forced in, and thus forced asunder by the pressure of the atmostphere, partly
to prevent the air from re-insinuating itself into the mass when the package
is opened for use & partly to save stowage. To assist the perfecting the
business of cementation by the exclusion of the air, it may be of use that the
operation of supplying the cement should teperformed in the vacuum chamber
itself, after the air has been extracted from the pores of the substanceinto
which the cement is intended to be introduced. Thus, for the gluing of two
boards together, for example, one may be flat upon the bottom of the vacuum
chamber, the other remaining suspended directly over it, and at such a distance
above it as there be sufficient to admit a brush to apply itself between them.
This brush may either have been previously impregnated with the glue, or it
may contain in the handle, for example, a reservoir of the fluid, which may be
discharged when wanted. In many cases of impregnation and transmission,
the fluid which it is intended should be forced through or into the subject
matter finds its intended place already occupied by another fluid, which it
must consequently drive out. In these cases and advantageous way of effect-
ing the exchange is so to order matters that the inclosure of the subject matter

page_text: in the vacuum chamber shall be partial, only leaving one part exposed to the
pressure of the external atmosphere, with no other covering than that of the
impregnating fluid. Suppose it, for example, a ekin, which is to be impregnated
with the liquids respectively used for tanning and currying; at the top, the
materials for the vacuuin chamber instead of beingair-tightare of a permeable
texture, in the manner of a sieve, of a convenient degree of fineness, with a
support of a strength proportioned to its extent, anil composed, for instance, of
bars or grating; upon this sieve, the skin being stretched, is covered with the
fluid. The figure of the skin, however, being irregular, will never exactly
cover the whole of the permeable part of the chamber, if it is equally extensive
in its greatest dimensions it will fall shortin other places; so far as this is the
case, the deficiency must be supplied by another covering impermeable to air,
such as oiled silk, leather, or some ductile cement, which supplemental cover-
ing must be made to apply itself as accurately as possible to the edge of the
skin, that the air may find little or no space at which it can insinuate itself
between them. Suppose now the body into or through which the fluid is
intended to be forced by a log of wood; the varieties, of which the construction
of the apparatus is susceptible, inny be comprised under two principal cases i
either the whole of the log, one end excepted, will be within the chamber,that
end ouly remaining exposed to the fluid without; or the whole of it, one end
excepted, will be exposed to the fluid,without thatone end alonebeingintroduced
within the chamber. In the first case, the chamber must be large enough to
contain the log; in the other case, there must indeed be without the chambera
vessel large enough to contain the log, together with the fluid with which it is
encompassed, but the chamber itself need only be of such a size as to have one
of its boundaries large enough for the log to fit into. What the log wants of
filling up the aperture thus left in the chamber to receive it must of course be
filled up air-tight at each operation, for instance, by wedges of wood with a
cement. It is scarce necessary to observe, that wherever air is intended to be
or happens to be extricated gradually, or at successive periods, there the
operation of exhaustion will in proportion require to be either continued or
repented. Where heat is to be transmitted from without the vacuum chamber
to a body within it, the intervention of an intermediate body or mass for the
more ready conducting of the heat such as a metallic substance or sand, for
instance, may sometimes be of use.
In witness whereof, I, the said Samuel Bentham have hereunto set my
hand and seal, this Twenty-fourth day of July, in the year of our Lord
One thousand seven hundred and ninety-five.
SAM BENTHAM. (L.S.)

page_text: AND BE IT REMEMBERED, that on the same Twenty-fourth day of
July, in the year above written, the aforesaid Samuel Benthani came before
our Lord the King in His Chancery, and acknowledged the Specification
aforesaid, and all and every thing therein contained, in form above written.
And also the Specification aforesaid was stamped according to the tenor of
the Statute in that case made and provided.
Inrolled the same Twenty-fourth day of July, in the year above written.