FOR PRESERVING DECKED SHIPS OR VESSELS, SO AS TO RENDER THEM LESS LIABLE TO THE DRY ROT, AND FOR PRESERVING GOODS ON BOARD SUCH SHIPS AND VESSELS FROM DAMAGE BY HEAT
Year: 1827

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
GEORGE, of No. 11, Chancery Lane, in the County of Middlesex, Esquire,
Barrister-at-Law, send greeting.
WHEREAS His present most Excellent Majesty King George the Fourth
did, by His Letters Patent under the Great Seal of Great Britain, bearing
date at Westminster, the Eighteenth day of December, One thousand eight
hundred and twenty-seven, in the eighth year of His reign, give and grant
unto me, the said John George, His especial licence, full power, sole
privilege and authority, that I, the said John George, my executors, ad-
ministrators, and assigns, and such others as I, the said John George, my
executors, administrators, and 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 "FOR
PRESERVING DECKED SHIPS OR VESSELS, SO AS TO RENDER THEM LESS LIABLE TO
THE DRY ROT, AND FOR PRESERVING GOODS ON BOARD SUCH SHIPS AND VESSELS
FROM DAMAGE BY HEAT;" in which said Letters Patent there is contained a
proviso that I, the said John George, 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 Majesty's High Court of Chancery within
six calendar months next and immediately after the date of the said in part

page_text: recited Letters Patent, as in and by 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
John George, do hereby particularly describe and ascertain the nature of my
said Invention, and in what manner the same is to be performed, as follows
(that is to say) :-
With respect to the nature of my said Invention, the same consists in the
making of the herein-after described combination of the herein-after described
alterations in decked ships and other decked vessels, for the purposes of navi-
gation, and of the herein-after described apparatus and machinery to be
placed and used on board of the same, for causing and keeping up, when and
as often as is requisite and the safety of the vessel will permit, a regulated
supply, circulation, and change of the common air of the atmosphere in and
through the interior, or any particular part of the interior, of such vessels, for
thereby and therewith as often as is practicable, and occasion requires, causing
heat to enter into or to pass off from the same in and along with such air for
bringing and preserving the temperatures at the opposite sides of the timber
of such vessels near to an equilibrium or the same temperature, and thereby
preventing either wholly or as far as is practicable, by the means used, any
current or stream of heat, or any considerable current or stream of heat, from
penetrating the timber of such vessels on one side of the timber, and passing
through its substance and out of it at another side thereof, for the better
preservation of such timber from the said premature decay and decomposition
of timber, commonly called the dry rot, and also by so causing heat to pass
off out of such vessels, for the better preservation of goods on board thereof,
from damage by heat.
Before proceeding particularly to describe the said alterations, apparatus,
and machinery, I shall, for the readier understanding of my said Invention,
state some matters chiefly explanatory of its more general and leading
principles. The reason for seeking to prevent any current or stream of heat
from passing through the timber, as before mentioned, for better preserving
it from dry rot, is, that when that kind of decay of timber takes place it is
commonly (if not always) where the temperature of the air, or earth, or water
and other substances in contact with and near to the timber on one side of it
is higher than the temperature at the opposite side, and where the timber is
placed in such a situation and circumstances as that a current or stream of
heat more or less rapid or considerable issuing from the substances of higher
temperature on the warmer side is commonly passing through the timber
from the warmer to the colder side, and out of it into the colder substances

page_text: at the latter, and that in such case it is the heat coming into immediate
contact with every part of the interior of the timber in such its passage
through it, and exerting an action of some sort on it, and on any wet (if
any) that happens to be contained within it, that by degrees, when the action
of the heat is sufficiently quick, and is continued in the whole sufficiently
long, causes the decay.
For further conducing to the readier understanding of my said Invention,
I next state that the reason why any such passage of heat through the timber
is sought to be prevented means of a regulated supply, circulation, and
change of the air of the atmosphere, as before mentioned, is, that heat rapidly
both enters and leaves atmospheric air, and that where timber is situated
as before described, while such a regulated supply, circulation, and change
of colder air on the warmer side of the timber, or of warmer air on the
colder side, will bring the temperatures on the opposite sides towards an
equilibrium, and will thereby prevent or lessen any passage of heat through
the timber, an immoderate and unregulated supply of such air may be
such as to convey such a quantity of heat to or from the timber as to produce
the evil by causing a current of heat to set through the timber from the
opposite side to that which was at first of the highest temperature.
Further, as to so much of the said combination constituting my said
Invention as is for the passing off of heat from the interior of vessels, tho
same comprises the following principal parts.
First, a separate passage or hollow shaft is to be made of some solid
material impervious to air, and placed upright within the vessel, so as to
descend from the deck or upper deck sufficiently low down in the interior
for introducing colder air without allowing it to mix with the mass or body
of air already in the vessel, directly down to near the lowest level from which
the passing off of heat may be required, and hollow trunks or other inclosed
passages, with sides impervious to air, are to be made and to be attached to
such shaft, so as to communicate internally therewith, for conveying the air
to the several parts of the interior from which the passing off of heat is
required; and where the depth of the vessel, and the quantity of heat which
it may be required to pass off, are sufficiently great to render it necessary.
The said trunks are to be joined to the shaft at different heights or levels,
in order to convey the air to the parts where it is needed at different heights
or levels, as occasion requires, and on each occasion of introducing colder air
it is to be conveyed as near as conveniently can be to the lower level of the
part from which the heat is to be passed off.
Secondly, the said trunks are to be furnished at different places at proper

page_text: distances from each other, as herein-after mentioned, with sliding hatches, or
other similar contrivances for regulating the size of the passages for the
air through the trunks at such places, and consequently the quantity of air
permitted to pass, and beyond the hatches (reckoning from the shaft) are to
be the orifices for the issuing of the air from the trunks, and these orifices are
to be furnished with valves, as herein-after described, constructed so as to
open by 8 slight pressure of the air, and permit it to pass out of the trunks,
and to shut of themselves on the ceasing of the pressure, and prevent the
air from returning.
Thirdly, separate apertures, to be situated at proper distances from each
other, as herein-after mentioned, are to be made in the highest parts or
decks, forming the roofs of the several holds, rooms, and other places into
which the colder air is introduced for the passing of it off after cir-
culating therein, together with the superfluous heat that has become mixed
with it, out of the vessel into the open air; and each of these apertures is
to be furnished with a valve, as before mentioned, for permitting the air to
pass out and preventing its return. The use or object of the hatches for
regulating the quantity of air to be permitted to pass is to prevent any such
consequence, as before mentioned, from an immoderate and unregulated
introduction of colder air into the interior of a vessel, and the reasons for
admitting colder air in the first instance by a distinct passage down to near
the lowest parts of the vessel requiring the passing off of heat, and for
conveying the same by hollow trunks or inclosed channels to the lower parts
of the several places or levels where colder air is required, and for passing it
off after it has circulated therein by separate. apertures in the highest parts
of such places, are, that colder atmospheric air is, ceteris paribus, specifically
heavier than warmer air, and that when the outer air is colder and is in fact
specifically heavier than the air in the interior of a vessel, if it be introduced
below the body of the warmer air in the interior it will by its greater weight, and
the weight of the column of outer air which continues to supply it, push the
warmer air before it up through such apertures out of the vessel, and as it
becomes warm it will be itself pushed up and out in its turn, and that thus
a more quick and regular circulation and change of such air and passing off of
heat can be caused than there could be if the colder air were only brought
immediately over the body of warmer air contained in the interior of a
vessel into contact therewith, or than if although conveyed as low down as
required it were not conveyed along within the interior to the parts where
required, or than there could be if no other aperture than that by which it
was introduced were provided for the passing of it off when heated..

page_text: Other parts of the said combination, constituting my said Invention, consist
in apparatus and machinery, herein-after described, as well for removing out
of the vessel such heavy gases or air as would otherwise by their weight
stop or prejudicially lessen the before-mentioned introduction, circulation, and
change of air for passing off heat, as for introducing the air of a higher
temperature which is to be introduced into any part of the interior, and which
is to be introduced by removing the colder air already therein, and thereby
causing the warmer outer air to descend into the vessel and take its place, and
for which purposes such apparatus and machinery are to be constructed (as
herein-after described) in such manner as to be capable of receiving the
heavy gases, or heavy or colder air at or near the lowest part of the hold, and
at such different heights or levels above the lowest as any material differences
of temperature are liable to be found at, or at any one only, or any more of
such heights or levels at pleasure. For ascertaining when to introduce into any
and what parts of the vessel either warmer or colder air than that already
therein, thermometers are to be provided and used for taking observations
of the temperatures at the same time of the air within the vessels and of
the air and water at the outside, at places immediately or as nearly as
practicable opposite each other at the opposite sides of the timber of the
vessel, and at such depths or levels, and at such distances from each other
at the same depth or level as any material differences of temperature are
liable to be found at; and on such temperatures being ascertained, and any
such differences of temperature found, the principal object will be by means
of introducing and passing off colder or warmer air, as the occasion requires,
and the circumstance of the case will admit of, to bring the temperatures on
each side of the timber as near to one and the same as is necessary or
may be practicable, by the means used, to prevent, as before mentioned,
either wholly or as far, as is practicable, the passage of heat through the
timber.
Having made the foregoing statements for conducing to the readier under-
standing of the general nature and leading principles of my said Invention,
I next proceed particularly to describe and ascertain the nature thereof,
and in what manner the same is to be manufactured and performed. With
respect to the alterations to be made in the vessels, instead of constructing
them, or suffering vessels already built, to continue, with only common hatch-
ways or other entrances into the interior thereof in the manner and for the
purposes now used, make in addition thereto, at or as near to the middle of the
vessel as conveniently may be, an opening through every deck directly down
to the bottom of the hold. In this opening (the most convenient form for
which will be square) construct and fit a hollow shaft or passage for the air,

page_text: reaching from the deck or upper deck down to the level of the top of the kelson.
This shaft should be of timber or some other substance impervious to air, and the
less pervious it be to heat the better, and its sides and bottom are to be air-
tight in every part, except where there are to be apertures therein, as herein-
after described. By placing the shaft at or about the middle of the vessel, its
lower end will continue of a more equable depth in the water in the different
changes in position of the vessel, and the trunks herein-after mentioned com-
municating therewith will be of more equal lengths. Provide for the opening
in the deck for the shaft a coaming, with a common hatch for closing the same
when necessary; construct and place within this shaft another hollow shaft,
made to fit and slide up and down in the former, and so as when drawn up to
constitute with it one hollow shaft, consisting of two parts, one part fixed
below deck, and the other moveable up and down within the first. Make the
moveable part open at the bottom, and make it of such a length as when fully
raised up to reach above deck to a height of from three or four of its diameters
in the largest sized apparatus to five or six diameters in the smallest, and
make it to let down in the other part so far as for its top when down to be
just below the level of the lower side of the deck. Any adequate tackle may
be used for raising and lowering this moveable part of the shaft, and sustaining
it at any required height. The opening in the deck being square, the shaft will
be rectangular, with equal sides. Make the moveable part of it at the four
corners, and at the top and bottom, of a sufficiently strong framework of
carpentry. Make a cover for the top, projecting sufficiently on every side to
shoot off rain. Immediately below the framework of the top of the moveable
part of the shaft make in each side of it an oblong aperture, equal to the
area of the hollow within. Provide each aperture with a shutter or sash,
fitted into suitable grooves, so as to slide up and down after the manner of the
window glasses of a coach, or the sash of a sash window, and so as when
drawn quite up to close such aperture, and provide and attach to each shutter
a web perforated with holes at small distances from each other for hitching
the same on a projecting metal button at the bottom of the aperture for
pulling the shutter up and down with, and sustaining it at different heights
according as may be desired, or provide any other convenient means of
effecting the same purposes. For using the shaft raise the moveable part
above deck and lower one or two of the shutters, and lower the most leward
or the most windward shutters, according to the quantity of the wind and the
quantity of heat which it may be required to pass off from the interior. The
principal objects of providing a moveable part of the shaft to stand up a certain
height above deck when in use are, first, to catch the wind; secondly, to regu-
late with more facility and exactness the size of the apertures for the entrance
s.

page_text: of the air; and thirdly, to provide the higher or taller a column of descending
air within it, for more quickly overcoming occasional checks to its entrance
into and circulation through the interior. Attach to each side of the shaft, fore
and aft, in apertures to be made therein just above the level of the kelson, a
hollow trunk or other such inclosed channel for the passage of the air from
the shaft, extending in as straight a line and as nearly along the middle of the
vessel as practicable, through every bulkhead or partition, and round or (if
necessary) through the step of the fore mast sufficiently near to each end of the
vessel to convey the air thereto, and continue the trunk for its whole length at
nearly the same height above or distance from the kelson; and in case there
be any separate inclosed places at either side into which the trunk does not
enter, attach lateral trunks to it to reach into such places at their lowest parts.
Insert in the bottom of the shaft an air trap to permit water to drain into the
well, and to intercept the farther downward passage of the air. In cases
of holds or other places of such a considerable depth as that it may some-
times be required to pass off heat from the upper parts thereof while the
temperature of the lower parts thereof ought not to be lowered, attach
to each side of the shaft fore and aft, as before mentioned, in the same
hold, over each lower trunk another trunk, with any necessary lateral trunks
thereto to extend near to each end of the vessel, and into any separate inclosed
places situated at either side of the leading trunk, as before mentioned, and
join the same to the shaft at such a height above the lower trunks as any
material difference of temperature is liable to be found at, and place the
additional trunks so as that they may have a sufficient rise from the shaft to
their farther ends for any water that may possibly in some circumstances
collect therein, to readily drain into the shaft when the vessel is upright, and
fix and suspend the additional trunks from the roof of the hold, or from any
beams crossing the same, situated below those of the deck, forming such roof
at the required height. And in general an advantageous situation for such
additional trunks will be at about half the height between the lower ones and
the roof of the hold, unless the level of the water line is somewhat higher than
this, and is at the same time some feet below the roof, in which case the
additional trunks may advantageously be placed somewhat higher than the
mid-height, in order to be nearer the level of the water line; and to specify a
particular depth of hold as sufficient to render such additional trunks desirable,
I recommend the same for any hold more than ten feet deep above the lower
trunks, and I recommend farther additional trunks for each further depth of
hold of from eight to ten feet, according to the greater or smaller quantity of
heat likely to require to be passed off therefrom. Where, however, the depth

page_text: of the hold is such that, according to the directions above given, it will not
require more than one level or main of trunks, instead of placing them as
directed just above the level of the kelson, place them at about one fourth of
the height of the hold above such level. Where the vessel contains more
than one deck, provide an additional set of trunks for supplying colder air to each
space between decks, and for this purpose the trunks may, as may be deemed
most convenient, either be placed upon and along the deck forming the floor
of the space between decks to which they are to convey the air, or be placed
at the under side of such deck, in which latter case attach other trunks to
them to pass vertically up through apertures to be made in such deck into the
several places immediately over it, and there make and construct such last-
mentioned trunks so as to turn and be bent at right angles to the vertical rise
thereof a sufficient length for inserting therein the sliding hatch and valve
herein-after mentioned and described. And where the vessel contains a
quarter deck poop or forecastle, in order to convey colder air to the cabins
and other places situate immediately underneath the same, attach one or more
upright trunks, as may be most convenient, to the trunk for supplying the air
to the places next below the deck forming the floor of such last-mentioned
cabins and other places, and pass such upright trunk or trunks directly up
through such deck, and there construct the same so as to be capable of receiving
the like hatch and valve as last mentioned. Make the trunks rectangular and
of timber or other materials little pervious to heat; make one or more orifices
for the issuing of the air from the trunks in each separate inclosed place
throughout the interior, and the distances of such orifices from each other in
the same hold or place should be greater or less according to the greater or
smaller quantity of heat liable to require to be passed off from the particular
place, and I recommend that such distances be from about twenty to thirty-
five feet. And wherever an orifice is required in any trunk (except at its
farther end from the shaft) attach a square hollow projection or box to one of
the sides of the trunk to communicate by an aperture in such side internally
therewith, and make in the top of the projecting part a circular orifice for the
issuing of the air, and make a like orifice in the top of each trunk itself, near
its farther end; place, so as to cover and slide up and down against each
such aperture in the side of each trunk, and also in and across the trunk itself,
near the orifice at its farther end, but between the orifice and the shaft, a
sliding hatch or other such contrivance made to draw in and out, and con-
structed so as to admit of being kept drawn in or out to any greater or lesser
extent at pleasure, for regulating the size of the aperture for the passage of the
air through the same. In each orifice place a valve that will permit the air on

page_text: a slight pressure to pass out of the trunk, but prevent it from returning. How
to make such a valve is herein-after pointed out. Make the orifice for the
lower half of the thickness of the board or other material of the trunk or its
projecting part of an inch smaller diameter than for the upper half, so as that
there may be a ledge half an inch broad all round for the valve to rest on
within such orifice. For protecting from accidents each valve not otherwise
protected, place a coarse wire grating over and round it, at a few inches from
it; whenever any of such hatches, valves, and orifices are situated in a part of
the vessel where they will be at a depth below goods, make and fix a lattice-
work of carpentry round the hatch and orifice to reach above the goods, and
make it sufficiently wide or large for passing the valve up and down within it,
and for it also to contain a rod of wood or metal to be attached to the hatch
for drawing it in and out. And in case the goods are to be stowed so high as
to leave no sufficient room in the same hold or place for passing to the rod,
continue the latticework up to the deck above, and make an aperture through
the deck for passing the valve when necessary up and down through it, and
for there raising and lowering the rod and sustaining it at different heights, as
may be required, and also for letting down thermometers within the lattice-
work to different depths in the interior. Provide for each aperture a plug or
cap scuttle, with a notch in it for the rod to pass through, and make it to fit
both the aperture and the rod for securing the former when necessary, and
provide also a jointed rod with a hook at one end, such as herein-after
respectively described, for taking up and letting the valve down with. For
the quicker circulation and change of the air in and through the interior, and
the consequent quicker introduction or passing off of heat into or from
the same, and more especially for the quicker passing off of heat from goods
liable to damage by heat, provide a sufficient number of loose rectangular
battens of wood, at least twice as wide as thick, perforated through the two
narrower sides with holes as large and numerous as the requisite strength of
the battens for the purpose for which they are intended will permit; and in
stowing the goods place the battens at convenient distances from each other,
both under and between the several tiers and rows of bales, casks, or other
packages, so as to preserve passages for the air between each tier and row, and
so as that the perforations in the battens will admit the air entering from the
valves of the trunks freely to circulate amongst the goods, and readily pass off
after circulating between the same. As well to prevent heated air from
remaining lodged against particular parts of the under side of any deck, as for
the quicker introduction of warmer air when necessary, make and leave
immediately beneath the planks of the decks open spaces of about one third

page_text: the width of each plank, and of the depth of from three quarters of an inch to an
inch and a half for the passage of the air between such planks and the beams,
ledges, and carlings, or other supports thereof; and in making this alteration in
vessels pay due regard to preserving them of proper strength; and for this pur-
pose I recommend giving to the beams and the other supports of the planks of
the decks an increased depth, equal to two thirds of the depth of the open spaces
intended to be left, and to make curved gougings of the length and depth above
designated in and across the upper sides of such beams and other supports.
Also leave the like open spaces at the tops and bottoms of all bulkheads or
other partitions in the interior, save that the open spaces at the bottoms of
bulkheads and other partitions may properly be of little more than half the
dimensions of those at their tops. If the open spaces just described are left
under the planks of decks, and at the tops and bottoms of bulkheads, openings
for the passing off of the heated air will not be necessary in the upper
part of every small separate inclosed place, but otherwise such an opening
should be made in the centre of the highest part or roof of every such
place. With respect to holds, and any rooms, cabins, or other inclosed
places of considerable dimensions situated underneath any deck, separate
apertures for the passing off of heated air, or the introduction of warmer
outer air, as the occasion requires, are to be made at proper distances from
each other in different parts of the deck, and they should be so arranged
therein as to best facilitate the passing off or the introduction of the air in
every position in which the vessel may be. And for this purpose the same
should be situated near the sides and ends of the vessel, and I recommend that
the same may be placed at least twice as near the sides as the middle, and that
their distance from each other be from twenty to forty feet lengthwise, and
from fifteen to thirty feet crosswise the vessel, according to the larger or
smaller quantity of heat likely to require to be passed off from or introduced
into the whole interior, and into the particular parts with which the particular
apertures communicate. If the open spaces above described are not left under
the planks of the decks the apertures should be the closer to each other. These
apertures are to be circular for receiving the valves next herein-after described.
For regulating the passing off of heated air, and preventing its return, place in
each of such apertures a valve, with the working part of it composed of some
light elastic substance that will readily yield to a slight pressure of air, and will,
from its elasticity, have a tendency to resume its first shape and position on the
ceasing of the pressure, and construct and place the same so as to open out-
wards, and permit the air to pass out of the vessel, and to shut on any opposite
pressure, and prevent any air from passing inwards. Aud the lighter the more

page_text: flexible, elastic, and strong, and the less liable to absorb much moisture from
the air such substance may be, it will be better adapted for the intended
purpose; and at present I know of no material in which these properties are
so well combined, or that will answer the required purpose so well, as thin
superfine writing paper, which material will answer the required purpose.
Any mode of making a valve that will readily act in the way mentioned will
be sufficient, as well for the admitting trunks for colder air as for the dis-
charging apertures for heated air. But lest any person should not know how
to construct such a valve, I describe and recommend the following as one that
will answer the required purpose:-Cut a thin board into a circle twelve inches
in diameter, describe on it two concentric circles, one ten inches and the other
two inches in diameter from the centre of the board to the ten-inch circle; draw
eight equidistant radii from the inner circle to the ten-inch circle; draw a
straight line on each side of each radius three sixteenths of an inch therefrom,
and parallel thereto; cut out all the parts of the board situate between the
inner and the ten-inch circles, and not inclosed between the parallel lines;
there will thus be eight arms extending from the inner circle to the ten-inch
circle, with an outer circular rim one inch broad; cut three pieces of writing
paper into circular figures, one eleven inches and another seven inches, and
the other three inches in diameter; perforate each piece in the centre, and
bore a small gimlet hole through the centre of the board; procure a round
metal pin of a size to fit but readily pass through the gimlet hole, with a
circular head an inch in diameter flat on the side next to the shank, and with a
screw round the shank, commencing at a distance from the head somewhat
less than the thickness of the pieces of paper and the board; provide a nutt,
with a screw to screw on the shank of the pin, and for greater quickness in
screwing it on and off make it a horned or forked nutt; pass the pin through
the holes in each piece of paper, beginning with the smallest, proceeding to the
next in size, and ending with the largest piece, and then pass it through the
hole in the board, and fasten it on the opposite side by screwing on the nutt
sufficiently firm to prevent so much of the paper as is under the head of the
pin from having any play. The pieces of paper will thus rest on and cover
the centre and arms of the board, and the largest piece will lap half an inch
over the ten-inch circle, and, together with the other pieces, it will yield to a
5 slight pressure of air acting from the opposite side of the board, and permit
such air to pass through, but the same, on the ceasing of such pressure, will
immediately shut, and will prevent any air from passing in the contrary
direction. The use of the smaller pieces of paper is, by their elasticity, to
protect the largest piece and each other from being crumpled up and doubled

page_text: by any sudden gust of wind, so as to fail of resuming their first shape and
position on the ceasing of the wind, and according to the force of air to which
the same will be exposed, and the size of the valve, no such smaller piece of
paper may be required, or one such may be sufficient, or more than two such
may be found necessary. Instead of using a board, as above supposed, for the
seat or parts of the valves for which a board is above supposed to be used, it
will probably be cheaper to make use of cast iron painted or other metal. For
the valves for permitting the passing off of heated air, the apertures through
the deck should, as above stated, be circular. The valve must either be put
down into the aperture from above, or be put up into it from the under side.
If the valve is to be put down from above make the upper part of the aperture
for a depth equal to the thickness of the valve a little more than twelve
inches in diameter, and make the rest of it a little more than ten inches in
diameter. If the valve is to be put up from the under side make the rim of
the valve itself half an inch broader than it will be according to the directions
before given, and so as to make the diameter of the whole valve thirteen
inches, and make the bottom part of the aperture for a height equal to the
thickness of the valve a little more than thirteen inches in diameter, and
make the rest of it twelve inches in diameter; put the valve up into the aper-
ture from the under side, and support it with three or four hasps or spring bolts
to be fixed to the under side of the deck close to the aperture, and to be placed
so as to hasp or bolt under the rim of the valve. Where goods are to be
stowed up close or near to the under side of any deck the valve must be let
into the aperture on the upper side; and supposing the aperture to be situated
in an orlop or other inner deck on which goods are also to be stowed, the
chimney to be provided for the valve as herein-after mentioned must (in like
manner as the latticeworks before described for the admitting valves) be of a
sufficient diameter for letting down and drawing up the valve through it from
above. That side of the valve to the center of which the paper or other light
elastic substance is fixed is always to be kept uppermost, and for greater
facility in changing the paper, when necessary, provide the head of the center
pin with a thumb piece, and when the valve is to be situated at a depth below
goods, instead of a mere thumb piece, provide the head of the pin with a fixed
ring, handle, or eye for letting the valve down and taking it up with, by means
of a hook to be attached to the end of a rod of wood composed of several pieces,
with joints with metal hinges at lengths of three or four feet from each other.
constructed so as for the rod to fold together, in order to admit of being used,
when necessary in low places between decks. For letting the valve low down
into or taking it up from a deep hold the pieces of wood for. the rod should

page_text: be flat-sided, and be as thin as is consistent with their having the requisite
strength; and the bottom of the book, instead of being curved, should be made
straight with a notch across it at the under side for pressing the valve down
home into its proper seat or rebate without endangering tearing the paper
with it by its slipping, and the direction of the hook should be in the same
plane with the wider sides of the rod, and the most convenient shape for it will
be with the shank somewhat bent out of a straight line, so as to form a heel at
the back of the hook, as in the common shape of irons for drawing on boots.
Round the upper orifice of the aperture for the discharging valves place a tube
of timber or other materials little pervious to heat. This tube is to perform
the office of a chimney for the heated air after passing through the valve, and
it is to be made sufficiently large for that purpose, and is to admit of being
removed or raised and lowered for putting in or taking out the valve from
within it, if necessary, as occasion requires. If the chimney be of timber it
will be best to make it of separate staves, to be kept together by metal hoops
with screws, constructed so as to screw into a smaller compass in proportion as
the timber shrinks by dryness, and the metal of the hoops lengthens by heat.
Where the aperture is in an inner deck or platform continue the chimney up
through the outer deck. At a convenient height above this deck, as for
instance two feet above it, attach to the chimney a top of metal for the passing
off of the heated air, without permitting rain to fall into it; make the top of
so much larger a diameter than the lower part of the chimney, and of such a
length as to descend a few inches below the top of the latter on the outside,
at a sufficient distance from it to leave room for any water deposited against
the inner side of the top to trickle down it, and drop into any receptacle to be
placed for the same on the deck instead of running down into the lower part;
and with the same view, and to prevent, as far as practicable, water from
dropping on the valve, make the upper part of the top on the inside convexed,
so as to make the hollow within it shaped like a sugar loaf. This top may
be made either so as to remain fixed or to revolve with the wind; if it be
made so as to remain fixed make it of a sufficient diameter for the passing
off of the heated air between it and the lower part of the chimney, as well as
for the trickling of any water down it, as before mentioned. If the top be
made so as to revolve with the wind make it curved at its upper part, so
as to pass the air off horizontally when the vessel is upright; and in order
that it may the more evenly balance and act properly in the changing positions
of the vessel construct it with as much accuracy as it conveniently can be for
causing its centre of gravity to be in the centre, and equidistant from the ends
of the axis round which it revolves. Whenever an aperture is directed in a

page_text: deck provide a coaming with a cap scuttle or other proper means of securing
the same when necessary. With respect to specifying the most proper and
advantageous dimensions for the hollow of the shaft, the trunks, with their
orifices, and the apertures for the discharging valves, the size of the shaft, and
the sums of the sizes of the trunks and discharging apertures, should be pro-
portioned to the quantity of heat likely to require to be passed off from the
interior, and this will depend principally on the size of the vessel, the heat of
the climate, the liability of the cargo or other goods to generate and give out
heat, and the number of persons or living creatures on board. The more
the heat which the goods on board are liable to give out, and the greater the
number of persons or living creatures within the vessel, it is obvious that the
larger will be the quantity of heat to be passed off; and with respect to the
size of the vessel, and the heat of the climate, the larger the vessel the greater
in proportion to the area of its outer surface will commonly be the quantity of
solid contents contained within it which will be alternately penetrated and left
by heat, with changes of the temperature of the interior, and of the outer air
and water, and consequently the quantity of heat to be passed off will be
greater in proportion to the solid contents and not merely in proportion
to the outer surface of the vessel. And as respects the climate, the hotter
the climate the greater and quicker (as a general rule) will be the changes
of temperature; and at the same time, in consequence of the more
expanded state of the air by the heat in hot climates, there will be less air for
the heat to mix and pass off in and along with through any aperture of a
given size, and consequently, on both these accounts the passages ought to be
the larger in proportion to the greater heat of the climate. Again, the the
more pervious the timber may be to heat, and the worse its quality for resist-
ing its decomposing action, it will require the temperatures on its opposite
sides to be brought more nearly to one and the same than timber of a superior
quality. These considerations, while they shew the general grounds on which
to judge of the most proper and advantageous sizes for the several passages
aforesaid, shew that the nature of the subject will not admit of any precise
directions as to any specific dimensions as being the most proper and advan
tageous, either in all cases or in any particular case; but with this understand-
ing the following general rules may be advanced :-
First, make the several passages somewhat larger than may, be thought
strictly necessary, rather than endanger their being two small, because in-
creasing the dimensions of any passage for air will serve to the passage of a
greater quantity than in an arithmetical proportion to the increase of dimen-
sions. In the next place make the sum of the sizes of the channels of the

page_text: trunks immediately attached to the shaft somewhat larger than the hollow of
the shaft itself to compensate for the greater hindrance air meets with in its
passage through smaller channels than through larger ones, and do the like
with any trunks that are branched into two or more, and diminish the size of
the shaft below any levels at which trunks are attached to it in proportion to
the smaller quantity of heat likely to require to be passed off from below such
levels, and reduce the dimensions of the trunks in like manner where they
are continued beyond any orifices in them for the admission of colder air into
the interior. With respect to the sizes of the orifices in which to place the
admitting valves and of the apertures for the discharging valves, study to
apportion their dimensions to the quantity of heat likely to require to be passed
off from those parts of the vessel with which they respectively communicate, and
study to make the sum of the sizes of the latter larger than of the former, in
proportion to the degree of expansion the air will be liable to undergo by the
heat while in the interior. And the object ought to be to so apportion the
size of each aperture to the quantity of air which it may be required to cause
to pass through it as that on the one hand it may not be too small for the
reasonably quick passage of the air through its valve in sufficient quantity
when the greatest quantity is required to pass, or, on the other hand, too
large for the force of the air to work the valve when the passage of but little
air through it is required, subject to what has been stated.
I now proceed to suppose and put by way of example a particular case, and
to point out the sizes which I recommend for it as being, in my judgment, the
most advantageous for the hollow of the shaft and the other passages aforesaid.
Supposing, then, a merchant vessel to be of ordinarily sound and well-seasone l
oak, and to be of four hundred tons burden, register measurement, and to be
intended to trade to places not situated within or very near the troprics, and
to carry cargoes not subject to generate and give out heat in any considerable
quantities, and to have no greater number of persons on board than the
common and usual crew of a merchant ship of the same burthen, I recom-
mend constructing and making the shaft with the area of its hollow or passage
down to the uppermost trunks from two feet to two feet three inches square.
To compensate for the increased hindrance to the passage of air through
smaller channels than through larger ones, I recommend that the sum of the
sizes of the smaller channels immediately communicating with a larger one,
supposing the number thereof to range from two to six, be made from about one
fifth to about one third part greater than the larger channel. And with respect
to the sum of the areas or sizes of the apertures for the discharging.valves
I recommend making the same about one fourth part larger than the sum

page_text: of those admitting valves. From what has been already stated, it follows that
for other cases the dimensions of the several passages for the air ought to be
larger or smaller than in the case put, according as a greater or smaller
quantity of heat under the same circumstances as to climate is likely to
require to be passed off. Supposing the timber of a vessel to be of inferior
quality, the nearer ought the temperatures on its opposite sides to be brought
to an equilibrium, and the more extensive and nicely adjusted ought to be
the means of so doing. But it is impossible to form a judgment as to what,
´if any, practicable approximation of temperatures to one and the same on the
opposite sides of timber of very inferior quality would be sufficient to preserve
it for any considerable length of time from dry rot, and it will be better to avoid
using any such timber in any vessel where good timber can be procured, than
by using such to be obliged to endeavour to preserve it from dry rot by
bestowing for that purpose extraordinary care, pains, and attention, which may,
nevertheless, fail through the worthlessness of the timber. With respect to
the preservation of goods on board ship from damage by heat, every passing
off of heat from the interior of a vessel will tend to preserve goods on board
liable to damage by heat from sustaining such damage. And the combination
of means which I have invented and been describing of passing off heat from
the interior by the circulation and change of air in and through the same,
and between the several tiers and rows of goods on board, as above described,
will pass off such heat from the goods for the better preservation thereof
from damage by heat in like manner as and at the same time that they pass
it off from the timber of the vessel.
I now proceed to particularly describe and ascertain so much of the said
combination composing my said Invention as consists of the apparatus and
machinery to be made and provided, as well for removing out of the vessel
such heavy gases or air as would otherwise by their weight stop or prejudicially
lessen the before-mentioned introduction circulation and change of air for
passing off heat, and (in so removing such gases or air) being subsidiary to the
shaft and admitting trunks for introducing colder air, as for introducing the
warmer outer air which is to be introduced into any part of the interior, the
temperature whereof requires to be raised, and which warmer air is to be
introduced by removing the colder air already in the interior, and thereby
making room for, and by providing in proper situations openings for the
entrance of such warmer air, causing it to enter the vessel and take the place
of the former. For effecting these objects the apparatus or machinery is to be
made and constructed so as to be capable of receiving the gases or air which
are to be removed at different depths or levels in the interior, and also at

page_text: different points lengthwise of the vessel at or near the centre and each end
as occasion may require. For this purpose make and fix in the vessel at or
as near the middle of it as conveniently may be a square hollow trunk, made
of timber or other materials of sufficient strength and little pervious to heat,
and place the same so as to descend straight down from the lower side of the
deck or upper deck to within about a foot of the bottom of the hold. This
trunk is to be closed at its lower end with an air-tight bottom. In that one
of its sides facing the side of the vessel which is nearest the middle, make at
different heights oblong apertures of sizes a little larger than the area of the
hollow of the trunk; make the lowest aperture close to the bottom, and
make each succeeding aperture situated in the same hold or place at a height
according to the greater or smaller quantity of warmer air it may be required
to introduce of from six to eight or nine feet above the one immediately. under
it, and place them at equal distances from one another, and from the deck
immediately over them. Where a vessel contains more than one deck, make
also such an aperture in the trunk just above the level of each deck below the
upper one; provide these apertures with wooden doors or hatches, or other
fastenings for closing the same from the outside of the aperture, and provide.
rods of metal or other means of raising and lowering such doors or other
fastenings to be attached thereto, and to reach to near the under side of or up
through the deck or upper deck, as may be judged most convenient for there-
with there opening and closing such apertures, and make such doors or other
fastenings so as to shut as air-tight as they conveniently can be made. For
removing colder air from any cabins or other places situated immediately
underneath any quarter deck, poop, or forecastle, or removing it more quickly
from any part situated at or near either of the ends of the vessel below any
deck extending from end to end while any intervening part situate nearer the
descending trunk is already of a temperature sufficiently high, make other
apertures of a little more than half the dimensions of the former in each
side of the trunk fore and aft at about the level of the middle height of the
hold, and also just above the level of any inner. deck, and make these aper-
tures circular, and provide them with sliding hatches and rods, or other means
of opening and shutting and keeping them air-tight, in like manner as the
other apertures. And for removing the air from any such last-described
parts of the vessel through these apertures, provide for each a hose of stout
leather, or other strong and lasting air-tight material, of a diameter equal to
that of the aperture, and attach one end thereof to each aperture, and con
tinue the hose into the parts from which the air is to be removed, and where
necessary pass it up through apertures to be made in the deck forming the
B

page_text: floor of any cabins or other places situated as above described, immediately
underneath any quarter-deck, poop, or forecastle. And also, where necessary,
protect such hose from pressure by goods by passing the same through a loose
hollow trunk open at both ends. And such hose, as it approaches any sepa-
rate rooms situated side by side, or one over another, at or near either end of
the vessel, should be branched into two or more, and be continued into each of
such rooms; and in such case provide a plug or other means of closing the
orifice of each branch, in order that the colder air may at pleasure be received
at the same time at one only or more of such orifices from one only or more
of such rooms, as occasion requires. And if in any case it has been neglected
or omitted to provide the perforated battens before mentioned, use other
means of leaving passages for the air to flow through (from each side and end
of the vessel to the descending trunk at the different levels of the apertures
therein, as for instance, by placing in proper situations for the purpose between
the goods or other things on board an adequate number of other loose hollow
trunks, open at both ends. The descending trunk being constructed as directed,
it may, by opening any one or more of the doors or other fastenings to the
apertures therein, and shutting the rest, be at pleasure made to receive the air
which is to be removed at any one or more of the levels whereat the apertures
are placed, and so as not to disturb the air situate lower down than the lower
level at which the introduction of warmer air is required. The descending
trunk, with the hoses being provided, any means adequate to the purpose may
be resorted to for causing the gases or air which are to be removed to pass
through the same up and out of the vessel. Such gases or air may always be
caused to pass out by pumping up or removing the same by a pump or by
a machine partaking of the nature of a bellows (respectively herein-after next
described), or commonly by means of a fire in a stove (also herein-after
described), to be respectively made to communicate with the descending trunk
at a part thereof situated above the uppermost of the before-described aper-
tures in its sides. Supposing it to be a pump that is to be made use of, the
most convenient situation for it will be to place that part of it in which the
piston is to work, and which may be called the piston-box, close to that
side of the descending trunk which is nearest to one of the sides of the vessel,
and close under the deck or upper deck, so as for the piston rod to be passed
up through a hole in the deck, for the purpose of being worked above deck.
For causing the pump to communicate internally with the descending trunk,
attach to the latter, a little below the level of the bottom of the piston-box, a
lateral trunk of the same diameter and hollow within as the descending
trunk, and projecting from it a sufficient length for conveying the air

page_text: to the central part of the bottom of the piston-box, and make in the
side of the descending trunk and the top of the lateral trunk the proper.
apertures for that purpose. Make the piston-box of large dimensions,
in order to pump up a large quantity of air at each stroke. The most
convenient form for it will be square, and make its sides within as smooth
and even, and to fit the piston as exactly as they conveniently can be made,
both for the more easy and the more effectual working of the pump; provide
the box with a cover, with a moderately air-tight collar for the rod to work in,
and provide it also, just below the top, at the side next to the nearest side of
the vessel with a covered channel or shoot, reaching along immediately under the
deck to a port hole to be made in such side of the vessel for discharging the
air beyond the same. Construct the pump so as for the upper edge of the
bottom of the piston to rise in working only to a level with the bottom of the
covered channel or shoot. For the quicker and more easy passage of the air
through the bottoms of both the piston-box and the piston, furnish the central
parts of the bottom of each with three common pump valves, to be placed
pretty close to each other, and to be made of light but sufficiently strong
materials, as, for instance, of leather, or of circular rims of wood, covered
with parchment, and to be respectively attached by hinges to the bottoms
of the piston and the box. Make the sum of the areas of the apertures
for these valves nearly twice as large as the area of the hollow of the
descending trunk, and make the apertures in the piston box within a
square space equal to about one third of the area of the rest of the
box, and make this part of the bottom so much lower than the remain-
ing part as will be sufficient to allow of the valves rising in working
the pump, without being forced against the bottom of the piston. Continue
the lower part of the box of. the same dimensions for the depth of two cr
three inches below the valves. At this part compleat the bottom, leaving
an aperture in the centre to fit the aperture in the upper side of the lateral
trunk, communicating with the descending trunk, to the upper side of which
lateral trunk it is to be attached. Make the area of the hollow of the above-
mentioned covered channel or shoot about twice as large as that of the
descending trunk, and make the latter about one sixteenth part as large as
that of the piston-box where the piston works. The piston-box should be
sufficiently large for pumping out all the air in the interior above the level of
the water line sufficiently fast for the increase of temperature occasioned by
the entrance of the warmer air, after allowing of the difference of temperatures
which is still to remain between the interior and the exterior to keep pace
with any ordinary increase of temperature in the outer air. And to suppose a

page_text: particular case, by way of illustration and example, and specify for it particular
dimensions for the piston-box and the descending trunk, I recommend that for
such a case, as that before supposed of, the vessel of four hundred tons, burthen,
the dimensions, of the interior of the piston-box for the range of the piston
be about equal to a tube of. four feet, so as to pump. up at each stroke, about
sixty-four cubit feet of air, and that the area of the hollow of the descending
trunk be about one foot square. Instead of providing a pump to be worked
with a piston as above described, a machine may be made and attached to the
upper side of the lateral trunk which communicates with the descending trunk,
differing in principle from a common bellows only in having, instead of a
common nozzle of smaller dimensions than; the orifice for receiving, the air
for creating a strong blast, a passage for the easy. discharge of the air of
considerably larger. dimensions than the area of the hollow of the trunk for
supplying the air, for instance, of about double its size, and furnished with
valves of corresponding dimensions for permitting the air easily to pass out
into such a covered channel or shoot as above described for the pump, and
for preventing it from returning; and in case of making and using such a
machine instead of a pump, make it of a sufficient size for receiving and
discharging in the same time an equal. quantity of air with what is to be
received and discharged by the pump when a pump is used. The removal of
gases or air through the descending trunk may also, except in the possible case
of the same being such as will not support combustion, be effected by means
of a fire in a stove, furnished with a tube or pipe, to be attached to the
descending trunk at a part thereof above the uppermost of the before described
apertures in its sides, and the stove to be constructed so as to be capable of
receiving all its air for the supply of the fire through such tube and the
descending trunk; and in case such a stove be provided, make the area of the
hollow of the tube somewhat more than half as large as that of the descending
trunk, and place in the tube near that end of it which is attached to the
trunk a sliding hatch, made to draw in and out across the tube, and this
hatch must always be let in home whenever the pump or other machine last
before described is worked; but in vessels of the largest sizes and the higher
rates of vessels of war, instead of attaching the tube from the stove to. the
before-described; descending trunk, it may be worth the expence, in order to
have the power of using both the pump or other machine last before described
and the stove at the same, time for removing the gases or air, to make
another and additional descending trunk for the tube from the stove to be
attached to. In all cases of removing colder for causing the entrance of
warmer air. into the interior, open the door or other fastening of one or more

page_text: of the apertures in the descending trunk situated the nearest to the lower
level at which the warmer air is required; and where the colder air is to be
removed from any part at or near either of the ends of the vessel, and for
which the hoses are provided, open the door or other fastening of the aperture
to which the hose for such part is attached, and let one or more of the orifices
at its farther end in the part of parts from which the colder air is to be
removed also be open, as the" occasion requires. On introducing warmer air
into any of the upper parts of the interior, take out and lay aside the before-
described discharging valves for heated air communicating more immediately
with the parts in which the warmer air is required, and for the more regular
introduction and diffusing or spreading of such warmer air immediately at the
under side of the deck or roof of such parts, the other openings or entrances to
the same should in general, during the time of introducing such warmer air,
be kept shut. In the possible case of its being required to introduce
warmer air to the lower part of the hold, the hatches in the admitting trunk
in such part should be kept open, and the air should be introduced through
the shaft and such trunk, although the same are intended in general only for
the introduction of colder air. Remove as often as is necessary any heavy gases
or air which, if suffered to remain in the interior would, by their weight, stop
or prejudicially lessen the circulation and change of the air admitted by the
shaft, and the presence of a prejudicial quantity of such gases or air will be
indicated when there is such a difference of temperatures of the outer air at the
shaft, and of some part or parts of the interior, as that the hatches in the
admitting trunks being drawn out, and the admitting and discharging valves
being in proper order for working, there ought, supposing the air already
within such parts of the vessel to be moderately dry, to be a circulation of air
through such parts of a known ordináry degree of strength or quickness; but
it is found that either no circulation is taking place, or only a circulation
materially less than there should be, and the absence or the degree of any
such circulation may be sufficiently ascertained by placing any light substance
in the upper part of the hollow of the shaft, and observing to what (if any)
extent it is acted on by the air passing down the hollow. The pump or other
machine before described will be sure means of removing the heavy gases or
air in all cases, and the stove in all except where the gases are such as will
not support combustion. For compleating the said combination composing
my said Invention, it remains to make and provide a sufficient number of
thermometers, with the means herein-after mentioned of placing and arranging
them in the different parts of the vessel hérein-after pointed out, for ascertaining
by means of such thermometers when it is expedient to introduce into any

page_text: and what part or parts of the interior air, either colder or warmer than that
already therein. In order to this the temperatures immediately at the opposite
sides of the timber of the vessel, both in the interior and at the outside,
and as well below as above water, must be ascertained as. compleatly as
practicable at as many situations or places as any material differences of
temperature are liable to be found at. For this purpose, with respect to the
interior, I recommend placing thermometers against the ends and sides of the
vessel, at distances of from thirty to forty feet from each other lengthwise of
the vessel, and at heights not exceeding from eight to ten feet above each
other, and to place the lower ones just above the level of the heads of the
floor timbers in midships, and just above the kelson at the head and stern,
and to place the others over the former at such heights as named, close up to
the under side of the deck; and where the vessel contains more than one deck
place a row of the thermometers close under and another row upon each deck,
and where necessary for letting down and taking up the thermometers to and
from the stations designated, attach grooves made of narrow battens to the
sides and each end of the vessel, of just sufficient size for passing the thermo-
meters up and down by means of a small flexible copper wire, or other con-
venient means, free from any obstruction by goods, and where necessary for
the same purpose, continue the grooves to the deck or upper deck, and make
small apertures in the decks for passing the thermometers through the same;
also, let down thermometers to the like depths or levels in the latticeworks of
carpentry before mentioned. On the outside of the vessel place a thermometer
at the entrance of the shaft, and place others on deck immediately over those
that are below in the interior. For greater quickness in taking the observations,
it will be useful, where not opposed by inconveniences outweighing the advan-
tage, to attach to the sides of the vessel above water, at places immediately
opposite to where the thermometers above the level of the water line are
placed in the interior, small grooved cases open in front, and of just sufficient
length and width for receiving and holding other thermometers, which place
in the same accordingly. Where no such cases are provided it will be neces-
sary on taking observations to suspend thermometers in the situations de-
signated, and to keep them there as long as is necessary for them to attain
the temperature of the particular place. Protect the thermometers, wheresoever
placed, from the direct action of the sun's rays. The thermometers used
should be such as will bear being taken from their respective situations to be
inspected without undergoing any perceptible change in the temperature
indicated by them. Having provided and placed the thermometers as directed,
take observations with them as often as any material change of temperature

page_text: in such circumstances as the vessel is placed in with reference to the climate,
the state of the weather, the time of the day or night, the number of the crew,
and the kind of cargo on board, is found by experience liable or at all likely
to take place, and in the meantime, till such experience is acquired, take
observations every hour. By means of other thermometers, take as accurately
as practicable, and as often as the temperature of the water is found liable
to any material change, observations of the temperatures of the water at the
several depths on a level with the bottom of the vessel, and with the ther-
mometers in the interior below the level of the water line. Compare the
temperatures at each place of observations at the sides of the vessel, at the
outside, with the temperatures at the corresponding places or levels within
at the opposite side of the timber, and compare the temperatures at the
different places on deck, or on any inner deck, with the temperatures at the
under side thereof, and compare all these with the temperatures where the
outer air enters the shaft. These comparisons being made, when such a
difference of temperature is found at the opposite sides of the timber of any part
of the vessel as can be lessened or removed by the introduction of the outer
air in its actual temperature into the interior of that part of the vessel, and
by, passing it off after circulating therein the same, subject to the general rules
herein-after stated, is to be introduced and passed off accordingly.. When the
introduction of colder air is called for, the moveable part of the shaft is to be
raised above deck at least sufficiently high for its apertures with the shutters.
to be above the deck, and for its lower end to clear all the apertures in the
fixed part, and in general it will be adviseable to raise it to its full height; and
on such introduction of colder air it should be observed, as a general rule, to keep
the other openings or entrances into those parts of the vessel into which it is
introduced close shut, except when it is required to open the same for the neces-
sary uses of the vessel. The quantity of colder air to be admitted for the whole
of the interior is to be regulated by lowering the working shutter or shutters of
the shaft to a greater or smaller extent in proportion to the quantity of air
required for the whole, and the quantity to be admitted to each particular part
is to be regulated in like manner by drawing out the hatches in the admitting
trunks in such part to a greater or smaller extent, according to the quantity of
air required; and the quantity required, and the regulating of the apertures
for its admission, will depend on and are to be judged of generally, first, by the
greater or smaller difference of temperatures in the interior and at the outside,
and the quantity of heat (if any) generated in the interior; secondly, by the
more or less expanded state of the outer air itself by heat; and, thirdly, by
the outer air being dry, or being more or less charged with moisture. The

page_text: colder and moister the outer air may be the smaller will be the quantity of it
required, and the smaller will be the bulk of it for the quantity, and the
smaller consequently will be the requisite sizes of the apertures for its admis-
sion. But for exactly regulating the sizes of the apertures in each particular
case, attention is to be paid to the quickness or slowness of the lowering of the
temperature on the entrance of the air, and care is to be taken not to reduce
the temperature in any part of the interior below that at the outside of the
same part. To prevent the temperature of any part from being brought too
low, return the hatches sufficiently far back into the admitting trunk for the
desired purpose.. When the vessel is provided with admitting trunks situated
at a different heights or levels one over another, draw out, for admitting colder
air, the hatches situated nearest to the lower part or level of the part from
which the passing off of heat is required. The temperature in any inclosed
place being seldom or never exactly the same in every part, and the temperatures
at different parts of the outside of the hold, or any other part of a vessel, being
liable to still greater differences, study to make the general temperature of any
inclosed place in the interior approximate the mean of the temperatures at its
ouside; and where the exact mean is not attained, make the temperature of
the interior approximate nearest to that at the outside, where water is in
contact with the timber; and where no water is in contact with the timber,
make it approximate nearest to the temperature at the outside over head; and
where practicable keep the temperature in such parts of the interior as are
below the level of the water line a little higher than that of the water, rather
than endanger its being lower, and keep the temperature immediately at the
under side of any inner deck a little lower than the temperature immediately
over it rather than higher; and where the air either in the interior or at the
outside is much charged with moisture, being the temperatures the nearer to
an equiblrium, but where practicable preserve the air in the interior the drier
and keep it of rather the higher temperature; and the reason for seeking to
keep the air in the interior the drier and of rather the higher temperature in
contact with timber is much charged with moisture, the heat forming the
excess of temperature therein above that at the opposite side of the timber
will pass through or leave the air to penetrate and enter such timber much
more rapidly than it will pass through or leave dry air, and it will consequently
penetrate and pass through such timber with a proportionably smaller differ-
ence in the temperatures at its opposite sides: And hence it follows, that
when the air in any part of the interior is dry and of a higher temperature
than that at the outside, a greater difference of temperatures at the opposite
sides of the timber may be permitted than where the warmer air is charged

page_text: with moisture, without the like danger of causing heat to pass through the
timber, and keeping the temperature in the interior the higher will preserve
the timber safe from the passage, of any current of heat. through it from the
outside into the vessel. And where both the air in the interior of the vessel
and the timber in its interior are dry, and a regular although a slow circulation
and change of air and passing off of heat are kept up, the temperature may be
kept considerably higher in the interior than at the outside in any part of the
vessel where, for the comfort of the crew, such a considerably higher tem-
perature. may be desirable. Whenever colder air is to be introduced into any
parts of the interior, the admitting and discharging valves for such parts must
be seen to be in proper order for working, and must, if necessary, be made
properly to work, that is, to yield to the pressure of the air, by substituting
thinner and more flexible paper or other light elastic substance, as before
mentioned, than what may happen to be therein, and thereby lessening the
resistance to the passage of air through the valve. When the temperature of
any part of the interior is lower than that of the outer air or water at the same
level, and as respects any such part of the interior as is below the level of the
water line, when the water at the same level is not, warmer than the outer air
at the apertures for the alternate passing off of heated air and entrance of
warmer air for such part of the vessel, the temperature of such part may, by
introducing the outer air, be raised as near to an equilibrium with the tem-
perature at the opposite side of the timber as necessary. And such warmer
outer air is commonly to be introduced, as before mentioned, through such
last-mentioned apertures, the valves whereof are to be taken out for the
purpose; but if it be only the lower part of the hold into which the introduc-
tion of warmer outer air is required, it will be most convenient to introduce
such air through the shaft and admitting trunks, as also before mentioned.
And in every case of introducing warmer air it is to be caused to enter. the
vessel by removing the colder air already in the interior up through the
descending trunk and out of the vessel by one or other of the means in. that
behalf before described, and for this purpose use such of the apertures in the
descending. trunk, for receiving the colder air as are situated most nearly at
the same level with and not lower than the part the temperature whereof is to
be raised. And when that part of the vessel, the temperature whereof is to
be raised is situated immediately underneath a quarter-deck, poop, or forecastle,
or in any other part at a distance from such descending trunk, with another
part intervening of a temperature already sufficiently high, make use of a hose
as before described for more speedily removing the colder air. The operation
of removing the colder air, so long as the temperature at the outside remains

page_text: unchanged, is to be continued till a quantity of the warmer air has been
introduced and passed off sufficient to raise to the height desired the tem-
perature not only of the air, but of the other substances contained in the
particular part of the vessel the temperature whereof is to be raised. When
the temperature of any part of the interior situate below the level of the water
'line is lower than that of the water at the outside at the same level, and the
temperature of the air at the apertures of the discharging valves for heated air
for such part, or at the entrance of the shaft, is at the same time lower than
that of the water, but somewhat higher than that of such part of the interior,
raise the temperature thereof, so far as it can be raised, by the introduction of
the outer air in the manner before mentioned; but no part of my said Inven-
tion is directly adapted to still farther raising the temperature in such case
to a level with that of the water, and I have purposely abstained from
endeavouring to invent and directing anything as applicable for that purpose,
because the case supposed need not be otherwise than of very rare occurrence,
and it may in almost all circumstances be guarded against by taking care not
to introduce any considerable quantity of air of a lower temperature than the
water at any given depth down to a depth on a level therewith, and by intro-
ducing air at the hottest time of day into such parts of the interior when the
vessel is approaching warmer latitudes, or the weather is getting hotter, so as
to raise the temperature of the water, and because under such circumstances
any machinery for the introduction of heat artificially produced from a fire
into such parts of the interior would, by its expence and the room it would
take up, compared with the rareness of the occasions on which it would be
required to use it, and the benefit it could produce, and by the risk of doing
harm therewith for want of apportioning the quantity of heat with sufficient
exactness to the quantity required, be, in my judgment, on the whole productive
of more disadvantage than good.
In such of the directions which I have above given as relate more par-
ticularly to the precise or exact situations, sizes, or dimensions of any of
the before-mentioned alterations in the vessels, or of any of the apparatus
and machinery before described, or to the situations and distances at which
to place the thermometers from each other, or which relate to the degree
of approximation of the temperatures immediately at the opposite sides of
the timber, and in all the directions generally which relate only to the
extent of the application and putting in practice of my said Invention,
I am to be understood as giving directions with the view to the most
perfect and compleat application thereof, and to giving it the most extensive
and thorough reach of operation, according to the best of my judgment,

page_text: without meaning or intending to be understood that my said Invention will be
either wholly or greatly ineffectual unless all such directions be literally and
in the fullest extent complied with; and on the contrary the same may and
will be commonly very effectual, provided a reasonable degree of care and
attention be bestowed in following the directions given, notwithstanding the
nicety or exactness pointed and aimed at in the matters just referred to be
not to the fullest extent observed and put in practice. .
Having now particularly described and ascertained the nature of my said
Invention, and in what manner the same is to be performed, I here, for
guarding against being construed to claim as new therein, and as comprised
within the power, sole privilege and authority granted by the said Letters
Patent, anything which is not new and cannot lawfully be comprised within
the said grant, repeat my declaration made at the commencement of this
Instrument of Specification of my said Invention, that the same consists in
the making and manufacturing of the before-described combination of the
before-described alterations in the vessels, and of the before-described apparatus
and machinery for the purposes before described, and not in the separate
manufacture of any of the separate parts thereof. And although I believe
several of the separate parts thereof to be new, and to have never heretofore
been invented, found out, or practised by any person whatsoever, I do not
claim being entitled to any exclusive power or any sole privilege or authority
under the said Letters Patent in relation to the separate manufacture or the
separate use of any of the separate parts in the said alterations, apparatus, and
machinery, or to the manufacture or use of any combination of particular
parts thereof which may, before the granting of the said Letters Patent, have
been combined, made, or used for the objects or purposes aforesaid, or for any
other objects or purposes. But I claim the full power, sole privilege and
authority granted by the said Letters Patent against any persons whomsoever
making, using, exercising, or vending, for the objects and purposes aforesaid,
either the whole of the said combination, or any combination of any two or
more of the separate and particular parts thereof which have never, before the
granting of the said Letters Patent, been invented or found out and combined
or practised combined 'for the objects or purposes aforesaid or for any other
objects or purposes.
In witness whereof, I, the said John George, have hereunto set my
hand and seal, this Sixteenth day of June, in the year of our Lord
One thousand eight hundred and twenty-eight.
JOHN (L.S.) GEORGE.

page_text: AND BE IT REMEMBERED, that on the Sixteenth day of June,
in the year of our Lord 1828, the aforesaid John George came before,
our said Lord the. King in His Chancery, and acknowledged the Specifi-
cation aforesaid, and all and every thing therein contained and specified, in
form above written. And also the Specification aforesaid was stamped accord-
ing to the tenor of the Statute made for that purpose.
Inrolled the Sixteenth day of June, in the year of our Lord One
thousand eight hundred and twenty-eight.