IMPROVEMENTS IN HEATING HOT-HOUSES AND OTHER BUILDINGS
Year: 1838

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, J, THOMAS
CORBETT, of Plymouth, in the County of Devon, Gardener, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Letters Patent under the Great Seal of Great Britain, bearing date at West-
minster, the Fifteenth day of August, in the first year of Her reign, did, for
Herself, Her heirs and successors, give and grant unto me, the said Thomas
Corbett, Her especial licence, full power, sole privilege and authority, that I,
the said Thomas Corbett, my exors., admors., and assigns, or such others as
I, the said Thomas Corbett, my exors, adñiors, or assigns, should at any time
agree with, and no others, from time to time and at all times during the term
of years therein expressed, should and lawfully night make, use, exercise, and
vend, within England, Wales, and the Town of Berwick upon Tweed, my
Invention of "IMPROVEMENTS IN HEATING HOT-HOUSES AND OTHER BUILDINGS;" in
which said.Letters Patent is contained a proviso that I, the said Thomas
Corbett, 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 Her said
Majesty's High Court of Chancery within six calendar months next and im-
mediately after the date of the said in part recited Letters Patent, as in and
by the same, reference being thereunto had, will more fully and at large
appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
Thomas Corbett, do hereby declare the nature of my Invention, and the
manner in which the same is to be performed, are fully described and ascer-
tained in and by the following statement thereof, reference being had to the
Drawing hereunto annexed, and to the figures and letters marked thereon
(that is to say) :-
My Invention relates to a mode of heating hot-houses and other buildings
by the circulation of water; and in order to give the best information in my
power, I will describe the Drawing hereunto annexed.
DESCRIPTION OF THE DRAWING.
A and B are two vessels, which are connected together at the bottom C, and
on a level with each other at the top. A gutter is then formed either by a
channel in the door or elevated ducts or troughs of any material, D, and on a
level with the vessels A, B, fitting to a gap or opening in their edges. A is to
be used as a boiler; B, C, is in the form of a pipe, of the same material as the
boiler. When fire is applied to the boiler, at F, the water will expand by
heating, and consequently rise above the level of the pipe B, flowing into the
gutter-D, till it returns to the boiler at C. During the progress of the water it
gives off heat along its whole course till, becoming colder, it contracts; thus a
difference of elevation, and consequently a constant flow of water will continue
as long as the temperature of the water in the troughs is higher than that of
the house.
Supposing the course of the gutter or trough to be interrupted by a path or
doorway, as at G, the stream will continue to flow by conveying it from one
trough to the other by means of a syphon or bent pipe, H, over the doorway or
under the walk by means of any common tunnel or pipe, I; the syphon is,
however, far preferable. The connecting pipe C may be made longer than
shewn at C, where considered necessary, so that the two vessels A, B, may be
at a greater distance from each other than represented, the connecting pipe C,
forming a return pipe below the trough, and giving off heat as such. As the
expansion of water by heating is the immediate cause of its flowing, it follows
that the deeper the boiler and return pipe are, the greater will be the motive
power. If the boiler and return pipe be two feet six inches deep, the water in
the return pipe being at one hundred and ten degrees, and that in the boiler
at one hundred and forty degrees, the water in the boiler will rise one eighth
of an inch higher than that in the return pipe, and this fall of one eighth of an
inch will produce such a motive power as to cause the water in the gutter to

page_text: flow along at the rate of ten feet per minute, supposing the gutter to be six
inches wide and six inches deep. If the boiler and return pipe be still deeper
the motive power will be proportionably increased.
To heat a hot-house thirty feet long and fifteen feet wide I would recommend
a boiler three feet six inches deep and two feet wide, and so set as to cause the
fire to pass round it twice. The, elbow of the return. pipe should be a trifle
lower than the bottom of the boiler, in order to insure the passing of the water.
contained within the connecting pipe C upwards towards the boiler, in case of
its receiving any heat from the brickwork which may surround it near the
boiler.
14
The small quantity of moisture held in solution by the atmosphere during
cold weather is very remarkable, and as the summer and warm weather advance,
the absorption of moisture from the sea, and every substance capable of yield-
ing, is equally remarkable,.so that in summer evenings it often happens that
the dew is falling when the thermometer stands at sixty degrees. It appears
then that during the hottest and driest weather the natural atmosphere contains
about six grains of watery vapour per cubic foot. To imitate nature, there-
fore, if we raise the temperature from forty degrees to sixty degrees it will be
necessary to raise three grains of moisture for every cubic foot of air; as far as
I have been able to calculate, and I have experimented on all the different
shaped gutters I can think of. I,find that if the gutters are as wide as they
are deep, say six inches wide, and six inches deep, they will raise, for twenty
degrees of artificial heat, about four grains of moisture to every cubic foot of
air; but if the gutters are twelve inches deep and six inches wide, (the pro-
portion most applicable to general purposes,) then so much heat will be evolved
from the sides, that for twenty degrees of artificial heat about two grains of
moisture per cubic foot of air will be raised from the surface, so that any
quantity of moisture may be produced according to the width and depth of the
gutters. I am aware that the vapour rising from the surface will-absorb a
great quantity of heat in a latent state, but this is all given off again in con-
densation upon the glass, and it will be easily seen that the condensation of
moisture will prevent the escape of heated air, and that in every case dry air
cools much more rapidly than moist air.
The object of my Invention is to imitate nature by.combining a due propor-
tion of moisture with heat. Every one accustomed to the system o of forcing
must have noticed the difference between a natural and artificial atmosphere,
between the elasticity of the summer air and a temperature forced up twenty
or thirty degrees by fire heat. All who have witnessed the regulated and

page_text: modified atmosphere produced by this important adaptation have concurred
in expressing their opinion that it exactly resembles the general heat of
summer.
According to this method there can never be a superabundance of moisture,
provided the gutters are of the proper shape; but should it be considered
advisable at any time to prevent the escape of vapour altogether this may at
once be effected by placing along the top of the gutter any flat substance, such
as slates, tin plate, &; the water never being in a boiling state the vapour is
not forced out, but will condense in any substance with which it comes into
contact.
For forcing vines, pines, &, it is admirably adapted, and with broader and
shallower gutters to produce more moisture there is reason to conclude that
this system will come into general use for the cultivation of cucumbers, melons,
&. For hot-house plants, and particularly orchided, gutters as broad or even
broader than deep are proved to be the most suitable. For the green-house it
will be of incalculable service. Every description of artificial heat without
moisture has been found by sad experience to injure green-house plants, when
hard weather has compelled its introduction. To many, and particularly to
Cape heaths, it is almost certain death, because the air in frosty weather,
containing perhaps not one grain of moisture per cubic foot, and raised by
fire heat to forty degrees, and sometimes even higher, becomes so intensely
dry and oppressive, and acquires such an affinity for moisture even at this low
temperature, that the rapid absorption, while the plants are in a dor-
mant state, causes their juices to be elaborated too quickly for their powers of
secretion.
. In reference to the adaptation of this system to other purposes it will be
admitted that as the evil to be avoided and the benefits to be applied are of
much greater consequence to animal life than to mere vegetable existence, so
where the health, comfort, and vigorous constitutions of human beings are to be
secured, the foregoing remarks will come with redoubled force to the subject of
applying artificial heat and moisture with ventilation to public and private
building, offices, apartments, &c.
In witness whereof, I, the said Thomas Corbett, have hereunto set my
hand and seal, this Twelfth day of February, One thousand eight
hundred and thirty-nine.
THOMAS (L.S.) CORBETT.

page_text: AND BE IT REMEMBERED, that on the Twelfth day of February, in the
year of our Lord 1839, the aforesaid Thomas Corbett came before our said
Lady the Queen in Her Chancery, and acknowledged the Specification afore.
said, and all and every thing therein contained and specified, in form above
written. And also the Specification aforesaid was stamped according to the
tenor of the Statute made for that purpose.
Inrolled the Fifteenth day of February in the year of our Lord One