328 
[ October 12, 1893. 
JOURNAL OF HORTICULTURE AND COTTAGE GARDENER. 
noticeable in the petals, which, though considerably longer than those 
of C. barbatu m, are yet proportionately shorter than those of 0. Stonei, 
and the colouring is shared in an equal degree. The labellum has 
a near resemblance to that of C. barbatum, but difEers in the greater 
size it attains. The obtuse upper sepal—tinged with crimson, striped 
with green and black—also imparts a very distinct attractive 
appearance to the flower. The petals are fringed with hairs, and 
bear on the upper surface numerous peculiar wart-like protuber¬ 
ances, while the labellum is dark-coloured, crimson and brown 
shades being combined. The foliage is also handsome, being of 
rich deep green, in which an approach to tessellating is faintly 
visible, and the plant is of vigorous habit, flowering freely, with 
similar treatment to that required by other Cypripediums.— 
Specialist. 
THE PRINCIPLES OF HEATING: 
INCLUDING THB ARRANGEMENT OP HOT-WATER PIPES FOR (a) FRUIT HOUSES I 
(6) FORCI G houses WiTH BOTTOM HEAT ; (c) BEST KINDS OF FUEL, WITH 
THB MANAGEMENT OF FIRES, AND THB REGULATION OP TEMPERATURES. 
Silver Medal Essay hy Mr. Harry Corlett, Foreman,, Woolton 
Wood Gardens, Liverpool, 
Introduction. —This subject covers a very large area, and it is one 
which, I am sorry to say, that many gardeners know too little about. 
It seems quite sufficient for some of them to know that a house, or a range 
of houses, has been erected and fitted with hot-water apparatus by a 
horticultural builder ; and, although the work done may be satisfactory 
to the builder, yet it does not always meet with the requirements of the 
gardener, and as he is the person who, very often, has to earn his liveli¬ 
hood by the products grown in the houses, the necessity of having some 
knowledge of the principles of heating at once presents itself to him. 
I trust the day is not far distant when young gardeners will be taught 
a thorough knowledge of heating, in a similar manner to what they are 
now taught when they should water a plant, because I consider one 
quite as necessary as the other from a practical point of view. When 
this becomes part of their education we shall then hear of less damage 
being done to boilers, pipes, and plants. I will treat the subject from a 
scientific point, yet making it plain and practical, with tables and 
diagrams attached, for the benefit of those who may require its assist¬ 
ance, making link by link, as it were, thus forming a chain of infor¬ 
mation which should be in the possession of everyone who works in, or 
receives any benefit from, an horticultural structure heated by hot 
water. 
This paper must be divided into eight distinct parts — viz., 
(1) Principles of heat, because we must first learn how, and why, hot 
water heats a house ; (2) Houses with their various positions, plants, 
and temperatures ; (3) The thermometer, to ascertain the different tem¬ 
peratures ; (4) Pipes to secure the various temperatures; (5) Boiler 
to heat the water in the pipes ; (6) Fuel to heat the water in the 
boiler ; (7) The stoker to work the fuel; (8) 
The duties of the stoker. Each part being 
individually treated, and, as one is, practically 
speaking, of no use without the other, they 
must be all linked together to obtain a final 
and satisfactory result. 
(1), Heat and its Transmission. 
A body or substance becomes heated when 
brought in contact with or placed under the 
influence of any other body or substance hotter 
than itself, the colder body receiving the heat 
by either of three modes, viz., convection, 
radiation, or conduction. 
In the “convection" mode the smallest 
parts of the body nearest the heat are the first 
warmed, and these when heated begin to move 
throughout the body, their place always being taken by the colder 
parts, and the motions thus started are called convection currents. A 
very simple and interesting example of this is to take an ordinary 
glass (fig. 47), nearly fill with clean cold water, place a spirit lamp 
under the bottom of the glass, and then watch the results. The 
particles of water first heated begin to rise in a direct line from the 
lamp flame to the top of the water. The colder particles of water 
from around the sides of the glass, being heavier than the heated 
particles, at once begin to descend, and thus two currents are formed, 
the direction of which can be made more apparent by adding a 
little fine sawdust to the water previous to putting the lamp under 
the glass. This example shows that convection currents carry the 
heated parts of a body away from and bring the colder parts nearer 
to the source of heat. 
In the case of “ radiation ” the mode of transmission is different to 
either of the others, the heat being carried through a material medium. 
Take an example. Expose a piece of steel to the direct rays of the sun ; 
its temperature soon begins to rise from its original point, whilst the 
atmosphere around it is scarcely changed, thus showing that one body 
may be heated by another body, yet the space between the two will not 
be noticeably changed in temperature.* 
By “ conduction ” we have yet another mode of transmitting the heat 
from one body to another, for a body heated by conduction always 
moves in the direction where the temperature is colder, and each 
particle of the body, as it moves through the mass, is slightly robbed of 
its heat by neighbouring particles. The heat by which the water in a 
kettle is boiled is transmitted from the coals through the bottom of the 
kettle by conduction. 
The three examples given will show the principles by which our 
houses are heated. First the heat passes from the furnace through the 
boiler plates to the water in the boiler by conduction. It is then trans¬ 
mitted through the mass of water into the pipes by convection, and 
from the pipes to the air in the houses by radiation, and the atmosphere 
thus warmed is then at our disposal.* 
(2), Houses, their Positions, Plants, and Temperatures. 
Assuming there is a particular piece of ground allotted, upon which 
a certain number of houses have to be erected, I have drawn a ground 
plan as a guide, this, I think, being the most systematic way of laying 
a foundation to work upon. The dimensions are given in each case, 
which can either be enlarged or reduced to suit various circumstances. 
As will be seen by the plan (fig. 48) there is a wall running north to 
south on one side, and a wall running east to west on the other side. 
The two remaining sides are hedges. Along the wall running east to west 
are placed the early, medium, and late vineries, early Peach house, and 
propagating Pine house, all of which are three-quarter span-roofed. 
The wall running north to south is occupied by a late lean-to Peach 
house, while the remainder of the ground between the late Peach house 
and the opposite hedge is utilised by three Melon houses, one Cucumber 
house, two forcing houses, and one fruiting Pine stove, all of which 
are span-roofed. If two forcing houses are not required then J can be 
substituted by L, and an orchard house M would occupy the position 
of L. On the plan will be found the exact position of the houses, 
boiler, sheds. Mushroom house, office, the direction of the hot-water 
pipes ; also showing how, by the assistance of valves, each house can 
be individually heated without affecting any of its neighbours. The 
pipes will perhaps he shown more clearly in the section (to follow). 
Vineries. —The early house should be started in December at a 
temperature of 45° at night, allowing a rise of 5° during the day. The 
heat should be gradually raised until it reaches a night temperature of 
G5°, and by this time the Vines will be in flower, when the heat must be 
decreased to 60° until the stoning period is over ; then further increase 
it to 65° night. This temperature may be continued until the Grapes 
are ripe, which will be about the middle of May. After the fruit is cut 
admit abundance of air to ripen the wood. 
The second, or medium vinery, must be started about the end of 
February at a night temperature of 45°. The various temperatures of 
the early house will answer admirably for this structure excepting when 
occupied by Muscats ; then an addition of 5° throughout will be 
necessary. The fruit in this house will be ready to cut about the middle 
of July, 
The Vines in the late house will start about the beginning of April, 
when the night temperature must be kept about 50°, and as the season 
advances and the growth makes headway the night temperature should 
be raised to 60°, with 70° during the day, allowing a rise of 10° by sun 
heat. The fruit in this house will be ripe by September, thus main¬ 
taining a supply of Grapes from May until January. 
Peaches and Nectarines. —The early Peach house may be started 
in January at a night temperature of 45° to 50°, gradually raising the 
temperature to 55° about this time, when the trees will be in flower. 
After the flowers have set again increase the heat until it finally reaches 
a night temperature of 60°, always taking advantage of sun heat by 
closing the house early, and by so doing raising the temperature to 75°, 
which will be found very beneficial to both growth and fruit. Under 
such conditions the latter will be fit for the table by the middle of May. 
The late house will naturally start of itself about the end of 
* R. W. Stewart, B.Sc.,. Loud., “ Text Book of Heat,” chap, x., pp. 191,192. Published 
by W. B. Olive & Co., 13, Booksellers’ Bow, Strand, W.O. 
