320 
THE COTTAGE GARDENER AND COUNTRY GENTLEMAN, February 26, 1861. 
is most pleasing to the eye. The 'walls of a house may be 
of fine Bath stone, and the sashes and woodwork of the 
best workmanship, with a roof all in moveable sashes : but 
another house of a similar form, with posts and boards instead 
of walls, and larch poles cut up the middle for rafter sash-bars, 
and these fixed to back and front, and glass laid across from 
one to the other, will, whilst the house lasts, answer the purpose 
as well as the other. Even on the score of retaining heat there 
will be no great difference ; for a wall of one-inch boards, 
especially if tarred and sawdusted, or covered with asphalt, will 
be pretty well as warm as a brick or stone wall. The matter 
of fixed roofs without moveable sashes, and using wide squares 
of glass between rafter sash-bars—say ranging from 1£ to 2 
inches in width and from 3 to 4\ inches in depth, is one of 
the greatest strides in the way of economy in modern hothouse 
building. The one great thing to be thoroughly secured in such 
houses is 
Ventilation , and especially at the top of the house. In 
building a lean-to house, whether the walls be of brick or wood, 
it is easy to arrange for thorough ventilation by leaving spaces 
2g 1 foot wide and 18 inches 
lg ' '' long, to be supplied with 
shutters or boards hung 
on pivots; and if the 
house is wide, it would 
be well to have openings 
near the base of the back 
wall as well as at the top, 
as shown in the dotted 
lines. The top air for 
forcing is, however, the 
most important. When 
a wall exists, and a fixed 
roof is resolved upon, and 
the space between the 
rafters is 18 or 20 inches, 
then every alternate 
square along the top should be made to open, either by hinges, 
_. „„ whichwouldbetheeasiest, 
I'isr 29 # * 
or by being moved on 
pivots. By a rod and 
pulleys, or a racket-wheel, 
in a small house, these 
could be all raised at 
once, and for half an inch 
or to their full extent. 
In a fixed, span-roofed 
house, no simpler plan for 
air-giving can be than 
having a double ridge- 
board separated from each 
other by a foot or nine 
inches, as at D, fig. 30. 
A stout piece of wood— 
say 3 inches square, goes 
between the ridge-boards every 3 feet or so. These ventilating- 
boards are hung on pivots, the pivots being fixed to about oue- 
Fig. SO. 
-T\ 
third of the width of the board, so that, when a holding-nut is 
removed, the board falls down by its own weight. From this cross ■ 
piece an upright piece of wood, with the help of a slighter piece 
irom the ridge-boards, supports a cowl of two boards, which pro¬ 
tects the opening from wet, &c., and allows the air to enter at 
the sides. Air may be given in front by moveable sashes, by 
shutters in the wall, by a board on hinges in wooden houses— 
one of which will be necessary as the season gets on; but the 
top air is the great thing in early forcing—in fact, where fuel 
was scarce we have frequently cut early Grapes without once 
opening the bottom sashes. A very small opening, given at 
the highest point of the roof, will not only let out the contami¬ 
nated air'-.but admit fresh, which will soon circulate through 
all the house, and, being admitted at the highest part, it will 
be heated and moistened before coming in direct contact with 
the plants. 
I am well aware that a great authority (Mr. Rivers) in his 
wide span-roofed orchard-houses, adds even to the economy of 
such houses by dispensing altogether with openings for air at 
the ridge of the roof, and finds he has enough by giving it 
liberally at the two sides and an opening at each end and over 
the doorways, through which, he says, the heated air pours out 
in a stream in a warm day enough to turn a windmill. Be it 
noted that these houses either are somewhat short in length 
(from 30 to 50 feet), and thus these end openings prevent 
the heated air accumulating at the ridge; or, if long as well as 
wide, the height is low in proportion, and the trees grown are 
chiefly in pots or as dwarf standards, so that the tops of the 
trees even do not reach near the ridge—at least, that is my 
impression. Note further, that when air is freely admitted at 
the sides, it is either to retard vegetation in the spring or to 
prevent too much sun heat affecting the plants in summer. 
In such circumstances I can at once see the propriety and use¬ 
fulness of Mr. Rivers’ plan in houses where, besides the pro¬ 
tection of the glass, the trees have no artificial heat given. In 
a forcing-house on a similar plan, if the house was of any length 
and the trees—such as Vines or Peaches, Cucumbers or Melons, 
reached the apex of the roof, not only would there be danger of 
scorching in the middle of the house, but the cold air would be 
admitted at the coolest part of the house; so that whilst the 
top of the plant was in Africa, the lower part might be almost 
in Iceland. Of course, modes might be taken to bring the air 
over the heating medium before admitting it into the house, 
and thus heat it previously ; and though that would always be 
desirable in front air in a forcing-house, its direct necessity is 
obviated by the means of giving air at the highest point, and 
proportioning the amount to the state of the weather and the 
heat inside the house. “ A Thinker,” who has desired me to 
clear up the seeming inconsistency between previous recom¬ 
mendations and the practice of such a man as Mr. Rivers, will 
see that the two circumstances not only admit but require 
different treatment. 
In forming economical fixed roofs by using fixed rafter sash- 
bars—says rafters 11 inch wide, instead of making a rebate for 
the glass, it will be cheaper to fasten a piece of deal along the 
centre with tacks, half an inch thick and half an inch wide, 
which will leave half an inch on each side for the glass to rest 
on. In glazing the laps should not go much beyond an eighth- 
of-an-inch, or at most little more than from one-fifth to one- 
quarter of an inch. When a very high temperature is needed 
in winter, we would putty or use thin strips of paper like lead 
or Indiarubber between the laps; but in all other cases we 
would place the glass as close as possible, and use nothing 
between the laps. Very little air will be able to enter after the 
house has been used for a few months. Even, therefore, without 
puttying the laps, ventilation must be carefully attended to 
when large squares are used. A house now will be cheaper 
covered with large squares 18 or 20 inches across by 12 deep, 
than it could be by the little pieces formerly used. 
Protecting .—Where the houses will admit of it, blinds of calico, 
tiffany or frigidomo,that did for shading in summer, will save fuel 
and keep the house more healthy in hard weather during forcing. 
These, however, are seldom used except for low houses or pits, 
When a high temperature is needed in winter and spring, a 
double glass roof, the one three or four inches from the other, 
and the air confined bet ween, would be the best protection, and 
would admit enough light. For pits and frames, Russian mats 
are handy and often used j but even though tied they soon 
get littery. Tarpaulin with rough woollen matter inside would 
be far better. When much covering is wanted in severe 
weather for Cucumber-beds, &c., a calico cloth next the glass, 
dry hay for a couple of inches above it, and a waterproof cloth 
over all, would keep out as much cold as four or five mats. 
Straw mats also answer admirably for the purpose. They are 
easiest managed when made from 12 feet to 20 feet in length 
according to the lights to be covered, and so wide that two 
cover the lights, the top cover lapping over the under one for 
about six inches, so as to let all wet fairly down. Thus made, 
