219 
THE COTTAGE GARDENER AND COUNTRY GENTLEMAN, Ja^tjaey l\ 1861, 
some years since, and if I recollect it is from 40 feet to 
50 feet long, about 20 feet wide, and about the height of 
20 feet or so. The whole front of it is upright glass 
down to the level of the paths. The roof is a span, and 
the back wall and the two ends are walls of parts of the 
mansion, and one or more doors from it open into the 
living-rooms. Heliotropes trained against the back wall, 
and Geraniums trained up the pillars between the front 
lights, and quite close to the glass, look now just as 
fresh as the plants in the centre bed of the conservatory. 
The same safety, and a rude degree of health, is also 
reported of the plants after last winter. And in con¬ 
firmation of my friend’s estimate of his new mode of 
heating, he told me that he will next season change the 
old-flue system, by which a second conservatory attached 
to the same mansion is now heated, to this plan. 
Some one in the last century had begun this system 
where it now is, and failed with it. Others who are dead 
and gone, and some who are now alive and well known 
to fame, have also had a finger in it with no greater 
success, and it stood still for the last twenty years or 
more, and was well nigh forgotten till “ a first-class 
man ” got hold of the rudder and took the lugger, not to 
haven, but to pieces, and rebuilt it on what appears to 
be a new principle—at all events on a good principle, and 
the cheapest principle I ever heard of for heating a plant- 
house ; for all this time with the frost often at zero, he 
burns nothing but cinders and slack coal mixed for his 
furnace. He bought twenty chaldrons of cinders from a 
dustman at the beginning of the season of fires for 65 . 
the chaldron, including delivery. To four bushels of 
these cinders he adds one bushel of slack coals—that is, 
the small dust that is screened out of the London sack 
coals, the price of which, if he told me, I forgot, but it is 
not over one-half of the price of common coals about 
London, and this conservatory is not fifty miles from 
London. 
The furnace holds two bushels of this mixture at once, 
if it is well packed and beaten down as when making up 
the fires for the night. The combustion is regulated by 
ventilators and a damper at the neck of the chimney. 
And the capacity of the furnace seems to be equal to 
double the work required; for if one of the doors from 
the conservatory is opened into the living-rooms, the 
whole mansion could be sensibly warmed by the current 
of warm air rushing in from the conservatory. 
The furnace is down below the mansion, but not in the 
cellars. There is an arched or bricked-off compartment 
separate from the cellars and devoted to the requirements 
of the furnace, which is fireproof; but all that was done, 
or may have been done, soon after the battle of Culloden 
and the dispersion of the clans from whom we have the 
author of this lucky hit. Many things went wrong at 
that period besides the huge iron cylinder, or whatever 
it was, which would not work in that vault, which had to 
be put right by “Fellows” from the fallen race, of 
which our present furnace is the last instance within my 
knowledge. It was some very expensive project at the 
beginning, with more iron about it than any of our present 
boilers require, except piping; but from some mistake in 
the setting the thing would not go or draw at all. All 
that iron had to be removed and sold for waste except 
one large plate, which is made to answer the purpose of 
the thick iron plate in Polmaise. All the rest is different, 
but the original channels of the hot air from the furnace 
to the floor of the conservatory have not been altered. 
There are two channels or air-flues going from the 
furnace, but join ere they reach the conservatory. The 
floor of the conservatory is ten or twelve feet or more 
from the top of the furnace; but that is not a necessary 
arrangement, as the very same furnace would have acted 
just as well if it had been on the outside, and on the level 
of the floor of the house. 
Now, any good bricklayer from here to Berwick-upon- 
Tweed could put up such a furnace, if you read to him 
what I am going to say, or if he can read it for himself 
all the better and the surer he will make the job ; but as 
it is possible that I may not have caught the full and 
precise meaning of my friend’s verbal descriptions, wait 
till he is “ asked ” a second time, for I make this his 
first time of asking to explain how he did it, if I have 
failed in any of the particulars. 
His furnace being of double the power required is no 
criterion to the size of the one which I mean to get made 
for myself, or to one that you might like to try. The 
expense need be no more than the bricks and mortar and 
the man’s labour, if we should not hit off the thing at the 
first trial: therefore, for a sort of guide, let us say the 
furnace or fireplace to any greenhouse now at work, or 
that of any other plant-house, will be just the right size 
for this system; but as it is more safe to have more 
ower than one seems to need, say the new furnace is to 
e one size larger than the one of which you take for 
your model; let the bricklayer set the new furnace as if 
he were making one to set a boiler on; the ash-pit to be 
of good stock bricks, and the sides of the furnace above 
the fire-bars to be lined with firebricks, the length, and 
depth and width of the fireplace as for a boiler of small, 
medium, or large size, and the top to be covered with an 
iron plate, or it may be arched over with firebricks if 
that is less expensive than a stout iron plate. Over the 
plate or arch is to be a hot-air chamber of the same 
dimensions as the fireplace, but one course of bricks 
higher. A hot-air flue six inches square, is made from 
the farthest end of the air-chamber to the greenhouse, 
and a ventilator is made in the front of the air-chamber 
to admit external air to be heated in the chamber, and 
then to pass through the air-flue to the greenhouse. The 
ventilator to slide like a damper to admit more or less of 
air. The flue to rise slantingly from the fireplace, and 
to be carried across through the air-chamber to near the 
front, so as to get all the heat from it for the hot-air 
chamber, and then to pass it into a chimney over the 
front corner of the air-chamber, right or left, as is most 
convenient for getting up a chimney. The one from 
which I describe passes into a chimney belonging to the 
mansion. The flue need not necessarily pass through the 
air-chamber. Suppose this furnace to be at one end of a 
greenhouse outside, the flue might be carried inside and 
across the house and up the back wall. The object 
either way is to get the heat appropriated as much as 
possible. 
The furnace is yet supposed not to be connected with 
other brickwork, but from the level of the foundation for 
the ash-pit a wall is built all round the furnace, and six 
inches from it, up to the level of the iron plate, and then 
covered over with a course of bricks set across the 
opening; thus a hot-air chamber is made all round the 
furnace as well as over it, and the two air-chambers do 
not communicate one with the other, but an air-hole is 
left at the farthest end of the ash-pit to let in the external 
air into the side chambers or lower chamber, and a flue 
from this lower chamber passes also to the greenhouse, 
and rising gradually till it meets on a level with the 
upper flue from the upper air-chamber. And thus, all 
the heat from the brickwork round the fire, and from the 
ash-pit, where the heat from the fallen ashes is often con¬ 
siderable, is caught in the chambers; and the cold air 
from without, passing over the ash-pit and in through the 
ventilator through the upper chamber, takes all this heat 
into the greenhouse. 
Tint is precisely the plan and principle which my 
friend has adopted, and found in this hard winter, and in 
the long one which preceded it, to answer most perfectly ; 
and when you hear his name most of you will rely on his 
judgment, for amongst us he is allowed to be one of the 
best practical men in our line ; but as I never name aioy one 
in these pages without consent, I cannot break the rule 
now. He assured me the heat in his conservatory was 
as uniform in every part of the house as if it were from 
