1G2 
THE COTTAGE GARDENER AND COUNTRY GENTLEMAN, December 18, 1860. 
nine inches for a couple of yards from the furnace, and brick 
on bed afterwards. In all cases where a continuous high 
temperature was wanted, we would use brick on bed, and a 
covering of three or four inches; because once heated it would 
require no more fuel to keep heated, and the bricks would not 
only form a reservoir of heat, but anything in the way of 
accident from smoke would be next to impossible. 
I ought to have said a word on furnaces. Their size may be 
regulated according to the fuel. One 2 feet long, 18 inches 
wide, and 18 inches deep will do for a good sized house, such as 
the one referred to, when Newcastle coal is used. When Derby, 
Midland coal or cinders are chiefly used, the furnace should be 
one foot longer and six inches wider. It is always best to have 
it large enough. The furnace should bo built with firebricks 
and Welsh lumps, not only because they stand the fire better, 
but conduct heat more slowly than most other materials that 
can be used. If in surrounding these with brickwork, a small 
open space two or three inches could be left nearly all round the 
lumps, the brickwork will be kept comparatively cool, and most 
of the heat thrown along the flue. Were it not for the first 
expense, instead of the usual furnace and ash-pit doors which 
soon get out of order unless managed carefully, Sylvester’s 
doors which slide in on a rod and groove, and can be regulated 
to the greatest nicety, are the best. In managing the fires keep 
in mind what has been said about stoves, and after the fire is 
lighted admit air only through the ash-bars. I have found, how¬ 
ever, that a very small hole in the furnace-door near its top 
from one-eighth of an inch to a quarter of an inch in diameter, 
tends to the more thorough consumption of smoke, and that 
for this purpose a small supply of fresh air supplied to the 
farther side of the furnace has also the same effect. In a chimney 
connected with a hot-water boiler there was a damper about 
two feet from the ground. Below that was a plate of iron for 
cleaning the flue close to the ground, and in making a hole in 
that plate a quarter of an inchin diameter, the smoke and heated 
gases seemed to be driven back and passed again and again over 
the fire. 
I have omitted to notice that much may be done in this way, 
by keeping the redhot fuel near the mouth of the flue, and the 
fresh fuel nearer the furnace-door. Much of the smoke and the 
lighter gases are thus consumed instead of bolting up the 
chimney and for a while cooling the flue too ; but, unless an 
amateur attends to these matters himself, he has little chance of 
getting them cared for. 
• I should also have mentioned, that where it is not convenient 
to have tiles hollowed for covering, earthenware vessels, or 
vessels of iron or zinc set upon the top of the flue and supplied 
with water, will give plenty of moisturq in the growing season. 
Unless the flue is comparatively cool we disapprove of sprinkling 
water on it—in fact, it is best avoided at all times. The vessels 
on the flue and sprinkling the paths will furnish a sufficiency of 
atmospheric moisture. 
In building the flues, iron doors a foot or so square should he 
let in at the sides at the turns, so that the flue may be cleaned easily 
without pulling it to pieces. When replaced some thin tiles and 
plaster will make these places look like the rest. If the flue is 
Used only for two or three months it should be cleaned when 
the crop is gathered ; when almost constantly in use they should 
bs cleaned three or four times in the year. Soot is a famous 
non-conductor of heat; and therefore the less on the sides of 
the flue the better, and the less the danger of soot-firing and 
explosions, which burst the joints of the flue. AVith the con¬ 
veniences referred to the brush or wooden hoe can be easily 
passed along, and no mess need bo made with common careful¬ 
ness. We li.ave seen flues half full of soot, clinging to every 
part, sides, and bottom and top. Fuel must have been cheap 
there to allow of such waste. 
Once more. I have said that to get the most from a flue it 
must stand clear and be above the level of the house-floor to be 
heated. This applies especially to seeing the effects of a flue at 
once. The heat of a flue though sunk is not lost; hut it may 
most likely be absorbed in brickwork or earthwork, which after¬ 
wards may bo given out slowly, hut which does not answer your 
present purpose if you wish directly to influence the temperature 
of a house. A current of air brought to act upon a flue in a 
somewhat confined position will neutralise very much these 
inconveniences. We once met with a span-roofed house heated 
by a sunk flue in the centre, and a plunging-bed of tan at each 
side, in which the plants at the outsides did not thi’ive until a 
drain-pipe was taken from the front to the sides of the flue 
every five feet or so in length, as shown in section 11th. Ilot- 
water pipes would be none the worse for a similar plan when 
sunk in a trench. Where round earthenware tiles are not handy, 
semicircular ones will do well for such air-drain placed against 
the wall. 
SECTION 11. 
aa Air-drains. b Path over flue. 
Earthenware Pipes , Iron Pipes, Spc. —Sonic of our correspond¬ 
ents have asked how these would do as a substitute for brick flues. 
Of iron pipes we have no liking, unless they were from nine to 
twelve inches in diameter, and then they would be more expen¬ 
sive than brick flues. If at all hot the heat given off is unhealthy 
to plants. All sort s of earthenware pipes, and Portland cement 
pipes, if from nine to twelve inches in diameter, will do well for 
greenhouses or where there is only an occasional fire to keep out 
frost. The hard-burned pipes now used so much for drainage 
in towns will do well where only a little forcing of Tines or 
Peaches is required. They should not be less than from nine to 
twelve inches in diameter; and in every case a brick flue should 
be continued two or three yards from the furnace before the 
pipes commence, to prevent cracking. At every place where it 
would be necessary to put the brush in for sweeping we would 
have a hollow brick pillar covered with a flat tile to receive the 
ends of the pipes, and thu3 sweeping could easily be done 
without deranging them. It is best to have such as will fit 
pretty well in the sockets. For particular purposes, and where 
the best hard pipes are used, Portland cement may be employed 
at the joints ; hut good lime mortar will answer well, wetting 
the joints before applying it, and letting all dry well before 
using. If a crack should show, daub it up with lime putty or 
even common lime mortar. 
Where a house is larger than I have referred to—say sixty to 
eighty feet in length, and to be forced early, it is best to have 
a lurnace at each end in preference to having a larger furnace 
and flue at one end. E. Fish. 
(To he contimied.) 
MILDEW ON GRAPES. 
I beg to add a few remarks in support of the assertion made 
by Mr. Gadd at pages 135 and 136, “that syringing does not 
cause mildew on Grapes.” I am glad to say that I never had 
the mildew on Vines yet, and I always syringe my Grapes up 
to the time they begin to change colour, taking care that the 
water I syringe with is fresh, and not under 80°. This season 
I have had an excellent crop of both early and late Grapes. 
Notwithstanding the very unfavourable season we have had, 
I have taken every opportunity of dashing water on my Vines, 
always taking care that the moisture was dried up before the 
sun came hot upon them. 
I ascribe mildew to the rays of the sun falling upon the glass 
while there remains a close, damp atmosphere in the house, and 
not, as Mr. Gadd says, to a low temperature. 
I use very little fire heat in forcing, and that only in the 
morning, lighting my fires by six o’clock, admitting an abun¬ 
dance of top air as soon as the flues or pipes are warm, or before 
if required. In the afternoon I syringe, and close the houses 
with as great an amount of sun heat as possible until the Grapes 
I begin to change. I then leave a portion of top air on all night. 
