4.—1846.] THE 
GARDENERS' CHRONIC 
LE. : 53 
-asa dwarf, will afford, in most cases, a sufficient supply 
during the time it remains in perfection. It succeeds 
on the Quince stock.—R. T. 
Home Corresp 
wherever the arrang for interfered 
with our convenience in working the pits they have 
been removed ; and in erecting another range of houses 
12 months back, the only part of the arrangement I 
Polmaise Heating—The great mistake which has 
been committed relative to the merit of this system, so 
far as its heating capabilities are concerned, is the con- 
sidering the Vinery at Polmaise heated at all ; because, 
from the evidence which has been as yet produced, it 
does not appear that the apparatus has been worked at 
2 season when the weather was such as to test its heat- 
ing capabilities sufficiently to enable anybody to pro- 
nounce a definite opinion upon the subject. To ripen 
Grapes (aye, and good Grapes too) in September and 
October, does not require much aid from a heating 
apparatus of any kind ; for the fruit which Mr. Craw- 
shay sent to the meeting of the Horticultural Society 
last year was in no way inferior to what that gentleman 
had sent in former years, nor, I will venture to assert, 
to the Grapes ripened at Polmaise; while it is well 
known that Mr. C. uses no fire heat at all, except what 
is necessary to expel damp in dull weather when the 
Grapes are ripening, and his sashes are glazed with 
wide unputtied laps, so as to admit a regular current of 
air at all seasons, let the weather be what it may. 
“Oh ! but,” say the advocates of the Polmaise system, 
“the Grapes were very fine ; so fine as to frighten ali 
competitors from the Stirling exhibition." Granted. 
But, surely, nobody who ever pruned a Vine, or thinned 
a bunch of Grapes, would, in the present advanced state 
of horticultural science, attribute the whole of the merit 
9f swelling fine Grapes in the dog-days to the heating of 
the Vinery alone. A kindly atmospherg, such as will 
We produced by the heat of a stove sttiking against a 
Wet blanket, and a free circulation of air, are two most 
important elements of suecess ; but we all know that no 
amount of atmospherie management will be suffieient to 
produee fine fruit upon plants which have not their roots 
in an equally healthy and well-managed situation. 
The whole secret of the production of fine Grapes 
at Polmaise is, the Vines have been well-planted, and 
being as it were pet children, have been attended with 
that solicitude which, in the hands of a good cultivator, 
would have resulted in good Grapes, had there been no 
heating apparatus at all; and nothing, in my opinion, 
can be more unphilosophieal than to suppose that the 
production of fine summer fruit can by any possibility 
be attributable to the system of heating employed at a 
time when, as we have already seen, but very little 
Artificial assistance from fire heat is required. How- 
ever, to speak of the system itself, I have very grave 
doubts whether the apparatus at Polmaise, or any other 
one similarly constructed, is capable of producing and 
maintaining a forcing temperature with anything like 
ordinary winter weather. A few years back, when 
everybody was advocating the use of Joyce’s, Arnott’s, 
Chunk, and other stoves, which were said to heat large 
buildings by very small supplies of fuel, I was induced 
to make the attempt to heat a small Vinery, consider- 
ably less than the one at Polmaise, for the production 
of winter Cucumbers. For this purpose, I used a plain 
Arnott stove, which, together with the pipe which con- 
veyed the smoke to the chimney, presented a radiating 
surface of about 30 feet superficial. Over the top of the 
stove, and also over the pipe, which was carried hori- 
zontally to the end of the house, I had large evaporating 
pans, and though I could heat the water nearly to the 
boiling point, and produce a temperature of 80°, in mild 
calm weather, I could not by any amount of attention 
keep the house higher than 605, without covering it, 
during the prevalence of a brisk wind, accompanied by 
a few degrees of frost. Now, if an apparatus of the 
preceding power was insufficient to heat a much smaller 
house than the one at Polmaise, with, say the external 
air at 20°, what power would be necessary to heat a 
larger house to 70°, with the thermometer outside at 
zero ? and when the advocates have answered this ques- 
tion, will they also solve the following problem : What 
will be the amount in the saving, say in 10 years, be- 
tween erecting a proper hot-water apparatus, which 
would cost, say 20/., and using the stove and its appur- 
tenances, which would require to be removed every al- 
ternate year, at an expence of from 77. to 107.2 From 
what I have seen, I suspect the strongest stoves made 
would not endure more than two seasons hard forcing. 
Depend upon it the strong jo» is the cheap job, and 
whoever thinks to garden economically by dealing at 
cheap shops will, in the course of time, find he has 
made a wrong calculation, Two years back I had 
orders to procure estimates for repairing old and con- 
structing such new erections as had been agreed upon, 
‘and to heat the whole in the best and most economical 
‘manner by hot water, This I did at an expense of 
nearly 700/., adopting the revised plan of Mr, Penn, 
and was told by the advocates of brick tanks, cement 
gutters, and other ephemera of the day, that I had in- 
curred an extravagant and unnecessary expenditure. 
But how stands the matter now? My apparatus will 
last a lifetime, while, if I had saved 100/. by using 
brick and cement, it would have required 200/. by this 
time to have replaced that material, In constructing 
these erections provision was made for circulating the 
atmosphere, according to Mr. Penn’s practice, and 
though I was very much pleased with the theory, in 
practice I have found no advantage to result from it. 
When I say practice, I mean I have not found plants 
to grow any better in the moving atmosphere than they 
have done in what is considered a stationary one. In- 
d it necessary to adopt wasthe making provision 
for the constant’ admission of fresh air through and 
about the hot-water pipes. This is an advance in the 
right direction, and so satisfied am I of its invigorating 
influence, that were I in a situation where fuel was less 
expensive, I wouldénot close the ventilators of my 
plant stove from year’s end to year's end. Place a 
coarse wet woollen net over your hot-water pipes, and 
moisten it either by the capillary attraction of a few 
strings of worsted, or occasional sprinkling ; admit air 
through the front wall to the hot-water pipes, and you 
have all the necessaries of a fine, fresh, and moist at- 
mosphere, or a dry one, if you require it, by withdraw- 
ing the net. ‘The heated air, as it passes through the 
net, absorbs moisture equal to its capacity of carryin 
it, and hence the hygrometrie state of the atmosphere is 
always uniform and proporti o the p 
a consideration of the greatest importance in all horti- 
cultural buildings, especially in the growing season. 
The Polmaise system is merely a revival of Mr. Penn's 
original plan, exploded in the first volume of the 
Chronicle, and abandoned by Mr. Penn himself as 
impracticable. T 
To make currents of heated air cireu- 
late contrary to the laws of Nature, as is attempted in 
thé Polmaise plan, enjoins a waste of power which one 
would think would not be attempted in the present day ; 
and though I had ample opportunities of seeing in 
Mr. Penn's houses that currents of warm air could be 
made to travel contrary to their natural course, yet 
I could also see that this could only be accomplished 
to a very limited extent, and that, too, by a waste of 
power whieh would have been sufficient to heat a house 
of double the size, and with the same result, if applied 
in the right way. Therefore, looking at the Polmaise 
system in all its bearings, and with no other object in 
view than that of wishing that right should prevail, I 
must regard the plan as an unpromising instrument, 
and one which must, like Mr. Penn's, and several others 
that have been broached within the last few years, soon 
be numbered “ among the things that were.” If Iam 
wrong, I am willing to pay the penalty of my mis- 
ealeulations, but until the laws of Nature are changed 
the Polmaise system cannot answer as at present 
arranged, except by a great waste of power, however 
well it might work for summer forcing, if the stove was 
placed in the front instead of the back of the house, 
and the heated air be permitted to work as is its natural 
bent. Arranged in that way, I have no doubt the plan 
will answer sufficiently well to please some people, but 
whoever wishes to have his table supplied with early 
Grapes will find it the cheapest in the end to erect a 
proper and substantial apparatus. Upon this I am 
quite willing to risk my professional character-— 
W. P. Ayres, klands Park, Blackheath - 
Importance of Motion to the Air in Vineries, &c.— 
Your observations on the Polmaise heating have created 
considerable sensation in this quarter, and I doubt not 
will bestir many an active mind in other lands “ to 
work out the problem.” The fact that the leaves of 
plants constantly imbibe certain necessary constituents 
from the atmosphere, suggests how requisite it is to 
produce motion in the air of Vineries, greenhouses, or 
stoves. The natural atmosphere also teaches us that 
it would not be well either for the vegetable or the 
animal kingdom did it want motion. When we enter 
a Vinery all is calm, and if we could investigate the 
functions of a small leaf as it selects certain consti- 
tuents for food, refusing and giving off other matters, 
we should be more able to calculate the importance of 
producing motion in the air, True, there is confused 
motion going on even in a common Vinery, where the 
air as it becomes heated ascends from the flues or hot- 
water pipes, descending again to colder parts of the 
house, but it seems as proper to give a direction to this 
motion as that Nature should cause the wind to blow 
only in one direction in a certain place at one time. It 
may also be found advantageous to change the direction 
of the current according to the lesson taught us by 
Nature, and it seems practicable enough to effect this 
upon the revolving system by baving two classes of air 
drains, with dampers, &c. have witnessed the 
splendid crops of Grapes at Polmaise for the last two 
seasons, I have breathed the lightness and experienced 
the pleasant feeling of the air, even when the thermo- 
meter ranged above 70°, and would have guessed the 
temperature at 55°, On one evening when the heat 
proceeded more from the stove than from the sun, 
could distinctly observe the leaves trembling as the 
descending air fell upon their upper surfaces in its 
rapid circulation.. I was more struck with the thick- 
ness of the leaves and their footstalks, and the 
size of the Grapes, than with the wood of the Vines. 
I did not think the borders superior. When the 
trough was filled with water, and the. woollen 
threads attached to the web in it, the capillary at- 
traction of the threads rendered the cloth wet and 
made every leaf drop with moisture in five minutes. 
This evaporation was at once rendered quick or slow 
by the greater or less number of worsted threads thrown 
from the web into the water. I had witnessed some- 
thing of the success of revolving air in Vineries some 
10 years ago, at North Berwick E 
= 
ouse, in East Lothian, 
where the external air was conducted from a sunny 
spot through a drain over a chambered furnace, and let 
e at occasional openings of a double covered flue. 
> 
deed, so satisfied am I that there is nothing in it, that | I have also for several years past had an opportunity 
=. 
of seeing very fine Grapes produced by the agency of 
White’s hot air stoves, under the management of Mr. 
Shearer, who has given the plan of his house in another 
column. The application of the “wet blanket,” and 
the particular current given to the air, are new features 
in heating, however, for which the horticultural world 
is indebted to Mr. Murray, of Polmaise. I ma 
mark, however, that eminent horticulturists calculate 
the original cost of the stove at from 12/. to 20L, and 
they say that the probable loss of heat by the warm 
smoke passing too directly up the chimney, in place of 
circulating round a flue, are strong barriers to the 
general introduction of the Polmaise system of heating. 
Mr. Gardiner, at Oxenford Castle, near Edinburgh, ia 
renewing the old flues of three forcing houses, has in- 
troduced feeding air drains across the Vine bord 
the bottom of the front flue. The front flue (by which 
o 
the smoke enters) is buried to the level of the floor, 
and has a circulating air chamber, six inches in width, 
around both sides of it, the back one being covered 
moistened at pleasure from water held in the hollowed- 
out fire-clay covers of the flues. "The returning smoke 
flue is built above the ground close to the b: 
with the trellis in front of it, so that the very produc- 
tive Vines on the back wall may oceupy the whole floor, 
as far as the retaining wall, which bounds the front 
flue. By this arrangement it will be observed, tha 
the interior of the house looks remarkably level 
and neat, and the heated air ascends both from 
the baek and from the front flue condensing along 
the middle of the house, where there are inlets to 
drains that return it again to be heated before it re- 
ascends. Some argue that the air should all arise from 
the front, while others hold to the back. Mr..Gardiner 
is combining both. In nature, I presume, the cold 
moist air generally descends over the upper surfaces of 
leaves, while the warmer air radiates upwards upon 
their backs., In the process of evaporation in the 
morning, however, I imagine that the back of the leaf 
is moistened, thus tending to counteract the effect of 
sunshine upon its upper surface. Mr. Gardiner has 
varied the arrangement of the flues in the different 
houses, and it will be interesting to know the result of 
their success and economy, as a few shillings will make 
the requisite alteration where old flues require repair. 
It is thus quite obvious that the important problem of 
giving motion to the atmosphere and leaves in hot- 
houses is on the fair way of being solved.— Robert 
Arthur, Waterloo-place, Edinburgh. 
Plants for Decorating the Greenhouse in Winter.— 
Your correspondent, Mr. Errington, has written well 
on the subject of winter flowers, but all of this matter 
has more or less related to plants forwarded for the 
purpose of the conservatory in higher temperatures. A 
most desirable, but more restricted class remains to be 
illustrated, that of strictly winter greenhouse plants ; the 
list, in additition to those already given, should comprise 
such plants as will flower in their natural colours and 
habits in a common, well-appointed greenhouse during 
the months of November, December, and the first fort- 
night of January. I am able to do little more than 
make a start by observing that my greenhouse (not 
conservatory) is now like May with Cinerarias, the 
old Coronilla, Chrysanthemums, Mignonette (standards), 
Fuchsia microphylla, in small pots, a vigorous, herba- 
ceous sucker, chosen in October, and the rest of the 
plant broken away; Salvia fulgens and patens; and has 
been during the above mentioned months, rejecting all 
i 
flowers which bloom at this time out of doors, amd al 
leavings of October. Out of half a dozen Coronillas, 
three will generally be in flower thus early. The Sal- 
vias were starved and stopped through the summer, 
and had a slight shift in September. - The Cinerarias 
were early seedlings of the year. Salvia splendens was 
not included, though present, being always effective 
but never strictly comfortable, and many others rejected 
as being liable to damp off in flower. Colour and quan- 
tity of the plants should be preferred to any floristieal 
‘cell or fine i ; the house shculd be kept 
like a drawing-room, all the flowering plants being put 
together in one or two compartments, and their sitna- 
tions changed with regard to effect almost daily. May 
I trust to the courtesy of amateur proprietors of green- 
houses (the most likely persons) to add to my lowly 
list, and assist with their information.— Micklewell. 
ANoises (see p. 40).—Your correspondent, “A. S.” 
had better, I think, before pulling down his wall; try 
the effect of nailing up the common Laurel all over it, 
thickly and closely ; this should be kept clipped and 
trimmed (chiefly in the spring), which will keep it 
regular and thick, The size to which the stem of the 
common Laurel grows is a recommendation in this case 
beyond Ivy. Magnolias fastened to the wall would be 
ornamental during the time of flowering. The common 
Laurel is used as a thick covering to walls, in the way 
I mention, at the Earl of Shrewsbury’s, Alton Towers. 
It is there cut close in the spring, and is green all the 
year round ; it harbours no insects, and is of a cheerful 
green colour. Should the wall in question be accessible 
to cattle, Laurel must not be used, but Holly will an- 
swer instead, without any risk. It must be nailed flat 
to the wall, and thus form a kind of eushion, which will 
deaden reverberation, as pictures and curtains do in a 
room, pictures particularly.—d. Z. [The wall adjoins 
the road. What is to be done while the trees are 
growing ? 
The Ombrological Almanac.—In a short notice of 
| this almanac in your Number for January 10 (page 23), 
