THE GARDENERS 
CHRONICLE. 
[DEc. 30, - 
cient attention to the state of that air; and I strongly 
suspect that some di ildew, for ill ti 
which have been hitherto placed to the account of a moist 
atmosphere, ought rather to be attributed to an arid one $4 
at least, this much I do know for certain, that, in a col- 
lection of young plants, the only one which was affected 
by mildew was standing in the driest part of the pit, and 
was, and probably had been for some time previously, suf- 
fering for the want of water. 
In imitating the strong currents and trade-winds which 
influence vegetation at the Cape of Good Hope, we for- 
get that the current is from the sea to the land during the 
diytime, and is therefore loaded with moisture; but, in 
the night, the current is from the land to the sea, and is 
consequently of rather a dry nature. Now although I am 
aware that, in the absence of the powerful light conse- 
quent upon the nearer proximity of the Cape to the 
Eguator, it would be wrong in this country to copy its 
climate as to drought and moisture, yet experience has 
proved that a strong moist heat, of from 60 deg. to 90 
deg. in the daytime, is not too much for Heaths in the 
growing season ; and that in it they will grow with a lux- 
uriance and vigour which is never seen under other cir- | 
cumstances. Some plants of Epacris which have been 
PLAN OF EPIPHYTE HOUSE IN THE GARDEN 
subjected to this treatment during the past season, have 
made very rapid growth. ‘A pair of them will be exhi- 
bited before the Horticultural Society on the 16th Janu- 
ary, and then people may judge for themselves. 
The only treatment which I know of that will suffice to 
keep plants in a healthy state after they haye attained the 
size desired, is to remove them into pots at least two 
sizes larger, into rather poor peat, which they will not 
root into very vigorously, and which will act as a non- 
conducting medium between the ball of earth and the pot. 
If a wooden box could be substituted for the pot, it would 
be an improvement. Plants that have been grown on the 
one-shift system should be subjected to this treatment as 
soon as the pot is filled with roots, because by that treat- 
ment the rite of growth is so rapid, that even a slight 
check is injurious to them ; and hence the complaints of 
their dying off. 
The time has now arrived when I must say adieu; and, 
in parting, I can only state, that if others have derived as 
much instruction from reading these articles as I have 
pleasure from writing them, we are all amply compen- 
sated.—W. P. Ayres, Brooklands, Blackheath Park, 
Kent. 
OF THE REV. J. CLOWES, BROUGHTON-HALL, 
MANCHESTER. 
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HOME CORRESPONDENCE. ‘ 
Pine Apples.—Having had extensive practice in the 
culture of the Pine for these 20 years, I venture to offer 
a few words on the subject. I quite agree with Mr. Barnes 
that it does not take three years to bring Queens to ae 
fection ; they are usually produced with me in about it 
or 18 months, and sometimes in even less time. 
imagine that the Monserrats of Mr. Barnes are the Black 
Jamaica with us in the North; and if Lam right, I beg 
to state that when gardener to Sir W. Brisco, I obtained 
fruit of these two kinds equal in weight in an equal oa 
of time, and in the winter season. A good cultivator ° 
my acquaintance cut 20 Queens 35 years ago which 
weighed altogether 118 lbs.; and I cut a Providence ue 
18 years ago, produced under the shade of Vines, whic 
weighed 10 lbs. It is therefore evident that recent pro- 
ductions do not surpass those grown 20 years ago in 
weight ; the only improvement in the culture of Pines 18 @ 
that they have of late years been brought more speedily” 
to maturity. The Monserrats with us in the North have 
fruit tun-shaped or cylindrical, flat pips with a very Nea 
top, and they are of rather a copper colour. The Black 
Jamaicas have pyramidal fruit with a small crown, 2” 
some of the pips are apt to get black in winter. The 
colour of this is generally darker than that of the forme! 
—R. H. Pope, Heaton Nursery. 
Mildness of the Season.—We have received several let 
ters on this subject. ‘A Hampstead Subscriber” ed 
that, from the unusual mildness of the season, he bas 2 
only Pelargoniums in bloom out of doors, but that he also 
found a fine lively specimen of the Thistle, or Painte 
Lady, Butterfly, and several other insects, common 
knownby the name of Lady-birds. Another correspondenh 
“ J. Mitchell, jun.,”” informs us that there is now grow" 
ing, in the open borders, in the garden of G. Grahams 
Esq., Stokefleming, near Dartmouth, two fine plants © 
Brugmansia sanguinea, three feet high, five feet in dia 
meter, and covered with beautiful trumpet-flowers. d 
also says that the following plants are quite healthy, a™ 
in full bloom, viz. :—Pentstemon gentianoides coccine 
many varieties of Pelargoniums, a few Verbenas, and like- 
wise Fuchsia microphylla, cilindrana, Thomsonii, and of 
globosa; with Ageratum mexicanum, Heliotropium pet 
vianum, Siph p bicolor, Lophospermum atr0- 
sanguineum, Polygala cordifolia, Anagallis Monelli grandi- 
ora, agnolia ferruginea, and Chrysanthemums. 
Knutsford:correspondent finds his Asparagus with buds tw? 
inches long, and an Ipomea Horsfallia, whose shoots ha 
escaped from a hothouse, in flower in the open air. , 
Plant Guards.—In guarding from hares and rabbils 
place a few small uprights round the plants at a short dis- 
tance from them, and let them stand about twelve inch? 
above the ground, then tie round them two pieces of strovs 
white yarn or cord, made either of cotton or wool; this 
forms a neat-looking fence, and is found to frighten ral: 
bits from the plants, as they take it fora trap. This 
plan I have seen fairly proved; where it was adopted, the 
plants were not eaten ; but where nets were used for the 
same purpose, they were eaten through and the plants 4¢ 
stroyed, both in the same garden and the same sort 0 
plants.—Facile, 
Heating with Brick-Flues.—In answer to ‘C.,” (P 
878,) respecting Brick-flues, I beg to state that there C4? 
de no doubt but that what ‘C.”’ asserts regarding the pfo- 
perty of expanded air possessing a greater capacity for 
heat than air more dense is perfectly correct ; but I wish 
to explain a fallacy into which he has fallen on the appl 
cation of that principle. The rule for air, as well as all 
other gases is, that its capacity for heat enlarges in neatly 
an inverse ratio to its density ; that is, at halt the density 
it has nearly double the capacity, or, in other words, in th? 
former that it will take nearly double the quantity of heal 
that it would in the latter, to raise it to the same degree # 
temperature : this is the cause of difference of climate 4 
different altitudes under the same parallel of latitude. Th? 
mistake into which ‘ C.’’ has fallen is this : he imagine’ 
because hot air moves along a flue gradually enlargi®S 
from the fire end, that this air must gradually expa®! 
also inthe same proportion, and must have its capacilf 
for heat increased, absorb it, and that it does not give i! 
off to the walls of the flue. But the very reverse of this 
is the fact; the air in the flue, instead of expanding an! 
becoming more rarefied in its course, contracts, and be- 
comes denser ; and it does this because it gets colder 12 
its passage along the flue. Air doubles its bulk for every 
480° of increased temperature ; and hence, in its progress 
along the flue, for every degree of heat it loses, it coD” 
tracts 73,5 in volume, or gets by that fraction more dense 
and, of course, in proportion diminishes its capacity for 
heat, giving it off in a sensible state to the brickwork 
around. The plain effects of a Brick-flue gradually en- 
larging from the fire are these: *—Ist. A current of hot- 
air diminishes in velocity as it, recedes from the fire, 80 
that where the air is hottest, it has least time to give 0 
its heat, and where coldest most time for this purpose. 
2d. The radiating surface increases where the tempera- 
ture gets lowest, and compensates as much as possible 
for that deficiency. Although not an advocate for Brick- 
flues where hot water can be obtained, I would still re- 
commend the flue noticed as one of the best of its kind.— 
J. LL. Newburgh. 
Oak Timber E. In the pi que Park 
at Porkington, near Owestry, the seat of W. Ormsby 
Gore, Esq., are two masses or clumps of aged Oak-trees, 
some, but not all, of the species Quercus sessiliflora, 
which are, for the most part, infested with excrescences 
* A simple illustration of the motion of air in a flue of this 
t may be seen in looking at a river. When its banks ap- 
proach and the channel gets narrow, the current is rapid; but 
when the banks recede, and the bed enlarges, the water moves 
more slowly. 
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