724 
THE GARDENERS' 
CHRONICLE. 
fOer 3h, 
they swell very rapidly just before changing colour. 
The size of these, however, will startle many a good 
grower and silence some of the noisy ones, who trumpet 
forth their own marvellous doings in these matters. The 
it above alluded to contains precisely 40 plants. Mr. 
Petvilain fruits his Pines in small pits ; his object for 
doing so will presently be explained in connection 
with other matters relating to their cultivation. 
In order to obtain a pretty accurate estimate of 
the relative size of these 40 Pines Iwas induced to 
measure the two smallest and the two largest 5 but then 
this, without measuring every one, was a most difficult 
and perplexing business, as it was impossible by the 
eye to distinguish much difference in the whole lot, so 
perfectly equal and uniform were they. It is, there- 
fore, just possible there may be some half an inch 
larger in circumference, and others as much smaller ; 
but it is quite certain the disproportion does not exceed 
DAR: 1—10 inches in height, 18 inches in cireumference.* 
No. 2—11 » 19 » Cael 
No, 3—11 » 21 s uo Ut 
No. 4—11* » 2 Vs 5 YET 
The size of the crowns varied very little, being gene- 
rally between 6 ins. and 8 ins, high ; but then, be it re- 
membered,there were no mutilations by the applica- 
tion of tweezers here. The crown was as it ought to 
be with good cultivation, a handsome and perfectly 
natural production, and like the noble fruit that 
supported it, perfect of its kind. The pips were 
swelling out flat ; none of them were lady waisted, or 
resembling an hour-glass. The form of every one in 
the pit was perfect; indeed, to an unpractised eye 
they appeared as if cast in the same mould, On a very 
careful and searching examination I could not discern 
an abortive pip, blemish, or deformity, of any kind 
whatever. These magnificent and princely fruit pre- 
sented altogether the most transcendant exhibition of 
horticultural skill I ever witnessed. They are at all 
times opened to inspection ; they are not beyond mortal 
gaze, as Mr. Pelvilain gladly and willingly permits any 
respectable person to inspect them, and with pleasure | 
details his mode of culture. Having furnished your 
readers with four tolerably weighty reasons wherewith 
to back my opinion of Mr. Pelvilain’s success in the art 
of Pine growing, I shall proceed in a future Number to 
detail his mode of culture, which I flatter myself will 
prove interesting.— Mirabile dictu. 
THE LAWS OF HEATING. 
Ir appears from the remarks of several correspond- 
ents, that there is some difficulty in understanding how 
the plates, over which the air passes, are fixed, and 
how, as they form the roof of the furnace and the flue, 
all smoke and gas are prevented from passing 
through the joints, and mixing with the air of the 
chamber, and thus passing into the house. Now, as 
we have not perceived anything of the kind take place 
in the Pine stove, and as there are now plenty of per- 
sons who can testify to the healthy appearance of the 
vegetation in the house, and as it has been in operation 
for the last 10 weeks, it is fair to suppose that the 
means taken to prevent this accident are sufficient ; 
and if so, we need not trouble ourselves with anything 
more complicated. At the same time, had anything of 
this sort occurred, there are numerous modes by which 
it might be prevented, and one or two which I shall 
presently notice, as, perhaps, worthy a trial by those 
persons who are fearful of trusting the simple expe- 
dient to which I have resorted. 
Your readers are aware that the stove is brick ; it 
is formed of four walls of 9-inch work ; the outside 
measure is 5 feet 5 inches long ; 4 feet 4 inches wide 
(I speak of the actual stove, not the chamber) ; the in- 
ternal measure, therefore, being 3 feet 10 inches long, 
and 2 feet 10 inches wide. Another wall of 9-inch 
work is carried up between the two ends, but not in 
the centre ; it is16 inches from the wall of the stove 
which stands nearest to the house, and, being 9 inches 
thick, of course leaves a space of 9 inches between itself 
and the farther wall. Thus, A is the wall next the 
plates are 3 feet 6 inches one way, by 1 foot 6 in 
the other; and are three in number ; so that, th 
length extending from A to C, they will take a bearing 
of 4 inches on the two outside walls (A and C), and, of 
course, will rest on the intervening wall (B) ; they are 
1 foot 6 inches wide each; so that, when laid in their 
places, and half an inch allowed between each for ex- 
pansion of the metal, they form a surface of 4 feet 7 
inches by 3 feet 6 inches. This gives them a bearin 
of 4 inches on the brick-work all round. Two of these 
plates are cast with a 4-inch extending rabbit, which, 
by its extension over the joint, prevenis the escape of 
smoke and gas, Thus :— 
A PTEN c 
Bo deg ncc e ui 
When these are laid, allowing half an inch between 
them for expansion, they will appear thus :— 
I have stated that they take a 4-inch bearing all 
The accu of these measurements has been recently 
confirmed by a re-examination of the Meudon Pines, — Ed, 
round on the 9-ineh work ; at the two ends of the stove, 
the walls are carried up three or four courses higher, 
in 4}-inch work, thus forming a groove between the 
edges of the plate and the brick- work, half an inch wide, 
at the wall A. Only one course of (half thick) bricks 
is laid, for the purpose of making this groove ; the wall 
C is also carried up similarly to end-walls ; so that 
there is a groove half an inch wide formed all round the 
edge of the plating. This being filled with fine sand 
(which may be put on in larger quantities than just to 
fill the groove), makes a smoke-tight joint. Some sand 
is also strewed along the rabbit-joint. Thus the weight 
of the plates keeps them in place, while they are free to 
expand, by squeezing up the sand, which follows back 
as they contract. If they were bound in the brick- 
work, they would pull it all down in less than a twelve- 
month, by their alternate contraction and expansion. 
I had a chemical sand-bath some years back simi- 
larly constructed ; it was in nearly constant operation 
for several years, and never required any repairs, The 
furnace is 3 feet high. This allows 3 inches for the 
paving of the ash pit; 1 foot deep, for ash-pit itself ; 
bars, 3 inches deep; and from top of bars to 
bottom of the plate (1 foot 6 inches) — 3 feet. The 
furnace is 16 inches wide, being formed by the 
walls and B, and the bricks, used where 
these walls form the furnace, are Stourbridge fire-bricks, 
far more durable than Welsh lumps, and but little more 
expensive, and set in Stourbridge clay. The furnace 
occupies a distance of 18 inches from back to front; 
that is, the bars are 18 inches long, The accompanying 
will give an idea of the ground plan of the stove as it 
stands isolated in the chamber at all points except 
where it is supplied, and where the flue crosses to enter 
the chimney. This area or space is very small, the stove 
occupying the entire chamber except 2 inches; air 
being a very bad conductor of heat, no appreciable 
heat is given off to the outer brick wall. 
Ground Plan of Stove. 
End wall of Hothouse under which cold air passes. 
a, Area of air. 
The tank is 4 feet wide and 5 feet long, with a longi- 
tudinal division, so that by caleulation it will be found 
to take a 2-ineh bearing on the outer 41-inch work of 
the end walls of stove, which are carried up to bear it ; 
and itis raised about 9 inches above the plating,’so that, 
from its position, this tank not only contains a surface 
of water to supply atmospheric moisture, but its bottom 
forms a channel by which the air is compelled to tra- 
verse the plate and become hot, as is seen in the sec- 
Section. 
a. Felt and 2 inches of sawdust ; b, Hot-air opening into hot- 
house beneath the bark bed; c, Level of hot-house floor; 
d. sand joints. 
r| tion ; and then, on its way back to the honse, beeoincs 
charged with moisture. It will be evident that, as the 
tank is divided, one side or both may be filled; and thus 
more or less moisture produced ; but not only this, the 
side marked B, from being more over the source of 
heat, evaporates much more moisture ; and at present, 
we are only keeping A full of water. For a greenhouse 
a very narrow tank will suffice, and a thin sheet of 
iron plating can be extended between the end walls of 
the stove, to secure the passage of the air over the 
plate ; this will, of course, also lessen expense. 
I trust these remarks will be of practical’ utility to 
your readers. If they are fearful of trusting to this 
plan, it would be easy to cover the entire plates with 
sand, then the air would blow over hot earth; surely, 
that will be natu:al enough to please the most fasti- 
dious. A little African desert, a Mediterranean sea, 
and a consequently moist sirocco, ought to. please the 
inhabitants of the hothouse; at all events, it does so 
with the bare iron plate. Perhaps your readers will 
think ‘so when I state that in the hothouse is a Cucum- 
ber plant, taken as a cutting barely five weeks past; it 
has nine fruit on it, one more than a foot long ; till this 
week it has been growing in a pot, and has leaves on it 
measuring 17 inches in diameter, and 5 feet in circum- 
ference ; in fact itis a perfect specimen of vegetable 
growth. 
Another mode of preventing all chance of gaseous 
exhalation would be to have the plate east with an edge 
projecting at right angles from the under surface to di 
into a sand groove in the briek-work ; thus allowing 
expansion, In truth, the ingenious mind will suggest 
many contrivances to obviate any exhalation ; I can 
only say that, at present, any further precaution than I 
have taken seems unnecessary. In a late Paper I 
saw a question, by “A Consiant Reader,” which can 
only be answered by long and numerous experiments, 
and these most carefully repeated. Iam asked, first, 
what proportion of heated surface there must be to a 
given quantity of air. I wonder it did not occur to 
your correspondent that this same surface might be 
heated extremely, or only just warm, and that the better 
point to seek to determine would be, the number of 
cubic feet of air a bushel of coals would raise to a given 
temperature; but even this would be influenced by 
numerous circumstances. I can only say that when we 
have had as much experience with this air-heating as 
we have had with water, we shall probably know as 
much about it! but it fortunately happens that, for 
practical purposes, it is of little consequence. J dare 
say that those who employ Polmaise will be content to 
adopt one principle, which those persons who have eur- 
ployed hot water have done, namely, to put up a 
machine of sufficient power, and then to regulate its 
force by the combustion of the fuel—a point espe- 
cially necessary in such a climate as our own, With 
regard to moisture, there is a division in the tank, as 
above stated ; of course, a conservatory will require a 
very small tank compared to a Pine-stove. It will be 
a practical improvement in the tank if it is supplied 
y a check cistern, leading by pipes into either divi- 
sion; and if the check cistern is furnished with a 
tap, the gardener can at all times procure chilled 
water. ith regard to the bottom heat, your cor- 
respondent need not trouble himself with any con- 
trivance ; it keeps perfectly uniform for a considerable 
time. If the fire was made up very powerfully, or if if 
was allowed to go out, liltle or no change would be ob- 
served for many hours, This arises from the soil or 
plunging material being so bad a conductor of heat; 
another point illustrative of the wisdom of Providence 
(how truly does Polmaise prove the beautiful simplicity of 
Nature's means) ; and the uniformity of the bottom-heat, 
will be found another great recommendation of this 
system for forcing. Thus I trust your correspondent 
will be satisfied. The first point time alone can answer, 
"The second is provided for, and the third unnecessary, 
In the Paper of Oct. 3, are some further remarks of 
the Dean of Manchester, in my epinion caleulated to 
mislead. He objects to my calling flues unsightly, 
because they might be ornamented with bas reliefs by 
Flaxman, I spoke of flues as they are, not as they 
might be. The wet blanket might be embroidered in 
flos silk with devices emblematical and allegorical, 
and some people might perhaps think it an object 
of beauty. However, the best proof that your corre- 
spondent really thinks with me on this point is, that he 
has taken especial care to put his flues out of sight, 
sacrificing much of the radiant heat from their sides ; 
but surely your correspondent has forgotten the sound 
principles of economising fuel, flue is a chimney, 
and it is only heated when more air is allowed to pass 
to the fuel than is necessary for the required consump- 
tion ; and this leads me to notice an assertion, but for 
which I should not have noticed. your correspondent’s 
letter. He says that his objection to my plan is, “ that 
with the same fire and attendance, three times the space 
might be heated.” He believes six times ; and then 
we are told how my chimney is to heat one house. But 
it is cold. I ean make it hot, but only at the expense of 
fuel. A boiler on the top of my fire is to heat three 
more houses. Where is it to procure its calorie ? Only 
at a further cost of fuel. Is it not most absurd to sup- 
pose that as a bushel of coals contains only a given 
quantity of calorie, it can do more than a given 
amount of work? If in my plan there is no appreciable 
waste of heat, how can I heat a greater space without a 
greater consumption of fuel, and then where will be the 
economy ? However, truth is fast making its way. 
After having had to fight so hard a battle for the prin- 
ciple, it is quite refreshing to be asked about a few 
points of practice, and more information I shall be most 
happy to afford any person on the Wednesday after- 
noons,—D. B. Meek. 
BRITISH ASSOCIATION FOR THE ADVANCE- 
MENT OF. SCIENCE. 
(Continued from p. 709.) 
CHEMICAL SECTION. — the Application of the 
Principles of a Natural System of Organic Che- 
mistry to the Explanation of the Phenomena occur- 
ring in the Diseased Potato Tuber, by Dn. Kumr.— 
— The object of the author was to urge the consideration 
of his views on the following grounds: Ist. That on the 
24th February last, he announced to the Cambridge 
Philosophical Society, as one of the main deductions 
from his analyses, that the nature of the morbid affec- 
tion in the Potato tuber consists in an abnormal ten- 
lency to premature germination, 2d. That the truth 
of this deduetion hab been proved to the very letter by 
£ 
thé progress: of the growth of the tuber subsequently 5 
and that attention was drawn to the subject by Prof. 
