49—1846.] TH 
E GARDENERS' 
CHRONICLE. 
805 
can be carried, there may arise some practical imp 
diments, such as crowns of vaults and monumental 
slabs ; but fortunately it makes little difference to the 
air if its journey be a little lengthened by a roundabout 
course ; it will still outstrip all competitors, and there- 
fore I trust that this, the only practical difficulty, 
will be more apparent than real; and I shall sup- 
pose we are in possession of a cold air channel, 
With a gradual fall, say of one foot in 30, towards 
the heating surface, for, by being brought in con- 
taet with such, the air must be heated; but heated 
surfaces are radiating surfaces, and radiation is the 
bane of uniformity, therefore, the heating surface must 
either be placed without the building, or else surrounded 
with sueh sul as shall eff prevent the 
passage of the heating rays. There can be no diffieulty 
in adopting either course ; in the latter case, let us 
suppose a church already supplied with a powerful 
Stove, Arnott or other ; for economy's sake, it is wished to 
retain it—can it be made subservient to Polmaise? and 
can its radiating annoyance be got rid of! Most assu- 
redly ; for if it is placed over the orifice where four 
concentric cold air drains coming from distant parts of 
the church meet, and if it is covered over with some 
non-conducting hood having apertures through which 
the air coming from the cold drains and passing over 
the stove can rush out the object will be lished ; 
e- 
decompose the air. It may be so. But we neither 
burn the water nor decompose it ; the current of water 
keeps down the temperature of theboiler. We do nof 
know what would be the effect of the current of air ; but 
this we know, that the velocity of that eurrent depends 
on the difference of the temperature of the two places be- 
tween which it is travelling, and that the plan is not 
unworthy a trial. I throw out all these suggestions, 
partly with a view to induce your readers to reflect on 
great principles, partly to show how completely Pol- 
maise is in its infancy (the power only waiting for de- 
velopment), but most of all, to induce those who delight 
in such investigations to make various experiments on 
the application of its principles to practice. Supposing, 
therefore, the cold air has been brought and been heated 
by passing over a stove of similar construction to my 
own, it only remains to consider the mode of distributing 
it; and about this, repeated experiments have proved 
to me that we may save all our trouble; the hot air 
will distribute itself, with a uniformity and speed almost 
ineredible, Unless we reflect on the well-known ve- 
locity of aerial currents, nothing more will be required 
than to let it flow out into the church, when it will be 
found thatat the distance of only a few feet, the air will 
be at the uniform temperature of the building. I have 
rep seen a, tl ter which I have the power 
ding in the hot blast, at 150° Fahr., while 
even if the hood were dispensed with, the radiating evils 
of the stove will be much mitigated, because the con- 
stant and rapid current of cool air will, by supplying 
itself with caloric, prevent its accumulation on the 
surface of the stove. Another mode of carrying out 
the Polmaise principle, and which I am inclined to 
think will be very generally adopted in churches, will 
e to sink the source of heat below the level of the 
oor, say in a vault, at one end of the church ; this will 
secure a fall for the cold air, and an entrance for the 
hot at the lowest possible level. I would advise the 
stove being built close to the foundation wall of the 
ehurch, so that it shall be supplied both with oxygen 
and fuel from without, by piercing the foundation wall 
for this purpose, and also to allow the flue to return 
into an external chimney, which in many instances can 
be carried up behind a buttress ; much good will be 
effected by this plan—first, we shall run no risk of havin 
a bad draught to the fire, we shall avoid all possibility. 
of gaseous exhalation or smoke from down-draught, 
either when the fire is first made, or when it expires, 
and which occasionally does and must occur, directly 
the weight of the external atmosphere overcomes the up- 
ward draught, a circumstance so often rendering stove- 
heated buildings unpleasant. The fire will not exhaust 
the air of the building, and though last perhaps not least, 
the architectural beauty of the church will not be 
sacrificed, either within or without, for in lieu of a great 
length of iron pipe, supported by sundry devices of iron 
bars, hanging from the centre of Gothic arches, or 
similar barbarisms, we shall perceive nothing within 
except the perforated plating in the aisles to admit the 
descent of cold air, aad a similar design to admit the 
hot air up, over the spot beneath which the stove is 
placed, while externally the furnace doors will be sunk 
below the level of the ground, and the steps down to 
them may easily be concealed, either by some neigh- 
ouring or stone balustrade, while the 
chimney will be the only portion of the heating 
apparatus necessarily apparent. Where circumstances 
prevent the stove being below the church, then it must 
be placed without, where (as it is advisable to place it as 
low as possible) it will not'be difficult te conceal it, 
Having considered the position of the heating power, 
the means of bringing the air to it, it will be expected 
that I should make some remarks on the heating 
apparatus itself, although I wish it to be understcod 
this has nothing whatever to do with the principles 
of Polmaise; for these might be applied even 
‘were the temperature produced through the inter- 
vention of water, and while I have not hesitated 
to help forward Polmaise, by reducing it to prac- 
tice in a most simple form, I trust I am not foolish 
enough to consider this form the best that can be de- 
wised. I already see errors to be got rid of, and im- 
provements that may be made ; and as it yet remains 
4o be seen how small an area will suffice for the cold air 
to flow to the heat, so it yet remains to be proved what 
are the best means of warming it on its arrival. The 
question really for solution is—the best air boiler. 
ave no hesitation in asserting that the means I have 
employed, namely a brick stove with an iron top, will 
secure the end desired; that where uniformity of tem- 
perature is required, it possesses peculiar advantages ; 
but it is equally certain that where other qualifications 
are required, euch as the power rapidly to raise the 
"temperature, other means may be adopted with advan- 
tage; and when the ironmongers are compelled by 
publie opinion to heat buildings in this manner, there 
will be no lack of ingenious stoves. I doubt not that 
both Mr. Haden’s and Mr. Hazard’s stoves would each 
be very powerful placed under the conditions of Pol- 
maise ; but then there is the question of cost, which, I 
hear, is necessarily very great, from the complication of 
the mechanism and the quantity of the metal ; but is 
all this eost necessary? There are water-boilers which 
‘profess to abstract all the calorie from the burning fuel, 
and which, even of a large size, cost but a few pounds. 
Why should an air-boiler be more expensive? Who 
can tell whether, if the contents were emptied out of 
one of these very boilers, and air conveyed through it 
instead of water, the result would not be satisfactory ? 
Of course I shall bo told that I shall burn the air, and 
m 
of 
another, 4 feet from it, was at 65°, or the uniform tem- 
perature of the place, and unless persons sat actually 
over the blast, they would not experience any inconve- 
nience from sitting near, Those who doubt I must 
refer to “ Facts from Polmaise,' published in the 
Chronicle, every one of which my experiments at Nut- 
field fully corroborate. 
Having thus far endeavoured to enlighten the [publie 
as to the right means of diffusing heat, and thus afford 
them a luxury whieh in this climate all know how to 
hands, one which I do mot believe I shall ask in 
vain from the friends of Polmaise, while even its op- 
ponents must admit that it is desirable its truth should 
be tested on a large scale. The case which I desire to 
lay before the public is this: A large and beautiful 
church, 130 feet long by 70 wide, is now nearly com- 
pleted in the city of Winchester. The funds subseribed 
will barely suffice to pay for its erection, and there will 
certainly be nothing left to provide the means of warm- 
ing this large building. The rector and committee, 
thinking favourably of the Polmaise “mode; of heating, 
are anxious to see it applied; but the necessary funds 
are wanting. Under these circumstances, I have ob- 
tained their permission to make this appeal to the public, 
with a view to raise the necessary sum by subscription. 
If this is done, I am quite willing to direct and person- 
ally superintend the work. It is proposed to limit the 
subscription to sums not exceeding a guinea. It is 
difficult in so novel an undertaking to estimate the re- 
quired sum, One very expensive portion of the work 
will be the formation of the cold-air drains. It is de- 
sirable the committee should be furnished with 100/., 
to meet all contingencies. A strict account will be 
kept of all actual expenses, and the surplus given to 
the general funds of the church. If a few separate 
parties who appreciate the importance of the subject 
would severally exert themselves in the cause among 
their friends, the sum would soon be raised.—D. B. 
Meek. 
Home Correspondence. 
New Theory of the Potato Discase,—1 have lately 
read something about the Potato disease arising from 
volcanic operation, and 1 am led therefrom to ask you 
for a little space in your columns for the mouse which 
my mountain is now about to bring forth to the wonder- 
ing world. You must know, that when I first witnessed 
the experiments at the Polytechnic, with Armstrong’s 
hydro-electric machine, it immediately struck me that 
the tl ds of steam |i ti incessantly travers- 
ing all parts of England, might be so many travelling 
factories of electricity, diffusing it through the atmo- 
sphere to an enormous amount. And if so, that after 
awhile we might all be the worse, somehow or another, 
for the superabundant supply of this not very idle nor 
inoperative agent. Cannot you imagine that a suffi- 
ciency of electricity might be thus generated, so as not 
only sensibly to disturb the nice equilibrium and ad- 
justment of the free and uncombined components of the 
atmosphere, but also to affect these in such manner as 
to induce the constituents to enter into some new 
chemical relationships, thereby rendering the air to 
a degree detrimental to the functional operations of 
animals and vegetables? I fancy I ean see how 
ammonia, nitrie acid, and perhaps that curious electric 
compound of hydrogen and oxygen, called ozone, might 
be formed, and whether my mouse, which by the bye is 
a very primum mobile, in all chemical matters, is play- 
ing any part in the production of these, or in the de- 
struction of the Potato, or in epidemics generally ; who 
can tell? You may say the Potato disease has oceurred 
before locomotives were known [we do not say that] ; 
a disease in Potatoes may have occurred, I grant, and 
that it is now occurring where locomotives have never 
even been heard of—very true ; but this will not anni- 
hilate my mouse, for once set electrieity free, and where 
between the poles it may be at the next moment, aye, 
in the twinkling of an eye, playing its pranks, neither 
I nor you (clever as you are, Mr. Editor) can tell. 
should much like to know if these locomotives do gene- 
rate electricity (and from the vast frictional forces 
exerted, I should think they must) what becomes of 
= 
appreciate, I am about to ask a favour at their|a 
itall. It must go 1 it must do hi 
You have no doubt, sir, produced water, by passing the 
electric spark through a mixture of oxygen and 
hydrogen, and who knows but that some such operation 
has been going forward for the last two or three 
years through the agency of the electricity generated 
by this mighty locomotive hydro-electric machiner 
giving rise to the rains, which have oceasioned the 
devastating floods now so continually oceurring through- 
out Europe. You, perhaps, have also resolved water 
into its elementary constituents by electricity ; now, 
should my machines throw off a sufficiency of elec? 
tricity into the atmosphere to effect the decomposition 
of water, or should some of the water as it escapes in 
steam from the boilers be decomposed by the electri- 
city known to be generated at the moment of escape, 
might not the disunited elements be brought (through 
the same agency) into new combinations; the oxygen 
with the nitrogen of the atmosphere forming beth 
ammonia and nitrie acid, and the oxygen with the 
liberated hydrogen — ozone — and thus by the nice 
atmospherieal balances, both chemical and electrical, 
being disturbed, the air becomes vitiated and inimical 
to auimal and vegetable life, producing cholera in man, 
rot in Potatoes, &e. You have given xvõos to the 
voleanie visionary, pray pat me on the head for my 
mountain labour. But should my poor wee pet not do 
well under your nursing, I shall consult Drs. Liebig 
and Scheenbein.—Ridiculus Mus. 
Gardeners’ Reading Rooms.—To the reading rooms 
already in operation J beg to mention that one has been 
established here by Mr. Epps, who has liberally fur- 
nished a comfortable room and a good library for the 
use of gardeners and young men employed in his estab- 
lishment ; and I am happy to add that one and all duly 
appreciate the generous act, and I doubt not but the 
employer as well as employed will be benefited by such 
proceeding.— Daniel Freeman, Bower Nursery, 
Viaidstone, Kent. 
Polmaise Heating —Having been alluded to by Mr. 
Meek in a Jate article as the “clergyman near Coven- 
try,” who had partially failed in his application of the 
Polmaise system of heating, I think it but due to the 
system, as well as to its zealous advocate, Mr, Meek, to 
inform you that I have since completely succeeded, My 
partial failure was chiefly owing to having too many 
openings from the floor of the house into the cold air 
drains, since, after closing all these but two, one at 
each end of the house, the current of air became amply 
sufficient to sweep into the hot air chamber an abund- 
ant supply of heat. During the last three or four nights 
of sharp frost, with an external temperature of about 
20°, the house has been kept at a regular heat of from 
54° to 60°, with one moderate fire put on at 10 o’clock 
in the evening.—W. Thickins, Keresley House, near 
Coventry, Dec. 2. 
Cambridge Botanic Garden.—The report of the Syn- 
dicate, mentioned in your last, was confirmed by the 
Senate, without opposition, on Wednesday last, and the 
Curator will now have directions to act upon it imme- 
diately. The land is quite ready to receive the trees, 
and has proved far better for its object than had been 
expected. The chief difficulty money. Although 
some of the colleges have large incomes (which, how- 
ever, are divided in small dividends toa large number 
of individuals), the University has hardly a sufficient 
aunuel income to meet its necessary expenditure. The 
colleges can do nothing, as their funds are all appro- 
g 
priated by their statutes.— Nov. 30, 1846 
The Potato Fly.—Yhe Aphis vastator, or destroyer, 
the insect which causes the Potato disease, is still spar- 
ingly to be found in enclosed gardens on the leaves of 
young Potato plants, Groundsel, the Shepherd's Purse, 
the Turnip, the Radish, the Solana, the Spinach, and 
many other plants. I yesterday not only found it upon 
these plants, but in addition to those which I have else- 
where detailed, I have even noticed that whole beds of 
Violets were dying from its agency, the leaves perish- 
ing like those of the Potato, Spinach, or Beet. At this 
period of the year, ion becomes quiescent, and 
from this cause a much smaller number of the destroyers 
appears to effect the destruction of the plant.— Alfred 
Smee, 7, Finsbury-circus, Nov. 23. [See the Reviews 
of to-day. 
Leggs Hydraulic Engine.—1 regret being obliged to 
trouble you again ; but from the letter of a “ Mill- 
ment I am not aware of any hydraulic engine existing 
with Legg’s application (whatever it may be), attached 
to it), and even should it prove to be a revival, I am at 
a loss to imagine how it can have remained so long in 
obscurity, as whether new or old, nobody can doubt its 
efficiency, where only a small stream is at command, 
When I first noticed the machine in question, my chief 
desire was to give gardeners and farmers an opportu- 
nity of saving mueh labour and expense. by employing 
an engine calculated to overcome difficulties which 
might appear without remedy, as in my own ease. 
had no idea of raising such a storm as I appear to have 
done. Let the engine be either a recent affair or as 
ancient as the pyramids, it is worthy*of being brought 
before the publie, and on a small seale such as i have 
before mentioned I do not know of anything to equal it 
(although such a machine may exist) If men expect 
the hydraulic to do the work of a steam-engine, they 
will probably be disappointed. I wish some of your 
correspondents would give their experience (authenti- 
cated by name), on any hydraulic engines they may 
