17—1845.] 
THE GARDENERS 
CHRONICLE. 
269 
necessary, and thus turn out the whole in a highly de- 
veloped state at the end of May or beginning of June. 
Many things will do well in this way, but generally, 
n t is not fi ble to plants which 
are afterwards to be turned into the borders. The ten- 
derness they acquire, by being kept under glass, or even 
being covered up at night, exposes them to checks when 
planted in the open air. This would not be the case, 
dndeed, if they were not turned out till the summer 
had become established ; but too much time would thus 
be d in preparatory g t. Another 
‘good plan is to cover over at night with a flower-pot, 
any plants which you are disposed or compelled to com- 
mit to their destined place. In all these questions an 
enlightened judgment must guide you, the object being 
to have your parterres gay with flowers for as long a 
time as possible.—H. B. 
DISEASES OF PLANTS. 
"[Erysiphe. Mildew. Mehlthau (mealdew) of the Germans.] 
Common as are the productions which it now comes to 
‘our turn to examine, and notorious as is their noxious 
Pansies, are often much injured by it. Its effects on 
Pea crops are too visible to escape notice, the whole 
plant being soon clothed with it,as if coated with a 
cinereous wash. Hops, too, are notoriously affected by 
a similar plague, and during the last year scarce a field 
of Wheat was free from the attacks of Erysiphe graminis, 
but probably from some favourable turn in the season 
did not seem to suffer from it. It is not probable that 
a sure remedy will ever be found for such an universal 
pest, to the development of which all seasons seem 
favourable, and which is alike produced in the most 
sheltered and exposed aspects, and if,as is certain, 
tion of your correspondent, I should have said, that it 
was a shrub peculiarly sensitive of wind, and that while 
one of these two plants has shrunk from the prevailing 
wind in this part—the south-west, the other being 
sheltered from it, has been enabled to take its natural 
form and growth.—R. W. 
The Potato Fungus.—Mr. Moore, of Glasnevin, has 
sent me this morning a leaf of a Potato clothed with 
our old enemy Botrytis infestans, from Potatoes in the 
Royal Botanic Garden, Dublin. Everything seems to 
tend to a repetition of the ravages of last year. I can 
persuade nobody here that there are any fears, and all 
advice is vain —M. J. B. 
though many true species exist, one or two forms are 
perfectly indifferent as to the plants on which they 
grow, it would be quite hopeless to attempt a remedy. 
We have exhibited one or two of the principal forms 
in one figure, from which it will be seen that the species 
are beautiful microscopic objects. The whole subject is 
well worth the attention’ of any one who has leisure to 
make the necessary observation 
WxxxLY Prices or POTATOES per ton, in Covent 
Garden Market, in 1845, and 1846. 
influence on vegetation, the history of their d pP 
‘is but imperfectly known. . They consist of little 
globules changing from a more or less deep yellow to 
‘lack, springing from a floceose web, and filled with 
~sacs containing the reproductive organs, and at a cer- 
"tain stage of growth putting out from all parts of their 
"circumference long variously formed fibres, which lift 
them up from the surface of the leaves in which they 
"grow, and imbibe their juices ; and they are always 
‘preceded by delicate threads which are mostly white, 
but occasionally greyish, consisting of little bead-like 
‘joints, of which the uppermost fall off and, it is believed, 
“like so many germs, vegetate, and thus quickly gain pos- 
‘session of the infested plant. These mealy patches are 
called by botanists, according to their degree of develop- 
“ment, Oidium cr Erysiphe, and are too well known to 
Cultivators under the general name of mildew. 
... 1, Erysiphe guttata; 2, E. penicillata; 3, E. graminis ; 4, 
Œ, adunca; 5, E. bicornis ; all after Corda. 
Tt has not, indeed, been positively proved that the 
“Oidium is an early stage of the Erysiphe, but the one so 
„Constantly precedes the other, that it is more than pro- 
bable that they are merely different stages of growth of 
the same thing. The Peach, especially, suffers from 
Xhe'attack of such a parasite, and is only very lately that 
“the second or more perfect form is developed. If, how- 
ver, the young shoots be examined late in the season 
“they will be found coated with a thin floecose web of 
the same nature as that which succeeds to the mildew of 
“the Rose, known to the French under the name of 
“Blane de Rosier.” ‘The Peach mildew is a well-l 
| 1845. || | 1846. 
March ......22) 60s.to100s| Mareh......21| 70s. to 180s 
29) 60 100 || 28| 0 
"Aprile sss 5| 60 90 | April ...... 4 76 180 
12| 60 — 90 || 11 70 180 
19| 60 90 18/70 . 180 
 . 26/60 990] 25| 70 — 180 
Also at the waterside, Southwark. 
Mareh...... 24 555. to 805. March .. 28] 60s. to 140s 
31| 55 80 30! 60 140 
April ...... 7|55 80 |April..... 6| 60 ' 140 
14| 55 — 80 | 13 60 — 140 
21| 55 — 80| 20| 60 140 
Home Correspondence. 
Vine-growing.—Grape growers, during the time in 
which Vines are in flower, recommend the house to be 
kept close, and by no means to admit air unless the sun 
happens to raise the temperature too much. What 
may the maximum temperature of sun-heat be during 
such a period? And how do the Polmaise growers 
get rid of the constant current of air, both by day and 
night, which would appear prejudieial to Vines in 
bloom, as they are supposed to set best in a close moist 
heat. As Mr. Roberts in his ** Treatise" recommends 
high temperature, and a very humid atmosphere, 
perhaps he will be enabled to state (if he has tested 
Simmons's Hygrometer) what that instrument should 
indieate when the Vines are in flower, and during the 
swelling of the fruit?—A Subscriber. [Nothing ean 
be more contrary to reason than the practice of keep- 
ing air moist and still while the Vines are setting. 
We have long since exposed this error.] 
shall be extremely glad to hear your opinion about 
a plague that has visited my Vines. The winter before 
last I put a wooden tank covered with slate and laid 
in whitelead, round a house of 40 feet, and took up 
part of the old Vines to replace them with Muscats and 
other first-class sorts. The half of the Vines remained. 
They showed fruit very well, but just before breaking 
into bloom, turned just as you see the specimens, and all 
with a trifling exception went off. I attributed it partly 
to the border, and partly to the old gardener insisting 
on an immense heat at night. This year, T divided the 
house temporarily, keeping one part for forcing, and the 
other with the old Vines as a Vinery. The portion of 
Vines left in the forcing house are gone, just as you 
see. Those in the outer house are, as yet, safe, with a 
perfection of healthy wood and show of fruit. The 
border outside is covered with dung, on Roberts's plan. 
Now, what is the cause? Can it be the whitelead, 
the fumes of which are too visible to the organs 
on entering the house when at 709. We can 
find no other cause. It cannot be the border, because 
the young Vines are in a new made one, of the best 
- 
pest not only of forced Peaches, but of those grown on 
‘exposed walls, even in the most favourable aspect, and 
When once it gains possession of a spot it is not often 
that it is extirpated. Various plans are resorted to by 
«gardeners to hinder the growth of this troublesome 
.Parasite, of which, perhaps, the most general is flowers 
:9f brimstone, at the best a very doubtful remedy. 
, Where it grows upon the fruit probably more is done 
by the action of rubbing it on than by the brim- 
‘Stone itself, which, in the shape of a crude 
-Powder, can searcely have much effect, and pos- 
` ‘Sibly the best remedy next to taking care that the 
trees are flourishing from proper attention to soil, and 
as free an admission of air as consistent with the object 
“n view of early produce, is washing the walls with 
Something which may either destroy or cover the 
‘Minute spores, or, as recommended by a German writer, 
and_have no possibility of damp or other 
inconvenience. Every plant in the house, of which, 
until I get additions made, there are a great number, 
Oranges, Azaleas, &e., &c., are all in perfect health, 
and not a sign of anything but in the unhappy bunches 
of Grapes,which curl up just as you see. The gardener 
thinks he perceives a black spot on some of-the heads 
just as they go off. In the meantime, we have lowered 
the temperature of the outer house to 60°, and covered 
the tube with soil to absorb the lead, if that be the cause; 
and the atmosphere is sensibly altered sinee yesterday, 
being now quite fresh, whilst the inner house has still 
the heavy dead feel, and the gardener says when he 
opened it this morning, it was oppressive in the ex- 
treme. I have gone to a great length, as it is interest- 
ing. If it be the whitelead, I will remedy it in some 
way, by substituting cement or some other means,— JP. 
[We do not conceive that the fumes of whitelead can 
"Syringing the whole plant well with a strong solution of| be the cause of the evil complained of, because, if they 
"brown soap. Where trees have been destroyed by 
mildew, it is quite useless to plant another in the same 
‘Position without some such precautions. We have seen 
“ree generations in succession destroyed by mildew, in 
the course of a few years. It is not, however, Peach 
‘trees alone that suffer from this cause. There is scarcely 
x hatural order of plants in our temperate climate which 
. 8 not affected byit. In tropical countries, the genus 
aS not at present been detected, unless, indeed, a. very 
"anomalous production on the leaves of Jacquinia armil- 
‘aris be justly xeferrible to it, which we have from 
amaica, Beds of seedling Whitethorn, and it is said 
were, they would have turned the edges of the young 
leaves yellow. We presume that the house is too damp, 
and ill atrated (see Leading Article of to-day). Mus- 
cats are very tender, and will not bear the treatment 
of Black Hamburghs.] 3 
Cotoneaster microphylla.— Of two plants of this on 
my lawn, one ‘only is growing as your eorrespondent 
* Curiositas " has described, with all its branches lean- 
ing towards the north ; the other throws its boughs out 
equally on all sides of the stem. The former of these 
is set on a sunny slope towards the south; the other on 
a bank with a north-eastern aspect. But for the ques- 
Weather Rules.—I feel much obliged to * M. E. A.” 
for his notice of my queries respecting Dr. Kircher’s 
weather tables. I wish, however, he had favoured us 
with his place of residence, as, from a comparison of 
his statement with that of “J. B. H.” which imme- 
diately follows; we are led to the conclusion that the 
wind blew from directly opposite points in their re- 
spective localities, and consequently are puzzled as to 
the application of Dr. Kircher’s rules. Are we to an- 
ticipate a dry summer at Abergele, and a wet one 
in the neighbourhood of « M. E. A. ?" and will not a 
similar discrepancy in different localities invariably tend 
to perplex an inquirer, and prevent anything like a 
useful application of Kircher's rules? “J. B. H.," who 
states the points of the compass from which the wind 
blew on some given days during the years 1843-4-5, 
omits to state whether the summers of these years 
agreed with the rules, or contradicted them.—G. W. 
Polmaise Heating.—A short time ago I was invited 
by 2 neighbour to inspect a new mode of heating horti- 
cultural buildings, which he termed the Polmaise sys- 
tem. He had erected a small pit running north and 
south, at one end of which, by way of experiment, he 
had built a chamber, in which he placed a very small 
iron stove. At the top of the chamber a hole was made 
into the pit, through which the hot air flowed at the 
bottom of the chamber. Immediately under the fire 
was the mouth of a drain, which ran to the other end of 
the pit, and through which the cold air was drawn. I 
went into the pit and found there was a stream of hot 
air flowing from the chamberat a very high temperature, 
so hot thatit had discoloured the paint on the wood directly 
above. A thermometer was placed at each end of the 
pit; the one most distant from the pit indicated 71°, 
and the other 70°. The current passing along the top 
could not have been less than 90° in the centre of the 
pit, and nearer the chamber’ much higher. He pro- 
posed to modify the heat at the entrance from the 
chamber, and moisten the air by hanging a wet blanket 
over the hole. This part of his plan I objected to for 
many reasons, and being about to erect a pit of similar 
form I resolved to get rid of the blanket, which I have, 
as well as of all the other objections given in your 
Paper, and that too at a very light expense. I think I 
can convince you that I have set this grand principle 
free, and thus disencumbered it of the load of objections 
so unworthily heaped upon it. Every other mode of 
heating horticultural buildings will soon disappear ; its 
cheapness, safety, and fitness will, I am sure, throw out 
of use the boiler, pipes, tank, and manure-bed. I 
will now attempt to describe my pit; it is 42 feet 
long by 8 feet wide inside, high roofed, having an 
east and west aspect, with a wall across the middle, 
dividing it equally. One half is used for propagating, 
and the other for greenhouse plants. At the end of the 
propagating compartment, I have built a chamber 20 ins. 
wide by 36 ins. long,and 24 ins.high. In this is placed 
an iron stove, 17 ins. long, 12ins. wide, and 12 ins. in 
height ; about 12 ins. of the air-chamber is carried into 
the pit; the propagating part is covered with strong 
slates, giving à chamber of 21 ft. long by 8 ft. wide, and 
30ins. deep. Into this the hot air flows through a hole 
at the top of the chamber, over which I have placed a 
piece of sheet-iron, which is bent downwards to diffuse 
the heat and prevent its violence doing injury. om 
the bottom of the chamber a cold-air drain is carried 
the whole length of the pit, terminating with an eye at 
the end of the cold compartment. On this eye a slide 
is fixed to close the drain when required. In the large 
chamber there is another eye, which is left constantly 
open. I have built a small flue round the large chamber ; 
the smoke is conducted through the hot-air chamber into 
the flue, and back into the chimney by iron pipes, which 
assist in heating this part as well as in giving an addi- 
tional draught to the chimney, as will be readily per- 
ceived by the return-pipe passing through great heat. 
When I wish to warm the part intended for plants I can 
do so in a few minutes, by drawing a slide which 
covers a hole that passes through the division 
wall into the large chamber. This second. cham- 
ber cannot be dispensed with, let you apply 
it to the greenhouse, stove, pit, or frame; the absence 
of a second chamber ‘must prove fatal, or at least be 
very inconvenient; hence it is that we hear of scorched 
leaves, wet blankets, boilers, &c. With a second 
chamber none of these will be either heard of or re- 
quired. The second chamber can be easily made in 
any house ; in the Orchid house or stove it may be the 
stage, and if a greater top-heat is required, draw your 
slide, and immediately you have a stream of warm air 
charged with moisture to any extent required. This I 
can prove by experiments in my own pit. I have gone 
into the cold compartment when the thermometer has 
stood at 65° in the propagating part ; having previously 
opened the door'of my air-cbamber about } inch, and 
drawn the' slide, the vapour gently flowing through has 
filled the place in a few minutes, at the same time 
