| 644 
THE GARDENERS’ 
CHRONICLE. 
[Serr. 16, 
and here a second struggle ensued—between the advocates 
of steam and hot water (see the first 4 vols. “ Gard, Mag.’’) 
| No sooner, however, had the advocates of hot water 
q influenced the public mind in its favour, than the most 
extravagant ideas were formed respecting the efficiency of 
| heat and moisture for all practical purposes ;—it even 
i became a question whether laundries could be heated by 
these pipes, or whether the moisture transmitted through 
their pores should not damp, rather than dry, linen! Thus 
it generally is with the public mind : a new proposition for 
facilitating operations must either be nothing at all, or 
u perfection at once—there is no room or time for interme- 
diate degrees. Experience, however, soon determines the 
fallacy of these hasty conclusions; and this it did very 
4 quickly with our subject of bottom-heat. Then hot-water 
pipes were placed horizontally, in rows of 6, 10, and even 
14, to give bottom-beat : these burnt every plant placed 
over them, A coat of tan or sawdust placed over the 
pipes did not mend the matter—the former soon rotted, 
and the latter, if kept dry to hold out longer, resists heat 
at the rate of 100° to every inch in depth: thus twoinches 
of perfectly dry sawdust over pipes will resist all heat up 
to the boiling point—a circumstance taken advantage of. in 
setting conical boilers. 
\ This being ascertained, the next step was taken in 
1830, by a clever gardener, Mr. Cameron, at Woburn 
House, near Beaconsfield, who directed Messrs. Grange, 
of Uxbridge, to place wooden tanks, lined with lead, 
under his Melon-beds, heated by a 2-inch leaden pipe, 
connected with the boiler and pipes that heated the pits ; 
these tanks were covered with pieces of wood placed 
across them, and at two inches apart, a thin covering of 
} turf over that, and then the soil for Melons. This answered 
t exceedingly well, and Mr. Cameron grew fine crops in 
i these pits (see Gard. Mag.,” vi. 616.) In less than two 
years afterwards Mr. Weeks made a more efficient and 
less expensive application of this principle, by the use of 
brick troughs, and by passing an iron instead of a leaden pipe 
through the water; the covering of the tanks was the same 
in both cases—rough wood, turf, then mould, &c.; the 
water could be lowered in both cases, also, and dry heat 
obtained, when thought fit. These are now called Green’s 
pits, and have been in use ten or eleven years, by scores of 
gardeners and nurserymen, withoutasingle objection having 
ever yet been raised against them, But Green’s pits are 
too expensive for general purposes, and Mr, Rendle’s tanks 
have come in as a substitute., These tanks are perfectly 
complete, and unobjectionable as far as they go, and for 
stove plants in pots, for propagating-houses, or for all 
sorts of flower-forcing in winter, nothing can be better. 
Ihave been working upon the very same principle and 
with porouscovers,ever since 1837. The bestgardenersand 
most scientific men in our line in Europe have seen my bed 
at work—Dr. Lindley, Sir William Hooker, De Candolle, 
and Mr. Loudon, among the number,—and an account of 
its management is given in the ‘ Proceedings of the 
Horticultural Society of London for 1840.” I ought, 
therefore, to know something of the subject ; if not, it 
must be more for the want of brains than of practice. 
Now, I contend that no gardener can grow Pines out of 
pots, winter Cucumbers, or early Melons, in these closed 
tanks with half so much ease and certainty as with the 
most objectionable modes of the old school, and for 
this very reason—that the principle is in direct opposition 
I stated to be two yards in diameter three weeks ago, is 
now six yards in diameter; which gives us a ninefold 
increase in area. The mere raking which this patch had 
received appears to have promoted the spread of the 
Cuscuta, possibly by having retarded the development of 
the flowers and by thus fitting the numerous fragments 
left upon the Clover for making independent and more 
vigorous shoots. Another patch is now a perfect mass of 
cream-white flowers, upon which a number of flies have 
stationed themselves, in seeming enjoyment of the succu- 
lency of the heads of flowers, As you have thrown out 
a suggestion that this Cuscuta may possibly become a 
future pest in our corn-fields, unless it shall be timely 
checked, I directed my attention to the plants upon which 
it is now growing, and I observed it was attached to and 
evidently attacking the following species—Geranium dis- 
sectum, Daucus carota, Carduus arvensis, Euphorbia 
exigua, Viola tricolor, Malva sylvestris, Linaria spuria, 
Senecio vulgaris, Medicago lupulina, Alopecurus arvensis, 
and another grass, which seemed to be Agrostis vulgaris. 
Some of these plants do not appear to be much, if at all, 
injured by it, as they continue vigorous where the Clover 
is completely dead. I was surprised to find it had so 
firmly attached itself to grasses, because I was impressed 
with a notion that no Phoenogamous parasite ever attacks 
an Endogenous species. I had imbibed this notion from 
De Candolle; but upon referring to his Physiology, 
I find that he does not speak quite so positively on 
the subject as I had imagined he did. He mentions 
two possible pti to the rul ly, that of 
an Orobanche said to have been found in Sicily on 
the roots of Chamzrops, and our very Cuscuta 
which is found twining itself about grasses, though he still 
doubts its deriving any real nourishment from them. The 
fact, he says, may be observed in fields where Clover and 
grasses are intermixed, but is never witnessed in a field 
composed of grasses only. Of course he includes Corn 
among grasses. He never succeeded in causing a Cuscuta 
to grow upon an Endogen. He names a garden which 
had become infested with Cuscuta, introduced into it by 
the upsetting of a waggon loaded with infected Clover ; 
in this garden he noticed the Cuscuta on plants belonging 
to thirty different families, but still they were all Exogens. 
He concludes from these observations, that, apparently, 
Cuscutz can exist only on Exogens, or at least much more 
readily than on Endogens. ‘The determination of this 
question may be worthy of experimental research next 
year. I certainly do observe that the Cuscuta has decidedly 
attacked the stems of the grasses round which it has 
twined itself ; but very possibly its attacks may bear some 
analogy to those of animal parasites, which cannot long 
subsist upon other than one particular species, or at least 
upon very few species of animals. Thus the dog-flea will 
sometimes bite ourselves, but will not remain with us ; 
and thus the lice which infest partridges will often annoy 
the sportsman by crawling about him, but he runs norisk 
of a colony permanently establishing themselves on any 
part of his person.—J. S. Henslow. 
—No. XXXVII. 
organisable, and fit for the reproduction of its kind ; and 
the first effort of reproduction is the formation of flowers, 
the object for which decorative plants are cultivated. I 
am led to make these remarks, because in my rambles I 
find many persons encouraging their plants to grow at 
the present time, than which they could not do a more 
injudicious thing. As, however, the weather is promising, 
there is yet time to ripen the wood; and to effect this, 
water must be gradually withheld, and the plants have all 
the sun and air possible, but if the weather should become 
dull, a little fire may be used, with air in the daytime to 
expel the damp from the house. These remarks are appli- 
cable to.all hard-wooded plants, let them be grown on what- 
ever system they may, but more especially to plants grown 
on the one-shift system, as the rate of growth is so rapid 
on that system, that more than ordinary attention is ne- 
cessary to get the strong shoots properly ripened. The 
progress and great improvement which this system of 
potting is generally effecting in collections of plants is 
very pleasing ; and though a few may traduce the system, 
because it does not accord with their preconceived no- 
tions and prejudices, it is a source of high gratification to 
me, that no person of acknowledged ability has yet ven- 
tured to combat the principles upon which the practice is 
founded ; and, therefore, if the principles are sound, it is the 
error of their application, and not of the system to which 
want of success is attributable.-- VW. P. Ayres, Brooklands. 
HOME CORRESPONDENCE, 
Encouragement to Planters.—Should you deem the fol- 
lowing circumstances worth inserting, I can, from personal 
investigation, vouch for their authenticity. It may possibly 
be an incitement, to persons to plant who otherwise might 
not be inclined, holding out a hope to them of seeing timber 
of their own planting, both ornamental and yaluable. The 
Society for the E rg nt of Arts, Manuf i 
and Commerce were pleased to vote, in three different 
years, their gold medal to Dr, Thackeray, of the city of 
Chester, for planting the greatest number of forest-trees, 
amounting altogether to 850 acres, from the year 1804, 
400 of which belonged to Mr. Wilson Jones, of Harts- 
heath Park, Flintshire (late M.P. for the borough of 
Denbigh) in the counties of Denbigh and Merioneth, and 
the remainder on his own property in the counties of Den- 
bigh and Flint. The plantations of Mr. W. Jones were, 
from their being formed, regularly pruned till this gentle- 
man came of age to manage them himself; and those 
planted from the year 1817 to the present time, upon his 
own land, have been regularly and annually pruned and 
thinned under the superintendence of Dr. Thackeray him- 
self. More than 200 bushels of Acorns have either been 
dibbled in the woods, or sown in the nurseries, for the 
purpose of filling up all vacancies which may arise. The 
hedgerows have also been filled with fine young trees 
taken from the woods, at the distance of four yards 
asunder ; and being judiciously pruned, the tenants have 
no cause to complain of their land being in any way 
injured by these ornaments to the country around. It 
will occur to those experienced in such matters, that the 
effect of neglect in thinning and pruning is very injurious 
to pl. i 
In the propagation of the Verbenas da last 
week, the compost used should be poor and sandy, as the 
object is to get the cuttings to make plenty of roots with- 
out producing much top; for as in most gardens it is 
to natural laws. am aware of the exp carried 
on this summer in the Chiswick garden with Melons on 
the tank system ; I went to see them in May, June, and 
July ; the plants and fruit looked exceedingly well, but I 
have seen as good with Mr. Williams, of Pitmaston. 
without anyheat at all. I cut my earliest Melons here in the 
same week that these were planted. In three years we shall 
hear of gardeners—and good gardeners too—having lost 
their places because they could not grow early Melons 
and Cucumbers by this system, just as others lost their 
places through Mr. Penn’s apparatus ; and is it, there- 
fore, to be wondered at, if one of their number, foreseeing 
all this, should thus remonstrate against it? Let Mr, 
Rendle consider these objections, which I offer with the 
best feelings to all concerned. From actual experience, I 
find he has already effected a very great improvement, and 
what I want, and insist on having, may be easily effected. 
The objection raised in a late Chronicle about the soil 
draining down into the tank and boiler is a valid one, and 
must be borne in mind ; but that about the vapour turning 
the soil into mud is not borne out by experience. From 
last January to August I had beds constantly subjected to 
strong vapours from below, one of which I turned over 
about the middle of August, to renew it for late autumn 
Cucumbers; the soil, for the first few inches on the top, 
was perfectly dry, as we hardly ever watered these beds 
after the plants got established ; the next foot of soil was 
ina moist friable state, such as you would choose for 
ordinary purposes ; but the bottom spit, next the turf, was 
as wet as the surface. of an ill-drained field i diatel 
after a fall of rain, and the roots of the Cucumbers formed 
anet-work over the turf. Now, if my bed were turned 
upside down, it would nearly represent one placed on 
pieces of solid slate or porous tiles—for I have tried’ both ; 
first foot below would be like ashes, while the 
Jim yped le, if the watering went in that way. 
nning an inch of rough cinders between 
burf, and pouring water through holes 
would save the surface-soil from this;— 
efer solid bottoms, thisis the best con- 
ig their beds. After I hear all that can 
for‘or against all this, 1. may perhaps write a paper 
é practical part of the subject.— D. Beaton. 
J) \\ Oo.) 7FHE TREFOIL DODDER. 
Vol eave uy Visited the Clover-field in this parish, which 
acked by Cuscuta. I find one of the patches, which 
id= 
Pp ble to store the young plants through the winter 
in the cutting-pots, it follows that the dwarfer the plants 
are kept, there will be the less fear of their damping off 
through being overcrowded. The soil we use here consists 
of the refuse of the potting-bench, such as peat, leaf- 
mould, and loam taken from the balls of plants in re- 
potting, to which about one-third of sand is added. In 
this soil common plants root with great freedom, and by 
allowing it to become dry before the plants are potted off 
in the spring, it falls from them so freely that scarcely a 
root is lost. In making choice of cuttings, we take the 
short-jointed branches, and we insert from 18 to 24 
cuttings in a 48-sized pot ; so that on an average we store 
about six dozen plants on every square foot of a pit or 
frame, so that a frame six feet square is capable of winter- 
ing nearly 2,600 plants. 
The various kinds of Anagallis and dwarf Lobelias make 
beautiful beds; and of the former, A. ceerulea grandiflora, 
Phillipsii, and Monelli, produce beautiful blue flowers ; 
while A. grandiflora makes a good pale orange-red group, 
A. Parksii a bed still paler, and A. carnea is of a pale flesh- 
colour, A. Brewerii is highly spoken of by the raiser, 
but as I have not seen it, I cannot speak of its qualities. 
Of the Lobelias, L. azurea is a lovely colour; also 
L. erinus, pubescens, and erinus grandiflora, of the 
Pineapple-place Nursery. L. bicolor furnishes a bed 
0 p 3 no less so is an unskilful mode of perform- 
ing this duty; and it is to be hoped, therefore, that a few 
hints may be useful to such of your readers as are anxious 
for information on this subject, from one not unaccus- 
tomed to the business, and having no personal interest to 
promote in the suggestions he offers, but a sincere desire 
to see his country prosper in all things. Many pruners, 
from an apprehension of injuring the stem of a tree, by 
cutting the branches too close, leave spurs, over which 
the bark can with difficulty, if ever, unite. Now, these 
should undoubtedly be cut close and smooth ; and should 
the bark receive a slight injury it would be of trifling con- 
sequence, compared to the leaving a dead stump. From 
ignorance of the bad effects, or from want of attention, 
too many pruners cut off a number of branches at once 5 
this, I am of opinion, has been practised to such a ruinous 
extent as to leave nothing but a broom at the top. Were 
the proprietors of estates sensible of the mischief they 
thus do to their plantations, they would no longer withhold 
animprovement. I would beg leave to call the attention of 
those who have any plantations to this important truth. 
Orderly thinning the trees is the next essential to pruning ; 
and for this purpose the following simple method should 
be adopted :—Take out such trees as are the least thriving 
and impeding the progress of the neighbouring flourishing 
trees, &c., and then the pruning of these will be found 
most beneficial ; and the training off judiciously the large 
with pale blue flowers very quickly; L. unidentata is | 
indispensable for vases and baskets ; and L. lutea, though 
a straggling grower, yet, being yellow, is a plant that can- 
not be dispensed with. 
Isotoma axillaris, makes a good pale blue group; and 
L. ramosa‘and heterophylla are two strictly annual kinds, 
of great excellence. The whole of these varieties are very 
valuable, and ought to be cultivated in every garden, 
In the management of greenhouse plants, especially 
hard-wooded ones, as Heaths, Epacrises, and other Cape 
and New Holland shrubs, Amateurs frequently commit a 
great error in permitting them, or too frequently forcing 
them, to grow late in the autumn ; and as the wood does 
not get ripe before the dull weather sets in, the conse- 
quence is, the points of the young growth become mil- 
dewed, and damp off in the winter, and the plants do not 
bloom well, if at all, in the following season, Now it 
would be quite as reasonable for Wheat cut quite green 
to produce good Corn, as for unripe wood to produce 
fine flowers, because maturation, in both cases, depends 
upon the due elaboration of the sap, by which it_becomes 
L., or, as it is generally called, | 
side-branches will cause the upright ones to shoot the 
stronger, and by cutting out the dead and decayed wood, 
the tree is preserved alive: this simple method will pro- 
duce clearness from knots, straightness, and length, and 
will advance the quality nearer to that of foreign timber ; 
for it may be traced that where trees are tall, and clear 
from boughs or knots, the whole substance of the wood is 
better and of finer grain ; and experience proves that such 
will always be the case. A considerable additional 
increase in circumference may certainly be expected, in 
consequence of the trees having almost double the room 
in which to extend their branches, not allowing them to 
whip each other, and for the admission of those powerful 
agents, sunshine and air. The practice should be decidedly 
condemned of cutting off large limbs to improve the 
timber, and lamentable effects of it may every day be 
seen, as the trees exhibit symptoms of early decay. The 
scientific pruning of forest-trees is but little understood, 
though such instructions may be easily had by any intelli- 
gent woodman earnestly seeking it, and must prove in every 
way profitable, and I hope to live to see annual pruning 
wherever there are any plantations, or hedge-row trees, 
to the benefit of the proprietors and the ornament of 
our country. A long and progressive work of thin- 
ramen 
