THE COTTAGE GARDENER AND COUNTRY GENTLEMAN, Mabch 5, 1861. 
is usual to be seen on large Orange trees in tbis country. 
They bad flowered most profusely, and enough still 
remained to scent the air to a considerable distance out¬ 
side on the lawn and around the house. The conservatory 
adjoins the house at the south-west end. It is 33 feet 
in length and 28 feet wide, with a dome in the centre: 
consequently a large surface of glass is exposed to 
radiation. But fire heat was only applied during three 
nights in the course of last winter, which was by no 
means remarkably mild; for on seventy-five nights the 
thermometer was below freezing, frequently below 24°, 
and even as low as 17° Fahr. The floor of the conserva¬ 
tory is grated, and underneath the grating there is a 
chamber with which a large drain communicates. This 
drain is 75 yards in length from the conservatory to the 
place where its further extremity is exposed to the open 
air. Pure spring water out of the sandstone flows con¬ 
stantly along the drain, imparting its temperature to the 
air passing over it into the chamber below the con¬ 
servatory. The running water insures the purity of the 
air ; and if the latter should enter cold and dry, it will 
become comparatively warm and moist before its in¬ 
troduction to the conservatory, as its temperature is 
progressively increased in its passage, so will likewise be 
its capacity for moisture; and this the evaporation of 
the water will abundantly supply.” 
Mr. Gorrie’s anticipation of the usefulness of running 
water from a spring is fully borne out by Mr. Thomson’s 
report; and as the thermometer was often below 24° that 
winter, and the fire was used on three nights only (the 
thermometer being at 17° on one of them), we may conclude 
that the hot air in the chamber under the conservatory, 
and oyer the “rill ” in the drain, supplied sufficient heat 
to keep out 10? of frost, exactly on the Kiddean system. 
If we imagine now one of Mr. Kidd’s air-chambers to be 
placed at 75 yards distance from that conservatory and 
at the mouth of the drain, we shall have no difficulty in 
understanding how an additional power of 22° of extra 
heat could be let loose into the drain, and on downwards 
to the chamber below the conservatory, and with the 
thermometer at zero, the Orange trees to be as safe as 
they were when it stood at 24°, and that by the very 
reverse of Polmaise. Mr. Gorrie started the idea prac¬ 
tically in 1830; Mr. Williams put the idea into successful 
practice ten or twelve years subsequently; Mr. Kidd, 
in 1859, confirmed the idea by a more powerful agent, 
which is sufficient to heat any ordinary conservatory, 
even if the furnace is 75 yards from the house; and we 
all know that there is not the smallest difficulty in sup¬ 
plying moisture to heated air up to the point of satu¬ 
ration. 
Why, then, bother about Polmaise ? But Mr. Kidd’s 
own ideas of his plan do not stop, or, I may say, stoop 
at such puny efforts. He says he could heat every house 
in Kingston from one furnace, and every room and 
passage in each house separately, or altogether, with as 
great ease as it is now lighted with gas, and much in the 
same way, and that with the air as purely heated as that 
from the well under the conservatory at Pitmaston. 
Then, about the Parisian fashion. It will be necessary 
to state that there was a wild idea prevalent here forty 
years back—that plants from warmer countries might, by 
degrees, be rendered more hardy by sowing their seeds 
in cooler and still more cool climates until they could 
bear the coldest point, which was our own climate. As 
if the Mandrakes of the Sahara were sown at Algiers, and 
their seeds in Caffraria, the next generation in Calabria, 
the next at Naples, and so on to Nice and Marseilles, 
thence to Pau, then to Jersey, and from there to Cornwall, 
and in time on to as far north as Dingwall at last. But 
such hopes have not been realised. 
The next idea was to secure greenhouse and half-hardy 
plants out of doors from frost by all kinds of coverings, 
and by placing jars of hot water, or pans with hot cinders. 
Then followed conservatory walls covered with glass, 
canvass, thatched hurdles, or mats; and this brings us 
on to the period of the first Reform Bill in 1832. 
F- om 1830 to 1840 these conservatory walls were very 
much trusted to for the acclimatising of plants ; and the 
notion that plants became more hardy as they advanced 
in years was still prevalent. But as early as 1836, the 
Rev. Dr. Herbert, who was the best practical gardener 
of all who treated scientifically on any branch of the 
craft, pointed out very fully what -was really wanted to 
bring the various schemes for acclimatising plants to a 
practical issue, or, in other words, to flower freely in the 
open air. That was to apply bottom heat in summer to 
warm the soil about the roots, to rest the plants in winter 
under tarpaulin and other coverings, easily moved up 
or down whenever the weather permitted, and to keep 
the frost from them in the usual way. ,The marrow of 
his plan is hereto appended ; and if the reader has heard 
of this “ geothermal cultivation,” the latest fashion from 
Paris, you will see that M. Naudin, the author of it, has 
only adopted Dr. Herbert’s plan, to which he has only 
added one condition, and that condition renders the whole 
scheme impracticable to the last degree. In England, 
however. Dr. Herbert’s suggestions led to the adoption 
of one of the best branches of the gardening of the 
present day—that of applying bottom heat in summer to 
the roots of Vines, and a more careful exclusion of heavy 
rains and hard frosts in winter from the borders. But 
here is Dr. Herbert’s plan in his own words, headed 
“Fitted Borders,” in his great work on the Amarylli- 
daceae, page 402. 
“ The vigour with which mules of the genus CrinuM, 
and many other plants, grow out of doors against the 
front wall of a stove, persuades me that a great variety 
of plants might with a little care be cultivated better in 
the open ground than under glass, if the border in which 
they are to grow were flued under ground, and a tar¬ 
paulin or any waterproof covering placed over them at 
the times when it might be requisite to exclude either 
rain or cold. The covering might hang on the two sides 
of a longitudinal pole, like the two slopes of a roof, and 
be made to roll up either with or without a spring. 
There are many plants which seem to enjoy a cool atmo¬ 
sphere, but will not flower or thrive vigorously without 
the stimulus of heated earth at the root. Having chosen 
a situation where a furnace and boiler could be placed 
under ground, I would carry the smoke-flue as far as its 
heat would extend on one side ; and hot-water or steam- 
pipes in a different direction, as might be found con¬ 
venient, enclosed in a stone or brick flue to as great a 
length as its influence might reach. In such a border I 
believe the genus Hedychium and many others would 
flower perfectly with the assistance of fire in the summer, 
requiring nothing but a covering to throw off the wet ; 
and the heat might be turned into other pipes for the 
advantage of plants which might require the warmth in 
winter rather than in the summer. If in front of a wall 
a moveable verandah, which might be either ornamental 
or made of thatched hurdles or hurdle-gates, would 
throw off the wet, which is the principal cause of injury 
in winter; for many shrubs will endure the access oi 
severe frost to the head, if all wet can be effectually 
excluded from the base of the stem and from the root by 
any sloped heading. Hnder such a verandah, with occa¬ 
sional heat to the flue during the early part of summer, 
and perhaps in severe frost, Amaryllis, Brunsvigia, 
Buphane, Nerine, Hsemantlius, and all the allied genera 
of African bulbs, as well as the South American, would 
certainly succeed better than with any other treatment. 
I believe that not only those, but even some of the 
tropical Crinums, would succeed better so than in a stove, 
and, probably, many shrubs which might not be expected 
to live there. The advantage of a verandah or pent- 
covering, however rude, on the north side of a wall, for 
the protection of half-hardy plants—such as Camellia 
japonica, Asiatic species of Rhododendrons, &c., is not 
