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sode in a shrubbery on the principle recommended in the introduction to this article.
a. American perennial herbaceous plants. b. American bulbs and annuals. c. American low flowering shrubs, such as rhododendrons, azaleas, kal
mias, &c. d. Magnolias. e, f, g, Counterparts to a, b, c, but containing quite different species.
Fig. 65., is a design which may also serve as an American garden, or for a garden entirely of peat earth shrubs and plants, of whatever country they may be natives, which require to be grown in moist peat. The herbaceous plants may be planted in the beds 1, 4, 5, 8, and the magnolias and low shrubs
Fig. 65. Garden of Shrubs and herbaceous Plants which require to be grown in moist Peat; the
moisture being communicated by pipes connected with the central basin.
in the beds 2, 3, 6, 7. The central circle, 9, is for a basin and fountain, from which there may be an underground communication to each bed, by means of small earthenware pipes, which can be plugged up at pleasure. This communication will admit of keeping the beds moist during the dry season, which contributes greatly to the beauty of all flowering shrubs, especially such kinds as the American Rhodoraceæ, most of which grow in moist peat.
Fig. 66. is a design for a garden, to contain a select collection of dahlias, to form an episode to a shrubbery walk.
The beds at a a embrace small basins of water, and in order to contrast with the others, may be planted with a collection of hollyhocks. The beds marked b b may be planted with evergreen shrubs, in order to prevent the
whole garden from being seen at once when entering also be a few plants of Cupréssinæ, or other evergreens, sprinkled down the middle of the garden, from b to b, in order to form a background to the dahlias and hollyhocks; for this garden, like fig. 64., is one of those the beauties of which are to be seen in succession, and not at a single glance, as in the design fig. 63. The dahlia beds are so disposed as that every variety may be seen from the walk. The width of the beds is 3 ft., which will admit of two rows, the plants of one row alternating with those in the other. In order to preserve the exact form of the beds, they ought to have concealed brick edgings, formed in the manner shown in figs. 56, 57. in p. 217., or by triangular bricks made on purpose. The shapes may also be preserved by iron rods raised 6 in. above the beds, and securely fixed.
Fig. 66. Dahlia and Hollyhock Garden,
ART. IX. Description of a Propagating House heated by hot Water
circulated in Brick Troughs. By J. M. LINDSAY. According to my promise, I forward for your inspection a plan and section (fig. 67.) of a propagating-house in the Hammersmith Nursery, recently heated (by my employers, Messrs. John and Charles Lee) by hot water circulating in brick troughs lined with cement; top and bottom heat being produced by the same means. We have now had the plan in operation a sufficient time to test its merits, and I feel quite justified in asserting that it far surpasses every other means with which I am acquainted for the purpose of commanding a regular, steady, genial, and moist bottom and top heut ; so much so, that I have not the least doubt that, when its superior advantages are fully known, it will ultimately supersede the use of all the fermenting materials which are generally used as a medium for bottom heat, and also the use of iron pipes for horticultural purposes.
The house to which the system has been applied here is fifty feet long and
eight feet wide ; it was originally used for propagation, but without the means of that useful stimulant for cuttings, &c., bottom heat, instead of which it had a platform of tiles three feet six inches in width, raised on brick arches, and running the whole length of the house, being of a sufficient height to make it convenient for placing pots of cuttings, &c., upon. The means of heating used was a common smoke flue, also raised on brick arches, and occupying two feet in width ; the remaining space was taken up by the path.
All that was found necessary to do in altering it to its present state, after procuring a boiler, was to pull down the smoke flue, which was next the front wall, and make the bench on which it stood on the same level with the platform on the other or back side of the path ; this done, two troughs were erected upon it for heating the atmosphere of the house, as represented in fig. 67. at bb. These troughs are formed by partitions two bricks on edge deep, set in cement, the bottom and inner sides of the lower bricks only being plastered with the same material. A covering is formed of common tiles, which were in use for covering the sinoke flue. On the three feet six inches platform are also erected two troughs (dd), as a medium for bottom heat. They occupy its full width, but are only formed one brick on edge deep (d d), also set in cement, and plastered with the same inside. Common plain tiles (as they are termed) are used for a covering for these troughs; but, as they are only nine inches in length, it was found necessary to support the end of each in the middle of each trough by means of a row of brick on edge laid in without cement, so as not to raise them above the level of the side bricks, and left pigeon-holed. The tiles were then bedded on in cement, all the joints being afterwards carefully pointed. This forms another platform, which is covered by about six inches of old tan for receiving pots of cuttings, &c., which tan is kept compactly together by a brick on edge, also set in cement along each side, as shown in the section.
The boiler is placed at the extreme end of the house at e, inside, being supplied with fuel from the outside ; it has a short piece of four-inch iron pipe to supply the two flow troughs, as represented by the dotted lines at e, and two return pipes which enter it at opposite sides. This boiler is of novel construction, the invention of Mr. Thomson, late gardener at Syon Fig. 67. Plan and Section House, and is well calculated for economy, both in
of a Propagating-House
Hammersmith fuel and labour; having a much greater surface ex- Nursery, heated by hot posed to the action of the fire than any boiler I have
Water circulating in
Brick Troughs ever seen of the same size.
with Cement. The water in the troughs rarely exceeds an inch in depth, with which quantity we can keep, with the greatest nicety, both the temperature of the house and the bottom heat to any required degree. I must not omit to mention, that in each flow trough is placed a sluice, formed by a piece of slate pushed down in two grooves in the cement, so that the water may be stopped from circulating in either at pleasure.
So satisfactory has the system proved here, and so very moderate in expense, a bricklayer and his labourer having completed the whole in a few days with two and a half tubs of cement, the old materials which formed the smoke
flues being found sufficient for the alteration, that my employers have determined on heating a large orchidaceous house, and also one for cacti on the same principle. The troughs in the latter house will be supplied by the boiler in use for the above propagating-house.
I believe that Mr. Beaton, gardener to Sir W. Middleton, Bart., at Shrubland Park, was the first that used brick troughs for heating the interior of horticultural erections ; he published a detailed account of it in the Gardener's Chronicle for 1842, p. 348., and it has since been adopted in various parts of the kingdom. Hot water has also been in use as a medium for bottom heat, for many years back, in different horticultural establishments, but upon · modes much less economical than those above described. To those who do not wish for the expense and litter of fermenting materials as a mode of producing heat, I can safely say that the trough system of heating offers great advantages.
Hammersmith Nursery, March, 20. 1843.
Art. X. On the Superiority of Span-roofed Greenhouses. By JAMES
M‘NAB, Superintendant of the Caledonian Horticultural Society's
Garden. At the last meeting of the Caledonian Horticultural Society, Mr. James M'Nab, the curator of the Society's Experimental Gardens, made an interesting communication, showing the superiority of plant-houses extending north and south, and having a span-roof fronting east and west, over such as have only an inclined roof fronting the south, commonly called by gardeners lean-to houses. This superiority holds good both in summer and winter, but is particularly remarkable in the latter season.
For example, in a span-roofed house, extending north and south, during the stormy weather of winter, air can be freely admitted, from whatever direction the wind may blow, there being always a lee side where sashes can be opened. In frames and pits, where top air alone can be given, plants suffer greatly from damp; but in a span-roofed house, the circulation of air may be constantly kept up so as effectually to prevent damp.
For such a greenhouse, fire heat is scarcely at all required ; for, if there be a free circulation of air during the autumn and winter months, and if the tables or shelves be carefully kept dry and clean, and water be sparingly given to such plants only as require it, cold, even though it should extend to the occasional freezing of the surface soil of the pots, will do less injury to most plants than the application of fire heat. Mr. M‘Nab has found the same kind of plants to become soft, spongy, and drawn up in the lean-to house, which continued hard, woody, and dwarfish in the span-roofed house. Last season he kept a number of fine cinerarias and geraniums in houses of both forms. After a severe frosty night in January, they presented in the morning much the same appearance in both houses; the leaves drooping, and being covered with a white rime, resembling hoar-frost. By ten o'clock the sun shone forth. The plants in the lean-to house were subjected to the full influence of the mid-day rays ; and, although air was given, they blackened and perished. In the span-roofed house, extending north and south, the influence of the sun was much less felt ; for, as he proceeded towards the meridian, the intercepting astragals and rafters necessarily formed a screen or shade ; and, air being given, the plants survived, and soon recovered.
Amateur cultivators who like to possess a small greenhouse, and to manage it for themselves, ought to prefer the span-roofed form ; and from Mr. M‘Nab they may learn this important lesson, that, by an early and anxious application of fire heat, in a frosty night in the beginning of winter (a common fault), they not only incur unnecessary trouble and expense, but do real injury to their plants, which would suffer little from cold, provided air were made to circulate freely among them, and damp were guarded against. The beautiful tribes of Erica and É'pacris will suffer little or nothing in a cold greenhouse, although the thermometer in the open air may indicate several degrees below freezing ; while the sudden application of fire heat will probably kill them.
Mr. M.Nab mentioned that the superiority of the span-roofed form was strikingly exemplified in the Society's garden about the middle of February last (1813), when the self-marking thermometer in the open air, during different nights, indicated 20°, 15°, and even 10° Fahr. During these frosts no heat whatever was applied to the span-roofed house, which contained a general collection of soft and hard wooded greenhouse plants. On the mornings of the 17th and 19th of February, the mercury in the thermometer within the house stood at 25°, or seven degrees below freezing; yet only two or three plants which were standing near the upright glass of the south end of the house, and were thus exposed to the mid-day sun, suffered from the intense cold to which they had been subjected. The temperature in the span-roofed house always remained much more equable than in the lean-to house. This was signally remarkable at 1 P. M. of the 14th of February, when the thermometer in the open air indicated 56° ; in the lean-to house 70° ; and in the span-roofed house 43°: in the lean-to house, therefore, where the whole glass roof was fully exposed to the sun's meridian rays, the temperature thus becoming fourteen degrees higher than the open air, and twenty-seven degrees higher than in the span-roofed house.
Having enlarged on the advantages of this form of greenhouse during winter, we shall only briefly state, in conclusion, that, in the warm weather of summer, the span-roofed house admits the freest possible circulation of air, by means of upright slidinge sashes on both sides of the house; while the rasters and astragals of the glazed roof break and intercept the sun's rays, and help to shade the plants from their direct influence ; and that in such a house the plants, instead of being drawn up and weakly, continue firm and bushy ; that they remain much longer in flower ; and that the colours of the flowers are generally brighter. (Edinburgh Advertiser, April 11. 1843.)
Art. XI. Arboricultural Notices. Pa Gus antárctica, Arb. Brit. p. 1982., and E. of Trees and Shrubs, figs. 1702. and 1703. p. 910., has been introduced from Tierra del Fuego, by Dr. Joseph Hooker, and there are plants at Kew, and in Mr. Knight's Exotic Nursery.
Ribes Beatònii, a hybrid raised by Mr. Beaton, between R. sanguineum and R. aureum, is now beautifully in flower in Lee's Nursery. It is a vigorous-growing plant, with long racemes of flowers, partaking of the colour of both species.
Magnolia Alexandrina, a hybrid between M. conspicua and M. purpurea, or perhaps M. p. gracilis, one of the most desirable of deciduous magnolias, was in full flower in Lee's Nursery on April 1st, when not a single flower bud of M. Soulangeàna was expanded, and when M. conspicua was just going out of bloom. Thus, by having plants of these three kinds, a succession of bloom will be kept up from the first week in March to the first week
Art. XII. On a Mode of growing late Melons. By B. AGREEABLY to promise I now attempt to send you an account of my method of growing late melons, which, as I have practised it with complete success
3d Ser.-1843. V.