820 PRACTICE OF GARDENING. Part III. 



the house at certain distances, by means of apertures in the top of the flue. The ar- 

 gument in favor of this arrangement, is that usually given for vacuities around furnaces 

 connected with flues, as adopted by Stewart, Gould, and various others ( Tr. on Hot- 

 houses, p. 132.), viz. that " the current of external air, by commencing, when cold, at 

 that part of the flue which is hottest, takes up the heat there where it is least wanted, and 

 carries it to those parts at a distance from the furnace where it is most needed ; and as the 

 valves are to be chiefly opened in the latter situations, to permit its escape, it diffuses a 

 nearly equal warmth over the whole house." Every thing in this plan evidently depends 

 on the management of these valves ; if they are left open during the night, the risk above 

 stated is incurred ; if during day, less heat being wanted, little advantage is obtained. In 

 stoves, however, this plan, under judicious management, might be useful ; but it must 

 never be forgotten, that air can be rendered much hotter by a fire-flue than by a steam- 

 pipe, and hence the danger to the plants. No one was ever more sanguine as to the ad- 

 vantages to be derived from furnace vacuities and air-flues than ourselves (see Tr. on 

 Hot-houses) ; but after twenty years' experience, we must acknowledge that they are so 

 liable to produce accidents, either by admitting smoke or burning up the plants (as the 

 phrase is), that we now seldom recommend their adoption. 



61 85. Various jrits and hot-beds will be required in the reserve-department of the flower- 

 garden, for forcing shrubs and flowers, raising annuals, &c. ; the construction of which 

 having nothing peculiar, need not be here detailed. (See 1591. et seq.) 



6186. The idea of cold-houses seems to have been first suggested by Sir W. Chambers (Dissert, on Orti. 

 Gard. p. 90.), and it may be worth while to submit some hints on their construction for such amateurs in 

 this country as maybe curious in the cultivation of muscUjungermannuE, and other cryptogamous veget- 

 ables which grow in the lowest temperatures ; and for botanists in warm climates, who may wish to cul- 

 tivate not only mosses, but the more perfect plants of elevated regions or northern climates ; as for example, 

 of the British or Swedish alpines in Spain, or in the south of Italy. The simplest form of a cold-house may 

 be a vault of rustic masonry open at one end, along the 'floor of which a rill of water may pass, and from every 

 part of the ceiling water may drop on the floor or bed, and descend to the rill in the centre. This is an ob- 

 vious imitation of the dripping caves sometimes found in tracts of country abounding with calcareous rocks, 

 of which, as an example, we may cite the dripping rock at Knaresborough, and the dripping cave near 

 Rousseau's walk at Lyons ; in which last, on the 19th day of June 1819, we found the thermometer at 48, 

 whilst in the open air, under the shade of an adjoining mulberry-tree, it stood at 72. Various mosses and 

 jungermannia? were in luxuriant vegetation in the interior of the cave ; and some sorts of ferns near its 

 mouth. Another imitation of such caves might consist of an open grove of elms or oaks, among the lower 

 branches of which lead pipes pierced with small holes, in Loddige's manner (1689.), might be fixed hori- 

 zontally at regular distances, and these being supplied, during the warmer months, with water from a 

 proper reservoir, would furnish a continual shower, which, with the assistance of the small rills furnished 

 by the collected rain thus produced, would lower the temperature of the atmosphere sufficiently for the 

 growth of such mosses and ferns as do not require much light ; and the margin of the grove might be 

 devoted to plants of a more perfect kind, requiring a low temperature and moist atmosphere. But a more 

 perfect plan would be to form a house like a large pit, with a double glass roof, fronting the north. Over 

 the outer roof should be a system of pierced pipes to keep it cool by a continual shower during sunset, and 

 at the top of the back wall an arrangement whereby two or more separate and concentric coverings of can- 

 vass could be let down to exclude the sun during the day. Instead of flues of masonry, large tubes of lead 

 or cast-iron should surround the house, to be kept cool by a continual stream of water passing through 

 them. The pit might contain a large metallic cistern, filled with ice, to be renewed when thawed, &c. 

 It would be advancing too far jnto the regions of speculation to particularise other minor details that 

 would be requisite to render such a house complete ; let it suffice to say, that such houses might be erected 

 either in Britain or the south of Europe, so as to produce a temperature of 32 degrees throughout the year. 

 This would admit the cultivation, in pots and on pieces of rock, of lichens, mosses, and of all the more per- 

 fect plants which grow in the regions of perpetual snow. (See 1696.) 



Chap. VI. 



Of the General Culture and Management of the Flower-garden and Shrubbery. 



6187. The cultivation of the flower-garden is simple compared with that of the kitchen- 

 garden, both from its limited extent and the general sameness of its products ; but to 

 manage it to perfection requires a degree of nicety and constant attention beyond any 

 other open-air department of gardening. As the stalks of flowering plants shoot up, they 

 generally require thinning, and props for support ; and the blossom, both of plants and 

 shrubs, no sooner expands than it begins to wither, and must be cut off, unless, as in 

 some of the Ornamental shrubs, they are left for the sake of the beauty of their fruit. 

 Weeding, watering, stirring the soil, cutting off stems which have done flowering, at- 

 tending to grass and gravel, must go hand in hand with these operations. 



6188. With respect to the general culture and manuring of the soil, it should be subjected, as far as 

 practicable, to the same process of trenching to different depths as that of the kitchen-garden. In the 

 shrubbery this cannot be done, but it, and also the earth compartments of the flower-garden, should be 

 turned over a spit in depth, and some vegetable mould, or very rotten cow-dung, added occasionally. 

 Every two or three years the plants in the flower-garden should be taken up and reduced in size, and the 

 beds or borders trenched, say one time at two spits deep, another at three, and so on (see 25i9.), adding 

 enriching compost or manure completely rotted, according to circumstances. If, instead of trenching, 

 the old earth were entirely removed, and replaced by good loam from a dry upland parterre, the improve- 

 ment would be still greater. Most herbaceous plants flower well in such loam, and for the more culti- 

 vated sorts, as border pinks, auriculas, &c. that require a rich soil, a portion of enriching matter could 

 be added to each plant as planted, and a corresponding attention paid to such as required peat-earth, sand, 



