818$ PRACTICE OF GARDENING. Part III 



house for tall plants, and the other in front for floating foliage, with a broad path between. But the 

 most elegant plan would be, to have a circular house, glass on all sides (fig. o/9.) f to have a cistern 

 in the centre for river-plants, and a surrounding cistern for those which grow in stagnant water lo 

 imitate the effect of the motion of water in the central cistern, the mould or pots in which the plants 

 grow might be placed on a bottom (a), apart from that of the cistern (b), and this bottom being on 

 the end of an upright shaft, might, by the aid of proper machinery in a vault below (c), be kept in 

 perpetual circular motion. Those plants, which grow naturally in rapid streams, might be planted or 

 placed on the circumference of the bottom (rf), and those requiring less agitation towards its centre (e). 

 If reversed motion was required to imitate tides (where marine aquatics were cultivated), nothing 

 could be easier than by the sort of wheel used in the patent mangle to produce it to any extent ; or 

 by another still more simple plan known to every engineer, it might be changed seldomer, say only 

 once or twice in twenty-four hours. If a rapid and tortuous motion was required, then let the 

 bottom on which the plants are placed, be furnished with small circular wheels (/) placed on its margin, 

 working on pivots, and furnished on their edges with teeth like a spur wheel Then let there be a cor. 

 responding row of teeth fixed to the inside of the wall or side of the cistern, into which they are to work 

 like a wheel and pinion. By this means, pots of plants set on the small wheels, will have a compound 

 motion, one round the centre of the small wheels, and another round that of the large bottom, something 

 of the nature of planetary motion, but more like that of the waltz dance. It is almost needless to add, 

 that exotic aquatic fowls and fishes might be kept in such an aquarium, and either of the sea or fresh- 

 water rivers, according as salt water or fresh was used. It may be thought by some that the machinery 

 would be intricate and troublesome ; but the power requisite is so very small, that it might easily be ob- 

 tained by machinery on the principle of the wind-up jack, such as was used by Deacon in his ventilating 

 Eolians. (Rem. on llot-h. 68.) This kind of mechanism very seldom goes out of order, or requires repairs, 

 and would require no other attention than being wound up twice in twenty-four hours, and oiled oc- 

 casionally. The same vault that contained it might serve for the furnace or boiler for heating the house. 



6181. Wind. If instead of water in a circular cistern with its bottom so constructed, we suppose air, 

 then the same arrangement would serve for producing artificial wind to plants, the beneficial effects of 

 which in producing bushiness and strength of stem are well known. The motion thus given would pro- 

 bably be extremely useful for young plants in close damp weather in winter, by preventing some sorts 

 from getting mouldy and damping off, and by moderating the growth, and preventing the etiolation of 

 others. For this purpose the machine might be considered as a kind of hospital, and the plants being in 

 pots, might be set on either the large or small wheels, and kept there in motion for a longer or shorter 

 period, according to circumstances. 



6182. The substitution of fire-heat for that produced by the fermentation of vegetable substances, is a re- 

 cent innovation in the construction of plant-stoves. This has been done by heating the air of a vault or 

 chamber below the pit, with smoke or steam, either by circulating these fluids in flues or tubes in the 

 chamber, or by simply filling the vault with them. In some cases, also, flues or steam-pipes have been 

 conducted through the tan with a view to prolong its heat. The mode by heating an air-chamber below 

 the pit was carried into execution by us so long ago as 1804, at Glenfuir (Tr. on Hot-h. p. 249.) ; and more 

 recently upon a larger scale, for the purpose of growing pines, at Underley Park. (Tr. on Coun. Res. p. 295. 

 pi. 11. fig. 3.) A plan very similar to the last has been adopted by Kent (Hort. Trans, ii. 389. and iii. 287.), 

 who at first plunged the pots in a bed of sawdust over the vault, thinking thereby to avoid the worms and 

 insects that generate in decaying tan. He found, however, that when the sawdust became rotten, worms 

 generated in it as freely as in any thing else, and has therefore given up the practice of plunging altogether, 

 setting the pots on a thin layer of coarse sand placed over the pavement, which forms the roof of the hot 

 air chamber. Thus situated, the plants are not apt to. run through the bottoms, and over the tops of the 

 pots, as is the case when they are plunged, which always occasions a serious check to the plants, whenever 

 they are removed or required to be shifted. After above a year's trial, he says, " I think I can with cer- 

 tainty pronounce that plunging is not only unnecessary, but really worse than useless to plants, except 

 where they have been injured and require' to be drawn." A very obvious extension of this principle was 

 the disuse of bottom heat altogether, and the substitution of a platform of brick or pavement, or merely a 

 bed of scoria or gravel for the bark-pit. This has been done extensively by Messrs. Loddiges, Kent, 

 the Comte de Vande, and various others, with perfect success as far as respects large plants ; but most 

 stove-plants require to be originated and brought forward till they are one or two feet high in bottom heat. 

 By keeping up a considerable atmospheric temperature, and by frequent waterings over the leaves, that 

 sort of moist heat is produced which seems most congenial to vegetation, and it may, we think, be assumed 

 as experimentally proved, that where such heat is produced in plant-stoves the bark-pit is unnecessary for all 

 general purposes. " If we reflect for a moment," says Kent," that in tropical countries, the stem, branches, 

 and leaves receive a greater degree of heat from the atmosphere than the roots can possibly do ; it appears 

 extraordinary that a system of management so directly opposite to nature should have ever been adopted, 

 or that it should have been so long practised. If a quantity of earth was to be raised from the root of any 

 tropical shrub, growing in its native situation, there is no doubt its heat would be below the temperature 

 of the air, therefore the roots of the plants in a stove ought not at any rate, to receive more warmth than 

 their other parts." (Hort. Trans, iii. 288.) 



6183. A propagation-house is a requisite appendage wherever a general collection of 

 exotic plants is maintained ; and the proper situation for it is in the reserve-garden. 

 Such a house, like the houses used by nurserymen, does not require to be so light as fruit- 

 ing or flowering houses ; it may be little more than a large pit with the roof very flat (say 

 from 12 to 15), in order that all the plants may be near the glass ; it should contain a 

 bark-pit. raised to within eighteen inches of the glass in front, and 2^ feet behind, a broad 

 stone shelf in front, and two or more shelves in the back of the house, close under the 

 roof, that is, over the path and flue. All shelves in hot-houses, it may be observed, 

 whether of stone or timber, ought to have narrow ledgrnents along their edges, not less 

 than an inch deep, by which the water which escapes through the bottoms of the pots is 

 not only prevented from dropping, but retained to generate a salutary coolness and mois- 

 ture. The fire-place should be formed at one end of the front (say the south-east corner), 

 and the flue conducted along the front from about nine inches or a foot from the parapet, 

 and so along the opposite end and back wall, till it terminates at the extremity of the lat- 

 ter, or the north-east corner. The door may be formed in the back part of the end in 

 which the furnace is placed, and the path which surrounds the pit, should be made suffi- 

 ciently low to admit of head-room. This plan may in some cases be doubled ; that is, 

 a similar arrangement of flues, &c. may be erected alongside the other, that is, the north 

 side, with a moveable boarded partition between them. The house fronting the north 

 may be used for striking cuttings, or raising seedlings, and that fronting the south, for 



