242. It may here be mentioned, that Mr Robert Fletch er, at Bonnyrig, near Edinburgh, a good many years ago, constructed a grape-house, in the form of a regular poly gon of 24 sides, having a base 24 feet in diameter. A thin brick wall, two feet high, passes around, forming the pro per angles : on this wall rest the couples which support the central or flat part of the roof, which is eight feet in diameter. An iron ring connects the couples at the base as well as at the top. The length of the couples is 10 feet 3 inches. Between these are glazed sashes, 3 feet wide at base, and tapering to 1 foot at top. In this way the ceil ing is 3 feet 6 inches from the ground, and the sashes in cline at an angle of 40°. The door of the house is to the north ; the furnace close by one side of the door ; the flue makes a circuit around the house at the distance of 2i feet front the wall, and the smoke escapes on the other side of the door. Air is admitted, as wanted, by means of three ventilators on the south-V/est side; but in point of fact air can pass in by many crevices, particularly at the flat part of the roof, and no putty has been used in glazing. The brick wall being founded merely on the surface of the ground, the roots of the vines pass under it in any direction. The soil is dry and rather shallow. In the end of June, Mr Fletcher forms a heap of vegetables, commonly the weeds from his garden, in the centre of the floor of the house : when this heap begins to decompose, some degree of heat is produced, a good deal of vapour rises, and nutri tious gases are exhaled: the heap is occasionally fed, so as to keep up the fermentation till about the middle of Sep tember. In this house, and under this sort of management, has this ingenious person, for a number of years, raised very good crops of grapes of different sorts, particularly the black Hamburgh, the Lombardy, and the white sweet water, the berries of all these kinds becoming large and of high flavour.
243. It may also be noticed, that Mr Henderson, nurse •ryman at Brechin, has constructed a small hot-house, which he styles the triple meridian. The narrow end of it is plac ed to the south, and the roof, which is ridge-shaped, is in clined in the same direction, by a slope of one 'Cot in six. In consequence of the position of the house, one side has the sun's rays approaching to perpendicular at 9 A. M. and the other at 3 P. M. ; and, on account of the slope to the south in the roof, the sun's rays arc enjoyed partially all the time he is above the horizon. Air is admitted by ventilators. After several years trial, Mr Henderson has found such a construction to answer all his expec tations.
If melons be the crop raised, no furnace is necessary. In place of fire heat, the warmth arising from the fermenta tion of weeds, or a mixture of grass and rushes, is suffi cient; proper chambers for holding these, and enabling them to communicate their heat, being prepared within this house. The employment of refuse vegetables in such a tnelon-house, or in Mr Fletcher's grape-house, must ope rate as a premium for the destruction of nettles, thistles, and other weeds.
244. At Lord Mansfield's garden at Scone in Scotland, the hothouses are constructed on a new plan, inasmuch as they have no upright front glass, and all the sashes arc fix ed, or not calculated to slide up and down. Air is admitted by ventilators in front, and at the top of the back wall. The houses are 12 feet high ; the back wall two feet higher, or 14 feet ; and the front or parapet wall only two feet. The advantages of this plan seem to consist in saving the ex pence, at first, of upright wooden rafters or pillars, and in preventing the breakage of glass, which must to a certain extent be occasioned by the moving of sashes up and down.
But it is not to be concealed, that these immoveable sashes are attended likewise with some disadvantages. A liberal circulation of air is sometimes necessary to the health of the young fruit, which, without it, drops off at the time of the first swelling ; and an equable exposure to the air is highly important for communicating flavour to peaches and nectarines when just approaching to ripeness. Air admitted, however, only by openings in the front parapet and in the top of the back wall, must in some measure form currents, which, as formerly remarked, (§ 209.) are seldom desirable. Even in avoiding injuries to the glass, the advantages cannot be very considerable, particularly if :he moveable sashes be drawn up and down in a steady manner by means of pulleys and weights. 'Whoever erects a house with a glass roof, must of course lay his account with occasional accidents, whether the roof be fixed or moveable, and one would be apt to think, that the repairs of panes accidentally broken on fixed roofs, could scarcely be accomplished without very considerable risk of increasing the damage, in clambering over them with ladders.
Gathering and keeping of Fruits.
245. Fruits in general should be gathered in the middle part of a dry day : not in the morning, before the dew is evaporated, nor in the evening, when it begins to be depo sited. Plums readily part from the twigs when ripe : they should not be much handled, as the bloom is apt to be rubbed off. Apricots may be accounted ready when the side next the sun feels a little soft upon gentle pressure with the finger. They adhere firmly to the tree, and would over-ripen on it. Peaches and nectarines, if moved upwards, and allowed to descend with a slight jerk, will separate if ready ; and they may be received into a tin cup or funnel lined with velvet, so as to avoid touching with the fingers or bruising. If this funnel have a handle two dr three feet long, the fruit may he gathered with it front any low or ordinary wall. The old rule for judging of the ripeness of figs, was to observe if a drop of water was hanging at the end of the fruit ; a more certain one is, to notice when the small end becomes of the same colour as the large end. The most transparent grapes are the most ripe. All the berries on a bunch never ripen equally; and it is therefore prOper to cut away unripe or decayed berries before presenting the bunches at table. Autumn and win ter pears are gathered, when dry, as they successively ripen. The early varieties of apples begin to be useful for the kitchen in the end of June ; particularly the codlins and the jenneting ; and in July they are fit for the dessert. From this time till October or November, many kinds ripen in succession. The safest rule is to observe when the fruit begins to fall naturally. Another easy mode of ascertaining, is to raise the fruit level with the foot-stalk ; if ripe, it will part readily from the tree : this mode of trial is also applicable to pears. A third criterion is to cut up an apple of the average ripeness of the crop, and examine if its seeds have become brown or blackish ; if they remain uncoloured, the fruit is not ready for pulling. Immature fruit never keeps so well as that which nearly approaches maturity ; it is more apt to shrivel and lose flavour. Win ter apples are left on the trees till there be danger of frost: they are then gathered on a dry day.