This kind of fruit house may be built in the same way as the common orchard house; but it is necessary to nail felt over the boards to prevent its being too airy in early spring, when forcing is commenced. It requires skill and attention; still, with only common care, a house heated by a brick Arnott stove placed in the centre, or by hot-water pipes, will not disappoint the careful amateur gardener, and will give strawberries in March, grapes in May, and peaches and nectarines in June.

I have a house thirty feet long, with a brick Arnott stove in the centre of the back border, which is excavated for it. Everything thrives admirably. My forced strawberries, placed on the front border near the glass, root into it, and give me abundance of excellent fruit. In like manner, peaches, grapes, figs, and apricots may be forced with but little trouble - in fact, with much- pleasure and gratification. The three modes of heating are by a well-built flue, the brick Arnott stove, and hot-water pipes; the first and second are about equal as regards economy, - the latter the most expensive, but certainly more agreeable than any other. A flue may be employed for houses under fifty feet in length and twelve or fourteen feet wide, efficiently, but not, I think, for houses above that length. Any country bricklayer can build one: its dimensions inside should be nine inches deep, and six inches wide, formed by bricks on edge, covered with two layers of tiles: the furnace should be fixed low, so that there is an immediate ascent from the end of the furnace into the flue, and a gentle rise - three inches in twenty feet - should continue to the chimney, which may be less than the flue with advantage, according to some gardeners; it is not, however, of much import.

In building these forcing orchard houses the constant ventilation through the cracks in the boards must be avoided; the boards must be rebated or be cased with asphalt felt; or, as bricks are cheap, the walls may be of brick, with the ventilating shutters in back and front. The forcing orchard house I have alluded to above is built with posts of larch cut once down and covered with half-inch boards; these being nailed on, were; well tarred with Stockholm tar, and the felt (M'Neil's) then nailed on, and done over twice or thrice with boiling coal-tar, in which lime that had been slaked a fortnight was mixed to the consistency of thick paint: this has formed a shining imperishable mineral coat. I know of nothing equal to it for felt, clay, or lime walls or fences. My clay walls on some old buildings have, by repeatedly using it, become coated with a substance as hard as stone.

I have mentioned that bricks may be used; but although I have many plant houses built with bricks, I have not employed them for building orchard houses, or even houses for forcing roses, etc. My preference for boards covered with felt for forcing houses may be owing to imagination; but I may as well state why I have and do prefer them; - it is because I have found them fiercely hot during the day, even in moderate sunshine, the evil effects of which are easily modified by abundant ventilation, and agreeably cool during the night, without that stifling atmosphere peculiar to houses with brick walls, only because bricks give out heat for many hours after sunset. Now, in thus rapidly cooling down, they certainly approximate to the descriptions given of the climate of the East, the birthplace of all our choice fruits; and so my peaches, nectarines, grapes, and figs grow and do well in houses with their walls of half-inch boards and felt.

Forcing of peaches and nectarines in pots, unless the fruit is required to be ripe very early, i. e., in April, or early in May, is not a difficult operation. The trees should be removed from the orchard house to the forcing house in December, and towards the end of the month have a good supply of water, so as to thoroughly moisten the earth; if severe frost comes on, a fire should be lighted at night to keep the earth in the pots from being frozen. About the middle of January forcing may be commenced, the temperature by day kept up to 50° by fire-heat (if the sun shines it will mount up to 60° and 70° for a short time without injury to the trees), the night temperature may go down to 40°. The trees should be syringed twice a day with tepid water; this will soon make the blossom-buds swell; and when they are fully open, which will be in about twelve days, discontinue syringing, and, if the weather is mild and sunny, give air very freely in the day and a little by night, so that no stagnant moist air, so fatal to the blossoms of the peach, exists in the house; if the weather is keen and frosty, air must still be admitted, and a brisker fire kept up, so that the temperature is not lower than 50° by day and 36° by night.

Close worsted netting, or Hay thorn's hexagon netting, placed over the ventilators, will allow of air being given night and day, even in frosty weather, without injury to the blossom. As soon as the fruit is set and commences to swell, syringing twice a day (with tepid water), as directed for peach culture in the orchard house, may commence; a day temperature of 60° and a night of 40° to 45° should be kept up, and, when sunny, abundance of air may be given, for the thermometer will then rise to 80° and 90°; instead of lowering the fire, which may lead to inconvenience, admit more air, to lower the temperature, for gleams of sunshine in our early spring months are not of long duration, and the temperature is completely at command by the ventilators. To sum up, give brisk fire-heat and abundance of air by day; very little fire-heat, or none if the weather is warm, and a slight portion of air by night; syringe twice a day - in the morning at 9, in the afternoon at 4 - till the fruit commences to color, and peaches and nectarines will ripen kindly, early in June, and be of fine flavor.

Apricots, May Duke cherries, and plums, may also be forced; and although in large establishments the two former often have houses especially allotted ,to them, as they require much care to fully succeed, yet a few trees placed near the ventilators, for they require even more air than peaches and nectarines, may do very well with them. It is a good practice to thin out the clusters of blossoms on the May Duke cherries with sharp-pointed scissors before they open, taking out quite half from each cluster.

[To be concluded in our next].