We have pleasure in announcing that the twelfth edition of Mr. Rivers's excellent little work The Miniature Fruit Garden has just appeared, which contains a great deal of new matter.

One of the most important of the new subjects is the bush culture of trees applied to market gardening, and which we have Mr. Rivers's permission to furnish to our readers. The work ought to be in the hands of every fruit grower.

"Our market gardeners, as a rule, are very deficient in their knowledge of fruit-tree culture, and they have much to learn. The usual practice with them is to plant standard or half standard trees in rows, some 20 or 30 feet apart, and between them Gooseberry and Currant trees. the ground is dug between the trees in spring deeply, and often carelessly. Nothing can be more barbarous, for the ground is so shaded that no surface roots can have the benefit of air and the heat of the sun; and if by any chance they could come to the surface, they are, as a matter of course, destroyed by the spade. It is true that in some of the rich market gardens near London large quantities of fruit are grown in spite of the uncouth treatment the trees receive, but this does not alter the case.

"In a well-ordered fruit garden every kind of fruit should have its department, and instead of seeing, as in Kent, a row of trees of all sorts, mixed in the most heterogeneous manner, no mixture of species should be allowed; every kind should have its allotment -- Apples on the Paradise stock, ditto on the crab stock, Pears on the quince stock, the same on the pear stock. Morello Cherries are pyramids on the Mahaleb stock -- the best of all methods for their culture -- and the various kinds of Duke Cherries on the same stock. Heart and Bigarreau Cherries on the common cherry stock. Plums as bushes, pyramids or, half standards, should all be separated, and not planted higgledy-piggledy, as they have been and are now. The sound-headed market gardener will, when his mind is turned to improved fruit-tree culture, see all this, and make his fruit garden a pattern of order.

"I have been led into these remarks on market garden fruit-tree culture by my own experience, and especially into a consideration of the great improvement that may be made in the culture of Apples on the English Paradise stock. these trees will this season, the third of their growth in their present quarters, and the fourth of their age, give an average of a quarter of a peck from each tree, so that we might have, from 4840 frees, growing on one acre of ground, 302 bushels of fine Apples, which, even this abundant season (1864), would be (if Cox's Orange), worth 5s. per bushel, or 75 pounds. In 1856, the trees then averaging half a peck each, would be double this sum, and make an acre of Apple trees a very agreeable and eligible investment. The kinds likely to sell best in the markets, and which are most productive, are the following; -- Cox's Orange Pippin, Reinette Van Mons, Ribston Pippin, Sturmer Pippin, Scarlet Nonpareil, and Dutch Mignonne. these are dessert Apples.

The following are valuable kitchen Apples, and abundant bearers: -- Hawthorneden, New Hawthornden, Small's Admirable, Cox's Pomona, Keswick Codlin, Dumelow's Seedling, Lord Suffield, Norfolk Bearer, Duchess of Oldenburgh, and Forge Apple. Such large varieties as Bedfordshire Foundling, Blenheim Orange, and Warner's King, should have more space, and be planted 4 feet apart, and be thinned out by removal, as recommended for those planted 3 feet apart.

It may be by some made a question of expense, for although the return must be large and profitable, the purchase of 5000 Apple trees would involve a large outlay. To this I reply -- first, that stocks costing only a small sum per thousand may be planted and grafted where the trees are to grow permanently; and, second, that a large demand, which my method of planting would create, will also create a cheap supply. The preparation of the ground should be as follows; -- It should, previous to planting, be forked over to a depth of 20 inches; if very poor and exhausted, from 30 to 40 tons of manure may be forked in -- not more, as trees such as I have recommended -- viz., Pears on the quince stock, and Apples on the English Paradise stock, do not root deeply -- this ought to cost 6P 13s 4d. The annual expenses are forking the surface in spring, 1P 6s 8d, and hoeing the ground, say four times during the summer,1P 4s. I give the amounts paid here fo such work. then comes the summer pinching of the shoots by a light-fingered active youth, and this may at a guess be put down a 1P, making the aggregate annual expenses 3P 10s 8d, or say 4P. the large return will amply afford this outlay, even adding, as we ought to do, the interest on capital and rent.

"It will be seen that what I propose is in reality a nursery orchard, which may be made to furnish fruit and trees for a considerable number of years. To fully comprehend, we must suppose a rood of ground planted, as I have described, with 1210 bush Apple trees. In the course of eight or ten years half of these, or 695, may be removed to a fresh plantation, in which they may be planted 6 feet apart; they will at once occupy half an acre of ground.

At the end of sixteen or eighteen years, every alternate row of trees in the first plantation, the rood, will require to be removed, which will give 302 trees to be planted 6 feet apart, leaving 303 in the original rood. The 1210 trees will by this time occupy one acre of ground at 6 feet apart. With proper summer-pruning or pinching they will not require any further change, but continue to grow and bear fruit as long as they are properly cultivated. The great advantage reaped by the planter is the constant productiveness of his trees; from the second year after planting they will be always 'paying their way'.

"The unprejudiced fruit-cultivator will quickly find out the great advantage of my mode of Apple and Pear cultivation.

In the usual old-fashioned mode, standard Apple trees are planted in orchards at 20 feet apart, or 108 trees to the acre. If the soil be good, and the trees properly planted, and the planter a healthy middle-aged man, he may hope, at the end of his threescore and ten, to see his trees commencing to bear, and may die with the reflection that he has left a valuable orchard as a legacy to his children, but has not had much enjoyment of it during his life. Now, although, like most fathers, I have a strong wish to benefit my children, I hold the idea that one ought also to think of one's own gratification; and so I plant trees, and recommend the planting of them, that will give me some satisfaction, yet leave a 'remnant' for my children.

A French pomologist, who paid me a visit last year, said "Ah! now I find an Englishman planting for himself as well as for his children"; and went on to say that he was struck by seeing in England so many standard trees in market gardens, the planters of which could have derived but small benefit from them; and the apparent ignorance of fruit gardening as a lucrative occupation. This he, in fact, imputed to our climate, which, Frenchman-like, he thought totally unfit for fruit culture in the open air, yet felt much surprised to see here the produce of a well-cultivated English fruit garden, in a climate not nearly so favourable as the valley of the Thames.

"I have only add that, besides my plantation of Cox's Orange Pippin, I have another of upwards of 400 trees, which has now been in existence upwards of ten years, so that I am not theorising, but deducing facts from a sound basis."