We must say, once for all, that the editor of the Horticulturist can enter into no controversies regarding advertisements inserted in the supplementary sheet attached to this work. If an advertiser there gives occasion of offence to other houses, by offering more goods than he possesses, or attempts to discredit others' wares, the same columns for reply are open to all, provided said reply is not offensive. We do not pretend to exercise any control over those pages; unless attention is called to a particular notice, by addressing the editor personally, the advertisement rarely meets his eye before publication.

A notice, last month, respecting the Dioscorea batatus,.is deemed offensive, and the publisher has therefore declined its continuance.

Letters and exchanges, intended for the editor, should be addressed to "Germantown Post-Office, Philadelphia, Pennsylvania".

Moorefield, Ky., Jan. 4,1855. Dear Sib: Will you, or some one of your correspondents, give me a plan for a "cold pit?" One best adapted for preserving and flowering plants in winter. Please mention the most suitable material for construction. I wish one of large size. Don't forget to mention the most convenient mode of protection by shutters; by so doing, you will oblige.

A Subscriber.

To flower plants is a very different thing from merely preserving them. A structure that would answer perfectly for the latter, might be wholly unsuited for the former. A "cold pit" is simply a miniature greenhouse, without any facilities for producing artificial warmth. If our correspondent wishes to flower plants in winter, a small furnace and flue will be requisite. Indeed, under any circumstances, the means for producing heat are desirable to keep the atmosphere free of damp. As this is a kind of house which, we think, ought to be more generally used, we have prepared the accompanying plan. The arrangements are so apparent, that no detailed description is deemed necessary. The dimensions of this pit are as follows: Inside width, 8 feet, height of back wall the same, and the front 5 feet. As all the other parts are in proportion, they can easily be ascertained; of course, the length may vary to any extent. If under 20 feet, the flue should return on itself, as shown in the figure. It should be constructed either of brick or stone; a dry situation should be chosen, and the bottom covered with 6 inches of gravel, sand, or coal ashes. It may be entered by a door at one 'end, or by merely lifting up one of the sashes.

The best covering is water-proof cloth, hung on rollers, and elevated 6 inches from the glass by a portable framework of lathos, so as to include a stratum of air between the glass and the covering. It is essential that the cover, when in use, should fit closely round the pit; as a protection from frost this system will be found more efficient and economical than any method of wooden shutters. Fire heat will seldom be found necessary, and all kinds of greenhouse plants may be kept in the highest state of health, and flower better than in a close, steaming greenhouse. The mere exclusion of frost only is required, and the day temperature may be allowed as high as 70° or 75° during sunny weather. Water must be carefully administered; the dryer everything can be kept, compatible with healthy growth, the better will it be for the plants. A southeast aspect is best.

(A. W. S.) You have shown great wisdom in saving all the leaves of your trees. They will probably not have decayed by this time, if stacked last fall, but you can have them for use very soon, by the following treatment. Slake fresh lime with brine or with water saturated with salt, till it falls to a powder of muriate of lime. Turn your leaves with a hay-fork, sprinkling this powder over every layer at the rate of four bushels to a cord of leaves. Turn the heap occasionally, and you will soon have one of the best fertilizers; the lime decomposes the leaves, and if the mass is applied to fruit and other trees, and shrubs, you need nothing better; as a top dressing to lawns, it is highly valuable. Mixed with peat, or dry muck, it might be increased in bulk as well as value. We save, annually, many cords of leaves ready for nourishing trees, etc. As they must be raked up, the cost is nothing.

(B. W., Illinois.) You are on the right track exactly, and can "go to sleep and make money." In planting your 5,000 young locust-trees, cut the plants down at the ground! they will be easier set, more likely to live, and, at the end of two years, will be larger than if the entire tree had been planted. You may have a crop of pumpkins, etc, among them without injury. Will you sell your locust plantation at double its cost? If so, drop a line.

J. Jay Smith, Esq. - Sir: On Kew Gardens, in No. 1, please to look in Loudon's Encyclopedia of Plants, under list of authorities for generic and specific names, you will find that Sir W. J. Hooker is an Englishman (1). Please to inform me if the accentuations in Paxton's Botanical Dictionary sore all correct. Scutellaria is accented Scutellaria, page 62, supplement, in Loudon's Encyclopaedia of Plants; and in Gray's North American Botany, it is Scutellaria. In Paxton, Primula is Primula; in Paxton's Supplement, Primula; in Gray and Loudon, Primula. Who is correct? (2). Can you inform me, in the Horticulturist, if there is any book published in which the botanical names of plants are divided into syllables, suitable for gardeners? (3). P. Q. R.

1. Sir W. J. Hooker would probably be styled an "English botanist," whether born in England, Scotland, or Ireland, as the works for which he is chiefly famed are English works. If we are correctly posted, Sir W. J. H. is a Scotchman by birth, who commenced life in Glasgow as a malster or brewer, and who, by his high botanical attainments, subsequently became Professor of Botany in the Glasgow University, and, in 1840, Director of the Kew Gardens, London.

2. Paxton is not considered high authority in botanical matters. The botanical part of his Magazine of Botany was edited by a clerical friend, now, we believe, his son-in-law. In the instances, Gray and Loudon are correct.

3. Paxton's Botanical Dictionary is the only one used by gardeners.

A New Beginner in the Nursery Business should not send us any communication to which he is not willing to append his name.

(H. E.) We have heard of no demonstration to employ the money ($5,000) left by the late Elliott Cresson, to plant trees in Philadelphia. We are quite curious to know how it will be employed, and who will administer the fund. It was a noble bequest; will it be properly carried out?

(Dr. W. S. Kimball, N. J.) You will find what you want in Buchanan's Grape Culture, published in Cincinnati.

Dear Sir: Should arbor vitae be planted in double or single rows for hedges and screens? An answer in your next number, will oblige A Subscriber.

A single row is ample.

(H. Davis, Waterville.) By trimming the tops of white cedar regularly twice a year, it will retain its lower branches for many years, but must ultimately lose them in obedience to the law of its nature; for this reason, it is not now much employed for hedges.