Mr. Editor: - Your leader, p. 57,58, I have carefully read, and the second time ran over it to have it fresh in my mind. Being one of the earliest Dwarf Pear growers in Mississippi, and an advocate of the Dwarf, and having to learn all about it from a dear-bought experience, I must, though in sincerity, reluctantly differ with you, yet, at the same time, I acknowledge the truth of all you say. This is " rather blowing hot and cold."' But let me explain. I would plant the Dwarf Pear one to three inches below the union, depending upon the quality of land; yet I would prefer to plant no deeper than they grow in nurseries, if they were grown right. Just as well to have the Dwarfs die off from too deep planting, as live standing and do no good. I have had Dwarfs budded, or grafted, six to ten inches above earth, planted as my experience and as you direct; after remaining two or three years, some died, some broke off at junction, and many made no growth. I found those did best which had been worked low, particularly a lot I got from Hovey, so worked as to admit the junction to be, say one inch in earth. I then took up all others and put them deeper, so as to hide the Quince entire. I lost some, but on the whole I succeeded better.

Since that time I have planted all below surface - meaning the junction. I have trees not over ten to twelve feet high, from which I have gathered some three to five bushels of pears, others of similar age not near as high, nor as thrifty; the D'Angouleme being the best bearer, though not any larger than others.

I have tried to insert the pear graft on the Quince cutting before putting out, thinking I might save time and get my tree lower worked. I succeeded with the only one I tried last fall, though it was put out under the north side of a fence and thus protected from the sun. I have some 2,000 cuttings put out, and will in a few days insert grafts on side of cutting without removing, (a little more trouble,) but it will not prevent the quince from growing, and if I succeed it may save one year. I am desirous of putting into orchard several hundred Pear Dwarfs, and will keep myself out of mischief by working them myself.

I insist that nurserymen should work Dwarfs so that they can be planted correctly, (as they grow in the nursery,) which I think will remedy much complaint; for really my experience is against Dwarfs while the Quince is above ground. Yours with respect, Edwards, Miss. M. W. PHILIPS.

[We must put Mr. Philips down for a good-tempered man, who can discuss a point of difference without losing his patience. Since he agrees with us in the most essential points we made, we will consent, with him, to throw away the badly-worked trees, as being the most speedy method of disposing of the evil. Trees ought by all means to be properly prepared in the nursery: this can not be too strongly insisted upon. We hope he will continue his experiment of preparing the stock before planting, and let us know the result - Ed].

Editor Horticulturist: When a useful invention is introduced into domestic life, it very often happens that its merits are not always understood, and sooner or later we are apprised of some defect, or we are informed that there is another and a more useful article in the market, to serve the same or a better purpose: in such cases ventilation is always useful.

Thus it is in regard to the Saddle and Conical Boiler, recently invented for the purpose of heating with hot water; touching the merits of which I have read two articles in the March and April numbers of the Horticulturist.

Having had some opportunity of seeing that apparatus at work in several places during the past winter, and being the owner of three boilers of a different pattern, now in active use, I ask leave to say a word in regard to it in the Horticulturist.

The principles upon which hot water boilers should necessarily be constructed are few and simple, yet they seem not to be well understood, and are rarely attended to by practical gardeners.

To obtain the greatest amount of heat from a given quantity of fuel, and to retain that heat when obtained within the boiler, by retarding its rapid ascent through the smoke pipe and chimney, are matters of the first importance in every beating apparatus of this description. For example, the slightest examination will show that a judicious combustion of fuel is not always obtained in the grate and chimney process of heating our dwellings, and by applying the hand to the flues they will be found to be infinitely hotter than any part of the house intended to be heated, thus carrying away at least three-fourths of the heat produced, without affording much benefit to the house, or its inmates; hence the necessity of stoves.

Count Rumford's improvements in the construction of chimneys did little towards economy in the combustion of fuel, and nothing at all towards retaining the heat when produced. His whole aim was to make a chimney draw well; and this, in many cases, and especially in boilers for horticultural purposes, is too much of a good thing.

Economy suggests to the gardener and horticulturist some means and manner of heating their plant-houses other than the old brick flue system, at the rate of from twenty to fifty tons of coal during six months of the year.

Oxygen, that great supporter of all animal and vegetable life, is the prime element in the combustion of fuel. In the construction of the boiler, its introduction should be carefully provided for, through the grate bars of course; the area of which should be in proportion to the maximum extent of pipes to be heated, and directly from the atmosphere.

It is held by learned chemists and men of science who have elaborately investigated the subject, that the quantity of oxygen necessary to effect complete combustion, so as to produce the best results, should be in due proportion; that too much is as bad as too little, - too much consuming the fuel too rapidly, and driving off the heat - too little producing imperfect combustion, and great quantities of smoke.

The Argand Lamp

The Argand Lamp affords a good example of complete combustion, and the principle it elucidates should not be forgotten in the construction of a heating apparatus. The chief difficulty Argand obviated by his invention, was in producing complete combustion of the oil, so as to keep the flame from smoking; this he effected by making the wick in the form of a ring, instead of the round cotton wick used in the old form of lamp, which was always attended with smoke and smell, because of its small extent of surface to the air. By A.'s invention the flame became a hollow cylinder, with a current of air ascending through the inside, bo that its burning surface was more than doubled, and by means of a glass cylinder over the flame, a draught was created - sufficient oxygen supplied - complete combustion obtained - and the greatest possible amount of light yielded.

Rogers' Conical Boiler

Rogers' Conical Boiler, introduced in England many years ago, gave satisfaction for a long time, but like the chimneys of our bouses, the smoke-pipe and flue being in direct connection with the fire, a great quantity of heat was uselessly carried away. In addition to this defect in boilers of a larger size, the higher portion of the boiler was too remote from the fire to produce the best result; hence it is, that the smallest boiler of this pattern has proportionately greater power than the larger size. The reason of this is the well-known fact, that the relative effect of heat upon substances is in the inverse ratio of the squares of their distances from the fire; for instance, A and B are sitting at a fire; A is two feet distant from it, and B is four; the square of B.'s distance is four times the square of A.'s distance; therefore A is four times hotter than B, though only half the distance from the fire.

The improvement in the Saddle and Conical Boiler under consideration, is the introduction of the saddle within the cone, or rather one cone within another, each holding water, and connected together by small pipes, with sufficient space within the cones to allow the escape of smoke.

Now the advantage here it, the inner cone being completely closed at the top, holds in suspension the light floating particles of unconsumed fuel which would otherwise rush up the chimney, until its combustion is completed, assuming that a due quantity of oxygen is admitted: and a further and most valuable advantage secured is, this inner cone, at all times during action, is a cap full of intense heat which it retains, and retards in its ascent up the chimney.

Sufficient heat - slow combustion - requiring little attention - with little smoke, are the objects to be attained in the construction of every heating apparatus for horticultural purposes.

The Saddle and Conical Boiler referred to combines these qualities in a greater degree than any other boiler I have seen in use.

Brooklyn, April 18, 1860. B.

[We have several articles on the "boiler subject," which we shall print from time to time. Thus far they are written with good temper, and this we shall insist upon as a condition. - Ed].