It is well known that the wood of trees is formed by annual layers of sap, which first encircles the pith, and then by protruding itself between the bark, which proportionally expands, and the last year's layer or circle of wood, it gradually concretes or becomes wood: this is continued during the summer, and forms the periodical addition.

Whenever a tree is wounded by a part of the bark being removed, or a limb or branch amputated, the sap pushes out all around the wound during the season of its flow, and annually extends itself, by sliding over the old surface until it meets, when, if not obstructed, it unites; and afterwards the annual increase, or layer of wood is formed, in uninterrupted circles, the same as if no wound had been made.

As the flow of sap over an exposed wound may be compared to that of melted tallow poured on a surface, it is obvious that a rugged surface must very much retard, if not wholly prevent, its ad

vance.

In this view Mr. Forsyth's practice of cutting away the obstructing dead wood in hollow trees will appear rational and proper; and when, by decay, the surface of a wound is sunk or hollowed, the extension of the sap is diverted, and prevented meeting and joining; and by its projecting above the wound and round, it forms a lodgment for the rain, and becomes in consequence a vehicle of putefraction, which extends itself through the tree. If those observations are correct, although we

may not approve the idea of his composition operating as a stimulant, and producing the effects on a tree which a top dressing of dung does on land, or of effecting the incorporation of new wood with the old, we may give Mr. Forsyth the credit of a remedy in its application, for many injuries which Nature, when left to herself, is inevitably exposed to, particularly internal decay from external exposure; but, notwithstanding we admit the efficiency of the composition in this respect, we may consider it as too troublesome and complicated in its preparation, and tedious and filthy in its application, to become of extensive use; and adopting Hitt's recommendation, of applying soot to the diseased part of apricots, and observing its effects, it will readily occur that as soot, like charcoal, is a powerful antiseptic and a preventive of the ravages of insects, it might, when mixed with oil, and rubbed over a wound, prove also a preservative against putrefaction and the injuries of the weather.

I have long since adopted this application, and found it completely efficacious; a quantity may at all times be readily collected and mixed up, so as to be laid on, like thick paint, with a brush, or rubbed over with a bit of cloth; and as very large wounds will require some years to enable the young wood to close over them, such parts should be covered or painted a second or a third time, at different periods, from six to twelve months, as the rain would otherwise find its way into the

little clefts, occasioned by the contraction of the drying wood; and if drying oil, such as linseed, be used, it will prove more lasting and perfect in its effects.

By these means, disease and rottenness will be prevented; the old wood will continue sound and hard, and the surface being preserved smooth, the new wood will form close upon the old wood, and consequently wounds thus treated will never prove so detrimental to timber as when they are left exposed.

It might be observed that the soot, thus applied, will adhere to the surface, and in consequence, the new and old wood cannot unite or incorporate, "but must remain perfectly separate and distinct from each other, without union or adhesion ;" this, no doubt, will be the case; and, according to Mr. Knight, this has been explained by Dr. Anderson, as all the effect he believed to be produced by Mr. Forsyth's composition, and all that he or Mr. Forsyth meant to assert it had produced.

There are, no doubt, instances within the scope of every one's observations, of tall, straight, healthy stems growing upon or from old wounded and hollow stumps, without the aid of art; but whenever it is desired to encourage and support the growth of trees in this manner, it is, as Mr. Forsyth observes, more effectually done by reducing all the branches to one, and from time to time removing all other shoots growing from the old trunk, and also all decayed or rotten wood, and

applying the covering recommended to the exposed and wounded parts; this, by excluding the air and moisture, will prevent decay and the waste of sap by putrefaction, and the future growth of the tree will consequently be better sustained.

L

RESULTS OF EXPERIMENTS

ON

GROWING PEACHES IN POTS.

BEING desirous of making some demonstrations as to the effect of different descriptions of soil and food, in the growth of peaches, nectarines, &c., it appeared to me that the most direct and decisive means would be to grow them in pots, and under glass, as thus circumstanced, they would be less exposed to casualty. I accordingly prepared a number of pots of about fourteen inches diameter and depth, and selected plants of peaches and nectarines, of one year's growth, from the bud; and as a basis for the soil or earth, in which these were to be planted, I took a strong black loam ; this I divided into different portions; one portion I mixed with an equal quantity of the scrapings of a flint road; another with one half as much of the same scrapings; another with one fourth; and another portion I mixed with an equal quantity of brick rubbish, pounded as small as drift sand;