The complete efficacy of lime-shells in preventing dry-rot is already proved—the coasting small craft frequently employed in the carriage of lime-shells not being liable to it. All that requires to be ascertained, is the minimum quantity which will effect it; and if the expense of this quantity will greatly exceed the average loss by dry-rot in our unemployed {161} shipping. If the quantity necessary be not greater than what we have supposed—even Mr Hume himself would not consider the expense extravagant—the preservation of a line-of-battle ship not exceeding that of one of our numerous army captains while lying in ordinary.
Lime is preventive of dry-rot in several ways,—when uncombined as an antiseptic, simply by drying, from its attraction for water; by its causticity, which remains for a number of months after it is slaked, destroying organic life; and by its absorbing putrescent gases. It is not easy, without trial, to form a correct estimate of the quantity of moisture which would enter through the inside planking of a man-of-war; but were the bottom of the vessel in good condition, the pumps attended to, and external air excluded, we should consider that the moisture would not greatly exceed 60 tons of water yearly, which would nearly be required to convert 240 tons of lime-shells into dry hydrate of lime. No very great injury or inconvenience would be produced by the opening of the seams of the ceiling (the inside skin), or of the inner decks or floors, or by the warping of the plank, resulting from the contraction of the timber by the dryness; but the caulking of the main deck would require to be looked to. {162} No danger from fire need be apprehended, from the sudden slaking of a thin layer of shells, even though a leak in the main deck should occur. The thickness beyond which shells could not be suddenly slaked upon dry boards without danger of fire, might be tried.
It is necessary to mention, that, though lime-shells, or dry hydrate of lime, when timber is so dry as to be liable to corruption by insects or by dry rot, is, by destroying life and increasing the dryness, preventive of this corruption; yet lime, in contact with timber for a considerable time in very moist air, from its great attraction to water, draws so much moisture from the air as to become wet mortar or pulp, which, moistening the timber, promotes its decay by the moist rot.
II.—NICOL’S PLANTER’S CALENDAR.
This volume, which ought to have been named Sang’s Nurseryman’s Calendar, is a work of very considerable merit and usefulness, where the craft of the common nurseryman is plainly and judiciously taught. The editor, Mr Sang, admits that he was very little indebted to the notes of his friend (the late Mr Nicol) for the matter of the volume; and the work itself bears evidence of this, being principally devoted to the operations of the nursery, the sowing and planting of hard-wood trees, which are described with a judgment and accuracy attainable only by long experience in that line, to which we understand Mr Sang belongs. Every person engaged with the sowing, planting, or rearing of timber, if he be not too wise or too old to learn, should forthwith procure this volume.
Mr Sang recommends sowing of forests in preference to planting, which many before him have done, we believe, more from conjecture that nature’s own process must be superior to any method of art, than from any experience of the fact or accurate {164} knowledge of—at least without giving sufficient explanation of, any cause rendering the tree of more puny growth in consequence of being transplanted. In the case of simple herbaceous vegetables, we find, on the contrary, that transplanting increases the size, protracts the period of full development, and retards the decay, the individual suffering no lasting injury from root fracture, or that injury being more than compensated by change to a new and more recently wrought soil; or even the root fracture, instead of being of prejudice to the growth, by throwing the energy of the plant in this direction to repair the injury, not only may do so, but delaying the superior process towards reproduction[38], may also give a {165} new vigour to the soft fibrous rootlets, and greater extension than they otherwise would have attained. But in regard to some kinds of compound plants of perennial stem, transplanting, especially when the plant has attained some size, by fracture, throws the main wide diverging roots into numerous rootlets and slender matted fibres, none of which has individual strength to extend as a leader far beyond the shade of the spreading top, thence forage in a drier, more exhausted soil, and, from consequent want of supply of moisture, the sap of the tree stagnates into flower, or merely leaf-buds, instead of flowing out into new wood. The fibrous softer rooting vegetables sustain no lasting injury from root-fracture and transplanting; but the harder, more woody, larger growing roots, losing their leader, never entirely recover their original power of extention. Yet we think that one or two year old plants, taken from the seed-bed, would suffer little or no injury from removal, as the tap-root, which is ultimately of no consequence, never constituting a leader, but eventually {166} disappearing, is the only part which suffers fracture in the woody state; and the side shoots, which become the grand root leaders, are in the fibrous state, which easily repairs small injury. These observations refer only to certain kinds of timber trees. The willows, poplars, and lindens, succeed better when their roots are cropped in near the bulb when removed. We planted a piece of trenched ground, partly with poplar plants, with good roots, from a nursery, and partly with poplar loppings, about the same size as the plants, stuck into the ground: the loppings grew more luxuriantly than the nursery plants. The same occurs with willows—with this difference, that willow-loppings do better with the top entirely cropped, without any twigs or external buds; the poplar only pruned a little, with a terminal bud left on every twig, especially on the top shoot. The superiority of the growth of those without roots, results from their having fewer buds and twigs to exhaust the juices before the formation of new fibrils to draw from the ground, these few buds thence continuing to push more strongly, and from the roots growing more vigorously when sprung anew, than when they are a continuation of the wounded deranged old ones.
New rootlets spring out much sooner and more {167} boldly from the thick vigorous green stem bark, than from the delicate tender root bark, and also more vigorously from the bark of the bulb than from the bark of the remote roots, of those soft-wooded trees; indeed, it appears to be owing alone to the great strength of the vitality of the bark of the stem, that those kinds are so capable of continuation by cuttings. The roots have nearly the same delicacy of those of other kinds of trees, and show no particular readiness to throw up sprouts when bared.
Mr Sang, in furtherance of his advocated scheme of raising forests in situ from the seed, sensible of the general impracticability of fallowing or working the ground all over previous to sowing, gives directions for pitting or stirring the earth the previous spring and summer, in spots about fourteen inches square, and from six to nine feet separate, burying the turf under the soil, in order that it may be rotted, and a fine friable mould obtained for reception of the seeds to be sown the following spring; several seeds are then deposited in each spot, equidistant; these require to be hand-weeded the first season, and the resulting plants hoed around for several successive years, till they have mastered the weeds, after which they are all plucked out but one (the most promising) in each spot. This is all very well, {168} if we could have patience and assiduity to proceed thus systematically; and if the mice, birds, and other enemies, would “let them be;” but although this plan, when a braird is obtained, and the tufts cleaned, and seasonably thinned, is probably the best, yet landlords, in general incapable of exertion, but under the excitement of a fresh thought, are so infirm of purpose; tenure of life and property are so precarious; and trusted servants, especially when the procedure has originated with another, are so liable to be negligent, that our amateurs ought to gratify their passion for improvement while it lasts, and proceed at once by purchase of plants, and pitting or slitting, which procures them a forest immediately palpable to view. There is no doubt, however, that wooing the soil to kindliness, rearing the infant plant from the germ, and superintending a principio the entire beautiful process of vegetable development, will afford a deeper charm to a patient lover of nature; and that the continued solicitude and attentions required during this process acting upon man’s parental instinct, will excite an interest hardly to be felt towards a child of adoption.
A nursery gives such facility to the rearing of the plants, that, taking into account the greater chance of failure by sowing in situ than by planting, the {169} latter practice will be executed for one half the expense of the former. Supposing that the progress, after twenty years’ occupancy of the ground, be equal in both cases,—at which period, however, we think the transplanted would still have the advantage,—it would require a considerable ultimate superior progress in those sown, to outbalance the accumulating value of the extra expense. It is probable a combination of both practices might be advantageously followed—sowing the soils and situations most suitable, and transplanting the thinnings of these into the more exposed unpropitious places[39]. The matter, however, must, after all, be left to the test of experiment in a variety of soils and situations.
This volume, being principally a monthly detail of a nursery practice, which has supported the test of competition, has, on this account, a very different credit and value from much that has been published of landlords’ practice, theorists’ conjectures, or adventurers’ quackery. The burthen of our author’s song, which, from the nature of the work, falls to be repeated at several of the calendary periods, and which perhaps cannot be too often repeated, is nearly as follows.