important discovery in the book; and finally, it is concluded, logically enough, that as we have but little timber, we ought therefore to take care not to expend much. This is the substance of what we can make out with any degree of certainty in the 'Precursor;' there is a good deal however concerning Lord Nelson's condolence with the author for the loss of his ship; and something about kidnapping the poor Chinese from their friends and families, and conveying them to the island of Trinidad to plant sugar-canes, a thing they never saw nor heard of in the islands they came from, and where they subsisted by fishing; and these free labourers, as they were called, were to be substituted for the African negroes! We are at a loss, however, to discover how this happy thought, which was partially carried into execution, to the disgrace of all concerned in it, is brought to bear on the project for seasoning naval timber. That secret may probably be revealed in the Exposé.' But as it appears to us that the noble lord in question has some notion of naval matters, and may perhaps be laudably looking forward, in the course of events, to succeed to the administration of the naval concerns of the empire, he may not be displeased with a slight sketch of what has already been done on the subject of his speech, which may convince him that it had not escaped attention before the appearance of Captain Layman's Precursor;' from which, indeed, we suspect that the noble lord will be able to extract just as much information regarding the seasoning of timber, and the dry-rot, as the ingenious artist already mentioned did sunshine from his cucumbers. Captain Layman is, in truth, come into the field at the "eleventh hour.'

It is an undoubted fact, that the duration of ships of war, and particularly those of the line, has of late years been very much shortened. They have died prematurely of a new disease, new, at least, with regard to them,-known by the name of the dry-rot, which we have supposed to originate in green timber, but which, having once planted itself, spreads its seeds and roots equally over green and dry, rotting and decomposing the fibre of the wood wherever it fixes itself.

The origin of this destructive disease is not, if our conjecture be right, difficult to be traced. We know not as yet precisely what is the supposed fluid matter called the sap of trees, nor by what laws it is propelled from the roots to the highest extremities; but that a circulation of something does take place has long been known and confirmed by direct experiment. It is this circulation, moreover, as it would seem, that communicates new life to the vegetable principle; that creates in its ascent buds and leaves, flowers and fruit, all of which die away and disappear when it again descends. Whether it be the acids or the oils, the resins or

the

the gums, or all or none of them, that are thus put in motion, or whether it be some gaseous or other subtle and volatile fluid, which at the proper season resuscitates the vegetable life, remains yet to be discovered. It is pretty clear however that whatever that power may be, which thus stirs up and calls into new life the active principle of vegetation, it does not cease altogether from the moment that the tree has been cut down and separated from the parent root. Every one knows that the trunks of elm trees, for instance, cut down in the spring of the year, if the bark be suffered to remain on them, will push out leaves and small shoots the following spring along the whole length of the trunk; the sap that was in the wood at the time of felling, impelled by the genial influence of the season, begins to circulate, puts the living principle in action, opens the pores of the wood, and makes a last and feeble effort at vegetation.

This simple fact, which could not escape common observation, must have led to the conclusion that winter felled timber, when the sap was supposed to have descended into the root or the ground, would not possess the same tendency to vegetate; and that if the bark was stripped off in the spring while the tree was standing, so that the sap could not rise, or rise but imperfectly, and left in that upright posture till the winter, the tendency to vegetation would be still further repressed; the fluid parts would subside; the fibres of the wood collapse; and the timber become more compact, solid, and strong; or, in other words, would at once be seasoned, and not liable to throw out those abortions of vegetation, those excrescences which form the lowest class of vegetables, and which, by some extraordinary process communicated to the wood, infect it with the disease above-mentioned; a disease which seems to act by depriving the wood of all moisture, and so completely decomposing the fibres, that, though in appearance sound, it crumbles between the fingers into a mass of impalpable powder.

We are fully aware that different opinions are entertained as to the origin of the dry-rot, many contending that this disease will as readily attack timber however long it may have been seasoned, when exposed to damp and confined air, as it will seize upon green timber. We are not of this opinion; and we are borne out, as we think, in our theory of the dry-rot being produced originally by the natural juices of the wood being brought into action, from the circumstance of the different genera of fungi, which are found to infest different kinds of timber. Mr. Sowerby, who was employed by the Navy Board to examine the Queen Charlotte, a new ship in a complete state of dry-rot, found the most prevalent of the parasitical vegetable which occasions the disease, to be the xylostroma giganteum, a gigantic leather-like fungus peculiar to oak, and known there

fore, in common language, by the name of oak-leather; but he found also the boletus hybridus, being the young state of the boletus medulla-panis, or white, ragged, soft fungus; the auricularia pulverulenta, and some others, among which the boletus lachrymans was the most scarce, although this last fungus is that which mostly infests dwelling houses and other buildings. Now, as the Queen Charlotte was injudiciously built of a mixture of English oak and American oak, of English fir and American pitch-pine, this assemblage of different sorts of timber will, we think, account for the different kinds of fungi found in that ship. In general, however, the xylostromu giganteum may be considered as the cause of dry-rot in ships, and the boletus lachrymans in houses, the former being the parasite that feeds on oak, the latter on fir.

It may fairly be inferred then that as different timber produces different kinds of fungus, there must reside in each kind of timber its peculiar moisture, and that mere wetness or damp could not produce a different vegetable on dry well-seasoned oak and other kinds of timber when exposed to such damps. It has been hinted to us, that fungi may be the effect, and not the cause, of rotten timber; as the fungi which form the mould of cheese are the consequence of previous rottenness, and not the occasion of it. We doubt the correctness of the fact with regard to cheese, and are rather inclined to believe that, if a cheese in a perfect state of soundness, be placed in a close damp cellar, it will very soon be covered with fungi, and long before the least tendency to internal rottenness has taken place; and with regard to timber, we know, for we have seen, that in the Mulgrave, the Barham, the Poictiers, the Dublin, the Stirling Castle, cum multis aliis, whole planks, timbers and beams were covered with a sheet of fungus, while the wood was still perfectly sound; though it is well known, that if not speedily removed, and a free circulation of air admitted, the consequence would be, a total decomposition of the fibres, either from some power possessed by the fungus of extracting the juices of the wood, or of occasioning some fermentative process within; and while the surface of the timber would still retain a smooth and sound appearance, the internal part would be reduced to a mass of dust and rottenness.

We have already had occasion to distinguish the dry from the wet rot; the latter has nothing to do with fungus, but is occasioned by alternate exposure to wet and dry; it is slow and gradual in its progress, and rather separates than decomposes the fibres of the wood.

Another circumstance may be mentioned in corroboration of our theory. The more sappy timber is, the more it is subject

to

to be infected with fungi and the dry-rot; thus all the timber brought from the forests of Germany, of which the Antwerp fleet has been built, is remarkably subject to the dry-rot; so is all the timber that is brought from the forests of America; whereas the timber of trees that grow in exposed situations, as on the sides of hills and commons, and hedge-rows, being more compact, and less sappy, is less subject to this fatal disease. Soil and climate have also, no doubt, considerable influence on the nature of growing timber; the farther south oak grows, the better the timber would seem to be; the oak on the bold shores of the Adriatic is the best oak known in Europe; and the oak timber which is produced in the southern counties of England is preferred to the timber of the northern counties; that of Sussex being considered as the best. In a contract for tree-nails, drawn up more than a hundred years ago, it is stipulated that they should be made of 'good Sussex oak, free from knots and shakes.'

All these points are of great importance to be ascertained, and we know of no one so well qualified for the purpose as Mr. Sowerby, who has had more experience of the nature and habits of fungi, and of their ravages wherever they fix themselves on timber, than any other person we have heard of; and his ideas, we understand, with regard to the seasoning of timber, accord very much with those of the officers of his Majesty's dock-yards, who have attended to this most important subject.

There can be little doubt that the custom of felling timber trees, except the oak, in winter, arose from a conviction that, when the sap has subsided, the timber is more compact. The exception of the oak from this general practice must have arisen entirely from the value of its bark and the facility of stripping it off for the purposes of tanning, while the sap is in the act of rising; and to this circumstance alone can be attributed the statute of the 2d James I. which prohibited the felling of oak trees when bark was at a given price, unless between the first day of April and the last day of June; with the exception, however, of such oak timber as was meant to be employed in the building or repairing of houses, ships or mills-an exception which points out very clearly what the opinions were of our ancestors with regard to the superior quality of winter-felled timber. This opinion has, in fact, been confirmed by the ingenious experiments of Mr. Knight, who ascertained that the alburnum or sapwood of trees felled in the winter is more firm and tenacious in its texture, and consequently more durable, than that of the same kind of wood which had been felled in the spring.

Doctor Plott, who wrote about 180 years ago, mentions a practice in Staffordshire of stripping the bark of their oak trees about May,

May, while standing, and when the sap was beginning to flow, and of felling them about Michaelmas. In Mr. Evelyn's book are some papers on this subject: and on the recommendation of Mr. Pepys, secretary of the Admiralty, to James the Second, that monarch issued his royal warrant to the Commissioners of the Navy, directing them to cause to be stripped in the spring, and felled in the ensuing winter, one hundred and fifty oak trees in Bushy park, fit for naval purposes. The result of the experiment is not known; though there is little doubt that, able and active, exact and laborious as Mr. Pepys was, the record would be found in his numerous manuscript volumes, now shut up in the Pepysian library at Cambridge, but which ought unquestionably to be lodged at the Admiralty among the records of that department.

The papers of Pepys, of Plott and Evelyn, induced the French naturalists Buffon and Du Hamel to undertake a set of experiments on the barking of trees in the spring, and leaving them to stand during the summer to season; by which process Buffon pronounces the timber to acquire additional compactness, weight and strength, and consequently greater durability. And it is laid down (in the Histoire Générale de la Marine, published in 1758) as a criterion to determine the quality of oak timber-that, to be good, it should be felled when the moon is at the full, and the wind north; and that it is sure to be bad, if cut at new moon, and when the wind blows from the south.*

In England the subject has not met with that attention which it so evidently deserves. Dr. Plott says the Royal Sovereign was built of winter-felled timber, and speaks of its uncommon hardness; but there is no evidence of this fact. The first experiment we know of was that of building the Montagu of winter-felled timber, as we mentioned in a former Number, by order of Lord Sandwich; this ship was launched in 1779, and we do not find that she required any repair for ten years afterwards, and, indeed, she is yet a good ship.

It is the less surprizing that the durable quality of this ship should not have attracted the attention which might be expected, when it is considered that the experiment was made when the ordinary duration of ships was calculated at eleven or twelve years, before they required much repair; but we own it does appear rather unaccountable that none of our builders, either public or private, should have felt the advantage of deviating from the ordinary routine, or that a mere spirit of curiosity should not have induced them to put to the test of experiment the comparative quality of oak timber felled in the winter when the sap was down,

* Hist. Gen. de la Mar. tom. iii. planche I. p. 282. de l'Archit. Nav.