TIMBER.

Τηε term “timber” is applied to wood of sufficient size to be adapted for building purposes, whether it be standing in the forest or after it is felled. While the timber forms a portion of the growing tree, it is distinguished as “standing timber when felled, it is called “rough timber.” After the rough log is converted, that is, sawn into the forms for which it appears best adapted, the various conversions, as the produce is called, are designated according either to their shape or their dimensions, as sided timber, balk, thickstuff, plank, or board. These several terms will be adverted to in a more advanced portion of this article, where they will either be defined or incidentally explained.

Timber is of such incalculable value as the material for the construction of our fleets, and it ministers also so largely and in such numerous forms to our every-day wants, that it is not surprising the best means for its successful cultivation should have occupied much of the attention of enlightened horticulturists; while it is certainly a subject of much wonder, and has been occasionally one causing no little anxiety, that the maintenance of an adequate supply should be almost wholly left to accident, and that it consequently should be greatly neglected.

The species of timber which are chiefly used for building are oak and fir. Our supply of fir is for the greater part drawn from abroad, as the climate of Great Britain does not appear to be favourable to the growth of the best varieties of this species of timber; but with oak the case is different. There is no doubt that England was originally, almost from one extremity to the other, covered with forests, in which the oak predominated; and perhaps the best oak in the world is indigenous to England. We learn from the Doomsday-Book, that even in the reign of William the Conqueror, timber was so plentiful that the woods were not valued according to the quantity standing in them, nor according to the quantity which might be annually felled. In fact, the woods, as timber, were comparatively valueless, and their worth was estimated by the number of swine which could be supported by the acorns. At present the produce of oak from our forests is not in any adequate proportion to the demand for it; and we are obliged to resort to foreign markets for this useful timber, or for substitutes. This is to be regretted, because undoubtedly it is very desirable that we should be independent of other nations for our supplies of so important a component of our naval supremacy; and it is the more desirable, because in general the substitutes which we are able to procure are not equal in quality to the produce of our own soil. The oak of Great Britain is, for ship-building especially, superior to most timber which we can thus obtain. The reason that the maintenance of the supply of oak timber does not meet with the attention which is required by the demand for it, evidently is, that although the demand is present and urgent, the advantages to be derived by any attempt to provide a supply are too prospective to tempt the cupidity of individual speculators. The home supply is therefore almost wholly left to be provided by those who have a hereditary interest in the produce of the soil, the great landholders. There are, it is true, large tracts of land which, as royal forests, are available for the services of the state; but it is only within a recent period that sufficient attention has been paid to planting them, while the enormous demand for oak timber during the late long naval war had completely exhausted the stock which was previously growing upon them. It may not be deemed irrelevant to state the extent of this forest-land; at the same time premising, that there is much of it which is but ill adapted for the growth of good timber. the following account of these forests is taken from the Seventh Report of the Commissioners of Lands Revenue. It states the extent of the land in which the timber belongs to the crown in each of the forests to be :—

Acres. R. P.

In New Forest 66,942 3 26

Dean 23,015 3 29

Aliceholt and Woolmer 8,694 1 31

Whittlewood 4,850 3 32

Salsey 1,847 0 23

Whichwood 3,709 3 5

Waltham 3,273 3 2

>Shcrwood 1,466 3 10

Bere 926 2 13

Sulehay Walk in Rockingham Forest 860 3 23

115,594 0 34

“Of which total quantity about 70,000 acres are fit for the growth of oak timber.” The Report also gives a statement, which we shall quote, as forming a criterion, founded on authority, to judge of the produce of forest-land: “If 700 acres, or 1 / 100 , of this land were enclosed and planted every year, until the whole 70,000 acres shall be completed, they will, if kept under proper management, furnish a perpetual supply of at least 35,000 loads of oak timber annually, from the time that the first planted trees arrive at 100 years growth.” Table V. will give a good idea of the enormous consumption of timber which is entailed upon us by the extent of our navy. It may also be observed, that since the alterations in the system of registry at Lloyd’s, merchant-ships consume nearly as much timber in their construction as ships of war of similar burthens.

The effect of the gradual destruction of the forests is a question of a speculative nature; a question too speculative, and involving consequences too far distant from our own time, to admit of discussion in this article: still it may be thus casually adverted to, because it is not a stretch of the imagination to suppose the time must arrive when the forests which furnish the present supplies will be exhausted by the unceasing and increasing demand upon them, and by the rapid spread of population. But a very few years have passed since it was comparatively easy to procure fir trees from the north of Europe, of sufficient size to make topmasts for the largest classes of men of war. Now there are no trees from thence to be purchased which will make such topmasts. Until about thirty-five or forty years ago Riga inch-masts were to be obtained as large as twenty-five inches in diameter. At that time, from the increased difficulty in procuring them, Canada yellow-pine sticks were substituted, which could then be got with ease as large as thirty inches in diameter; but now it very rarely happens that a stick of larger diameter than from twenty-five to twenty-seven inches is imported, and even this timber of these sizes is gradually becoming more scarce. Until lately timber of sufficient scantling to make stern-posts for the largest ships was to be procured; now such logs are not in the market.

The first English writer on timber was the celebrated Evelyn, who published his “Sylva, or Discourse of Forest Trees,” in 1664. This book still continues one of the standard works on the subject in our language. In 1774 a new edition of it, with most extensive notes, and also engravings of the trees mentioned in the text, was published by the celebrated Dr Alexander Hunter of York. The last edition with these notes was published in 1825. In [7:21:290]France the two celebrated philosophers Buffon and Du Hamel have both devoted a great portion of their useful lives to the investigation of the physiology of timber, and their writings on the subject have long been the text-books of arborists. In modern times the phenomena of the growth of plants have occupied the attention of many men, some of whom have eminently distinguished themselves in this particular branch of natural history, and to whose works we shall have occasion to refer in the course of this article. The master-mind, however, in these researches, and the one whose indefatigable labours have left but few of the mysteries of vegetable physiology undeveloped, is Mr Knight, who was for several years president of the Horticultural Society, and whose valuable papers on the growth of plants in the Philosophical Transactions leave little scope for further investigation on several of the most important questions.

Botanists divide plants into two classes; exogenous, which are those that increase in their growth by an annual accession of matter externally; and endogenous, which are those that increase in their growth by an annual accession of matter internally: therefore in exogenous plants the external parts are the younger; and in the endogenous it is, on the contrary, the internal parts which are of the latest growth. It is almost entirely of the exogenous plants that we shall have occasion to treat in this article, the whole of the timber trees classing under that head.

The horizontal section of the stem of a plant of this description shows the perfect or heart wood occupying the central and larger portion of the area of the section. This wood must evidently, from what has been already stated, be of the oldest growth in the centre of the tree, and the several concentric layers must be younger in proportion to their distances from this centre. Around this perfect wood there is seen a concentric belt of yet younger growth; so young ns not yet to have attained to the maturity of the perfect wood. This belt is called the alburnum or sap-wood; around it is another concentric belt, called the liber; and this again is enclosed in the bark, or cortical substance, the liber forming an internal coating to the bark. The centre of the heart-wood is occupied by the pith; and there is a communication between the pith and the bark, that is maintained by what are called the medullary rays, which, as their name expresses, radiate from the pith, in the centre of the perfect wood, to the external coating of the tree, the bark. The outer covering of the bark is sometimes called the epidermis.

We shall now proceed to describe, in a general manner, the process of the growth of the plant, and the gradual formation of these several portions. The germination of the seed is a mystery of nature yet undeveloped; but when the seed has germinated, and the existence of the plant has commenced, the labours of physiologists have enabled us to trace the various processes by which its increase is effected. Mr Knight has related, in the papers which we have already mentioned as having been published in the Philosophical Transactions, a series of most conclusive experiments made by him, in order to ascertain the course of the sap, the manner of its deposition, and the method of its influence on the growth of the tree. He removed a ring of bark about half an inch in breadth, from a number of trees, and compared the growth of these trees with that of others not so treated. This was done early in the spring. The effects were, that although the branches shot, and the parts above the incisions in the incised trees did not appear to suffer, there was no increase in the parts below the incisions; and that while the upper lips made considerable advances towards establishing a reunion, the lower lips of the wounds remained without alteration. In the course of the summer the wood from which the rings of bark had been stripped, became dry and lifeless to some considerable depth beneath its surface, and several buds made their appearance below the incisions. In those trees in which a shoot produced by one of these buds was suffered to remain, the parts of the stem below the shoot very soon began to increase in size, while the part between the shoot and the annular incision still remained so nearly stationary as to be, in the autumn, almost a year’s growth less in diameter than the part of the stem above the incision. Mr Knight varied these experiments in many different ways, but in every case he found the result to be the same; that is, those parts of the stem and branches which were above the incisions, and had a communication with the leaves through the bark, increased rapidly; while those below the incision scarcely grew at all, but remained with little perceptible change, until a new communication was obtained through the bark with the leaves of a shoot from some bud below the incision; the increase of the timber thus evidently depending upon the growth of the leaves.

These experiments were so far conclusive as to establish that the current of sap which ran upwards from the roots, was not impeded in its passage by the annular incisions and the removal of the belt of bark; but that it was probably the downward current which was interrupted, and also that it was this downward current by which the annual increase of the tree was effected. By a series of experiments with coloured infusions, Mr Knight traced the upward current through the pores of the wood beyond the annular incisions in the bark, and found that it had neither coloured the bark nor the sap between it and the wood. He traced the coloured infusion along the leaf-stalk into the leaf, through one series of vessels; and he observed another series of vessels which were conveying a colourless fluid in an opposite direction, that is, out of the leaf. He traced this second series of tubes downwards, and found that they entered the inner bark, and, without having any communication with the tubes of the wood, descended through the inner bark from the very extremities of the leaves, apparently to the points of the roots. Mr Knight considers that there are two series of these descending tubes, one of which forms the new annual layer of alburnum, and the other the new annual layer of internal bark. It thus appears that the sap is conveyed upwards through the pores of some part of the wood, into the leaves, and that when there, probably by its exposure to light and air, and by the evaporation which takes place, it undergoes some peculiar process of elaboration which tits it for contributing to the sustenance and growth of the tree. It also appears that the cause of the growth is the deposition which takes place in the downward passage of this perfected sap. The sap, after this curious preparation in the leaves, is called cambium.

The same persevering physiologist then pursued his investigations a step farther. He took trees, and not only removed a ring of bark, but also a ring of the younger wood, to such a depth as to cut through and remove the whole of the alburnum. These trees did not exhibit the slightest symptom of vegetation in the ensuing spring; which fact evidently proved that the ascent of the sap had been prevented, and also that it had been prevented by the removal of the alburnum; for the previously-mentioned experiment had shewn that the removal of the bark was not attended with such an effect.^[1. This experiment is continually making on a far more extended and therefore more conclusive scale, in the removal of the whole of the bark excepting the liber, from the cork oak, Quercus Suber, which takes place once in about eight or ten years, not only without injury, but with actual advantage, to the tree, which vegetates with increased luxuriance. ]

It is the generally received opinion that the ascent of the sap through the alburnum is the reason that this gradually[7:21:291] becomes perfect wood, in consequence of the deposition of matter which then takes place, and fills up its pores; so that the rationale of the process appears to be, that the sap of one year deposits nourishment, in its upward passage, which strengthens the sap-wood or alburnum of previous years; that then, after being elaborated in the leaves, it becomes cambium, and in its descent adds bulk both to the alburnum and the bark. It must however be observed, that there is not in timber any appearance of a gradual change from alburnum to perfect wood. On the contrary, in all cases the division is most decided; one concentric layer is perfect wood, the next in succession is alburnum. Mr Knight gives it as his opinion, that “towards the conclusion of summer, the true sap, that is, the cambium, simply accumulates in the alburnum, and thus adds to the specific gravity of winter-felled timber, and increases the quantity of extractive matter.” He says he has “reason to believe that the true sap descends through the alburnum as well as through the bark: that is, that the superabundance of true sap is there deposited, and enriches the upward current of aqueous sap, or the sap of the ensuing spring.” In confirmation of this, he tested the ascending current of spring sap, extracted from the trunks of trees at various heights, and found that the specific gravity increased with the height, and that the taste also very sensibly altered. He argues from the foregoing facts, that by girdling trees in the spring, and suffering them to grow until the ensuing winter, the wood above the girdling would be increased in specific gravity. In one experiment, in which the belt of bark had been abstracted for several years, he found that the specific gravity of the wood above was 0∙590, while below it was only 0·491, and also that the alburnum had acquired a greater degree of hardness, and consequently of durability. This is important, for Du Hamel established by experiment very conclusively, that the strength of timber of the same species varied very nearly as its weight. There are many other theories as to the growth of plants, founded also on experiment, but we cannot, within the limits of this article, enter into the rationale of the whole of them. We have therefore taken this of Mr Knight, because, although there may be some points in it which may be objected to, we conceive that, as a whole, it probably approaches more nearly to the truth than does any other, and indeed leaves but little doubt upon the mind as to its general correctness.

There are not less than 140 species of oak known, and although there are many sorts cultivated and growing in England, botanists and arborists agree that there are principally two varieties; these are, the Durmast oak, and another, which is commonly called the old English oak, although both are supposed to be indigenous. In the Durmast oak, the Quercus sessil∣flora, the acorns grow in clusters close to the twig, and the leaves are set on short leafstalks: while in the old English oak, the Quercus Robur, or Quercus pedunculata, the acorns grow generally singly, at most two together, on stalks of from one to two inches in length, and the leaves are close to the twig, without the intervention of any length of leaf-stalk. These are the principal distinguishing marks between the two varieties. Many writers attempt to draw distinctions from the colour and shape of the leaves, and the colour and appearance of the bark; but it is doubtful whether these may be depended upon, as, from a careful examination of the evidence, it is more than probable that the colour and appearance vary much with the soil and locality. There is no doubt, however, as to the comparative inferiority of the timber of the Durmast oak. Almost all the English writers on timber have asserted it, and both Buffon and Du Hamel corroborate their assertions, and give a most decided preference to the oak bearing large acorns on separate stalks, over the oak bearing acorns in clusters; which characteris tics are just the distinguishing differences that have been particularized as existing between the English and the Durmast oaks.

In favourable soils the old English oak has seldom more than twelve to fifteen concentric layers of alburnum; but in the Durmast oak there are frequently from twenty to twenty-five or even thirty. This proves at once, by analogy, the inferiority of the Durmast oak; for it is an established fact, that the best hard-wood timber is that in which the proportion of heart-wood to sap is the largest; besides which, the numerous layers of alburnum form the basis of a proportion which shows the greater age the Durmast timber must attain before it becomes perfect wood. And therefore it is evident, that in order to attain large scantling, comparatively older timber must be felled, and consequently a greater risk be incurred of its being overgrown. The following table of the number of concentric layers of sap-wood observed in various species of timber trees is extracted from a valuable work on Naval Timber by Patrick Matthew; a work which abounds in much sound practical information, though mixed up with many things irrelevant to its subject.

Trees of Home Growth.

Common oak, some trees 10, others 14, others 18.

Spanish chestnut, 2, 5, 6.

Scotch elm, U. Montana 16, 25, 32.

English elm, U. campestris........ 0, 10 0.

Red-wood willow 8, 14, 0.

Laburnum 3, 5, 0.

Wild cherry 16, 24, 0.

Black Italian poplar 9 0, 0.

Scotch fir 20, SO, 40.

Pinaster 0, 10, 0.

White larch 5 , ...... 12, 18.

Trees of Foreign Growth.

Memel fir 0, others 44, others 0.

Red Canada pine 0, 100, 0.

Yellow Canada pine 38, 44 0.

Several of these, which are not cultivated generally as timber trees, are yet valuable, and are made available for local building purposes, and for the manufacture of the conveyances and implements for agriculture. Of these, the redwood willow may claim the first rank in utility. It is a timber much used in France in cottages and farm buildings, and it has the advantage of being very easily worked. The numerous varieties of the willow tribe are also useful in the manufacture of baskets. The woods of the laburnum, the cherry, and the apple and pear trees, are greatly used by cabinet-makers for articles of furniture.

Although in most parts of England there is soil favourable to the growth of timber, it may well be supposed that all soils are not equally favourable to all timber, nor will they produce timber of equally good quality. Thus in England the Sussex oak has always been celebrated as being superior to all other; and in France the oak of Provence enjoys a similar reputation. Still, an oak tree grown in a soil but ill adapted for it, as, for instance, a marshy soil, will retain its superiority of species over the inferior timbers, as the willow and the poplar, to which such a soil is less unfavourable, although in quality it will fall very short of the standard of perfection for oak timber. In fact, oak grown on such soils will in some measure partake of the qualities of the timber to which they are better adapted, and be of more open texture, of softer fibre, and of less durability than average oak timber. Oaks of slow growth, those, for instance, from the mountains of Scotland, and from Cumberland and Yorkshire, are proverbially hard and durable. The oak from marshy soils is often of a dull-red colour, or has “foxey” stains in it, as this incipient decay is [7:21:292]called. These stains are generally around the heart of the tree. Timber grown in loose soils is often what is termed “quaggy that is, the centre of the tree is full of shakes and clefts. Sometimes a shake will extend around a great portion of the trunk, between two of the annual concentric layers, so as to divide them from each other. This is called a cup-shake, and the timber is said to be “cuppy.” It is not attributable to the soil, but is supposed to originate in the effect of frosts on the aqueous sap in its ascent. When the alburnum of a tree has been wounded, or a branch improperly lopped or damaged, the subsequent growth of the tree will cover it, and it is then called a rind-gall, which, should the injured part have had time to become decayed, or partially so, or even sodden with the rains, will frequently cause an extensive rottenness in the plant. This is remarkably the case with elm timber. Doatiness, probably dottiness, which is a spotted or speckled appearance, like small stains in the wood, is most commonly a disease of beech timber; it is, however, occasionally seen in all, and frequently in the American oak. These diseases are in general incidental to the soil.

In treating of soils in connection with the qualities of the timber which grows upon them, it may be necessary to remember that the object is not to compare various sorts of timber, but to compare the differences in the same species in connection with the soils which produced them. It may also be observed, that as oak is by far the most valuable timber of English growth, the general inquiries we may enter into in the course of this article principally apply to it, unless other species of timber are particularized.

We have already casually adverted to marshy soils, and to the state of the timber grown on them. The grain of such timber is open, its colour of a deep yellow, sometimes with a tinge of red, especially towards the heart; the texture is soft, and the fibre coarse. The quantity of alburnum, and also of bark, is large in comparison with the quantity of perfect wood, and the outer surface of the bark is very coarse and rough. The wood splits easily, and when split it has not the same bright and varnished appearance possessed by the best timber. The chips from the axe do not cling well together, but fall into separate fragments; and a shaving or a small splinter may be easily crumbled between the finger and thumb. When such timber is weighed, although it is far more saturated with moisture, it is of less specific gravity; and when weighed after seasoning, the weight lost will be comparatively greater. Such timber, it is evident, will be more subject to decay, and to become worm-eaten, the softness of its texture inviting the attacks of these insects.

These peculiar characteristics attach more or less to timber grown in all soils which are of a moist nature, whether they are marshy, or wet from long-continued periodical inundations. They also apply to timber grown in deep sandy soil, in which almost the only nutriment for the roots is the water which percolates downward, and the bottom damps which rise upward through it. In all these soils the timber is of rapid growth, and the trees attain early to a large size. A similar result attends the timber grown in sandy soils on a clay bottom, for the water which falls not being able to penetrate the clay, cannot escape, and the roots of the trees are therefore virtually in the same circumstances as if they were growing in marshy land. As a general axiom, timber trees have an antipathy to stagnant waters; and therefore these observations on marshy soils, and on sandy soils with clayey bottoms, refer themselves to this fact. The soil generally the best adapted for the growth of timber appears to be a rich loam. This may have a considerable admixture of sand, without any apparent detriment to the timber. In such soils roots can penetrate and spread without difficulty, while the loam is capable of retaining sufficient moisture to dissolve and hold in solution the various substances that are found combined with it, so as to fit them to be absorbed as food by the roots of the plants. If the soil be too sandy, it neither retains the moisture sufficiently long in it, nor does it contain adequate nutriment. If, instead of a loam, some of the very stiff clays be mixed with the sand, they do not counteract this quality; for although such clay is capable of combining with a great quantity of water, it will not easily absorb and mix with it; and the tender roots have great difficulty in penetrating the masses of clay. For these reasons, soils composed wholly of stiff clay are not favourable to the growth of good timber, but the lighter clayey earth produces very fine oaks. As has been before stated, sand or gravel, with a large mixture of rich loamy earth, is precisely that sort of dry generous soil which affords ample nourishment to the roots of trees, and allows of their spreading themselves freely in search of it. Of all timber, however, oak accommodates itself most easily to soil; growing in almost every thing but sterile sand, if there be sufficient depth of stratum. Wherever oak will grow, even in those soils the least genial to its growth, it is a valuable timber. This fact cannot be too often pressed upon the attention of landholders. It is admirably adapted for planting in hedge-rows between arable fields, because it is found to be less destructive to the undergrowth than almost any other timber; and as its roots seek their nourishment deep in the soil, they not only do not impoverish the ground for the growing crop, but are themselves protected from any injury which they might otherwise sustain from the tillage. Oaks so planted require, however, to be protected during several years, as their early growth is slow. The timber grown in such exposed situations is seldom large; the trees are stunted and crooked; but this rather increases their value for ship-building purposes, as they convert as compass or knee timber. The timber of hedge-row oak is very close grained; that of park-grown oak is more open, and the trees being better protected, spread more freely and grow to a very large size, with strong lateral branches; while forest oak will frequently grow to a great height without pushing out any lateral shoots. Forest oak is invariably inferior in quality to that which grows singly; and in forests the trees that grow on the skirts are always the best timber. The oak flourishes in variable climates, which is probably the cause of the superiority of the English oak.

In whatever soil planted, each vegetable will retain its own peculiar characteristics. These apparently result from some property inherent in the plant itself, which leads it to extract only that nourishment from the soil which is appropriate to it. This has been illustrated by the example of a pea and a grain of wheat both planted in the same soil, and both treated in exactly the same manner: the corn will have absorbed silex from the earth, which will visibly form a component of its stalk, while the pea will not have taken up any. This indicates that at least a degree of selection with respect to their food is inherent in vegetables, without which indeed it would be difficult to account either for plants of various sorts all flourishing equally well in the same soil, or for others which cannot be reared in certain soils. This selection of food is however limited; for it is a well-ascertained fact that vegetable life is destroyed by the same poisonous substances that are fatal to animal life, and that plants do not possess the power of refusing to absorb such substances when mixed with the food in which their roots are plunged. Although the root of corn would absorb silex and the pea refuse it, they would both perish from the unavoidable absorption with their food, of substances inimical to animal and vegetable life. This is, however, merely saying that the vegetable is not possessed of greater powers of discriminating the beneficial from the hurtful, than is the animal under similar circumstances.

A curious fact connected with the supply of food for trees is also established, proving that there is not only a proportion between the spread of the roots and that of the branches of [7:21:293]a tree, but that the branches on any one side of the trunk of the tree are dependent for their support on the roots which protrude from the trunk on that same side. Both Buffon and Du Hamel found experimentally, that when the limbs and branches of any part of a tree showed symptoms of decay, the corresponding roots were invariably in a diseased state. They also found that on that side of a tree from which the roots had pushed most vigorously, the annual concentric layers of wood were thicker, and that consequently the form of a section of the tree would be eccentric towards that side.

The facility with which the roots of plants seek out for themselves the best localities, is surprising. If two trees of different species be growing on the edge of a marshy space, that tree which requires most moisture will push its roots towards the marsh, while that which requires a dry soil will push its roots into the dry firm ground. Du Hamel relates an instance in which he dug two trenches crossing each other at right angles; he then returned the soil into these trenches, and planted a tree at the point of their intersection. Some years after, upon examining the roots, it was found that they had invariably pushed into the four lines of trenches, leaving the intermediate undisturbed earth wholly untouched by them.

An equally important consideration with the quality of the soil, is its quantity, that is, its depth from the surface. In fact, in speaking of soils in connexion with the growth of timber trees, it must of course be understood that it is not merely the surface-soil which is meant, but that soil in which the roots of the trees would push and spread,—the soil for several feet in depth. It often happens that the surface-soil may be well adapted for tillage and for vegetation, and yet the sub-soil, that which is essential to the growth of timber trees, may be totally incapable of supplying them with nourishment. Trees which grow singly, as in hedge-rows or in parks, do not require equal depth of soil with those which grow in forests, because they have the power of spreading their roots in search of food. But for forest trees, either oak, chestnut, or beech, a depth of at least four feet of appropriate soil is absolutely necessary to produce fine timber trees. Elm and ash do not require so great a depth.

Buffon has given a scale for the ages at which it is desirable to fell timber. It is dependent upon the depth of soil in which it grows. He says that a depth of from two to three feet will not support a tree in a thriving condition for a longer period than fifty years. From three to four feet of soil will enable the tree to continue improving until about seventy years old; and in a soil from four to five feet deep it will flourish for a century. These periods are for strong and favourable soils. In lighter soils at least ten years must be taken from each period, and the timber will then also be inferior in quality. As a general rule, the more generous and favourable to the growth of the timber the soil may be, the longer it is advantageous to wait before felling it. Trees should never be allowed to become stag-headed, that is, to have their upper branches bare of leaves. It is in the top branches that the first symptoms of the decline of the tree are to be perceived. The leaves have a faded, weakly appearance, gradually diminish in number, and finally the branches become barren of foliage, and decay. The least appearance of want of vigour in the vegetation of the top of a tree should be the signal for its being felled; and even then it is also a sure token that the timber is past its prime.

The nature of the soil in a tract of country may be observed, either by opening it, or by examining the products. Thus, at all times of the year, if plants which grow only on marshy land are found on any tract, we may evidently assume that tract to be marshy land, whatever its temporary appearance may be. The nature of the sub-soils may often be ascertained by the ditches. The goodness of earth is easily tested by making an excavation in it. If the whole of the excavated earth can be returned into the cavity, the soil is poor, but if, on the contrary, there is an excess, its quantity is a sure criterion by which to judge of the richness.

In the preceding observations as to soil, moisture has been decried as unfavourable to the growth of good timber; but it must be observed, that a deficiency of moisture has also its evils, although they are not of the same kind as those which arise from a superabundance of it. Water is absolutely necessary to the growth of timber; for even if the soil be rich, and light, and well adapted for the reception of the roots, and for affording them nourishment, there must be sufficient moisture in it to form a vehicle for a supply of that nourishment, otherwise the trees will be of very slow growth, not from the lack of proper nourishment, but from the want of a sufficient supply. The timber does not appear to suffer from this in its quality, but in its size. On the contrary, indeed, wood of such growth is extremely heavy, hard, and dense, as, for instance, the Scotish mountain oak. Where there is a greater supply of moisture, the growth of the timber will be more rapid; and, in consequence, although its fibre will be tough, its grain even, and its colour the same as the other, the concentric layers will be thicker, and therefore there will be fewer of them in the same space; but, to compensate for this, we have in a less number of years an equal sized tree, which has the advantage when felled of being in its prime, while the tree of slower growth may have already, from great age, the defects attendant on what is called overgrown timber. There is also another point to be considered; the quicker the growth of the tree, the more it will shrink when converted as timber. Trees of rapid growth, therefore, are not fitted for any thing but large conversions. Timber of slow growth, and of considerable age, is by far the best adapted for panelling and for furniture.

These remarks afford an idea of the difference in the appearance of timber grown on good soil from that produced on bad soil. As to this difference, it may however be desirable to enter more into detail. An oak tree, grown on the soil adapted to the development of its best properties, not only has its concentric layers thin and close together, but they are also of very uniform thickness, and the texture of the grain is fine. When the wood is split it has a glossy varnished appearance, and is of a very pale yellow or straw colour. There is sometimes as much as one fourth difference in weight between samples of oak timber; and the heaviest loses a much less proportion of its weight in drying, and will also, if immersed in water, absorb Jess, than the lightest. The alburnum of the best timber is small in quantity, and the bark thin and of an even smooth texture. In breaking such wood, it produces a sharp decided noise. Having comparatively little moisture in its composition, and being less hygrometric in its nature than wood of more open texture, it is little subject to decay; and its grain being hard, it is not easily pierced by insects.

The great size to which oak trees will attain when favourably situated as to soil and locality, is truly astonishing. We will mention two instances as examples of this fact. One is the celebrated chapel-oak of Allonville in the Pays de Caux in France, which is still standing. The other is that of an oak which was felled in Monmouthshire in 1791. The oak of Allonville measures at its base thirty-five feet in circumference, and at six feet above the level of the ground it is twenty-six feet in girth. It is hollow, and the interior is fitted up as a chapel. This transformation was effected in 1696. The computed age of the tree is between eight and nine centuries. The other instance, the Monmouthshire oak, produced, when it was converted, the following enormous quantity of materials:—
[7:21:294]

The main stem, 91 feet long, when sided, 330 cubic feet. A branch 29 feet long, sided 17 inches, 58 —

— 24 — 19 — 60 —

— 19 — 17 — 38 —

The two main slabs produced 86¼ feet of

3 inch-plank; other conversions; in all, 216 —

13 sided knees, taken together, 217 —

Other minor but useful conversions, 276 —

Total, 1195

the weight of which was nearly 30 tons. The bark weighed 3 tons 17 cwt. 3 qrs. There were 31¾ cords of cord-wood, 84 hogshead, 67 barrel, and 106 kilderkin staves, 256 coopers’ ends: 28 hogshead, 38 barrel, and 49 kilderkin heads were also converted from the slab wood.

The largest oak on record grew in Dorsetshire. It was called Damory’s Oak, and was used as an ale-house. It was sixty-eight feet in circumference, and the room formed in it was sixteen feet in length. This tree was blown down in 1703.

As a general average of the size of oak timber, 56 cubic feet for each end or log of rough timber, and 30 cubic feet for each end of sided timber, may be assumed as tolerably correct. In order to convert rough timber into sided timber, about two thirds the diameter of the rough log, in the middle of its length, is assumed as the most advantageous siding; and, on an average, it is estimated that not above one third of each log or end of rough timber is used in the principal conversion from it, and this principal conversion is estimated to be about three fourths of the total conversions.

In consequence of the great value of the bark of oak, it is the practice to fell the timber in the spring of the year, because then the bark is easily detached from the tree, while the bark of winter-felled timber is lost. There can be little doubt, however, that the durability of the wood is much deteriorated by this practice. It was a received opinion among the ancients that timber should be felled in the fall of the year; and not only do modem experiments confirm this opinion, but modern discoveries as to the flow and return of the sap, and its nature at various seasons, tend to show the reason for its correctness. The practice which almost all the eminent arborists have recommended, and supported by their experiments, is to bark trees standing in the spring, and then allow them to remain in this state at least one twelvemonth. This was not an uncommon practice in some of the midland counties of England, and was first strongly recommended in the reign of James the Second by Dr Plott, an arborist of great celebrity at that time. Buffon presented a memoir in 1738 to the Royal Academy of Sciences in Paris, “on increasing the Solidity, Strength, and Durability of Timber for which purposes it was recommended to strip the tree of its bark during the season of the rising of the sap, and then to leave it to dry completely before being felled. Du Hamel gives most minute accounts of experiments made by himself, all tending to the same conclusion; and Dr Hunter, in his notes on Evelyn’s Sylva, says, “that by stripping off the bark, and allowing the tree to stand and die before it is cut, the sappy part becomes as hard and firm as the heart.” Here is a collection of opinions, of such weight, that the general fact which they assert must be considered to be established beyond contradiction. Buffon also says that he caused pines, firs, and other species of evergreens, to be barked standing; and as he found them live longer after the operation than oaks which had been also stripped, he considered their wood acquired proportionately greater hardness, strength, and durability. He recommended the practice for fir trees destined to be converted into ships' masts.

Elm, of which there are two principal varieties, like oak, will not bear a damp soil with stagnant waters, but it thrives well in moist declivities, provided the land be not too rich. The trees grown on too damp a soil either die prematurely, or their timber is of a soft spongy nature, and prone to decay. There are two British varieties of this timber, the Ulmus Montana, or Wych elm, and the Ulmus campestris, or, as they are sometimes called, the Scotish and the English elms. Of these the Wych elm is decidedly the most valuable as timber, and, when used in situations where it is kept constantly moist, is extremely durable; but no elm timber will bear the trials of change of temperature and moisture to which oak in all its varieties is comparatively insensible. The close and interwoven grain of elm, the absence of decided longitudinal fibre, and its power to resist rending from exposure to the heat of the sun, and the alternations of weather, cause its timber to be very useful for small articles, such as the blocks used in the rigging of a ship. It is valuable in many parts of the millwright’s machinery, where the wood is subjected to great friction. It is also valuable and much used both for the timbers and for the planking of ships below the surface of the water; and the planks of clinker-built boats are very generally of elm. There is one peculiarity about elm timber, namely, that the alburnum or sap-wood is possessed of nearly equal power to resist decay with that which is matured; that is, when both are used in situations where they are not exposed to alternations in moisture. A variety of timber has of late years been introduced into the market under the name of Canada elm, or American rock elm. It is a smooth, even textured, pale coloured, and strongly fibrous wood, almost devoid of knots, and admirably adapted for boat-building, and all works which require a flexible and close-textured wood. The Canada elm appears to have many of the peculiarities of toughness and flexibility which distinguish the ash.

Chestnut, Fagus castanea, and Beech, Fagus, appear to suffer the least of all the timber trees from being planted in moist sandy soils; but as the chestnuts push their roots far downwards, they require a proportionate depth of soil. The roots of beech, on the contrary, spread widely, but without going to any considerable depth. Beech is a timber which easily adapts itself to and flourishes in almost any soil. Even among rocks its roots will, like those of firs and larches, insinuate themselves into the smallest fissures, and find means to extract sufficient nourishment to produce a useful timber. Beech-timber, when used shortly after being felled, and for works where its dampness will be continued, is a long-enduring wood. It is largely applied in the mercantile navy, for the lower planks of the bottom of ships. The best variety has its wood of a yellow tinge. Chestnut is even a more durable timber than oak, and was much used formerly; but the cultivation of it has been so neglected that few trees remain in this country. Ash, Fraxinus Excelsior, which is another valuable timber tree, accommodates itself to all soils. It will grow in marshy grounds and in arid lands, in depth of soil or in shallow soils. It will push its roots into hard gravelly bottoms, and even into the sandstone rocks; but the ash-timber from very poor soils is brittle, and loses the elasticity which is the valuable peculiarity of this wood. Ash is a very useful timber for carts and implements of husbandry, for machinery, for tools of almost all trades; and it supplies oars to our shipping. Of late it has also been much used in the construction of the beds for locomotive steam-engines, tenders, and carriages.

In consequence of the immense consumption of timber for the maintenance of our fleets, there is much imported. We import oak of excellent quality as planking, from the forests on the shores of the Baltic, especially from those of Poland. From Italy and from both shores of the Adriatic, sided timber and plank are imported in large quantities. the Italian timber is extremely subject to rends, but is both strong and durable; and the Adriatic oak has been [7:21:295]celebrated for centuries. The Americas do not produce fine oak timber; but considerable quantities are imported from Canada, in consequence of the lowness of the price at which it can be sold in England. There are two sorts of oak growing in America, the white and the red, but both are very inferior to European timber. There is, however, an American oak, called the live oak, produced principally in the Floridas, which has the character of being among the most durable timbers in existence. It is said to be comparatively incorruptible, but it is not a timber much known in Britain. The great resource of our dock-yards for timber of large scantling is an African timber, called Tortosa, more commonly only “African.” It is a heavy, hard, close-grained, and even textured wood, well adapted for beams, and for internal works, but does not resist alternations of moisture, and deteriorates rapidly whenever it is in contact with iron. The wood round the bolt-heads is carbonized in an incredibly short space of time—incredible when the strength, texture, and hardness of the wood are considered; but it appears to be a timber wholly without any protective oleaginous or terebinthinous juices. There are several species of timber that are much used in Britain in the construction of merchant-ships, but which are unknown in the royal dock-yards. We shall in a subsequent portion of this article notice these, for the purpose of showing their relative values. We consider that the most satisfactory course we can pursue to effect this object, without occupying more space than can be appropriated to this article, will be to give the tabular arrangement of woods, as enforced by Lloyd’s surveyors, under the direction of the committee of that establishment.

We have hitherto confined our remarks to the hard-wood timber trees, and have said but little of the numerous firs which are so valuable to us. Their timber is admirably adapted, by its growth, lightness, and strength to supply our navies with masts and spars; while, from its comparatively small cost, and the ease with which it is worked, it is also used very largely for all purposes of building. Indeed it is questionable whether fir is not more generally useful to us than any other species of timber. Du Hamel, in his treatise Du Transport et de la conservation des Bois, has drawn a distinction between firs and pines, although it is usual to designate the timber of both as fir timber. Pines, he says, have the leaves thready and slender, growing in clusters from the same leaf-stalk, while firs have straight leaves, each growing separate, but many growing on the same leaf-stalk, like the teeth of a comb. These are the general characteristics between the two sorts of trees which produce fir timber. The pines grow with their trunks much less tapering towards their tops than the firs; they are therefore, from shape, more adapted for masts than firs. Their wood is also more resinous, and the resin is of a more glutinous nature, and therefore less easily evaporated; it also, in consequence of this quality, enables the timber to resist better the absorption of water or moisture when exposed to it. The pine is more durable than the fir, and its fracture is, even when partially decayed, much more fibrous, and takes place with more previous warning. The timber of the pine, when healthy, is close-grained, even textured, and of a bright-yellow colour. The fir is, although frequently little inferior in appearance in other respects, always of a much paler shade of colour.

The most valuable of all the varieties of fir timber is that which is called Riga fir. It is the red-wood pine of the north of Europe, the Pinus Sylvestris, which, although spread over a very large portion of the globe, appears to flourish in its greatest perfection in the forests of Lithuania and Poland, where the cold is severe and the soil generous. Riga fir is not only extremely flexible and elastic, but is by far the most durable of all the pine timbers; and as long as it could be procured of sufficient size, it was therefore generally used in the royal navy not only for topmasts, but also to build the lower or standing masts. At present, from the increased difficulty of procuring large sticks, the use of it is confined to topsail-yards and the smaller description of spars. The American continent also produces this red-pine timber of good quality, although much inferior to that of the north of Europe. It is imported from Canada and from Virginia. The Canadian red pine is of small size, seldom exceeding fourteen hands. The Virginian pine is large, sticks of twenty-four and twenty-five inches in diameter not being uncommon. It is a resinous and flexible wood; but the sticks are more subject than the Canadian red pine to the defect of having large knots in them, which, from not being firmly united to the surrounding timber, that is, not being what is technically called “well collared,” injure its value. The red pine thrives extremely well in Scotland, where it is called Scotish fir. There are many extensive forests of it in that part of Great Britain, but the timber will not bear comparison with that which is imported. Notwithstanding this, Du Hamel makes “Scotish pine" the generic name of the best variety of the pine timber, that which we designate as “Riga.” The French dockyards are supplied with mast-timber from the red pine of the Pyrenees and of the island of Corsica; but neither of these varieties of this timber is considered at all on an equality with that which is grown in the more northern parts of Europe. Indeed a low temperature of climate appears to be essential to the production of superior fir timber. The firs on the northern sides of hills and mountains, in all temperate climates, thrive better than those growing on the southern exposure, and even the timber on the northern side of an exposed fir tree is far superior to that on its southern side.

Yellow pine, the Pinus Strobus, which is imported from Canada, is the principal timber now available for large masts and yards, and is therefore very generally used both in the royal and the mercantile navies. It has neither the flexibility nor the elasticity of the red pine, nor is it so durable, but it is much lighter. Its great recommendations are its large size and its comparatively small cost. Sticks of this timber run from sixteen to twenty-seven or twenty-eight inches in diameter; and for bowsprits they are sometimes received in the royal yards as large as twenty-nine and thirty inches in diameter; but sticks of these large diameters are becoming very scarce. To Mr Cradock of Portsmouth dockyard, a member of the late School of Naval Architecture, we are indebted for the following information as to the more extensive application of this species of fir for spars of all sizes in the American navy than in our own. In June of the year 1837, he surveyed the mast and spars of the American frigate Independence, then lying at Spithead. “They were generally as large, and in some instances the spars were larger, than those of the Britannia, a British first rate; and the whole of them, without any exception, were made of yellow-pine timber. Her topgallant-masts were about twenty feet longer than those of the Britannia, and yet were only of the same diameter, while those of the Britannia are made of Riga hand-masts. The topmasts were of the same length and diameter as those of the Britannia, which are made of Virginia red pine; the topsail-yards were three feet longer, and were yet only one inch more in diameter than those of the Britannia, which of course are made of Riga; and so on with the other spars. This proves, that the yellow-pine timber may be safely used if necessary for all masting purposes, with a very little increase in the diameter of the spars made from it, and with thicker battens on the yards.”

The yellow-pine timber grows also in Great Britain, where it was first introduced by an earl of Weymouth, and thence is called the Weymouth pine; but it does not appear to thrive in this climate.

Scotish and Norwegian spruce spars, Pinus Abies, are very [7:21:296]generally used in the mercantile navy for yards and topmasts, and also in the royal navy for the smaller description of spars and boats’ masts. They are tough, close grained, and elastic, but are very full of large knots; and care is therefore required in selecting them. The timber also is soft and far from durable, it having very little appearance of resin. The Norwegian spruce grows frequently to a large size.

Cedar, Pinus Cedrus, would be among the most valuable of all timber trees, were it sufficiently common to be available for building purposes. It is almost indestructible from time, and no insects will ever attack it. It thrives well in this climate, but hitherto has only been planted either as an object of curiosity or of ornament. It requires a more generous soil than any other of the tribe of pines, and is considered to be a timber of very slow growth. Pitch-pine is also a very valuable timber for building purposes, but it is too heavy for spars.

Fir sticks, the Riga hand-masts especially, are very liable to have serious defects in them, which it is often impossible to discover until the stick is worked. They are technically called upsets. The grain appears to be partly separated, so that a shaving from the stick at that place would bend to a sharp angle at the upset, as if partly broken. There always appears to be a greater or less accumulation of the turpentine about the injury, as if it had originally exuded at the wound, and become congealed around it. These defects are most frequently found in the smaller sticks, those especially that are more resinous and knotty than others; and they sometimes are so numerous as to extend, at very short distances apart, for a great portion of the length of the stick. Mr Cradock, who has long superintended the mast-making at Portsmouth dock-yard, considers them to be the effect of violent winds on the more exposed trees of a forest. He founds this opinion on the facts that they are most common in the most flexible timber; that they are not perceived in sticks of large diameter; and that in the firs of little flexibility, as the yellow pine, they are seldom or never found; although the sticks of this fir, from being cut in every variety of direction, to form the components of made-masts, are more searched than any other. The cowdee, a New Zealand timber, lately introduced both in the royal and mercantile navies, is, he says, much subject to this defect; and he has observed it once in a poon topmast. The defect seldom or never appears in the outer layers of the timber, but only after some of these have been removed by the axe, and the older timber laid bare of the sap-wood.

The sap-wood in all fir timber is useless, and very generally there is a large proportion of it in comparison to the quantity of heart-wood. It is rather a curious fact, that there appears to be a difference between the pines and the generality of the hard-wood timber in this, that a small proportion of sap-wood in fir is indicative of the inferiority of the timber. Thus the red pine of Scotland has fewer layers of sap-wood than either the red pine of Canada or of the Baltic. As a general remark, it may be stated, that the greater the quantity of sap-wood there is about a tree of any description of fir timber, the better will be the quality of the spine, which is the technical name given to the mature wood.

The cowdee, which is now largely imported into this country, is a close and even-grained timber, almost entirely free from knots. It grows to so large a size as to be available for the topmasts and other principal spars of the largest classes of vessels; but from its want of elasticity, and its liability to warp and rend, it is not so suitable for small conversions. It varies greatly in its quality, even so much as often to be of different colours, grain, and texture, in the same stick. It is of about the same average weight as Virginia red pine

Larch timber, Pinus Larix, formerly unknown in Great Britain, has, within the last century, been very extensively planted. The first plantations of it were made on the vast estates of the duke of Atholl, in the Highlands of Scotland. The following account, which is extracted from Knowles on Preserving the Navy, was, as the author of that work states, furnished to him by the late duke, and it contains, consequently, the results of the longest experience as to the growth of larch timber in Britain which can be obtained. The account is interesting, because plantations of larch are becoming very numerous, as they are found to be very profitable. The returns from a larch plantation during the time the trees are arriving at their full growth, are estimated to be at least double what they would have been from an equal plantation of any other timber. “Seedlings of larch were probably first brought into Scotland in the year 1738, by Mr Menzies; but it has been asserted by some, that they were introduced into that part of this country in 1734, by Lord Kames. Some were left at Dunkeld, and some at Blair Athole, by the former gentleman; and being exotic plants, were placed by the gardeners in green-houses. Not thriving in those situations, they were planted in the pleasure-grounds, where they grew luxuriantly. When the present duke succeeded to the titles and estates (in 1774), there was a considerable number of trees in a thriving state; and on a general survey of his estates in 1783, there were found to be 900 Scotish acres of plantation, 600 of which were of larch; since which time his grace has planted extensively every year, and in the spring of 1820, 10,820 Scotish, or about 12,984 English acres, were covered with trees. The different species were, of

Scotch Acres.

Oak 800

Scotish firs . 1,500

Spruce firs 500

Mixed plantations in the pleasure-grounds 200

Birch 200

Larch 7,620

10,820

“The larch thrives in very exposed situations. The lower range of the Grampian Hills, which extends to Dunkeld, are at an altitude there of from 1000 to 1700 feet above the level of the sea. The larch trees are planted as high as 1200 feet up these hills, and grow exceedingly well; a situation where the hardy Scotish firs cannot rear their heads. The spruce fir, however, thrives equally well as the larch on high and exposed hills. The growth of the larch trees is very rapid, and Scotish fir of the same age will measure only half the quantity; and so much is the wood esteemed in Scotland, that while the former is worth 2s. 6d. per cubic foot, the latter brings only 1s. 3d. The following account of a larch tree, planted in the year 1738, and measured February 1819, will give some notion of its growth.
[table]

“The top was fifteen feet in height, making the whole height ninety feet; and the tree measured 300 feet, or six loads, in cubical contents. The white and red larch trees are those chiefly planted. The duke has made trial of the black or American, and also of the Russian larch, but has found that they do not thrive well. The timber in question has been used for many years in Scotland for almost all local purposes, such as posts, rails, mill-wheels, fishing [7:21:297]and ferry-boats; and in all these situations has been found to be very durable. The author has seen part of a ferry-boat twenty-three years old, which remained very sound, and the iron nails driven into it as perfect as when they first came from the forge. This perhaps was occasioned by their being constantly covered with an insoluble varnish (the Venice turpentine of the shops), with which the larch abounds. The duke of Atholl has recently built a vessel of 170 tons w holly of larch, the necessary knees and crooks being formed from the roots of the trees; the lower masts and boats are also of that wood, the topmasts and yards of spruce firs grown upon his estates. One of the qualities of larch for building merchant-ships, is its great lightness, a cubic foot weighing, when seasoned (which it does rapidly), only thirty-four pounds. Although it is not so strong as many sorts of wood, it has great resilience. Cabinet-work of great beauty has been made from larch; it polishes well, and when seasoned is not found to warp or shrink. In addition to its other properties, it is slow of combustion, and is said to let shot through without splintering. A most important fact in agriculture has arisen from planting larch trees on rocky ground; the vegetable compost formed thereon by the falling of the leaves has been the cause of producing herbage for feeding cattle, and made that land which on the average did not formerly bring more than 8d. or 9d. per acre, now to be worth from 12s. to 14s. per acre annually.”

Larch timber, although so generally planted, and so generally thriving, requires considcrable attention in the selection of proper soil for it. It is very subject to a heartrot, which seizes on the roots, and rapidly proceeds up the centre of the stem of the plant, which swells considerably for several feet above the surface of the ground. Larch cannot bear a cold, damp soil, or any stagnation of water, or even the moisture of the rich vegetable moulds. Nor will it thrive in the light sandy soils; for although it dislikes marshy stagnant waters, its roots require to be preserved from the droughts of summer. Sandy and gravelly soils, if situated so as to receive from declivities the moisture percolating through them, will produce excellent larch timber; as will also the sides of rocky hills and mountains, in which no moisture can stagnate, and into the fissures and clefts of which the roots easily penetrate, and find ample nourishment. Larch trees attain to a very great height. In some of the public buildings of Venice, there are said to be single-pieced beams of larch which are 120 feet in length. It must be very durable, for it is almost the only wood which was used in the palaces and public buildings of that city. Larch is imported from Canada under two names, hackmatack and tamarack; at least the timbers bearing those names have every appearance of being identical with the Scotish larch.

On the Measurement of Timber.

Timber is bought and sold by solid measure, according to the number of cubic feet in the tree or log. The measurement of timber is therefore the operation by which these cubic contents are determined; that is, the multiplying together the three dimensions, or the mean length, the breadth, and the depth of each log. If the log should vary much in size in different parts, then the length, breadth, and depth of each of these parts must be multiplied together, and the contents of the log will be the sum of the products. When the log tapers, a mean breadth or depth is taken; the object in every case being to attain the most correct approximation to the contents of the log. In measuring rough logs, it is however usual to gird the log at the measuring place with a string, and then, folding the string into four equal parts, to assume this fourth part of the girth to be one side of the square area at the measuring place; which area, when multiplied by the length, will give the solid contents of the log. The arithmetical operation, simple as it is, is universally superseded by the more simple and far more correct plan of referring to published tables of contents, calculated for every foot in length of a log, and every quarter of an inch in the side of the square. Those most generally used for this purpose are in Hoppus’s Practical Measurer.

In measuring standing timber, the length is taken as high as the tree will measure twenty-four inches in circumference, less than which measurement is not considered as timber. At half this height, the measurement for the mean girth of the timber in the stem of the tree is taken; one fourth of this girth is assumed to be the side of the equivalent square area. The buyer has in general the option of choosing any spot between the but-end and the half-height of the stem as the girding place. All branches, as far as they measure twenty-four inches in girth, are measured in with the tree as timber. An allowance, which varies according to circumstances, is generally deducted for the bark. In oak it is from about one tenth to one twelfth of the circumference at the girding place; in other sorts of timber it is less. In all, however, this allowance depends much upon special agreement.

It is usual to speak of timber by the load, which means fifty cubic feet of squared timber, or forty cubic feet of rough timber. A load of plank is dependent upon its thickness. Thus it will require 200 square feet of three-inch plank to make the load of fifty cubic feet; therefore the load of plank is the number of square feet of its respective thickness, which is necessary to make the load of fifty cubic feet. Deals are measured, according to their thickness and lengths, by the hundred, reckoning 120 to the hundred.

The practice of receiving and measuring timber for the use of the royal navy is more specific and strict in its detail than that which has been described; and as the customs of the public service in this branch of commerce must greatly influence the timber market, we shall proceed to give an outline of them.

Rough oak timber must be so hewn or squared, that at each measuring place the width of the surface or square shall not be less than one fourth the diameter of the piece at the place where the measurement is to be taken. The lengths for measurement are regulated by the several stops or joggles. Each piece of timber is measured for contents, by calliper measurements, as far as the spine^[2. Spine is the technical term used to designate the perfect wood. ] will hold twelve inches in diameter; and no tops are received excepting the spire and one other limb, remaining on the piece, and admitting of being converted with it. These limbs are only measured as far as they will hold twelve inches in diameter, unless the timber will convert as compass timber, in which case it is measured as far as it will hold nine inches in diameter.

Rough elm timber is measured in the same manner as the oak, excepting that the piece is measured as far as it will hold nine inches in diameter.

Sided timber, which may be defined as the rough log with two and opposite slabs sawn from it, is measured according to the following conditions. The term “siding” is synonymous with thickness, and the term “moulding” with breadth. It must measure at least twelve inches in parallel thickness. The moulding at the but-end must not exceed the siding by more than one half. The moulding at the middle of the length must not exceed the siding by more than one fourth, nor by less than one eighth; and the moulding at the top-end must not exceed the siding by [7:21:298]more than one eighth, nor be less than the siding. The piece must be fairly tapered from the but-end to the middle of the length, and must not have more than four inches in the two wanes taken together on either side; that is to say, if there be but one wane,^[3. Wane is the technical term used to designate the hypothenuse of an angular portion of timber which is wanting to complete the rectangular boundary of a log; while pane is the term applied to the side of the log between the wanes. ] that wane shall not exceed four inches. The piece must be so sided, that between the wanes, at half its iength, there shall not be less than the siding with one eighth in addition, and the pane at the top-end must not be less than two thirds the pane at the middle of the length. The piece is measured for contents as far as it holds between the wanes three fourths of its siding. It must be so hewn the moulding way, that the surface of the square shall not be less than one fourth the diameter of the piece at that place, and this dimension must be set off previously to the diameter for measurement being taken. No but-length is allowed, but the timber is measured for contents at the middle of the length. If any piece of timber has length beyond the prescribed proportion of pane, and which is really convertible with the piece, it is received at a reduction of price. Timber having five inches or more of naturally grown rounding in any twelve feet or less of its length, is denominated compass timber.

Timber of certain sidings must have at least certain proportionate lengths. These are as follow:

Siding. Length.

20 inches to 19½ must be at least 24 feet.

19 18½ 22 ...

18 17½ 20 ...

17 16½ 18 ...

16 15½ 16 ...

15 14½ 14 ...

14 12 12 ...

12 10 10 ...

Compass oak timber is measured in the same manner as straight timber, with the exception that its moulding must not exceed its siding less than one fifth of that siding; and that the moulding at the but-end is to be measured as large as it will hold without more than four inches on the two wanes on either side taken together.

Thick-stuff is a name used to designate all planks beyond a certain arbitrarily assumed thickness, which is now four and a half inches and upwards, to ten inches inclusive. All below four and a half inches in thickness is called plank. It must be cut straight and of a parallel thickness, and the breadth for measurement, which is taken at half the length of the piece, must not exceed nineteen inches nor be less than twelve inches clear of sap. This breadth, at the middle of the length, is measured by taking in half the wanes, thus, provided the breadth clear of the sap is within two inches of the breadth at which the piece is received. No thick-stuff can be received of less length than twenty-three feet, at which length it must measure nine inches clear of the sap; and all extra length, as far as it measures nine inches between the sap, is measured into the contents.

The rules for measuring thick-stuff and plank vary slightly, in order to accord with the growth of the sort of timber from which they are converted. For example, in the case of Lorraine oak thick-stuff, the minimum length is twenty-four feet; the measurement for breadth, which must not exceed eighteen inches, nor be less than fourteen inches, is taken at eight feet from the but-end of the piece. The piece must be square edged from end to end, and must measure nine inches at the top-end clear of sap on the most sappy side. English elm thick-stuff of five inches and four and a half inches in thickness, must not be less than fourteen inches broad in the middle of the length, nor less than twelve inches broad at the top-end clear of shakes and dead sap. The planks must average twenty-six feet in length, and no plank may be of less length than twenty-three feet. North American rock elm thick-stuff of five inches and four and a half inches in thickness, is received at twelve inches broad, clear of shakes and sap, of the average length of twenty-eight feet, but none shorter than twenty-four feet in length.

English oak plank of four inches thick must be at least twenty-two feet, and of three inches thick at least twenty feet in length. The breadth between the sap at those lengths must be seven inches, and the plank is measured as far as it holds six inches clear of sap. The breadth for measurement, which is taken at half the length of the piece, and clear of sap, must not be less than nine inches for the four-inch plank, and eight inches for the three-inch plank. This is taking in half the wanes, provided the breadth clear of sap be within two inches of the breadth at which the piece is received.

Dantzig oak plank of four and a half and four inches thick is to mete at thirty-two feet long, with a minimum length of twenty-four feet. It is to be from twelve to fifteen inches broad, and cut square edged its whole length. Plank of three and a half and three inches thick is to mete at twenty-eight feet long, with a minimum length of twenty-four feet, and to be from twelve to fourteen inches broad. Lorraine plank must be square edged from end to end. No plank of four inches in thickness is to be less than twenty-four feet in length, or more than sixteen inches or less than thirteen inches in breadth, at seven feet from the but-end. The length is to be measured for superficial contents as far as the plank runs eight inches in breadth, clear of sap on the most sappy side. For three-inch plank, the minimum length is twenty feet. The breadth at six feet from the but must not exceed sixteen inches, nor be less than twelve inches; and the length is to be measured for superficial contents, as far as the plank runs seven inches in breadth, clear of sap on the most sappy side. The sap on the two edges taken together on either side of this plank, after the edge is squared, must not exceed one inch; that is to say, if there be no sap on one edge, that on the other edge must not exceed one inch.

Fir timber received for general purposes is measured for its size at the middle of its length, and the size for measurement must be the mean of the sizes taken at the but and top, and the spine must be seen on the four sides from end to end of the piece. The red-pine timber, whether from the north of Europe or from Virginia, is not received of less length than eighteen feet, nor less in diameter than eleven inches. The Canada red-pine timber, which must be felled above Montreal, must not be of less length than twenty feet. The North American yellow pine must be at least twenty feet in length, and sixteen inches square. That which is received for the cheeks of made-masts is required to run as high in dimensions as sixty-three feet in length, and cighteen inches square at the measuring place.

Fir that is received especially for mast-making is required to be of certain proportionate dimensions. It is divided into two sorts, inch-masts and hand-masts. The inch-masts are designated according to the number of inches they measure in diameter at a measuring place called the partners, after they have been chopped on each square, so as to show spine; and their length must be nine feet more than three times the number of feet which they have inches in diameter. The distance of the partners from the but-end is in a given ratio to the whole [7:21:299]length of the stick. Between the partners and the top-end certain measuring places are determined, at each of which places, called “quarters,” the diameter of the stick must be in a given proportion to the diameter at the partners; and all these conditions must be fulfilled before the stick can be received at the number of inches first assumed as the diameter at the partners. If the sticks are intended for yards, the measuring place is at the slings, in the middle of the length, and the stick is measured from that point towards each end, the quarters being set off each way. If the sticks are intended for bowsprits, the given diameter is at the bed, and the quarters are set off towards each end.

All these proportions for masts, yards, and bowsprits, are determined from tables which have been drawn out for the purpose, and framed to suit the peculiarities of the growth of the various sorts of timber to be applied to these different uses.

Hand-masts are measured in their round state, according to the number of hands they are in circumference at the but, the hand being four inches. Their length must be cighteen feet more than three times the number of feet that they are hands in circumference, and the top-end must measure in circumference two thirds of the measurement of the but. Sticks which measure less than six hands are received under the general name of spars, and are designated as cant, barling, boom, middling, and small spars, according as they measure above five, four, three, two, or one hand respectively.

On the Woods of India.

The following account of woods, the growth of our possessions in the East Indies, is compiled from a series of reports with which the writer of this article was favoured, through the enlightened liberality of the Court of Directors of the Honourable East India Company, and also from a paper in the Asiatic Annual Register, written by Daniel Lambert, Esq., which accompanied those reports. The reports were made to the honourable court by their surveyor of shipping in Bengal, John Millingar Seppings, Esq., a son of the late able surveyor of the royal navy, Sir Robert Seppings. The account embodies all those points in the reports which contain information consistent with the purpose of this article; and, as nearly as has been possible in such a compilation, in order to insure correctness of information, the language of the reports has been adhered to. The report of the experiments made by Captain H. C. Baker has been given entire, as it would not admit of condensation; but in order to economize space, only the mean results of the experiments have been printed; and the number of experiments of which the given results are a mean, has been inserted in the table.

We have also been enabled, through the great kindness of a friend, to enrich this article by a most valuable tabular series of original observations on the effect which seasoning produces on almost every species of timber that has been treated of in the course of the foregoing remarks: to which are appended some most interesting and judicious observations and deductions by the author of the table, Mr Bennett, of her majesty’s dock-yard at Portsmouth, a member of the late School of Naval Architecture.

The woods used in India for ship-building are, teak, saul, sissoo, jarrol, poon, and toon. Teak is the most durable among these timbers, but it varies very much in quality. There are two kinds of the Malabar teak, the northern and southern; the first is far superior in point of durability, but is the most difficult to procure. The Malabar teak is classed at Bombay as follows. No. 1, Northern, curved timber, which is brought a distance from Bombay of from 130 to 140 miles; No. 2, Southern, Calicut teak;

No. 3, Northern Pattey, or straight timber, used for small vessels and boats; No. 4, Bassein, or curved timber.

The great length of time which several vessels built of Malabar teak have lasted (from thirty to fifty years, in some particular instances nearly a century) has established the prime Malabar northern teak as the most valuable timber in the world for ship-building. It is, however, like every kind of wood, liable to early decay, if not properly or gradually seasoned, by exposure to a moderate current of air after being felled. Malabar teak is so seldom imported into Calcutta, from the expense of bringing it round Ceylon, and on account of the distance, that it may be said never to be used there for ship-building.

Pegu and Moulmein teak is extensively used by the ship-builders of the Hooghly, and is the only description of teak timber imported in any quantity to the Calcutta markets. It is brought in a half-wrought state, the logs or planks being squared. Pegu and Moulmein teak is a coarse, porous, open-grained wood, when compared with Malabar teak. It is not a timber which can be depended upon, particularly that which is of a pale-brown colour, which frequently goes very rapidly to decay. It is also of such a mixed quality, and the importation to Calcutta is so limited, that it is frequently difficult to select sufficient prime dark timber out of all the cargoes to build a ship of 200 tons burthen. Its weight, when moderately seasoned, may on an average be stated to be forty-two pounds per cubic foot, while the weight of Malabar teak on an average is from forty-five to fifty-two pounds per cubic foot. The forests of Tonga and Irrawaddy supply the whole of the Pegu teak. That of the Tonga forests is of the best quality, the country being high, and not flooded during the rainy season; whereas the forests of the Irrawaddy are always in a swampy state, and are part of the year covered with water sufficient to allow of the trees being floated from where they are felled. The Birmans are in the habit of tapping the teak trees, particularly those which are straight grown, to extract a varnish or oil, which is highly prized by them, and used chiefly for protecting their pagodas or temples from the weather, for which purpose it is very effectual. These edifices are built entirely of untapt teak, as the Birmans consider the timber to be much injured, both in its strength and its durability, by being deprived of this oil. The principal parts of these temples are sunk in the ground, and although so fixed, the timber remains perfectly sound, notwithstanding many of them have stood nearly a century.

The importation of teak from Moulmein and the Tenasscrim coast has only taken place since the Birman war. Prior to that period, Calcutta was supplied almost exclusively from Rangoon, but only with straight teak. The Moul-meia market first supplied crooked teak timbers, which sold at such prices as to induce the Rangoon merchants also to send crooked timber from thence. The quantity, however, is so very limited, that the greatest difficulty is at present experienced upon the Hooghly in completing vessels from 100 to 400 tons entirely of teak.

Inferior as the Pegu and Moulmein teak is in quality when compared with the Bombay teak, it is preferable either to the saul or the sissoo, which has been brought to Calcutta within the last fifteen years, and which will be presently noticed. The accounts of the forests of Pegu and Tenasscrim are, that they are inexhaustible, and, if encouraged and properly worked, would supply timber of the largest size, and in sufficient quantity to meet the whole demand of the royal yards of Britain. In the batches of teak brought from the Tenasscrim coast, a species of darkcoloured teak, approaching to black, may be noticed, which appears to be a superior description of timber. It is very tough, with the grain close and irregular. It is said to be brought down from the forests mixed with the common [7:21:300]or brown teak. The following useful information as to the expense of both workmanship and material was obtained, in October 1832, from Captain Forzar, who was engaged in the Moulmein timber trade.

“The head Birmah carpenter, Mistry, offered to supply and trim teak timbers all round for a ship of 400 tons, at four rupees each; or to execute the whole of the work, as it regards the supply of carpenters, for 10,000 Sicca rupees, including joiners’ work for the hull, and the masts, yards, &c.”

“The price of teak crooks at Moulmein was, lst sort large, to side about 12 to 15 in. 7 rup. each. 2d ditto middling, ditto 11 to 8 in. 3 to 5 rup. each.”

“The 'Cashmere Merchant’ cargo (imported into Calcutta) cost at Moulmein in 1832,

From 15 feet { 1st sort large... 9 rupees each, to 18 feet { 2d do. middling 6 ditto, in length. { 3d do. small 4 ditto.

“Boat timbers, to side from three to six inches, and from four to seven feet long, cost from twenty to twenty-five rupees per hundred.”

The other kind of teak used in India for ship-building is the Java teak, of which considerable quantities were imported into Calcutta during the time the English governed that island. Of late years scarcely any has been imported. The Java teak is of a very superior quality, and, judging from the state of the vessels built of it, it is nearly if not quite equal to Malabar teak.

All descriptions of teak, if sound, free from defects and from sap-wood, are proof against the white ants; whereas all other descriptions of timber enumerated in this memorandum are liable to the attacks of these insects.

Saul is a hard heavy wood. It is imported from Behar, Oude, and the inexhaustible forests that skirt the hills which form the northern boundaries of Bengal and Behar. It is used extensively in all Calcutta ships, for the timbers, beams, &c. It is of two kinds, the Goruckpore and Morung; the first is a most inferior timber, and goes rapidly to decay. An intelligent gentleman long engaged in the timber trade of this country writes as follows. The forests situated to the east of the Coosey river, and to the west of the Teestan, produce the only good saul in India, which, like the elephant, deteriorates in quality the farther it is produced to the westward. The best timber is found at the foot of the hills, on a rocky ground. Sauls of large dimensions are now becoming exceedingly scarce, as the whole of the forests within a reasonable distance of the navigable streams are completely exhausted; and every good timber must now be conveyed by land-carriage a journey of two days. A great part of the natives, and all the Europeans (with the exception of one gentleman), have given up timber cutting altogether. The great superiority of Morung saul over that produced to the west of these forests appears to have been but a recent discovery in Calcutta, though always well known to the native boat-builders. That found to the west of the Coosey river, for instance, Goruckpore and Bogah, being of a soft spongy nature, but little better than Mango wood, is now driven out of the market. The prejudice existing against the smaller timbers (dakar), on the ground of immaturity, would be done away with were it known that every fine tree produces a large and a small timber, the bottom the chakar, the top the dakar.

Good saul is inferior to the very fine description of sissoo which was used in Calcutta-built ships about thirty years ago. The best description of saul, if well seasoned, may be classed, in point of durability, with the best sort of African timber, now so extensively used by the ship-builders of England. The greatest care is necessary in the selection of saul for immediate use, on account of its requiring a long time to season. It is very heavy, and will not answer for any part of a ship exposed to the sun, as it shrinks very much. Saul continues to be used for the frame, beams, shelf-pieces, breast-hooks, and inside planking, of ships built at Calcutta.

Sissoo may be classed of two kinds, the dark and the light coloured. The first grows in the forests of the same districts where the best saul is to be found; but it has become so very scarce for some years past, that it is now seldom or never brought to Calcutta, although scarcely thirty years have elapsed since the forests of the north-west districts of Behar, where the finest sissoo timber is produced, were pronounced to be almost inexhaustible. The other kind (the light) has been the only crooked timber of late years brought down the country for ship-building: it is decidedly an inferior sort of wood, very subject to the dry rot, and to the attack of white ants.

Jarrol is of two sorts, the red and the white. The red jarrol grows to a size fit for the largest ships, and may be obtained in any quantity near Chittagong; at which place several fine ships have been built, some of which are now running, although from fifteen to twenty-five years old. They were built of red jarrol timbers, with Pegu teak plank. Jarrol is very extensively used in Rangoon-built ships, but of a mixed and inferior sort. Comparing the superior sort of jarrol with the best kind of sissoo or saul, it must be considered an inferior wood in point of durability. White jarrol is very inferior, and never should be used in ship-building.

Poon is also of two kinds, the dark and the light. It is a wood that answers very well for masts, for which it is used; but it is perfectly unfit to be introduced into the hull, either as timbers or planks. The Malacca red poon is that of which masts and yards are made.

Toon should never be used for ship-building. It has however been introduced into several Cochin-built ships, and after five years has been found perfectly rotten. It is a porous open-grained wood; and the only use it can be applied to is for making furniture, for which it is extensively used in Calcutta.

Perhaps the best test of the durability of a Calcutta-built ship which can be cited, will be the Hastings of seventy-four guns, built there in 1818. The hull is composed of saul, sissoo, Pegu and Java teak, all of the best kind. So great was the expense incurred in the building of this ship, that when completed, the account, after giving credit for her freight, exhibited the cost of the hull for sea 11,63,754 Sicca rupees, or, ten rupees to the pound, L.1 16,375 sterling. It is usual in Calcutta-built ships to convert the frame, with the knees, breast-hooks, &c. from sissoo timber; the beams and inside planking being of saul, and the bottoms, wales, topsides, decks, keels, stem, and stern-posts, of the Pegu teak.

Results of'a Series of Experiments on the Elasticity and transverse Strength of different hinds of Timber. By captain H. c. Baher, Superintendent of Suspension Chain-Bridges in Bengal.

The experiments, of which the results^[4. The great extent of these experiments precludes the possibility of printing the whole of the results. In this article we have therefore confined ourselves to the averages which Captain Baker has deduced from them, and have merely stated in addition, the number of separate experiment from which these averages were shown. The experiments were made between the years 1827 and 1831. ] only are here recorded, were conducted, as nearly as circumstances admitted, with similar apparatus to that used by Mr Barlow, and described in his treatise on the strength and stress of timber.
[7:21:301]

The specimens, many of them, were obtained from the Commissariat Timber Depot; some very fine ones from the Cossipore Gun-Carriage Agency, and others were the produce of the Calcutta market. Those of three and two feet in length were, generally speaking, cut from the sound fragments of the larger specimens.

The central deflections of the seven and six feet specimens were usually noted immediately after the application of each fifty pounds of fresh load, at which time the set taken by each appeared more regular than after some interval had elapsed. The first deflections were commonly recorded with 150 pounds weight, in some cases with only fifty pounds. Sometimes the specimen was turned upon the trestles and subjected to two or more trials; and in a few instances the load was left suspended for many hours, deflections being noted at different intervals of time.

The depth of the neutral axis was occasionally observed, but this has been found to vary so little (being generally five eighths of the depth) as to render its insertion in the table of little practical utility.

The direct cohesive strength of the wood having also been subjected to experiment, the calculation of it from Mr Barlow’s formula has not been thought necessary; but the curious in such investigations are here presented with abundant materials for pursuing the inquiry.

lt is much to be regretted, that from the circumstances under which most of the specimens were obtained, so little accurate information respecting the timber could be procured. The age, size, time of felling, and circumstances under which the trees had been respectively placed subsequently to their being cut down, would all have materially enhanced the value of this statement of results to the man of research; but, unluckily, no such information was accessible. Indeed in few cases was it even precisely known from what part of the timber the specimen itself was cut out, or what number was off the same trunk. The year of importation, where known, has been however inserted.

The following were the woods experimented on. Saul^[5. The saul and sissoo are obtained from the forests north of the Ganges line, between the 25th and 3lst degrees of north latitude, and 74th and 88th degrees of east longitude, but chiefly from the tract lying north of Purneah and Goruckpore. ] ( Sharea Robusta Rox). This timber is too well known to render a lengthened description of it requisite; but its value for building purposes does not yet seem to have been fully appreciated. The great mechanical resistance it affords in cases of strain, however applied, renders it unquestionably the most valuable of Indian timber yet generally known for engineering purposes. The regularity of its deflections is indeed such as to render calculations of the requisite scantling for any particular stress, at all times simple and sure.

The general appearance of its fracture beautifully illustrates Mr Barlow’s theory of the axis of motion or rotation being centrically situated; the upper or compressed fibres being smooth as though cut with a sharp knife, those in a state of tension so fine and intimately blended as to resemble those of hemp rope when violently torn asunder.

The saul of the Calcutta market is seldom above thirty feet in length, but the trees grow to a much greater height. From the injudicious practice of squaring it after felling, its mean girth is only about six to seven feet, but must be naturally much greater.

Saul has lately been very successfully substituted for teak in many of the component parts of the gun-carriages, cheeks, beams, and transoms; poles and framing of gun and ammunition boxes; occasionally spokes, naves, and fellies. Its toughness in cases of percussion must obviously render it a much safer material than teak to be near in action. It has also been used for door and window panels. It however shrinks more, from its greater density.

To both the above woods, the teak (Tectona grandis), in point of strength and elasticity, is decidedly inferior. Its brittleness renders it indeed rather hazardous to stand near the specimens when they are subjected to heavy strain, as the pieces, sometimes several of them, fly with considerable impetus in different directions.

A reference to the tables will show, that of a great number of specimens tried, three only, 80, 81, 88, of which only the mean result is given in this abridged table, see ( 1 ), at all approximate in results to those of Mr Barlow. the mean of my experiments is about 2∙078, of Mr Barlow’s 2∙462, a number which exceeds that of the saul tried by me. Mr Barlow’s specimens must therefore have been vastly superior to any in common use throughout India, for the comparative superiority of saul in point of strength is, I believe, indisputable.

The teak grows to a great height, seventy to eighty feet and more, but cannot be easily obtained good of that size, the heart being frequently very much decayed. It is a durable wood when exposed, and is not subject to the depredations of white ants until it has been very long in use. The uses to which teak is applied are too generally known to render much remark necessary; planking, boxes, panelling, doors, windows, venetians, furniture, beams of houses, are amongst the most common.

Sissooh (Dalbergia Sissooh Box') in structure somewhat resembles the fine species of teak, but it is tougher and more elastic. The sissooh grows to the height of about thirty feet, but it is generally rather crooked, and therefore not so well adapted for beams. Sissooh is said to get harder with age.

It is by the natives employed for house-furniture, beams, cheeks; spokes, naves, and fellies of wheels; keels and frames of boats, blocks, printing presses; and generally in all work where crooked timber is required.

Jarrol (red) is a fine even wood in structure, and grows to great size in the Chittagong district; but that brought to the Calcutta market is too small to be of much use except for picture-frames and other similar purposes.

The Chittagong forests are said to be dearly cleared of the best or thorny species of jarrol; the others are of little value. It is considered a treacherous wood in ship-building.

In the following tables, it is necessary to bear in recollection that the letters represent the following qualities.

∕. The length in inches.

a. The breadth or thickness.

d. The depth.

W. The breaking weight.

Δ. The last deflection.

W. Greatest weight whilst the elasticity continued unimpaired.

δ. Deflection ditto ditto.
[7:21:302]
[table]

In order to make this valuable series of mean results as useful as possible, we have formed a similar Table from the mean results of the experiments made by Professor Barlow, and published by him in his work on the Strength of Timber. The two Tables taken together form a most interesting and perfect series of results.
[7:21:303]
[table]

On the Woods of British Guiana.

In Table III., which is the classification of timber adopted by the Committee of Lloyd’s Register Book of British Shipping, there are two sorts mentioned as timber of the first quality, which are yet little known in this country in private building yards, and not at all in our public establishments. These are greenheart and morra. They are both the produce of British Guiana, a colony that will in all probability ere long be a chief source from which this country will draw her supplies of naval timber. The territories of the colony have never yet been clearly defined. Its extent has been variously stated, by some as not much exceeding 12,000 square miles, by others as extending over an area of 76,000 square miles. It is situated almost immediately under the equator, and has consequently the vigorous and luxuriant vegetation inherent to such regions. The forests of the interior are said to be of immense extent, and abounding in valuable timber trees. Among these are, the morra, which nearly resembles in appearance the best African oak; the simiri, or locust, a wood well known in England; and the siperi, or greenheart, so called from a peculiar green tinge which the timber has when cut with a tool. There arc many other valuable timber trees, both for building and for ornamental work; but these perhaps are the most important to notice here.

The morra may be obtained easily to square twenty inches, and the logs run from thirty to fifty feet in length. It is said not to be susceptible of dry rot; but there can hardly yet be sufficient experience of it when combined in the masses of timber to be found in large ships to establish this important point as indisputable. If it be as similar in its qualities as it is in its appearance to African oak, it certainly can claim no exemption from the attack of dry rot. The trees grow to a great height; and although the trunks are generally straight, the branches afford good compass timber.

But the most important timber produce of British Guiana is the greenheart. It is a hard close-grained wood, having, like teak, an oily feel to the touch. Its specific gravity is about equal to that of African oak, but it is decidedly superior to it in strength, toughness, and durability. These, however, are not its chief advantages: its great value consists in its being completely exempt from the attacks of worms. It is on this account used in Demerara for sluice-gates, piles, and all marine engineering works which would be exposed to their ravages. Experiments of a most conclusive nature as to its really resisting these insects have been made in this country. The port of Liverpool is much infested with worms, and the wood-work of the docks there is constantly destroyed by them. Clows of greenheart timber have now been down upwards of seven years at the west entrance of the Brunswick half-tide basin, and are as yet untouched; while experience has proved that clows of other timber in the same situation would have been destroyed in less than half that time.

This is a most important quality, and renders this timber invaluable for marine engineering works. It is imported in logs of from twelve to sixteen inches square, and from twenty to forty feet in length. It is exceedingly hard, and difficult to work as planking, although latterly some colonial vessels have been planked with it. There is another Gui-anian timber, the siruaballi, of a softer texture, and much used for planking, as it is also said to be able to resist the ravages of the worm.
[7:21:304]

TABLE III.

A Table exhibiting the different descriptions of Timber, of good quality, to be used in the Timbering, Outside and Inside Planking, of Ships, as the same mill be applicable to the several terms of Years appointed for Ships to remain on the First Description of the First Class. From Lloyd’s Register of British and Foreign Shipping for 1840-41.
[table]
[7:21:305]
[table]

In this Table it is to be understood tint any timber which has been named for a specific use in a preceding class, may be used for a similar purpose in any succeeding class; and also, that wherever blank spaces are left, it is to be understood that for that appropriation the timber is to be as for the preceding class.

The Committee or Lloyd’s Register Book permit the best Honduras mahogany to be used for all those purposes to which African timber is permitted to be applied by this Table; but they do not yet deem it expedient that it should be inserted in their Table, as, although disposed to think favourably of it, they consider sufficient evidence as to its durability has not been obtained.
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TABLE IV.

Table shewing the Original Dimensions and Solid Contents of various Specimens of Wood; together with their Dimensions, Weight, and Capacity after certain intervals of time; also the Weight of a Cubic Foot when seasoned and when unseasoned. Compiled by James Bennett, Esq. of Η. M. Dockyard at Portsmouth, and formerly a Student at the late School of Naval Architecture, from specimens collected by himself, and now fist published.
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“In the above table, the first weight of each specimen was taken within or shortly after one year of the felling of the tree. This is to be generally understood, unless otherwise expressed.

Remarks.

“Few authors agree as it respects the weight of various species of timber in a seasoned and in an unseasoned state. This diversity of opinion often arises from an indefinite use of the terms ‘ seasoned,’ and ‘ unseasoned and we need not be surprised at these seeming contradictions, when we remember that many other words which denote the state or condition of bodies, are equally indeterminate. Thus, when we speak of heat and cold, light and darkness, moisture and dryness, we may naturally inquire what diminution of heat occasions cold, what decrease of light causes darkness, or what absence of moisture constitutes dryness. Hence, generally speaking, the word ‘ seasoned’ implies a relative rather than an absolute state of the wood. To prevent as far as possible any ambiguity on the subject, the dates and circumstances under which the wood was placed are carefully recorded, by which means the reader may form his own conclusions respecting the gradations of weight at intervals of time varying from one to twenty years. It should be understood, that large masses of timber, even if placed in dry situations for many years, in buildings or ships, would have their specific gravity diminished if cut into small portions. This will be manifest, if the reader refers to those specimens in the table which were taken out of a ship of war, the Marlborough.

“It occasionally happens that the specific gravity of timber is increased instead of being decreased by seasoning. This occurs when the shrinkage diminishes in a greater ratio than the weight. See No. 75 and 78.

“Shrinkage rarely takes place in the direction of the length of timber; when it does so occur, it seems to arise from a want of uniformity in the direction of the grain; for instance, when the wood is ‘curly’ and knotty. Independently of the length, the greatest shrinkage is in a direction at right angles with the ‘ silver grain the least in the direction of the plane of the ‘ silver grain.’ Hence, when the heart of the tree is in the middle of the wood, so that the silver grain radiates from the heart to the exterior, there is no greater tendency to shrinkage in the one than in the other direction.

“In those cases in which the specimens are known to be tops and buts of trees, they are so distinguished; otherwise they must be supposed to be indiscriminately taken from the top, but, or middle of the trees. It is a generally-received opinion, that the but of English and other oak is heavier than the top; still men of great eminence differ on this subject. The view of Du Hamel may probably partly account for these conflicting ideas. He asserts, that in healthy vigorous trees, the but is heavier than the top; but that in trees past their maturity and on the decline, the top is heavier than the but. Whatever deference may be due to this opinion, an analysis of the facts contained in our table will show, that another cause materially affects the condition of the question, which is the hygrometrical state of the specimens subjected to experiment; for it is an interesting fact, which will be presently verified, that the but of a tree may be of greater, of equal, or of less specific gravity than the top, according as each is more or less advanced to a state of seasoning.

“Among others, the following results are derived from the foregoing table.

“1st, The average weight of a cubic foot of unseasoned English oak, derived from twenty-seven specimens, viz. No. 9 to 35 inclusive, is 1000 oz., or 62 lbs. 8 oz.

“2d, From the same specimens the average weight of a cubic foot of English oak allowed to season during the space of from thirteen to twenty years is 45 lbs. 9 oz.

“3d, Among the above twenty-seven seasoned specimens, [7:21:309]the average weight of those which were kept in a warm room, in which there was occasionally a fire, was 47 lbs. 6 oz. to the cubic foot; whereas those which were kept in a shed weighed only 44 lbs. 13 oz. to the cubic foot. This result seems to warrant the conclusion, that within certain limits artificial heat does not season wood so expeditiously as natural heat and ventilation. It should be however remarked, that the average original weight of the specimens kept in a warm room exceeded that of those kept in the shed; the former weighing 63 lbs. 4½ oz. to the foot, while the latter weighed 62 lbs. 3 oz. to the foot. The difference, however, is too small to vitiate the conclusion just drawn.

“4th, From the specimens of English oak in which the tops and buts are distinguished, it appears that in seasoned oak the top is heavier than the but; the average weight of a cubic foot of each being respectively 48 lbs. 7¾ oz., and 44 lbs. 4 oz. On the contrary, in unseasoned oak the but is heavier than the top, the average weight of a cubic foot of each being respectively 64 lbs. 14 oz, and 62 lbs. 13 1 / 3 oz. It hence follows, that there must be a medium state of seasoning, in which the top and but are equally heavy.

“5th, From specimens No. 37 to 42, it appears that the average weight of a cubic foot of French oak is, seasoned 48 lbs. 0¼ oz., and unseasoned 68 lbs. 2 oz. These specimens not having been seasoned four years, are not to be considered as having arrived at their ultimate state. Nos. 47 and 48 were not cut out until August 1840, although the trees were felled in 1836. These, however, together with 49 and 50, serve to show the degree of seasoning of the solid log, as compared with the seasoning of No. 37 to 42, being the same kind of timber cut into small portions.

“Taking the five specimens, 37 to 41, it will be seen that, both in a seasoned and in an unseasoned state, the tops are, at least at present, heavier than the buts. Thus,—
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“A like result will be obtained by examining the weight of No. 47 to 50, in which the logs remained some years in an unconverted state.

“6th, From an analysis of specimens, 53 to 59, it appears that the weight of a cubic foot of Adriatic oak, allowed to season twenty years, is 48 lbs. 6½ oz. The same specimens unseasoned weighed 65 lbs. 10¾ oz. to the cubic foot. As the tops and buts are not particularly distinguished, no conclusion can be drawn respecting their comparative weights.

“7th, The specimens of Italian and American white oak are not sufficiently numerous to draw conclusions from them. The top and but of the Italian oak, No. 60 and 61, after being felled six years, were the same weight.

“8th, From specimens 64 to 86, it appears that the weight of a cubic foot of African oak allowed to season from thirteen to twenty years, is 60 lbs. 3 oz. The same specimens unseasoned weighed 64 lbs. 1 oz. to the cubic foot.

“It further appears that, both in a seasoned and unseasoned state, the buts are heavier than the tops. Thus,—
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“9th, The average weight of a cubic foot of teak, seasoned during the space of nineteen years, is 42 lbs. 2¼ oz, unseasoned 48 lbs. 11 oz. Moreover, in an unseasoned state the weight of the but exceeds that of the top; while in an unseasoned state the weight of the top exceeds that of the but. Thus,—
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“10th, With respect to larch, cedar, Riga fir, and a few varieties of the pines, their weights may be seen by inspecting the table. But it was thought that the specimens were not sufficiently numerous to justify any general conclusion respecting their weights in different states of seasoning.

“11th, Of the Dantzig fir, the average weight of a cubic foot of the unseasoned specimens is 39 lbs. There are only two seasoned specimens recorded; their average weight to the cubic foot is 32 lbs. 9¾ oz.

“Of the unseasoned specimens, from No. 103 to 112, the average weight of the buts (39 lbs. 14¾ oz.) exceeds that of the tops (35 lbs. 15½ oz.).

“12th, The specimens of cowdie are not sufficiently numerous to form a decided opinion respecting the weight of this wood. Omitting No. 121 and 122, which, when weighed, was still saturated with salt water, we find the average weight of a cubic foot of the seasoned timber to be 36 lbs. 15¾ oz.; while the mean weight of the two specimens No. 117 and 118, in their unseasoned state, is 41 lbs. to the cubic foot. The but exceeds the top in weight.

“13th, With respect to Canada yellow pine, there are no specimens recorded in the table in an unseasoned state.

“In taking an average weight of the seasoned specimens, No. 129 to 132 are neglected, inasmuch as two are 'partially seasoned,’ and two were weighed shortly after being taken out of salt water. With this explanation, the average weight of seasoned yellow pine is 27 lbs. 10 2 / 3 oz. per cubic foot.

“Out of the five trees from which the ten specimens of yellow pine are cut, it appears that in three of the trees the buts arc heavier than the tops, whereas in the remaining two the tops are heavier than the buts.”

The following articles may be referred to for information on timber: Horticulture, P lanting , S trength of Materials, and Ship-building. Some of the most celebrated works which may be consulted, besides those already mentioned, arc, Sir John Hill, M. D., on the Construction of Timber as explained by the Microscope; first published in 1770: the work of Forsyth on Fruit and Forest Trees, which is also of importance, as he was the first to treat on vegetable surgery: the Planter’s Guide, by Sir Henry Steuart of Allanton: and especially the Arboretum et Fruticetum Britannicum, by J. C. Loudon, in eight volumes; one of the most scientific and important books published on the subject. There are many other works which may be advantageously read, but it would exceed our limits to enumerate them.

The concluding short table will give some idea of the immense consumption of timber incidental to our being a maritime power; and the estimate that each ton of our merchant shipping has consumed at the very least a load and a quarter of timber, will perhaps tend to diminish the surprise which may have been excited in the early part of the article, by the assertion that the demand for timber was fast outrunning the supply, and exhausting the forests.
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In this Table the contents of the “sided oak” and of the elm timber are expressed in sided contents, which are derived from the converted contents by assuming the converted contents to be to the sided contents as 2 to 5. The sided contents of the fir timber are derived from the converted contents by assuming them to be to each other as 4 to 3. The quantities of deals are expressed in “feet running” of the rough deals expended on the ships. (b z.)