" Sonic carpenters make use of grease and saw-dust mingled ; but the first is so good a M ay," says my au thor, "that I have seen wind shock timber Si exquisite ly closed, as not to be discerned where the defects were. This must be used when the timber is green.
" We spake before of squaring; and I could now recommend the quartering of such trees, as it ill allow useful and competent scantlings, to be of !ouch more durableness and effect for strength, than tt here (as cus torn is, and for want of observation) whole beams and timbers are applied in ships or houses, with slab and all about them, upon false suppositions of strength beyond these quarters. For there is in all trees an evident in terstice or separation between the heart and the rest of the body, which renders it much more obnoxious to de cay and miscarry, than when they are treated and con verted as I have described it ; and it would likewise save a world of materials in the building of great ships, where so much excellent timber is hewed away to spoil, were it more in practice. Finally, " I must not omit to take notice of the coating of timber in work used by the Hollanders, for the preser vation of their gates, portcullises, draw-bridges, sluices, and other huge beams and contignations of timber, ex posed to the sun and perpetual injuries of the weather, by a certain mixture of pitch and tar, upon which they strew small pieces of cockle and other shells, beaten al most to powder, and mingled with sea-sand, or the scales of iron, beaten small and sifted, which incrusts, and arms it, after an incredible manner, against all these assaults and foreign invaders; but if this should be deemed more obnoxious to firing, I have heard that a wash made of alum has wonderfully protected it against the assault even of that devouring element; and that so a wooden tower or fort at the Pirwum, the port of Athens, was de fended by Archelaus, a commander of Mithridates, against the great Sylla. But you have several composi tions for this purpose, in that incomparable Treatise of Naval architecture, written in Low Dutch by N. Wit sen, Part I. chap. vi. The book is in folio, and he that should well translate it into our language (which I much wonder has not yet been done) would deserve well of the public.
" Timber that you have occasion to lay in mortar, or which is in any part contiguous to lime, as doors, win dow-cases, groundsels, and the extremities of beams, &c. have sometimes been capped with molten pitch, as a
marvellous preserver of it from the burning and destruc tive effects of the lime; but it has since been found rather to heat and decay them, by hindering the transudation which those parts require; better supplied with loam, or strewings of brick-dust, or pieces of boards ; some leave a small hole for the air. But though lime be so destruc tive whilst timber lies thus dry, it seems they mingle it with hair, to keep the worm out of ships, which they ,heath for southern voyages, though it is held much to retard their course. Wherefore, the Portuguese scorch them with fire, which often proves very dangerous; and, indeed, their timber being harder, is not so easily pene trable.
" For all uses, that timber is esteemed the best, which is the most ponderous, and which, lying long, makes deepest impression in the earth, or in the water, being floated; also, what is without knots, yet firm, and free from sap, which is that ratty, whiter, and softer part, called by the ancients alburnum, which you arc diligent ly to hew away.
" My Lord Bacon, Lxper. 658, recommends for trial, of a sound or knotty piece of timber, to cause one to speak at one of the extremes to his companion, listening at the other; for if it be knotty, the sound, says he, will come abrupt.
" For the place of growth, that timber is esteemed best Which grows most in the sun, and on a dry and hale ground; for those trees which suck and drink little are most hard, robust, and longer lived—instances of so briety. The climate contributes much to its quality; and the northern situation is preferred to the rest of the quar ters; so as that which grew in Tuscany was of old thought better than that of the Venetian side ; and yet the Biscay timber is esteemed better than what they have from colder countries ; and trees of the wilder kind and barren, than the over much cultivated and great bear ers." Dr Parry has published an excellent paper on the causes of the decay of wood, and the means of prevent ing it. From it we take the liberty of abridging what follows; but would recommend a careful perusal of the whole of it to those who wish for further information on the subject.* Wood Dr Parry supposes to be subject to destruction from two causes, rotting and the depredations of insects. Of rot there are two supposed kinds, the first takes place in the open air; the second under cover.