ROT. 



incommodious, as to half-inch wainfcot, &c. The incor- 

 ruptibility of charcoal is proved by a variety of indifputable 

 facts. 



A great many ufeful facts on this fubject have been 

 itated by Mr. Batfon, of Limehoufe, in the twelfth volume 

 of the fame Tranfaftions, in refpeft to his methods of pre- 

 venting the dry rot in a room much anecled with it. The 

 mode he adopted was to clear the ends of his timbers, to 

 take away the infected earth to the depth of two feet, and 

 to fill up that fpace with anchor-fmith's allies, or allies from 

 a foundry, before his flooring boards were laid. 



And on minute examinations being made under the di- 

 rection of the fociety, at the dittances of fix and twelve 

 years after the flooring was laid, the boards, wainfcot, and 

 timbers, were all found entirely free from any appearance of 

 the dry rot. The ufe of Itone-work next the ground, as the 

 foundations of pofts, door frames, partitions, &c. has alfo 

 been found ufeful in preventing fuch wood-works from being 

 attacked by this difeafe. And alfo the caufmg a more free 

 circulation of air about fuch foundations by the fixing of 

 iron gratings in Hone-work in different places, fo as to pro- 

 duce the molt perfect ventilation. But notwithstanding all 

 that has yet been done in refpect to the nature and modes of 

 preventing this fort of rot, much (till remains to be effected 

 both in regard to the nature of its origin, and the molt 

 certain means of eradicating it under different circum- 

 ftances. 



It will probably, however, be found the belt and molt 

 effectual plan, until further trials and difcoveries have thrown 

 more full and complete light on its nature and caufes, to take 

 care that the wood-works near the aground in all buildings 

 in fuch places as rot timber have as little contact with it as 

 poffible, by being raifed and fupported at fome diftance 

 from it, by means of folid ftone or brick and mortar work, 

 by a full and free circulation of air being every where ad- 

 mitted in the foundations near fuch wood-works, by being 

 eareful to make ufe of fuch timber only as is perfectly well 

 feafoned and prepared, and by having conftantly a fufneient 

 number of drains made all round to difcharge any moillure 

 that may occur. It may likewife be of farther advantage 

 in all fuch cafes to avoid painting or coating over the wood- 

 work near the parts which are liable to be dileafed or become 

 rotten, for fome confiderable length of time after they have 

 been done ; as well as to allow of large fires to be occa- 

 fionally made, where convenient, as near to fuch fituations 

 as poffible, in order that every fort of moifture and damp- 

 nefs, together with the peculiar rawnefs of fuch new works, 

 may always be removed as much as they are capable of in 

 the firit inltance, or as foon after the works have been 

 finiftied as may be compatible with their nature and extent. 



In regard to the boletus lachrymans being the caufe of the 

 dry rot in timber, it has lately been contended that the dif- 

 ferent forts of fungus, which are met with upon decaying 

 timber of different kinds, are the production of the remaining 

 powers of life in the fap of the unfeafoned wood ; and that 

 the fame fort of living organizable matter, which, whilft its 

 powers continued in their perfect condition, would have 

 gen-rated the branch of an oak, will, when debilitated and 

 enfeebled, give exiftence to a certain kind of fungus, and 

 become the caufe of this difeafe. 



Mr. T. Wade, in a recent publication, obferves, that 

 the term dry rot feems to be improperly applied to the decay 

 in timber, which it is generally employed to defignate, and that 

 the impropriety of the expreffion, probably, has not a little 

 contributed to involve this fubject in oblcunty. A very 

 fhort advance in the inveftigation of this fubject will fhew, 



that moilture is a condition neceffary to the putrefactive 

 procefs, and that water is the molt efficient agent in the de- 

 compolition of organized bodies. 



By capillary attraction fluids are carried to the tops of 

 the highelt trees, a phenomenon which has been long ob- 

 lerved, but has not been fatisfactorily explained. Precifely 

 the fame effect takes place when one end of a piece of timber 

 is immerfed in water, or placed in a damp fituation. It 

 happens even in vacuo. 



Timber, fo placed, at firit fwells, after fome time it 

 changes colour, then it emits gafes which have a mouldy or 

 multy fmcll. In the more advanced period of decay, the 

 mafs dries, and cracks in tranfverfe directions. Laitly, it 

 becomes pulverulent, and forms vegetable mould. Generally, 

 in fome of thefe ftao-es of decompolition, the different fpecies 

 of fungus are found to vegetate on the mofs. 



When a vegetable is deprived of life, the matter con- 

 Itituting it begins to undergo changes in order to enter into 

 new combinations. It is reduced to fimple principles by the 

 aid of warmth, and the prefence of air and water. In 

 houfes, fhips, &c. we cannot prevent the influence of thele 

 powerful agents, but it may be retarded. It feems the 

 ufual mode of feafoning timber by exficcation is of little ufe. 

 Timber, thus prepared, is found, indeed, to fhrink and lofe 

 much of its weight ; hut even very old oak timber, (pro- 

 curt-d from ancient buildings,) when immerfed in water, or 

 expofed in a damp fituation, readily acquires the weight, 

 and Iwells to the dimenlions of green timber, from which, 

 in its properties, it does not materially differ. 



Mr. Wade therefore endeavoured to difcover fome other 

 means by which timber may be made to refill change, or 

 decay. 



Lignum vitae, box, ebony, &c. are nearlv indeftructible, 

 owing to their being of fo clofe a texture that water cannot 

 be abforbed by them, neither do they give out any foluble 

 matter to water, at lealt not without long boiling, or digeft- 

 ingata very high temperature. Therefore the great agent 

 that determines the changes in wood in general, here has not 

 any influence. 



Other durable woods, fuch as teak, cedar, &c. though 

 of an open grain, and very porous, contain refinous, or 

 oleaginous matter, repelling moifture, which cannot infinuate 

 itfelf, as is the cafe with the feathers of fome fowls, &c. 

 On thele principles the common perifhable woods may be 

 made to refemble thofe which are very lalting, or, indeed, 

 nearly indeltructible. 



Thus, to prevent the decay of oak, &c. it is neceffary 

 either to caufe it to be incapable of abforbing moilture, or 

 to render the ligneous fibre infoluble. 



Some of the effects produced bear confiderable analogy 

 witli tanning, by which procefs a fkin, entirely foluble in 

 water, forming jelly or glue, and quickly fufceptible of 

 putrefaction, is made into leather, a fubftance not at all 

 foluble in water, and capable of enduring for a long period, 

 fometimes for feveral centuries. 



For various methods of performing this, we beg to refer 

 the reader to Mr. Wade's book, in which the operations re- 

 commended feem fimple and economical. 



Rot in Timber, a difeafe in trees which quickly injures 

 and.deitroys the woody parts of them by inducing a fort of 

 rotting and decay. It has been Hated to proceed from dif- 

 ferent caufes, but the principal, according to the author of 

 the Practical Planter, are thofe of external wounds or 

 bruifes, the trees growing in unfavourable foils, the roots of 

 which have been barked at the period of planting, or in 

 cutting out plants. And fecondly, by the tree growing in 



fpouty 



