OF FOREST-TREES. 



233 



gotten upon it a hard, black, coaly crust, and the secret carries with it cHAP. 

 great probability ; for the wood is brought by it to such a hardness and "^"^^ 

 dryness, that neither earth nor water can penetrate it : I myself remem- 

 bering to have seen charcoal dug out of the ground amongst the ruins 

 of ancient buildings, which had, in all probability, lain covered with 

 earth above fifteen hundred years *. 



Timber which is cleft, is nothing so obnoxious to rift and cleave as 

 what is hewn ; nor that which is squared, as what is round : and there- 

 fore where use is to be made of huge and massy columns, let them be 

 bored through from end to end ; it is an excellent preservative from 

 splitting, and not unphilosophical ; though to cure this accident, painters' 

 putty is recommended, also the rubbing them over with a wax-cloth is 

 good ; or before it be converted, the smearing the timber over with cow- 

 dung, which prevents the effects both of sun and air upon it, if of neces- 

 sity it must lie exposed. But besides the former remedies, I find this, 

 for the closing of the chops and clefts of green timber, to anoint and 

 supple it with the fat of powdered beef broth, with which it must be 

 well soaked, and the chasms filled with sponges dipt into it ; this to be 

 twice done over. Some carpenters make use of grease and saw-dust 

 mingled ; but the first is so good a way, says my author, that I have 

 seen wind-shock timber so exquisitely 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 would now recommend the quar- - 

 tering of such trees as will allow useful and competent scantlings, to be of 

 much more durableness and effect for strength, than where (as custom 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 interstice, or 

 separation, between the heart and the rest of the body, which renders it 

 much more obnoxious to decay and miscarry, than when they are treated 



* It is upwards of seventeen hundred years since the city of Herculaneum was destroyed 

 by an eruption from Mount Vesuvius, and very lately the beams of the theatre were dug 

 out of the ruins, completely charred by the burning lava. Charcoal is a body of so un- 

 alterable and indestructible a nature, that none of the elements, excepting fire, can de- 

 stroy it. 



