ON PREVENTING THE DRY-UOT IN WOOB. ^f 



sequence to know, that the bark of such timl)er contain* 

 imich less tan than that of the younger and more succulent 

 wood; and that this principle, together with the proper ex- 

 tractive matter, is considerably more abundant in the bark Bari* 

 of the Leicester or Huntingdon willow, than in that of any 

 oak. According to the experiments of Mr. Daty, 7| lbs. 

 of the former will go as far in tanning leather as 9 or 10 lbs. 

 of the latter. It has however been asserted, that if an oak, 

 or any other tree, which is stripped of it;- bark, be suffered 

 to stand two or three years before it is felled, the wood will 

 have acquired a very great degree of strength and durabi- 

 lity. 



Next, where it is practicable, a current of air should be The wood 



frequently made to pass along; the surface of the wood. This «^'oukl be ex- 

 ,. , , 11 ijxi^ posed to a cuJfi 



expedient seems to have been particularly attendea to by rent ot air. 



the ingenious architects of ourGothlc churches, who are said 

 with that view to have left various openings in the walls be- 

 tween the two roofs of those edltices. In order also to pro- 

 mote evaporation, a certain degree of heat, such as that of 

 air heated by the sun or fire, should, if possible, be from 

 time to time applied. Cellars themselves ought to have Cellars, 

 some communication with the outward air by means of win- 

 dows and shutters, or trap-doors. And that these may be 

 for a short time opened in proper weather, so as to have a 

 draught of air; and that no very low degree of temperature 

 is necessary for the preservation of fermented liquors, pro- 

 vided that temperature be uniform, is evident from the prac- 

 ticability of keeping wine extremely well in cellars which 

 are not damp, and in which, therefore, one or both of these 

 circumstances must have taken place. 



The destruction of wainscotting may be Ipng deferred by 

 keeping in the apartment suitable fires. 



Lastly, the dry-rot may in all cases be infallibly prevented vvhen the 

 where it is practicable to cover the surface of the wood, woud is dried, 

 properly dried, with a varnish which is impenetrable and in- covered wUli 

 destructible by water. With this view two or three coats of varnish. 

 the composition before described should be laid on the dry 

 wood, before it is erected or put together, and a third or 

 fourth after it is put in its place ; and proper means should 

 be taken thoro-ughly to dry each successivsj coat of varnisjh. 



