On the Dry- Rot hi Timler. 329 



t^eent experiment of applying solidifying substances in openings 

 will doubtless l)e found highly beneficial. These regulations it is 

 inauifest are unnecessary, if water can be kept out of wood, or 

 preserved when in it, in the compound state. The cause and 

 preventive in the dry loay having been pointed out, it may be 

 possible also to arrive at the same object, the retention of the 

 gravitating base, by the humid way, and upon principles which 

 are common to both. 



Cheap acids might be injected into wood, for the purpose of 

 keeping all internal juices proof against being decomposed. The 

 manner is simply this: — As /?re attracts, boiled wood is neces- 

 sarily rendered in a minus or deficient state, by the act of boil- 

 ing. In that deficient or spongy state, it siiould be i\\xo\\nJ)X)m 

 the hot boiUng kiln into the cold preserving mixture, m order 

 to absorb indecompo'ialile moisture ; which in time, by combining 

 with the wood, would contribute to its strength, so far as to 

 prevent the premature loss of the gravitating base, which is al- 

 ways at the expense of the strength of that which it parts from. 



Lastly, to preserve a proper medium next the timbea-.s, be- 

 tween the lower decks, and to keep away one which is conducive 

 to dry-rot circulation, there can be nothing better done, than to 

 introduce as a permanent fixture, a condensing pump into each 

 ship's hold, for the purpose of getting rid of heavy foul air down- 

 wards, through the ship's bottom. Air in this situation is to 

 atmospheric air, as I "5 to 1 in weight: therefore pure air, in- 

 troduced by wind-sails and the like, may dilute, but cannot re- 

 move this species of deleterious air out of a ship. To pump it 

 downwards, and after the manner a double levered fire-engiive is 

 worked, must necessarily get rid of all impure air, from every 

 hole and opening in the orlop, as well as fiom every sick birth, 

 to which the suction hose, which may be of any length, may be 

 introduced ; and pure air must instantly occupy the place of that 

 which has been pumped out. The resistance to be overcome, in 

 all cases, will be precisely that of a column of water, equal in 

 height to the ship's draught at the time, which can never be 

 more than equal to one-fourth the resistancte which afire-engine 

 surmounts, when it throws water only one hundred feet in the 

 air. So that there is nothing more practicable; and as con- 

 ducing to the health of the crew, and theship's durability,tlie be- 

 nefit may he infinite, and the expense saved annually of the most 

 .serious amount. 



Dry-rot and combustion appear to be precisely the converse 

 of each other. In the former, it is the flame or ponderable l)ase 

 which is attracted, and what is chemical alone is left: whereas 

 in combustion, flame only is left, every thing chemical being 

 attracted from it. That which attracts flame from wood, com- 



Vol. 5G. No. 271. I^ov. 1820. T t bines 



