071 the Dry-Rot ifi T'lmler. 327 



it is, that flame is never naturally uncombined ; that it recoin- 

 bines immediately when set free by art ; and that it is always 

 surrounded by one species of chemical elements or other, as is 

 the case with a piece of wood or stone : — from p. piece of wood 

 take the chemical elements awav, and flame only remains*. 



These things being premised, dry-rotted wood manifestly pre- 

 sents the phaenomenon of wood which has somehow been deprived 

 of its gravitating base ; or of so much internal flame, as equals 

 the loss in weight which the wood has suffered. The strength only 

 of the wood with the weight is gone: whereas what relates to 

 form, bulk and grain, are in all other respects perfectly unaltered. 

 The remaining timber, although it may be immense in volume, 

 is comparatively devoid of all weight: and there is no kind of 

 fuel whatever, it is well known, which yields less flame than dry- 

 rotted wood. It may be concluded therefore, that the loss of 

 the element of flame, which is the ponderable base, is the cause 

 of the wood losing its strength and weight ; tvliick constitutes 

 the dry-rot. The same thing happens also with other than 

 woody substances. The human body, upon opening sepulchres, 

 is found to consist of an impalpable powder only, which retains 

 the original form of the body, but drops upon the admission of 

 air, or on the slightest touch, and might with ease be compressed 

 into a uut-shcll. 



The PROCESS which brings this state of the wood or timber 

 about, is connected with principles which show, that a specie'; 

 of galvmiic circulation takes place between the wood and the 

 medium of air by which it is surrounded j or between the wood 

 and the solid body with which the wood may be in contact. 



It is the admitted fact, that without humidity in the wood, 

 there is no dry-rot to be apprehended ; neither is there any cir- 

 culation in the galvanic pile, when dryness prevails. Two pieces 

 of wood in the closest contact, induce no circulation through 

 them, if both or either of them remain perfectly dry : nor does 

 a dry piece of wood give out its gravitating base, when in con- 

 tact with a humid piece, unless it receives humidity from the 

 latter. Hence it is, that sound and rotted wood are found 

 united ; and that wood which has been considered impervious to 

 dry-rot, has fallen a sudden martyr to it, by being in contact 

 with wood of ;i different kind, or in a different state. 



Different kinds of wood in close contact, and containing mois- 

 ture, are more likely to act on each other, and with greater 

 energy, after the manner of the galvanic plates, than pieces of 

 the same species : still, as no two pieces of wood are |)erfectly 

 alike, where there are moisture and contact, g.ilvanic, or, in this 



• See Treatise on Heat. Flame, and Combustion: by T. H. P. Sold by 

 Baldwin, Cvadoel<, and Joy. 



