OF FOREST-TREES. 



247 



" The reason of all which phaenomena seems to be, CHAP. IV. 



" That this petrified wood having lain in some place where it was well ^"^'"V^^ 

 soaked with petrifying water, (that is, such a water as is well impreg- 

 " nated withstonyandearthy particles,) didbydegreesseparate,bystraining 

 " and filtration, or, perhaps, by precipitation, cohesion, or coagulation, 

 " abundance of stony particles from that permeating water ; which stony 

 " particles having, by means of the fluid vehicle, conveyed themselves 

 " not only into the microscopical pores, and perfectly stopped them up, 

 " but also into the pores, which may perhaps be even in that part of the 

 " wkDod which through the microscope appears most solid, did thereby so 

 " augment the weight of the wood, as to make it above three times hea- 

 " vier than water, and perhaps six times as heavy as it was when wood : 

 " Next they hereby so lock up and fetter the parts of the wood, that the 

 " fire cannot easily make them fly away, but the action of the fire upon 

 " them is only able to char those parts as it were ; like as a piece of wood, 

 " if it be closed very fast up in clay, and kept a good while red-hot in the 

 " fire, will, by the heat of the fire, be charred, and not consumed ; which 

 " may perhaps be^the reason why the petrified substance appeared of a 

 " blackish brown colour after it had been burnt. By this intrusion of the 

 " petrified particles, it also becomes hard and friable ; for the smaller 

 " pores of the wood being perfectly stuffed up with these stony particles, 

 " the particles of the wood have few or no pores in which they can reside ; 

 " and, consequently, no flection or yielding can be caused in such a sub- 

 " stance. The remaining particles likewise of the wood among the stony 

 " particles, may keep them from cracking and flying, as they do in flint." 



The casual finding of subterraneous trees has been the occasion of this 

 curious digression, besides what we have already said in chap. xxii. book i. 

 Now it were a strange paradox to affirm, that the timber under the ground 

 should, to a great degree, equal the value of that which grows above the 

 ground ; seeing, though it be far less, yet it is far richer, the roots of the 

 vilest shrub being better for its toughness, and, for ornament and delicate 

 uses, much more preferable than the heart of the fairest and soundest tree. 

 And many hills and other waste places, that have in late and former ages 

 been stately groves and woods, have yet this treasure remaining, and per- 

 chance sound and unperished, and commonly (as we observed) an hin- 

 drance to other plantations ; engines, therefore, and expedients for the 

 more easily extracting these cumbrances, and making riddance upon such 



