332 STRUCTURE OF WOOD, &C. 



Sap and vola- consisting of the sap-wood, weighed 93*61 grammes, and dis- 

 ttte parts in p | ace( j 1 i V45 grammes of water. 



The specific gravity of the core was, therefore, 08251 ; that 

 of the sap-wood, 817*64. But as the faggot had lain exposed 

 to all the summer rains, the wood was far from being dry. I 

 was, however, much surprised at discovering, that the core of 

 this wood was more charged with sap, or water, than that of 

 the same kind of wood when in a growing state. A fact which 

 induces a suspicion, that the sap in trees is not enclosed in,ves- 

 sels or tubes apparently impervious to that liquid. 



To obtain a better knowledge of the wood in question, I 

 planed off 40 shavings, six inches in length, and hdlf an inch 

 in breadth, from a small board cut from the core ; with an 

 equal number of shavings, of similar dimensions, from another 

 board cut from the sap-wood. 



The 40 shavings from the core, taken just as they were planed 

 off, weighed 16*37 grammes, and 1053 grammes after they 

 had been thoroughly dried in the stove. 



The 40 shavings of sap-wood weighed 1697 grammes before 

 they were dried, and 1 1*99 grammes afterwards. 



Thus possessed of the specific gravity of the solid parts of 

 this kind of wood, it only remained to determine, from these 

 data, the constituent parts of an inch of the wood, which was 

 readily performed, as follows : 



Ligneous parts. Sap. Air. 



In the core of the elm. . 0*41622 I 035055 I 0*23223 

 In the sap. wood 0*38934 | 0*23094 | 037072 



It appears, from the results of these experiments, that the 

 sap-wood of the elm contains rather more ligneous parts in its 

 timber, than the core of the same tree j and that it contains 

 much less sap, and more air. But as the tree had been felled 

 nearly five months before it became the subject of investigation, 

 it is very possible that the sap wood had become much drier 

 than the core of the tree. 



1 had purposed to repeat these experiments upon wood in a 

 growing state, and upon seer-wood • but the interference of 

 other occupations has prevented a continuance of the inquiry. 

 It cannot, however, but le d to results curious in themselves • 

 and I therefore recommend it to the notice of all students in 

 vegetable economy, as well as to those who love that noble 



science, 



