STRUCTURE OF WOOD, &C. 325 



the wafer* j whence" I conclude with certainty that this piece of Sap &c in 

 oak, filled with sap, possessed a bulk equal to Q50g3 cubic different kind* 

 inches, that its specific gravity was 965 15, and, consequently, wood * 

 that a cubic inch of it weighed 19- 134 grammes. 



When the piece of wood had been reduced to the shape of 

 a small board, about half an inch in thickness, I took from 

 it forty very thin shavings weighing 199 grammes, but when 

 thoroughly dried in the stove, at a temperature of 262° F. they 

 weighed only 1245 grammes. 



From this experiment, it is evident that the wood in ques- 

 tion, being full of sap, was composed of 12'45 ligneous parts* 

 and 7*45 parts of water, or of sap, whose specific gravity is 

 nearly the same as that of water. 



Now, as one cubic inch of this wood weighed 191 34 gram- 

 mes, it is very certain that it was composed of 1 l'Q^l grammes 

 of ligneous parts, which were, consequently, solids, and of 

 7* 163 grammes of sap. 



But we have already seen, from the results of the experi- 

 ments detailed in the former part of this memoir f, that a cubic 

 inch of the solid parts of the wood of the oak, weighs 3042 

 grammes } consequently, the 11*971 grammes of solid parts 



* In order to determine and keep an account of the quantity of 

 water remaining on the surface of this piece of wood at the instant 

 ot" withdrawing it from the vessel, it was weighed when taken out, 

 whilst still quite wet. As its weight had been taken previously to the 

 operation, the augmentation it had acquired from the water was as- 

 certained to a nicety. 



The vessel when empty weighed 188*22 grammes, and when filled 

 with water at the temperature of 60 F. 474'9- grammes ; so that it 

 contained 286*68 grammes of water. When the piece of wood was 

 plunged into the water, a small glass plate, about two inches in 

 diameter, and two lines in thickness, ground with emery, to fit it to 

 the edges of the vessel, so as to close it hermetically, was laid upon 

 its mouth to shut up the piece of wood with the water still remaining 

 in the vessel, whilst its outside was wiped with a dry cloth. 



When the exterior of the vessel had been thoroughly dried, the glass 

 cover was carefully removed, and the piece of wood withdrawn ; the 

 vessel was then weighed again with its remaining contents of water ; 

 and from its weight the quantity of water displaced by the wood, wa* 

 calculated. 



t See the table, page 5?3. 



found 



