X.] 



ELONGATION. 



113 



3, and 4 inches (Table XVI.) show that the force re- 

 quired to crush them waSj severally, 7,640 lbs., 7,224 lbs., 

 and 7,058 lbs., per square inch of base, which, if com- 

 pared with 7,978 lbs. on the one-inch cube of the same 

 seasoned wood, shows an apparent diminution of strength 

 in each of the next larger sizes ; the average force 

 required to crush the complete parcel of four sets of 

 cubes being 7,475 lbs. The average strength of the un. 

 seasoned pieceS of the same dimensions only 4,915 lbs. 

 to the square inch of base. 



There is yet another description of test to be noticed, 

 namely, that for ascertaining the elongation of the fibres 

 under certain strains. The experiment was made in 

 one of the royal dockyards upon two pieces of English 

 Oak, each 2 x 2 x 48 inches, and very carefully con- 

 ducted — note being taken of the elongation in a length 

 of 3 feet ; the mean results were found to be as follows, 

 viz. : — 



