OF ARTS AND SCIENCES. 



287 



then roinovt'd from tlie beam and the set noted, after which the beam 

 was allowed a certain time to recover from the set. 



After the piece had returned, or at least nearly returned, to its orig- 

 inal position, it was subjected to a load of forty pounds in the same 

 manner. 



Table ir. gives the deflection of each piece under the loads of thirty 

 and forty pounds, both immediately after the weight was applied ami 

 after it had rested upon the beam the length of time designated. 



TABLE II. 



The values of the Modulus of Elasticity calculated from these de- 

 flections are also given. The Moduli of IClasticity obtained from the 

 deflection of the beams immediately after the weight was applied have 

 been denoted by £J, and those obtained from the deflection of the 

 pieces after the weight had been applied one or more hours, by JE^. 

 Table I. gives the values of E and ^j for each piece, obtained by 



taking the average of the values given in Table 11. 



IF/3 . 

 The values of B were computed by the formula B = 4 a/j/>3 ' ^" 



which fF denotes the weight in pounds producing the deflection ; I the 



clear span in inches ; A the deflection of the beam at the centre ; B 



the breadth of the beam, and D the depth, both in inches. 



After all of the beams had been treated in this way, piece No. 3 



was again put in the machine and subjected to a load of 100 lbs., 



