The load upon the beam was gradually increased until it amounted 

 to 32,20i> Ibs., when it failed by the tearing apart of the fibres on the 

 ten -ion side. 



The maximum skin stress corresponding to this load is 4370 Ibs. 

 pei- square inch. 



The coefficient of elasticity, as deduced from an increment in the 

 deflection of .805-in., betwe. n the loads of 1000' and 19,000 Ibs., is 

 1,1 8 1.240 Ibs. 



T;.bJe Q shows the several residing,*. 



The weight of the beam was 509 Ibs. 12 ozs. or 33.64 Ibs. per cubic 

 fix.t, on March 10th, the date, of test, and ;">75 Ibs. 8 ozs., or37.25-lbs. 

 per cubic foot, on February 1st, showing a loss of weight at the rate 

 of .0975-lb. per cubic foot per day. 



OLD WHITE PINE. 



Beams LI to LIII ate three old white pine stringers sent to the lab- 

 oratory by Mr. P. A. Peterson. These stringers had been in service 

 since 1885, i.e., for about eight years ; they were removed from the 

 tirstles during the summer of 1892. 



/v-/* i* *e'!^/>^/> 



Beam LI was tested Diicembe;- 1st, 1893, with the annular riiins as 

 in Fig. 101. 



The load upon the beam was gradually increased until it amounted 

 to 22,730 Ibs. when the beam failed by shearing, longitudinally as in 

 Figs. 102, 103, the distance between tin portions of the beam above 

 and below the plane of shear bein;r | in. 



The maximum skin stress corresponding to this load is 3i'12 Ibs. per 

 square inch. 



The co-efficient of elasticity, as determined by an increment in the 

 deflection of .55-in., between the loads of 2500 Ibs. and 12,000 Ibs. 

 is 982,480 Ibs. 



Table E shows the several readings. 



The total weight of the beam on December 1st, date of test, was 

 445 Ibs., or 28.3 Ibs. per cubic foot. The weight of a length of 14 

 ft. If ins. was 370 Ibs., or 2S.12 Ibs. per cubic foot on December 2nd, 

 and 367 Ibs. 5 ozs., or 27 47 Ibs. per cubic foot on December 8th, 

 showing a loss of weight at the rate of.l083-lb. per cubic foot per 

 day. 



Beam LII was tested December 9th, 1893, with the annular rings 

 as in Fig. 104. 



.4, 



\ 



raeoo. 



/06 



The load upon the beam was gradually increased until it amounted 

 to 26,320 Ibs , when the beam failed by the tearing apart of the fibres 

 on the tension side. 



The maximum skin stress corresponding to this breaking load is 

 3589 Ibs. per square inch. 



The total compression of tho material at the support was .37 in., so 

 that, taking 14 85 ins. ;l s the effective depth, the maximum skin com- 



30 



