The weight of the beam on May 7th, date of test, was 128 Ibs. 8 

 ozs., or 31 .87 Ibs. per cubic foot. 



Beam (Plank) XXXIV. This beam was tested May 8th. 1894, 

 with the annular ri ng.s as in Fig. 76. 



8+00 



.. 



The load upon the beam was gradually increased until it ainountr i 

 to 5600 Ibs., when the fibres on the compression face crippled to a 

 small extent. On still further increasing the load, the fibres on the 

 compression face were completely crippled, Figs. 77, 78. and fracture 

 nlso simultaneously occurred on the tension side when the load 

 amounted to 8400 Ibs. 



The grain of this beam was straight and parallel with the axis, and 

 the timber was apparently free from knots for a distance of about 24 

 inches on each side of the centre. 



The maximum skin stress corresponding to the breaking load of 

 5600 Ibs. is 5079 Ibs. per square inch, and the skin stress corres- 

 ponding to the load of 8400 Ibs.. which caused the fracture on tin 1 

 tension side, is 7597 Ibs. per square inch. 



The co-efficient of elasticity, as deduced from an increment in the 

 deflection of 1.14 ins. between the loads of 500 and 5600 lb=., was 

 1,784,800 Ibs. 



Table M shews the several readings. 



The weight of the beam on May 8th, date of test, was 96 Ibs. "i o/.>., 

 or 36.59 Ibs. per cubic foot. 



Beam (Plank) XXXV was tested May 8th, 1894, with the annular 

 r ings as in Pig. 79. The heart of the tree was very nearly coincident 

 with the axis of the beam, and the grain ran in the same direction. 

 Season cracks occurred intermittently throughout the beam. 



79 



The load upon the beam was gradually increased until it amounted 

 to 7600 Ibs., when the beam failed by the crippling of the fibres on the 

 compression face, Fig. 80. The load was still increased, and well 

 defined crippling occurred when it amounted to 10.050 Ibs. When 

 t!.e load had reached 13,700 Ibs. the beam failed by the tearing 

 apart of the fibres on tho tension face, Fig. 80. 



The maximum skin stress corresponding to the breaking load of 7600 

 Ibs. is 433!) Ibs. per square inch. 



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

 deflection of ,92-in. between the loads of 500 and 7600 Ibs., is 

 1,589,250 Ibs., and as determined by an increment in the deflection of 

 .025-in. for the corresponding increase of 200 Ibs. it is 1 ,642.900 Ibs. 



Table M shows the several readings. 



The weight of the beam on May 8th, date of test, was 128 Ibs. 12 

 ozs. or 37.69-lbs. per cubic foot, 



24 



