esaoo 



ccnfrr, offtrttsti 



/a. 



The maximum skin stress coi responding (o this load is 0912 Ibs. per 

 square inch. 



The co-efficient of elasticity as determined by :m increase in the 

 deflection of .805-ins. between the loids IdOO-lbs. and 13,000 Ibs. is 

 1,643,193 Ibs. 



Table E shows the several readings. 



The beam weighed 381 Ibs. 15 oz., or 34.50 Ibs. per cubic foot on 

 Oct. 3rd, and 375 Ibs., or 34.13 Ibs. per cubic foot on Nov. 15th, 

 showing a loss of weight in the laboratory at the rate of .01 Ib. per cubic 

 foot per d iy. 



The time c ccupied by the test was 45 minutes. 



Beam XIV is in reality Beam XIII re-tested, the second test having 

 been made Dec. 2nd, 1893. The beam was replaced in the machine 

 with the crippled side reversed so as to be in tension. The load was 

 then gradually applied until it amounted to 17,1500 Ibs., when the 

 beam failed on the tension side by the tearing apart of the fibres aloutr 

 the surface at which the crippling took place on the previous test. 



The maximum skin stress corresponding to this load is 4082 Ibs. per 

 square inch as compared with 0912 ll>s. per square inch in the tii.-t 

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

 the deflection of .51 ins. between the loads of 1,000 Ibs; and 8,000 

 Ibs.. is 1,513,950 Ibs. as compared with 1,643,193 Ibs. in the first test. 



Table E shews the several readings. 



This experiment therefore shews that although the beam may have 

 been crippled by undue pressure, it still retained a large amount of 

 strength as well as elasticity. 



Table K gives the several readings. 



Beam XV. This beam was tested Nov. ISth, 1893. The timber 

 was excellent in quality, equal to first qua'ity in the market, clear ami 

 straight grained and free from knots. Its history is the same as that 

 of Beam XII. The annular rings were oblique as in Fig. 20. 



Uuder a load of 37,000 Ibs. the beam failed by the crippling of the 

 fibres on the compression face, Pig. 21. 



The maximum skin stress corresponding to this load is 8020 Ibs. per 

 square inch. 



The total compression of the material was .34-in., and the maximum 

 skin compressive stress, taking 1466-iu., as the effective depth, is 8189- 

 Ibs. per sq. in, the corresponding skin tension tress being 8577 Ibs. 

 per in. sq. 10 



