giad'.l illy im-reavd until it aiii'Hititrd In 47,1'l'ilt IK-., when a rumpl, i> 



fracture in ik pi. ice by the tearing apart of the fibres ,\ \\.<- >, 

 side :it 'In' .-i-'itri-, :uicl sitniilHne-Hirdy by a longitudinal sir 

 llimu-jhoiit on half of the length ofthe heim, as in Fi 



Tin- maximum skin stress corresponding In the breaking load "I 

 38,1001l, i^.'ill'.ll Hi-. pT hquare inch ; the ii:;i\iiiiiMii skin 

 (drre.-pnnding to tin; Inail of I7,!HIO His. is filllT H >. per sq *c inch. 



The tnt:il compression of the timber at the e litre ;<- !tll-in., SO 



tliat, takiiiLT llic rtti'rtiv.' ili jilli to lie I l..'i--7."> ins.. ili.> inaxiiiiuiii coin- 



M skin strips at llic sii|.|nri w.mM l.c lllil ilx. prr >i|iiiirc inrli, 



the COrrMpOOding luaxiiniini tensile skin stress liein^ Mi.t- His. per 



M|iiarc inch. 



Assuming the usual law tn \\<-\il jimul fur the \\hnlc dl'thu effective 

 depth, tlie iiiaxiiiiuin skin stress would h.> -I 1 17 Itis. per square inch. 



The co-efficient of elasticity . as detrriiiiiieil hy an increment in the 

 deflection of .375-in., between the loads cl' 2(100 II, N and 10,000 His., 

 is 1,11)4,700 lh>. 



Table () ti'ives the several reading! 



The total weight of the beam on March 1st, tie (!a'e of test, wa.- 

 ">_ I Ibs. 10 ozs., or 41.08 Ibf. for tulir Im t, and on February 1st 

 the weight wa> 5!i7 lb?., Or 46.73 Ibs-. jcr cubic foi t, showing a loss 

 of weight at the rate of .209-lb. per cubic loot per day. 



The time occupied by the test w.is 48 minutes. 



Beam \MX was tested March 2nd, 1894, with the annular rings as 

 in Pig. 97. The darkened portions represent sapwood. 



The load upon the be.im was gradinlly incr.'a-iud until it amounted 

 to 47,080 Ibs., when the beam failed by ihj teiriij; apart of tiio fibres 

 on the tension side, accompanied simultaneously by a longitudinal sh ir 

 and a crippling of the mat rial in the compiess:i n side, Fig*. I'S, 99. 



The maximum skin stress corresponding to the bn aking load is 

 4936 Ib.s. per square inch. 



The total compression of the material at the centre was 2.8 ins., so 

 that taking 13.095 ins. as the effective depth, the maximum skin com- 

 pressive stress would be 5156 Ib- 1 . p^r square inch, and the correspond- 

 ing skin tensile stress would be 7353 Ibs. per square inch. 



Assuming the usual law to hold good lor the whole of the effective 

 depth, 6835 Ibs. per square inch would be the maximum skin .stress. 



The co-efficient of elasticity, as di termiued Ly an increment of .435- 

 in., between the loads of 3000 and 21,000 Ibs., i-i 1,052,600 His. 



Table Q .-hows the several readings. 



The weight of the be-irn was 525 Ibs. 12 ozs., or 41.33 Ibs. p r cu- 

 bic foot February 1st, anil 473 Ibs. 12 ozs., or 37.24 Ibs. per cubic 

 foot on March 2nd. showing a loss of weight at thj rate of .141 -Ibs. 

 per cubic foot per day. 



The time occupied by the test was fifty minu'es. 



Beam L was tested March 10th, iS!(4, with the annular rings a< 

 in Fig. 100. 



