ill tl.vtimi ol l.l.'i in-. I,.|\MCII the loads "of 1000 and 15,000 Ibs., it, 



i..v_>s,.i!>!i ids. 



T.iMi- S .-how* the -cvcral rea<l 



Tin 1 weight oftlie beam on Oct. 3rd WHS 751 Ibs. 6ozs.,or 27.206 

 ili- per ruble Coot, and on Nov. 3rd, tin- date "I" test, it weighed 7::.". 

 11 . 2A ozs., ur 26.(>14 Ibs. per cubic font, showing a loss while in the 

 laboratory at the rate of .010 Ibs. per cubic foot pur day. 



lieanis LV and LVI are the eudsof Beam FJ V, the central pnnini, 

 Containing thf fracture having been cut. out. 



liraiu l.V mi lestcd Nnv. 3rd, 1803, with the annular linir- as in 

 Fig. 10S. 



/~sg./oe j 



The load was gradually increased until it amounted to 73,000 Ibs., 

 when it failed l>y tin- crippling- of the fibres on the compression side- 

 Fig. 109. 



The maximum skin stress corresponding to this load i 4839 lb.-. 

 per square inch. 



The maximum compression of the material at the ecntral support 

 was 2 ics., so that taking 15 5 ins. as the effective depth, the maximum, 

 comprcssivc i-kin i-trcss is 5123 Ibs. per square inch, the corresponding 

 tensile skin stre.-s being (J(i4l Ibs. per square inch. 



If it is assumed that the usual law holds good for the whole of the 

 effective depth, the maximum skin stress becomes 6170 Ibs. 



As soon as the beam was relieved of load, the. amount of compression 

 at the support was immediately diminished by ,9-in., and at the end of 

 thirteen days the amount of compression w:is .82 in. 



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

 deflection of .17-in., letween the loads of 3000 Ibs. and 10,000 Ibs., is 

 1,070,950 Ibs. 



Table T shows the several readings. 



The weightof the beam on JCov. 3rd, dsitc of test, was 2<!.i;i-l Ibs. per 

 cubic foot 



Beam LVI was tested Nov. 4th, 1893, with the annular tings as in 

 Fig. 110. 



The load was gradually increased until it amounted to 70,000 Ibs. 

 when' itfailid by the crijpling of the fibres on the compression side 

 Fig. 111. 



The maximum skin stress corresponding to this breaking load is 

 4614-lbs. per square inch. 



The maximum compression at the centre of support was 1.9 ins., so 

 that taking 15.0' ins. as the effective depth, the maximum compressive 

 skin stress is 4916 Ibs. per square inch, the corresponding tensile -kin 

 stress being 6280 Ibs. per square inch. 



If it is assumed that the usual law holds good for the whole of tin- 

 effective depth, then the maximum skin stress becomes 5806 Ibs. per 

 square inch. 



Ten days after this beam had been relieved of load, the amount of 



33 



