I 



D E 



Fig. 11 — ^Photomicrographs of Fatigue Specimens. 

 Nickel-Silver, 4 B. & S. Nos. Hard, Stress 28,750 Psi, 800,000 cycles, mag. 200. 

 Phosphor Bronze, 4 B. & S. Nos. Hard, Stress 25,500 Psi, 2,600,000 cycles, mag. 



200. 

 Alloy G Brass, Annealed, Stress 15,750 Psi, 2,471,200 Cycles, Mag. 200. 

 Everdur, Spring Hard, Stress 25,500 Psi, 1,186,900 Cycles, Mag. 200. 

 Hardened Brass Alloy No. 33, Stress 18,200 Psi, 850,000 Cycles, Mag. 200. 



Prepared by Miss A. K. Marshall 



