657 INDEX. Internal strains in gun forgings—Continued. Page. 5-inch R. F. gun tubes—Continued. No. 11791 Bl, after annealing at 650° F— Breech________________________________________________306 Muzzle..................................................... 308 No. 11791 B2— Breech__________________________________________________ 310 Muzzle_____________________________________________________ 312 No. 11794 B5, discard !-inch— Breech___________________________________________________ 314 Muzzle.................'......._ , 316 No. 11794 B5— Breech__________________________________________________ 318 Muzzle____________________________________________________ 320 Breech, after annealing at 665° F________________________ 322 No. 11837 B3— Breech................................................ 324 Muzzle___________________________________________________ 326 Breech...........j_____________________________________ 328 Muzzle................................................. 330 No. 12485 B7 BI— Breech _ _...................... .......... _ _ _ 332 No. 12485 B7 BM— Breech__________________________________________________ 334 Breech, annealed at 750° F________________________________ 336 Breech, annealed at 600° F__________ . 338 No. 12485 B7 BO A— Breech, annealed at 450° F .. _ 340 No. 20691 B3— Breech____________________________________________________ 342 Muzzle_____________________________________________________ 344 Breech................................................. 346 Muzzle___________________________________________________ 348 Steel tube after treatment— Remarks and conclusions_________________________________ 353-355 Tube intact__________________________________________________ 356 Tube cut apart at middle of length_____________________________ 356 Tangential strains and stresses__________________________ 357-865 Longitudinal strains and stresses__________________________ 366,367 Mortar. (See Cement). Mortar carriages, helical springs for______________________________ 385-392 Nickel steel: lf-inch round.___________________________________________________ _ 398-400 3-inch round___________________________________________________... 395-397 Tabulation_________________________________________________________ 400 Overstraining wrought iron, effect of______________________________ 417-450 Paper, tensile tests______________________________________________ . 645 Pig irons, chemical analyses and tensile tests_________________________ 376 Pine, yellow, push bars embedded in concrete_______________________ 622 Piston rods for gun carriages, proof stresses__________________________ 378 Pressure gauges, copper cylinders for______________________________ 459-461 Private tests, list of_____________________________________________ 650,651 Push bars, yellow pine, embedded in concrete____ __________________ 622 Recoil mechanism of Driggs-Seabury 15-pounder grm No. 12: Remarks___________________________________________________ 189-191 With bronze oscillating slide— Gun in firing position— Bottom side up________________________________________ 191,192 Right side up__________________________________________ 193,194 Bottom side up_________________________________________ 195-197 Gun in recoil position— Right side up____________._____________________________ 197-201 Gun in firing position—• Bottom side up— Counter recoil springs in_____________________________ 203 Counter recoil springs out______________________________ 204 Gun in recoil position_______________________________________ 205 Piston rod, test of elongation of__________________________________ 202 H. Doe. 508-----42