INDEX. 658 Recoil mechanism of Driggs-Seabury 15-pounder gun No. 13—Cont’d. Page. Piston rod, free test of_________________________________________ 206 With steel oscillating slide in place of bronze— Gun in firing position— Bottom side up___________________________________________ 207 Right side up________________________________________________ 208 Right side up with iron dog______________________________ 209 Bottom side up with and without iron dog_________________209,210 With reenforced cast-steel sleeve and reenforced bronze oscillating slide— Remarks _____________________________________________________ 211 Gun in firing position, bottom side up_______________________ 212,213 Gun in position at half recoil_______________________________ 214 Gun in recoil position_______________________________________ 214,215 Gun in firing position__________________________________________ 216 Rifle-barrel steel, .30 caliber: Hydrostatic tests— Annealed as usual____________________________________________ 87-89 Annealed by residual heat________________j___________________ 89-91 Cooled in air________________________________________________ 92-94 Tensile tests— Remarks _______________________________________________________ 69 Specimens from the bars________________________________________ 69-71 Prom butts of finished barrels— Rolled and annealed as usual____________________________ 72,73 Rolled and annealed at residual heat____________________ 74,75 Rolled and cooled in the air_____________________________ 76,77 From middle of lengths of finished barrels— Rolled and annealed as usual____________________________ 78,79 Rolled and annealed at residual heat____________________ 80,81 Rolled and cooled in the air_____________________________ 82,83 Tabulation _. ............................................... 84 Rotating shafts, steel: Endurance test...................................................... 633 Tensile tests of metal___________________________________________ 637-643 Silk cartridge cloth_________________________________-............... 644 Specific gravity: Bronze........................................׳..................453 Cast iron and pig iron_________________________________________ 371-376 Cements______________________________________________________ 476-490 Springs, helical, for gun carriages: 3-inch experimental carriage................._................... 389-391. 7- inch mortar carriage......................-.......-........... 388 8- inch carriage--------------------------------------------------- 387 12-inch mortar carriage-----------------:------------------- 385-387,392 15-pounder gun, recoil cylinder-------------------------------------- 388 Brake lever springs for 12-inch carriage ________________________ 392 Standardizing testing machine at the works of the Driggs-Seabury Gun and Ammunition Company___________________________________________ 403-406 Steel, chemical analyses........................................- - - 649 Steel bars: Adhesive resistance of, in concrete.............................. 620 Anchor bolts for gun carriages------------------------------------ 377 Eyebars, chemical analyses and tensile tests________________ ____ 409-414 Gun specimens______________________________________________________ 13-65 Nickel steel________________________________________________ 395-400 Piston rods, proof stresses__________________________________________ 378 Plate________________________________________________________________ 406 Rifle-barrel steel, .30 caliber-------------------------------- 69-94 Rotating shafts, metal from__________________.................... 637-643 Standardizing testing machine--------------------------------- 403-406 Steel castings: For gun mounts— 15-pounder— Carrier ring ............................................. - 185 Inner bases-------------------------------------------- 143-162 Outer bases____________________________________________ 165-182 Pivot sockets___________________________________________ 105-114 Pivot yokes............................................. 117-139