| 1931 BONNEY FLOYD COMPANY Mine Car Bumper Patent |
| 1931 LONG ARMISTEAD Mine Car Patent Print Art |
| 1931 JOHNSON WARREN Mine Car Patent Print Art |
| 1931 ELECTRIC BOAT CO Dry Mine Laying Submarine |
| 1931 GRIESHABER Dry Mine Laying Submarine Patent |
| 1931 MARTIN Transfer Means For Mine Cars Patent |
| 1931 AMERICAN CAR FOUNDRY CO Drop Bottom Mine Car |
| 1931 SHULAR JOSEPH Mine Car Patent Print Art |
| 1931 WATT Mine Car Art |
| 1931 HENRY Drop Bottom Mine Car Patent Print Art |
| 1931 CENTRAL MINE EQUIPMENT Blasting Cartridge Tamper |
| 1931 FREDERIK Submarine Mine Layer Patent Print |
| 1931 AMERICAN CAR & FOUNDRY CO Mine Car Patent |
| 1931 JONES Mine Car Art Print |
| 1931 ELECTRIC BOAT CO Mine Laying Submarine Art |
| 1931 SPEAR Mine Laying Submarine Patent Print |
| 1931 RUFFING SR Mine Car Patent Print Art |
| 1931 VETH Mine Car Art |
| 1931 WATT CAR AND WHEEL CO Mine Car Patent Print |
| 1931 SANFORD INVEST COMPANY Mine Car Patent |
| 1931 GRIESHABER Mine Laying Submarine Patent |
| 1931 EDMUNDS GLENN Mine Car Bumper Patent Print |
| 1931 NAAMLOOZE VENNOOTSCHAP KONINK Submarine Mine Layer |
| 1931 NIKOLAUS Electric Mine Firing Device Patent |
| 1931 CENTRAL MINE EQUIPMENT Blasting Cartridge |
| 1931 BLYTH PRATT Submarine Mine Patent Print Art |
| 1931 WARREN E POUDER Transfer Means Mine Cars |
| 1931 MARCO Submarine Mine Method Anchoring Same |