Oakum stops leak, 205. Oats cause tragedy, 178. _Oceana_, blasting operations, 50. _Oceana_, difficulties of salving treasure, 50. _Oceana_, wreck of, 49. Octopus attacks diver, 202. Oil hinders divers, 84. Oil obscures leaks in battleship, 86. Oil salved from tanker, 163. Oil tankers take fire, 161–163. _Onward_, scuttling of, 163. Ostend, 115. Ostend, how Germans bottled up harbour, 116. Overturned ship, methods of salvage, 164. Ownership of war wrecks, 112. Palsy, diver’s, 36. Patch, standard, 100. Patches, emergency, 206. Patching battleship, 85. Penk, Diver, 59. Periscope, 137. Peru, gold of, 11. Peruvian treasure, 11. _Philadelphia_, see _City of Paris_. Phosphate, island of, 14. Pino, Cavaliere, inventor of hydroscope, 210. Pirates, chased by, 62–64. Pit disaster near Falkirk, 42. Pizarro, 11. Pneumatic chisels used by divers, 165. Pomeroy, Captain H., 176. Pontoon raises 800 tons, 177. Pontoons, 116. Pontoons and _Araby_, 177. Pontoons and salvage operations, 89. Pontoons, assist to raise the _Gladiator_, 166. Pontoons, how used, 89. Pontoons used in salving F.4, 153. Port Arthur, raising Russian fleet at, 211. Portsmouth, 167. Pressure and divers, 35. Pressure crushes diver, 154. Pressure, how it affects diver, 155. Propeller shaft cut into bollards, 191. Pumps, electric, weight of, 104. Pumps keep ship afloat, 105. Pumps, sand, 29. Pumps, types of, 103. Pumps _versus_ torpedoes, 103. Pumps, wonderful reliability of, 105. Quay, threatened destruction of Folkestone, 163. Queenstown, 94. _Racer_, salvage vessel, 65. Racing yacht salved, 204. Railway engines raise a ship, 164, 165. Recompression chamber, its uses, 70. Record depth from which treasure has been recovered, 48. Record, diving, 38. Record, twelve-hour diving, 137. Record weight raised, 158, 159. Record, world’s diving, 155. Redding pit disaster, 42. Refloating H.M.S. _Britannia_, 172. Refloating the _Timbo_, 186, 187. Refrigerator, unpleasant task in a, 171. Rescue of crew of submarine S.5, 145. Rescue of survivors of K.13, 139. Ridyard, Diver, 59. Righting a battleship, 92. Risk of salvage work, 8. Risk of salving German submarines, 128. Rock-cutter, 195. Rock reveals a fortune, 13. Rocks blasted away to salve ship, 183. Ropes, breaking strains of, 192. Ropes, giant, 192. Ropes, steel, 191, 192. Rosyth, 159. Royal Exchange, 46. _Royal George_, salvage operations, 200. Rust handicaps divers, 190. St. Bees Head, 105. St. Helena, 25. _St. Paul_, collision with H.M.S. _Gladiator_, 165. _St. Paul_ converted into troopship, 167. _St. Paul_ overturns, 167. _St. Paul_, salvage operations on, 168. S.5, discovery of, 144. S.5, rescue of crew, 145. S.5, strange accident to the American submarine, 141.