Thinking this somewhat strange, he got into a boat and rowed out alongside. He still heard the tapping at regular intervals, and was astonished to see a small boat alongside; then he struck the _Argonaut_ with his oar and immediately got a rapid tattoo in response. Feeling sure now that somebody in distress must be down in the _Argonaut_, he got a lantern, went down inside the boat and forward to the diving compartment. There, on the other side of the lookout window, he saw the face of the engineer. The chief had made the mistake of closing the forward air-lock door, so that when he got the pressure on in the diving compartment and the diving door open he could not close it again. There was no way for him to relieve the pressure and open the air-lock door without flooding the whole boat; while, had he closed the first or inner door he could have gone through into the air-lock, closing and securing the forward door behind him. He could then have released the air from the air-lock and escaped, in the meantime leaving the pressure on in the diver's compartment and the divers' door open. When the watchman appeared the chief wrote a note and put it up to the window, instructing the watchman to close the inner air-lock door. This was done, and then he and his friend got out. It was nearly midnight when they were released; and, feeling a natural curiosity in the circumstances, I asked the chief if his friend found his bride still waiting for him at the station. He replied that after they had managed to get out his visitor would not even speak to him, and that he had never heard from him since the occurrence. I have described above how I ran grave risks while navigating in Russian waters, and it was in connection with the construction and delivery of these same boats for the Russian Government that I met with still other interesting experiences. [Illustration: THE LAUNCHING OF THE "PROTECTOR" Built in Bridgeport, Connecticut, in 1901-1902. Sent to Vladivostock, Russia, during the Russian-Japanese war, and was the only Russian submarine in full commission during that war. She was the forerunner of the German U type of boat, with her large flat deck, light-weight watertight superstructure and hydroplane control.]