During one of these submerging tests a wonderful and fairy-like spectacle was presented to us. I had caused the boat to be steered so that the conning-tower lay nearly two fathoms under water. Above, the sun shone brightly and filled the deeps with radiant light. The water was lit by many colours. Around us the sea was of brightest azure blue of an almost dazzling clearness, and transparent as glass. From the window of the conning-tower I could see the whole length of the boat, round which rose twinkling air bubbles, like pearls. In strange, fantastic distinctness the deck lay stretched out before me, even the furthest bow end was visible. Further ahead was a dim-coloured twilight. It seemed as if the bow of the boat was gliding silently through a wall of opal green, which opened up as she moved, and broke into a dazzling radiant-coloured transparency of light. We were spellbound at this wonderful sight, and the strangeness of the effect was increased by the jelly-fish as they floated through the transparent blue and were caught in the wires of the deck rails, where they shimmered first rose colour, then pale yellow, changing slowly to purple. We were not able at that slight depth to observe any fish. The next day a little incident occurred which afforded us much amusement, though it turned out rather differently from what we had expected. My ambition was to follow in the tracks of my comrades of the merchant service and the navy, who had disguised their ships from the enemy by painting and clever alterations in their outward structure. During the previous fine spell of weather we had made a wonderful trap for steamers, in order to disguise our identity as a U-Boat from ships passing in the distance. We had rigged up a funnel out of some sail-cloth, which could be fixed to the periscope with several wire rings, till it rose proudly in the air. The conning-tower was also provided with a covering of sail-cloth to make it resemble the upper middle deck of a small trading vessel. Thus, ready for all emergencies, we travelled on in the brilliant sunshine, till at 7.30 in the evening a steamer appeared in the distance to starboard. We soon realised that she must pass quite near to us if we continued on our present course. We held aloof from her therefore and proceeded to try the effects of our disguise. The "funnel" is fixed up on to the periscope and rises proudly erect in the wind. In order to give it a more realistic appearance we burn some cotton waste steeped in oil at its base. Then the conning-tower disappears under the rather flattering "middle deck."