Then into our lives came a heroic figure. Just at that moment he appeared the greatest man in the world--philanthropist, navigator, philosopher! He was the skipper of Canal Boat No. 18 which swept majestically down the pool. His boat appeared as big and formidable as the new superdreadnaught Pennsylvania. Dexterous work with the paddle enabled us to get in its lee. Up there on his quarterdeck stood the skipper. I since believe that he must have resembled Noah, but to we two--we felt like castaways--he was indeed a mighty admiral. But he was the admiral of a friendly power and amid all his dignity there was a benign expression also of stern consideration for a brother mariner in distress. We gazed at him and his noble craft in mute appeal. "Ketch the line!" Like spent swimmers grasping for a straw, we seized the line and made it fast. For the second time "Sometub" was humiliated by being towed by a prosaic freight boat. [Illustration: Above--Upper Level at Four Locks Below--Old-Time Mill] Two miles an hour is top speed for a laden canal boat and No. 18's tired mules kept well inside this limit. At the end of the towline we nosed along in perfect complacency. We chatted with the skipper, admired the scenery, examined our maps of the route, chaffed the villagers, ate our luncheon, jogged the motor, read a little, took short naps and made ourselves absolutely comfortable. Our only effort was to keep on the shady side of the boat, for the weather was the hottest we had endured. As a remedy for tired nerves I can testify to the curative qualities of canalboating. The skipper was a man of parts. He had run the canal for more than 20 years. He had walked every inch of the towpath from Cumberland to Washington every hour of the day and night and he declared that he could pace those 184 miles with his eyes blindfolded. He recognized every hill and house and tree and could tell their history. He knew all the neighborhood gossip, and all the neighbors knew him. Toward the end of the drowsy afternoon we floated into the little village of Four Locks which takes its name from the fact that a chain of four locks are here. No. 18 cast us off and we prepared to paddle through. To our surprise the motor condescended to run. At the time I was ready to believe that it heard the mule driver's sublime cussing and was frightened into obedience. With the motor running again we soon passed No. 18 and snorted off around a sharp bend, through Two Locks where we were lowered into the waters of the Potomac. I say "snorted" advisedly. "Sometub" exhibited colt-like behavior when unleashed from the slow-moving canal craft. The towpath follows the northern bank of the river and the boats hug the shore closely, but we careened far out into the stream. "Sometub" had found a nautical playground more spacious than it had ever enjoyed before.