He came a little nearer, and I was confident the bait would prove irresistible. But my assurance was ill-founded, for in spite of all my coaxing, Nab only circled round and round me until I was dizzy trying to keep track of him. Either he had had fairly good luck fishing for himself that morning, and was not suffering very keen pangs of hunger, or else he still associated my benevolence too closely with the little square splash-tub of the seal-house. When I had begun to grow weary from the incessant motion necessary to keep myself afloat, Nab suddenly made a dash so close that his flippers brushed my side. He snapped the fish out of my hand, and in the same instant he was again beyond reach. The fact that he had come up for one fish encouraged me to hope he would come also for the second, and I began to coax with renewed energy. Nab was seemingly as much on his guard as before, however, and again went through his complete list of maneuvers, first rearing high out of the water, turning one side of his head and then the other toward me, then ducking into the depths with a final flourish of his tail, to reappear presently on the other side of me, as sportive as before. By this time I had begun to feel pretty well exhausted, and when I suddenly thought of the undertow, I decided to swim back. So intent had I been upon urging Nab near enough to get the lariat about his neck that I had not once looked toward shore. As I now did so I was terrified to find that one of the unaccountably shifting currents along Moss Beach had swept me a long distance out to sea. Without more nonsense, I dropped my remaining shad and started back with long, even strokes. Nab snapped up the fish and disappeared in the deep green water. In spite of my efforts, I found that I was making small speed against the current. The rock and tree on the point of land to my right, by which I judged my progress, kept almost in the same straight line. Knowing it was useless to spend my strength directly against a current, I shifted my course in the direction of the point. From the sand-hills to my left I could see that I now made more progress, but the distance I had to cover was greater than straight to Moss Beach. Before I had covered half the distance I was almost too fatigued to take another stroke; then the feeling of weariness seemed to leave me, and I swam on as if turned into a machine. It was in a mechanical way, too, that my brain seemed to work. "If the undertow's as strong as when I came out," I thought, "I can never get through the breakers." I wished I had told father my plans. He might have come out with a boat to get me. Then I wondered how it was that my arms and legs kept on moving when there was so little feeling in them. The roar of the breakers had suddenly grown louder, and I saw I was within twenty yards of shore. I swam on with the same steady strokes, but at a certain distance from the water-line came to a standstill.