"Man overboard!"It rang in Felix Thurstan's ears like the sound of a bell. He gazed about him in dismay, wondering what had happened.The first intimation he received of the accident was that sudden sharp cry from the bo'sun's mate. Almost before he had fully taken it in, in all its meaning, another voice, farther aft, took up the cry once more in an altered form: "A lady! a lady! Somebody overboard! Great heavens, it is her! It's Miss Ellis! Miss...