WHITHORN.—On the evening of the 12th July several small boats were fishingfor mackerel while a moderate breeze was blowing from W. The wind suddenly shifted to N., and increased to a strong gale. One of the boats contained the coxswain of the Life-boat, and on board others were the. assistant coxswain and other Life-boat men. They managed with considerable difficulty to get into port, but another member of the crew, whose boat was farther out in the offing, was seen drifting fast to sea. The Acting Honorary Secretary had the keys of the Life-boat house ready, and a few minutes after landing in their own boats the men were off in the Life-boat Henry and John Leighton, proceeding to the assistance of their endangered comrade. They came up with him about five miles distant from the laud, took him into the Life-boat, and towed his boat home. When the gale came on he let go his anchor, but the rope parted, and in trying to pull to the shore he broke one of his oars, and was therefore in a helpless condition when rescued..