WEXFORD.—At 9 P.M. on the 18th March signals of distress were observed,from a vessel on the North end of the Dogger Bank. The Civil Service No. 1 Life-boat was immediately launched, and proceeded to render assistance. On arriving alongside the vessel, which was the schooner Blue Jacket, of Beaumaris, bound from Bangor to Wexford, with a cargo of slates, some of the Life-boatmen went on board, assisted to lighten her, and got her afloat at about 7.30 on the following morning. She carried a crew of three men..