A sad drowning accident occurred in St. John harbor early yesterday morn. Frank BECKWITH, belonging to Harvey (Albert Co.), a sailor on board schr. "Ettie" lying at Dunn's wharf, left his vessel and started to mail a letter to his parents which he had written the previous night. It being quite dark and the wharf in a somewhat delapidated condition, it is supposed that Beckwith stumbled and fell into the water. His shipmate, Charles LEWIS, was on the wharf at the time and hearing Beckwith cry out rushed to the spot and threw a plank overboard, but he failed to grasp it. Lewis then boarded the "Inglewood" and with the mate of that schooner put off in a boat, but Beckwith had sunk before they arrived and was drowned.