DECEMBER TERM, 1859. The principle established in the preceding case extends also to a steamboat employed as a lighter and towboat, sometimes towing vessels beyond the outer bar of the bay, and into the gulf to the distance of several miles. The character of the navigation and business in which this boat was employed cannot be distinguished from that in which the vessels it towed or unloaded were engaged. The lightering or towing was but the prolongation of the voy age of the vessels assisted to