A number of fine steam propellers, of moderate tonnage, have lately appeared on oui waters, and more are in progress of construction. A Una of schooner-rigged propellers ply between this city and various places or Long Island Sound. They are well built anc run very fast. A new line of propellers has been established to carry freight and run or the North River between New York and Al. bany. The firstone ofthe line has been built at Newburgh. The boat is of large dimensions160 feet keel; 29 feet 4 inches breadth oi beam,S feet depth of hold. The machinery consists of two double cylinder engines, direct action, formed upon an improved principle, the invention of John Baird, of the Highland Iron Works. The piston of each cylinder is connected to the crank-wheel pin oi the Piopeller-shait, directly under it. The condenser and air-pump are placed between the cylinders ; the air-pump being horizontal and double acting, receiving its motion from a link attached to one of the slides. The engine is on the Wolte principle, but is new so tar as regards the construction and arrangement ol its parts.