In the Clarke engine, the exhaust pipe from the high pressure cylinder leads to the steam chest of the low pressure cylinder, while the piston in the upper cylinder is secured on a piston rod extending downward and connected with a piston operating in the lower cylinder, the exhaust pipe from the latter leading to the outside. On the piston rod common to both cylinders is secured a crosshead pivotally connected by two pitmen with opposite crank arms on crank shafts mounted to turn in suitable bearings on the base, which also supports a frame carrying the low pressure cylinder, on top of which is a frame supporting the high pressure cylinder. The valves in the two steam chests are connected with each other by a valve rod connected at its lower end in the usual manner with the reversing link, operated from eccentrics secured on one of the crank shafts. The crank arms stand at angles to each other, so that the crank shafts are turned in opposite directions, and the position of the link is such that it can be readily changed by the reversing lever to simultaneously reverse the motion of the crank shafts. On the crank shafts are also formed two other crank arms pivotally connected by opposite pitmen with a slide mounted in vertical guideways, supported on a frame erected on the base, the motion of the crank shafts causing the vertical sliding motion of the slide traveling loosely in the guideways, and thus serving as a governor, as, in case one of the propellers becomes disabled, the power of the shaft carrying the disabled propeller is directly transferred to the other shaft through the crank arms, pitmen, and slide, and the other propeller is caused to do all the work. All the parts of the engine are within easy reach of the engineer, and there are so few working parts in motion that the friction is reduced to a minimum. It is said that the plan of construction and the operation of this engine have been carefully observed by practical engineers, and that, considering the dimensions of the boat, her speed, the smallness of the power, the ease with which she passes the centers, the absence of vibration while running, and the very few working parts in motion, the engine is a notable success. She can be run at a very high velocity without injury or risk, and is designed to be very economical in cost and in weight and space. This engine has been recently patented in the United States and foreign countries by Mr. James A. Clarke, of New Westminster. * * * * * IMPROVEMENTS IN THE CONSTRUCTION OF RIVER AND CANAL BARGES. By M. RITTER (KNIGHT) VON SZABEL, late Austrian Naval Officer, of Vienna.