Of course, this article refers entirely to the Curtiss hydroaeroplane, which I have been operating since its invention. The Curtiss pontoon is divided into six water-tight compartments, three of which will support the machine under average conditions. Recently, while the writer was abroad, a demonstration was made of these compartments for safety in case of accident to any part of the pontoon. This demonstration took place at Monaco, and consisted in removing the drain plugs from two compartments, after which the hydro with pilot and passenger was pushed out into the harbour and allowed to stand thirty minutes to let the opened compartments fill with water, after which the motor was started and a flight made without the slightest difficulty. The operation of a hydro is very similar to that of the ordinary land machine–only, if anything, considerably easier and more simple. The start of the hydro is simply starting the motor while the hydro is resting on the land or bank of the lake or river, with the front towards the water. The operator takes his place, and on opening the throttle gradually the thrust of the motor slides the apparatus along the ground, or planks if ground be unsuitable, and into the water. The pontoons being fitted underneath with steel shod runners makes it possible to start on rocks, gravel, or in fact most any reasonable surface. The finish can be made in the same manner, without assistance. It is possible to start the hydro on dry land if the surface is reasonably smooth, with the assistance of one or two mechanics. It is also possible, in an emergency, even to land on the earth with the hydro pontoon attachment; and, of course, with wheels attached to the landing gear, one can come down on land as with the ordinary type of machine. Once out upon the water, the operator rapidly increases his speed by opening the throttle, taking care, however, to accelerate gradually, to allow the pontoon to mount the surface of the water without throwing an unnecessary amount of water into the propeller. Once a speed of twenty-five to thirty miles an hour is obtained, the pontoon skims lightly over the surface of the water. As the ailerons do not become effective until the machine acquires considerable speed, the small floats on the lower ends of wings maintain the balance until necessary speed is acquired. The small flexible wooden paddles on the lower rear ends of the wing tanks slide over the water and exert a great lifting effect, thus rigidly preserving the balance on the water at slow speeds or standing, and also preventing damage to wings in case a bad landing is made whereby one wing strikes the water first. In such a case, instead of the wing digging into the water, the paddles cause a glancing blow which levels the machine automatically.