Cylinders made of steel with water-jackets welded on. Motor is direct-driven and develops 250 horse-power at 1,500 r. p. m., and 270 horse-power at 1,700 r. p. m. The weight of the bare motor is 240 kilos, or approximately 528 pounds, while the weight of the motor complete with radiator and water is 305 kilos, or 671 pounds. There seems to be a reasonable doubt regarding the exact weight of the bare motor, as while the French Commission gave us the figure of 528 pounds, information from other sources indicates a weight of 552 pounds; probably some intermediate figure is more nearly correct, but in any event the motor gives a horse-power for approximately two pounds of weight when figured at its maximum output of 270 horse-power. After obtaining this information and considering the matter very carefully, we next investigated the matter of testing such a motor, as we knew that a motor of this type could not be run at full power for long periods of time without developing serious trouble. Here again the French Commission gave us valuable information. They stated that in using a motor of this type it is only run at full power for short periods of time while climbing or fighting, and that all other times it is run at speeds 200 to 300 r. p. m. slower. In view of the fact that the motor is built to run under these conditions, it is, of course, necessary to test it under similar conditions, and they stated when trying out a new model of motor it is their practice to mount a propeller which will just hold the motor down to maximum speed under full throttle. The motor is then run for fifty hours, in periods of six to eight hours each, but the motor is not run up to full speed for more than a total of ten hours during this entire period, nor is it run more than thirty minutes at any single time under this condition. The other forty hours’ running is under throttled conditions, turning the same propeller 200 to 300 r. p. m. less than maximum speed. This information is of the utmost importance, as it enables us to reduce all factors of safety and make possible the light-weight per horse-power now being obtained in Europe. After obtaining this information we immediately laid down a proposed motor which we believe can be produced promptly in large quantity in this country. Built carefully out of proper materials, this motor will have approximately the following characteristics and be as good, or a little better, than the Loraine Dietrich, which is not as yet really available abroad.