The steam pressure at the time of launching was 110 pounds, which was obviously insufficient. The aerodrome had lifted fifty per cent of its weight on the pendulum, and its sluggishness of movement seemed, therefore, unaccountable even for this pressure. It seemed probable, however, that the pressure ran down immediately after the machine was launched, on account either of the use of the light-weight burners in place of the larger and heavier ones, or of the diminution of the air pressure in the gas tank. At 7.55 the aerodrome was again launched, and this time made a still shorter flight than before, being in the air only three seconds. A serious leak in the engine cylinder was, however, discovered just as the machine was launched, and this probably accounted for the lack of power. Not only had the tests which have just been described indicated that there was a lack of power during flight, although previous pendulum tests had repeatedly shown lifts greater than fifty per cent, but, furthermore, the wings themselves, while appearing perfectly capable of supporting the aerodrome when viewed with the machine stationary, were seen to flex to such an extent in flight that it seemed probable that much of the power was consumed in merely overcoming the head resistance of a large portion of the wings which had lost all lifting effect. During the fall and winter, as recorded in Chapters VII and VIII, Aerodrome “New No. 4,” which had been reconstructed during the summer, and which upon test was found radically weak, was almost entirely rebuilt and afterwards known as No. 6. Important changes were also made in No. 5, which greatly increased its strength and power. The improvements, however, which contributed more than anything else to the marked success achieved in the next trial of the aerodromes, were those which had to do with the nature and disposition of the sustaining surfaces and the means for securing equilibrium. [p106]