Until we should see either the horizon or the sky or the sea, and thus restore our sense of the horizontal, we could tell only by the instruments what was happening to the Vickers-Vimy. Unless there be outside guidance, the effect on the Augean canal in one's ears of the centrifugal force developed by a turn in a cloud causes a complete loss of dimensional equilibrium, so that one is inclined to think that an aëroplane is level even when it is at a big angle with the horizontal. The horizontal, in fact, seems to be inside the machine. A glance at the instruments on the dashboard facing us made it obvious that we were not flying level. The air speed crept up to ninety knots, while Alcock was trying to restore equilibrium. He pulled back the control lever; but apparently the air speed meter was jammed, for although the Vickers-Vimy must have nosed upwards, the reading remained at ninety. And then we stalled--that is to say our speed dropped below the minimum necessary for heavier-than-air flight. The machine hung motionless for a second, after which it heeled over and fell into what was either a spinning nosedive, or a very steep spiral. The compass needle continued to revolve rapidly, showing that the machine was swinging as it dropped; but, still hemmed in as we were by the thick vapor, we could not tell how, or in which direction we were spinning. Before the pilot could reduce the throttle, the roar of the motors had almost doubled in volume, and instead of the usual 1650 to 1700 revolutions per minute, they were running at about 2200 revolutions per minute. Alcock shut off the throttles, and the vibration ceased. Apart from the changing levels marked by the aneroid, only the fact that our bodies were pressed tightly against the seats indicated that the machine was falling. How and at what angle it was falling, we knew not. Alcock tried to centralize the controls, but failed because we had lost all sense of what was central. I searched in every direction for an external sign, and saw nothing but opaque nebulousness. The aneroid, meantime, continued to register a height that dropped ever lower and alarmingly lower--three thousand, two thousand, one thousand, five hundred feet. I realized the possibility that we might hit the ocean at any moment, if the aneroid's exactitude had been affected by differences between the barometric conditions of our present position and those of St. John's, where the instrument was set. A more likely danger was that our cloud might stretch down to the surface of the ocean; in which case Alcock, having obtained no sight of the horizon, would be unable to counteract the spin in time.