Immediately afterwards an utterly unbearable foetor welled forth from the unseen heights, choking and sickening the trembling watchers, and almost prostrating those in the square. At the same time the air trembled with a vibration as of flapping wings, and a sudden east-blowing wind more violent than any previous blast snatched off the hats and wrenched the dripping umbrellas from the crowd. Nothing definite could be seen in the candleless night, though some upward-looking spectators thought they glimpsed a great spreading blur of denser blackness against the inky sky—something like a formless cloud of smoke that shot with meteorlike speed towards the east.