about three o'clock in the morning
So just as the clocks were striking the midnight hour Rob mounted skyward and turned the indicator of the traveling machine to the east , intending to make the city of Vienna his next stop . He had risen to a considerable distance , where the air was remarkably fresh and exhilarating , and the relief he experienced from the close and muggy streets of Paris was of such a soothing nature that he presently fell fast asleep . His day in the metropolis had been a busy one , for , like all boys , he had forgotten himself in the delight of sight-seeing and had tired his muscles and exhausted his strength to an unusual degree . It was about three o'clock in the morning when Rob , moving restlessly in his sleep , accidently touched with his right hand the indicator of the machine which was fastened to his left wrist , setting it a couple of points to the south of east . He was , of course , unaware of the slight alteration in his course , which was destined to prove of serious importance in the near future . For the boy 's fatigue induced him to sleep far beyond daybreak , and during this period of unconsciousness he was passing over the face of European countries and approaching the lawless and dangerous dominions of the Orient . When , at last , he opened his eyes , he was puzzled to determine where he was .