three o'clock
Let me be as I am . '' And time went on , with Tom plunging more and more deeply into the grand science , and rapidly becoming his uncle 's right-hand man , helping him with the papers he sent up to the learned societies , till in the course of a couple of years people began to talk of the discoveries made with the big telescope at Heatherleigh . Then came a morning about two years and a half after the terrible storm . Tom , who had not retired till three o'clock , for it had been a gloriously clear night , and he and his uncle had been busy for many hours over Saturn 's satellites , which had been observed with unusual clearness , was sleeping soundly , when he was awakened by the sharp rattling of tiny pebbles against his window . `` Hulloo ! what is it , David ? '' he cried , as he threw open his window .