about midnight
`` To-morrow we will explore the island , '' said Tom , as he rolled himself up in his blankets and turned over to sleep . The others followed his example , for it was decided that no watch need be kept . Thus passed several hours in comparative quiet . It must have been about midnight that Tom was suddenly awakened by a feeling as if someone was shaking him . He sat up quickly and called out : `` What 's the matter ? '' `` Eh ? What 's that ?