about four o'clock
She was only just in time . A moment later , Isabel van Cannan came into the room with a packet of letters in her hands . `` Oh , Miss Chaine , '' she said , with her pretty , child-like air , `` would it be too much to ask you to take down these letters to the store presently ? The mail is to leave about four o'clock . I have to go out myself by and by , but the Saxbys ' house is in the opposite direction , as you know , and I am really not able to knock about too much in this heat . '' `` Certainly I will take them , '' said Christine . `` But the children ? ''