five o’clock
`` Let us reconstruct . At four o'clock , Mrs. Inglethorp quarrels with her son , and threatens to denounce him to his wife -- who , by the way , overheard the greater part of the conversation . At four-thirty , Mrs. Inglethorp , in consequence of a conversation on the validity of wills , makes a will in favour of her husband , which the two gardeners witness . At five o'clock , Dorcas finds her mistress in a state of considerable agitation , with a slip of paper -- ` a letter , ' Dorcas thinks -- in her hand , and it is then that she orders the fire in her room to be lighted . Presumably , then , between four-thirty and five o'clock , something has occurred to occasion a complete revolution of feeling , since she is now as anxious to destroy the will , as she was before to make it . What was that something ? `` As far as we know , she was quite alone during that half-hour .