About ten minutes before eleven
`` At her own chamber door . We bade each other good-night , and I retired to rest immediately . '' `` What hour was that ? '' `` About ten minutes before eleven . '' `` What communication were you making to Lady Kingsland at that hour ? '' `` I came to tell her the household had all retired -- that she could quit the house unobserved whenever she chose . '' `` You knew , then , that she had an assignation for that night ? ''