ten o'clock
I had up to the sixth day experienced no inconvenience from the fog , and this was largely due , I am convinced , to the unnoticed operations of the American machine . On the fifth and sixth days Sir John did not come to the City , but he was in his office on the seventh . The door between his room and mine was closed . Shortly after ten o'clock I heard a cry in his room , followed by a heavy fall . I opened the door , and saw Sir John lying face downwards on the floor . Hastening towards him , I felt for the first time the deadly effect of the deoxygenized atmosphere , and before I reached him I fell first on one knee and then headlong . I realized that my senses were leaving me , and instinctively crawled back to my own room , where the oppression was at once lifted , and I stood again upon my feet , gasping .