seven
o'clock in the evening
I subsequently obtained some of the same brand -- Price 's stearine candles , six to the pound -- and experimented with them . Each candle was seven and a quarter inches in length , not counting the cone at the top , and I found that they burned in still air at the rate of a fraction over one inch in an hour . We may say that one of these candles would burn in still air a little over six hours . It would thus be possible for the person who inhabited these rooms to go away at seven o'clock in the evening and leave a light which would burn until past one in the morning and then extinguish itself . This , of course , was only surmise , but it destroyed the significance of the night porter 's statement . `` But , if the person who inhabited these chambers was not Jeffrey , who was he ? `` The answer to that question seemed plain enough .