The following dream is still more remarkable. A lady dreamt that an aged female relative had been murdered by a black servant, and the dream occurred more than once. She was then so impressed by it, that she went to the house of the lady, and prevailed upon a gentleman to watch in an adjoining room during the following night. About three o'clock in the morning, the gentleman, hearing footsteps on the stairs, left his place of concealment, and met the servant carrying up a quantity of coals. Being questioned as to where he was going, he replied, in a hurried and confused manner, that he was going to mend his mistress's fire, which at three o'clock in the morning in the middle of summer was evidently impossible; and, on further investigation, a strong knife was found concealed beneath the coals. Dreams, to whatever causes they may be attributed, vary according to the nature of our sleep: if it is sound and natural, they will seldom prevail; if, on the contrary, it be broken and uneasy, by a spontaneous association dreams will become fanciful, and might indeed be called visions, so fantastic and chimerical are all the objects that present themselves in motley groups to the disturbed mind. This derangement in the sensorium may be referred to various physical causes,--the sensations of heat or of cold, obstruction in the course of the circulation of the blood, as when lying upon the back, a difficult digestion. In a sound sleep our dreams are seldom remembered except in a vague manner; whereas, in a broken sleep, as Formey has observed, the impression of the dream remains upon the mind, and constitutes what this philosopher called "_the lucidity of dreams_." It not unfrequently happens to us that we have had a similar dream several times, or at least we labour under this impression; nay, many persons fancy that particular events of their life at the moment of their occurrence had clearly taken place at a former period either in reality or in a dream. Morning "winged dreams" are more easily remembered in their circumstantial vagaries than those of the preceding night, for at that period (the morning) our sleep is not sound, and dreams become more lucid. These _revasseries_, as the French call them, are admirably described by Dryden: A dream o'ertook me at my waking hour This morn, and dreams they say are then divine, When all the balmy vapours are exhal'd, And some o'erpow'ring god continues sleep.