When soft sleep the body lays at ease, And from the heavy mass the fancy frees, Whate'er it is in which we take delight, And think of most by day we dream at night. The transition from sleep is very natural to that of dreams, the wonderful and mysterious phenomena of that state, the ideal transactions and vain illusions of the mind. According to Wolfius, an eminent philosopher of Silesia, every dream originates in some sensation, and is continued by the succession of phantoms; but no phantasm can arise in the mind without some previous sensation. And yet it is not easy to confirm this by experience, it being often difficult to distinguish those slight sensations, which give rise to dreams, from phantasms, or objects of imagination.[81] The series of phantasms which thus constitute a dream, seems to be accounted for by the law of the imagination, or association of ideas; though it may be very difficult to assign the cause of every minute difference, not only in different subjects, but in the same, at different times, and in different circumstances. And hence M. Formey, who adopts the opinion of Wolfius, concludes, that those dreams are supernatural, which either do not begin by sensation, or are not continued by the law of imagination.[82] The opinion is as old as Aristotle, who asserted, that a dream is only the [Greek: Phantasma] or _appearance_ of things, excited in the mind, and remaining after the objects are removed.[83] The opinion of Lucretius, translated in our motto, was likewise that of Tully.[84] Locke also traces the origin of dreams to previous sensations. "The dreams of sleeping men," says this profound philosopher, "are all made up of the waking man's ideas, though for the most part oddly put together."[85] And Dr. Hartley, who explains all the phenomena of the imagination by his theory of vibrations and associations, says, that dreams are nothing but the imaginations or reveries of sleeping men, and that they are deducible from three causes--viz, the impressions and ideas lately received, and particularly those of the preceding day, the state of the body, more especially of the stomach and brain, and association.[86] Macrobius mentions five sorts of dreams. 1st. vision--2nd. a discovery of something between sleeping and waking--3rd. a suggestion cast into our fancy, called by Cicero, _visum_,--4th. an ordinary dream--and fifth, a divine apparition or revelation in our sleep; such as were the dreams of the prophets, and of Joseph, as also of the Eastern Magi. CAUSE OF DREAMS.