its own reflections, and free to apply to its own views. In some of these cases it has been known to solve difficulties better than when awake, as in the instance of the man mentioned by Henricus ab Heeres, of whom it is related, that when young, being a professor of a distinguished university, and engaged in the composition and improvement of verses, he has been known, after being dissatisfied with his labours in the day, to have risen in the night, to have opened his desk, and to have written and composed, reading aloud his production, and applauding himself with satisfaction and laughter, and sometimes calling to his chamber-fellow to join in his commendation after which he has been observed to arrange his papers and shut up his desk, and then undress and retire to bed, and sleep till the morning, when he retained no recollection of the transaction of the night*.'

"

*Henricus ab Heeres Observat. Medic. L. i. Obs. 2. p. 32, 33. Wanley's Wonders, p. 625.

The same conclusion may be drawn from the relation of Cælius Rhodiginus, who informs us, that when he was twenty-two years of age, being busied in the interpretation of Pliny, while as yet the learned emendations of Hermolaus Barbarus on that excellent author had not performed to him all that was requisite, he was reading that place in the seventh book, which treats of those who grow up beyond the usual proportion which Nature has assigned. The word Ectrapali, by which such persons were described by the Greeks, was of some trouble to him. He knew that he had read something concerning it, but not being able to recall the author, nor the book in which the word was mentioned, and fearing the imputation of unskilfulness, he retired with uneasiness of mind to sleep, when his thoughts continuing still to employ themselves on the subject, he recollected the book, and even the page which he wanted *.

*Schotts Phys. Curios. L. iii. C. 25. p. 50. Cæl. Rhod. Antiq. Lect. L. xxvii, C, 9. p. 1250. and Wanley's Wonders, Ch. 23.

Persons are very commonly known to walk in their sleep over ridges and parapets, at which Mad Tom would have shuddered. Upon these occasions it appears, that they often act merely from recollection, since they stumble over objects placed in their way. The recollection, however, is often defective, and however circumspectly and steadily the persons may guard against danger in some parts, they often forget where it exists in others. The imagination is also generally so ascendant, that the judgment is not allowed time to act. The eyes of the person are frequently open, but objects which appear before them are usually unheeded, the mind being so absorbed by its own contemplations, as to be inattentive to impressions conveyed by the senses. Sometimes, however, the eyes continue, even in sleep, to present objects to the mind which engage its attention; as in the case of Johannes Oporinus, a printer, who, being employed one night in correcting the copy of a Greek book, fell asleep as he read, and yet ceased not to read till he had finished not less than a whole

page, of which, when he awoke, he retained no recollection *.

The attention of the mind, in this case, appears to have been gradually withdrawn after the body began to lie. This disposition to walk and act in sleep is usually considered as a disorder occasioned, according to the opinion of some persons, by a plethora, to which young men are chiefly liable: we may conceive in these cases the turgid and foaming blood to excite sensations which affect the mind: the disorder is understood to be curable by purging the primæ viæ. Whatever be the remote cause which affects the mind on these occasions, it certainly affords to it an opportunity of displaying its superior powers of in

* Plater. Observ. L. i. p. 12.

+ Levinus Lemnius describes these night-walkers as men of a relaxed habit of body, and great fervour and activity of mind, as chiefly young persons; observing that old persons, in whom the vital powers begin to flag, are incapable of the exertion. De Oceult. Nat. Mirac. L. ii. C. 5.

telligence, raised and excited, as it were, by new sensations, and moving the body only as an incumbrance to which it is chained. A similar but less remarkable effect is displayed, when, by an agitation of the spirits, persons are found to talk in their sleep, or to cry out and move, and even to execute their designs by external actions.

There is another faculty of the mind distinct from those hitherto specified, if we may credit a singular relation of Mr. Halley, who declared to the Royal Society, that being carried by a strong impulse to visit St. Helena, in order to make observations on the southern constellations, being then twenty-four years of age, he dreamed, before he undertook the voyage, that he was at sea, sailing towards that place, and saw the prospect of it from the ship in his dream, which exhibited the perfect representation of that island, as it afterwards appeared on his approach. It is possible, that the picture was formed agreeably to the ideas of the island, which his correct mind had formed