Somnambulism and other nocturnal deceptions frequently lend their aid to the formation of such phantasmata as are formed in this middle state, betwixt sleeping and waking. A most respectable person, whose active life had been spent as master and part owner of a large merchant vessel in the Lisbon trade, gave the writer an account of such an instance which came under his observation. He was lying in the Tagus, when he was put to great anxiety and alarm by the following incident and its consequences. One of his crew was murdered by a Portuguese assassin, and a report arose that the ghost of the slain man haunted the vessel. Sailors are generally superstitious, and those of my friend's vessel became unwilling to remain on board the ship; and it was probable they might desert rather then return to England with the ghost for a passenger. To prevent so great a calamity, the captain determined to examine the story to the bottom. He soon found that, though all pretended to have seen lights and heard noises, and so forth, the weight of the evidence lay upon the statement of one of his own mates, an Irishman and a Catholic, which might increase his tendency to superstition, but in other respects a veracious, honest, and sensible person, whom Captain ——had no reason to suspect would wilfully deceive him. He affirmed to Captain S—— with the deepest obtestations, that the spectre of the murdered man appeared to him almost nightly, took him from his place in the vessel, and, according to his own expression, worried his life out. He made these communications with a degree of horror which intimated the reality of his distress and apprehensions. The captain, without any argument at the time, privately resolved to watch the motions of the ghost-seer in the night; whether alone, or with a witness, I have forgotten. As the ship bell struck twelve, the sleeper started up, with a ghastly and disturbed countenance, and lighting a candle, proceeded to the galley or cook-room of the vessel. He sate down with his eyes open, staring before him as on some terrible object which he beheld with horror, yet from which he could not withhold his eyes. After a short space he arose, took up a tin can or decanter, filled it with water, muttering to himself all the while—mixed salt in the water, and sprinkled it about the galley. Finally, he sighed deeply, like one relieved from a heavy burden, and, returning to his hammock, slept soundly. In the next morning the haunted man told the usual precise story of his apparition, with the additional circumstances, that the ghost had led him to the galley, but that he had fortunately, he knew not how, obtained possession of some holy water, and succeeded in getting rid of his unwelcome visitor. The visionary was then informed of the real transactions of the night, with so many particulars as to satisfy him he had been the dupe of his imagination; he acquiesced in his commander's reasoning, and the dream, as often happens in these cases, returned no more after its imposture had been detected. In this case, we find the excited imagination acting upon the half-waking senses, which were intelligent enough for the purpose of making him sensible where he was, but not sufficiently so to judge truly of the objects before him.
But it is not only private life alone, or that tenor of thought which has been depressed into melancholy by gloomy anticipations respecting the future, which disposes the mind to mid-day fantasies, or to nightly apparitions—a state of eager anxiety, or excited exertion, is equally favourable to the indulgence of such supernatural communications. The anticipation of a dubious battle, with all the doubt and uncertainty of its event, and the conviction that it must involve his own fate and that of his country, was powerful enough to conjure up to the anxious eye of Brutus the spectre of his murdered friend Cæsar, respecting whose death he perhaps thought himself less justified than at the Ides of March, since, instead of having achieved the freedom of Rome, the event had only been the renewal of civil wars, and the issue might appear most likely to conclude in the total subjection of liberty. It is not miraculous that the masculine spirit of Marcus Brutus, surrounded by darkness and solitude, distracted probably by recollection of the kindness and favour of the great individual whom he had put to death to avenge the wrongs of his country, though by the slaughter of his own friend, should at length place before his eyes in person the appearance which termed itself his evil genius, and promised again to meet him at Philippi. Brutus' own intentions, and his knowledge of the military art, had probably long since assured him that the decision of the civil war must take place at or near that place; and, allowing that his own imagination supplied that part of his dialogue with the spectre, there is nothing else which might not be fashioned in a vivid dream or a waking reverie, approaching, in absorbing and engrossing character, the usual matter of which dreams consist. That Brutus, well acquainted with the opinions of the Platonists, should be disposed to receive without doubt the idea that he had seen a real apparition, and was not likely to scrutinize very minutely the supposed vision, may be naturally conceived; and it is also natural to think, that although no one saw the figure but himself, his contemporaries were little disposed to examine the testimony of a man so eminent, by the strict rules of cross-examination and conflicting evidence, which they might have thought applicable to another person, and a less dignified occasion.
Even in the field of death, and amid the mortal tug of combat itself, strong belief has wrought the same wonder, which we have hitherto mentioned as occurring in solitude and amid darkness; and those who were themselves on the verge of the world of spirits, or employed in dispatching others to these gloomy regions, conceived they beheld the apparitions of those beings whom their national mythology associated with such scenes. In such moments of undecided battle, amid the violence, hurry, and confusion of ideas incident to the situation, the ancients supposed that they saw their deities, Castor and Pollux, fighting in the van for their encouragement; the heathen Scandinavian beheld the Choosers of the slain; and the Catholics were no less easily led to recognize the warlike Saint George or Saint James in the very front of the strife, showing them the way to conquest. Such apparitions being generally visible to a multitude, have in all times been supported by the greatest strength of testimony. When the common feeling of danger, and the animating burst of enthusiasm, act on the feelings of many men at once, their minds hold a natural correspondence with each other, as it is said is the case with stringed instruments tuned to the same pitch, of which, when one is played, the chords of the others are supposed to vibrate in unison with the tones produced. If an artful or enthusiastic individual exclaims, in the heat of action, that he perceives an apparition of the romantic kind which has been intimated, his companions catch at the idea with emulation, and most are willing to sacrifice the conviction of their own senses, rather than allow that they did not witness the same favourable emblem, from which all draw confidence and hope. One warrior catches the idea from another; all are alike eager to acknowledge the present miracle, and the battle is won before the mistake is discovered. In such cases, the number of persons present, which would otherwise lead to detection of the fallacy, becomes the means of strengthening it.