- A wand'ring fire

Compact of unctuous vapour, which the night

Condenses, and the cold environs round,

Kindled through agitation to a flame,

(Which oft, they say, some evil spirit attends,)

Hovering, and blazing with delusive light.

Misleads th'amaz'd night-wanderer from his way

Through bogs and mire, Milton.

The Ignis Fattius is a luminous appearance, which is most frequently observed in boggy districts and near rivers, though sometimes also in dry places. By its appearance, benighted travellers are said to have been sometimes led into imminent danger, taking it for a candle at a distance; from which seemingly mischievous property it has been thought by the vulgar to be a spirit of a malignant nature, and been named accordingly, Will-with-a-Wisp, or Jack-with-a-Lantern; for the same reason that it had its Latin name Ignis Fatuus. This light is frequently seen about burying-places and dunghills. Some countries are also remarkable for it, as about Bologna in Italy, and some parts of Spain and Ethiopia. Its forms are so uncertain and variable, that they can scarcely be described, especially as philosophical observers seldom meet with it. Dr. Derham, however, one night perceived one of them, and got so near that he had a very advantageous view of it. This is very difficult to be obtained; for, among other singularities of the ignis fatuus, it avoids the approach of any person, and flies from place to place as if it were animated. That which Dr. Derham observed, was in some boggy ground betwixt two rocky hills; and the night was dark and calm, by which means he was enabled to advance within two or three yards of it. It appeared like a complete body of light without any division, so that he was sure it could not be occasioned by insects. It kept dancing about a dead thistle, till a very slight motion of the air, occasioned, as he supposed, by his near approach to it, made it jump to another place; after which it kept flying before him as he advanced.

Beccari obtained information, that two of these lights appeared in the plains about Bologna the one north, the other south of that city, and were to be seen almost every dark night, especially that to the eastward, giving a light equal to an ordinary faggot. The latter appeared to a gentleman of his acquaintance, as he was travelling; moved constantly before him for about a mile, and-gave a better light than a torch which was carried before him. Both these appearances gave a very strong light, and were constantly in motion. Sometimes they would rise, sometimes sink; but commonly they would hover about, six feet from the ground; they would also frequently disappear on a sudden, and appear again in some other place. They differed also in size and figure, sometimes spreading pretty wide, and then contracting themselves; sometimes breaking into two, and then joining again. Sometimes they would appear like waves, at others they would seem to drop sparks of fire: they were but little affected by the wind; and in wet or rainy weather, were frequently observed to cast a stronger light than in dry weather: they were also observed more frequently when snow lay upon the ground, than in the hottest summer; but he was assured, that there was not a dark night throughout the whole year, in which they were not to be seen. The ground east of Bologna, where the largest of these was observed, is a hard chalky soil mixed with clay, which retains moisture long, but breaks and cracks in hot weather. On the mountains, where the soil is looser, the ignes fatui were less. From the best information, M. Beccari found that these lights were very frequent about rivers and brooks. He concludes his narrative with the following singular account.

"An intelligent gentleman travelling in the eveninog,be-tween eight and nine o'clock, in a hilly road about ten miles south of Bologna, perceived a light which shone very strongly upon some stones which lay on the banks of the Rio Verde. It seemed to be about two feet above the stones, and near the water. In size and figure it had the appearance of a parallelo-piped, above a foot in length, and half a foot high, the largest side being parallel to the horizon. Its light was so strong, that he could plainly see by it part of a neighbouring hedge and the water of the river; only in the east corner of it the light was rather faint, and the square figure less perfect, as if it were cut off or darkened by the segment of a circle. On examining it a little nearer, he was surprised to find that it changed gradually from a bright red to a yellowish, and then to a pale colour, in proportion as he drew nearer; and when he came to the place itself it quite vanished. Upon this, he stepped back, and not only saw it again, but found that the farther he went from it, the stronger and brighter it grew. When he examined the place of this luminous appearance, he could perceive no smell, nor any other mark of fire." Another gentleman informed M. Beccari, that he had seen the same light five or six different times in spring and autumn; and that it always appeared of the same shape, and in the very same spot. One night in particular, he observed it come out of a neighbouring field to settle in the usual place.

A very remarkable account of an ignis fatuus is given by Dr. Shaw, in his Travels to the Holy Land. It appeared in the valleys of mount Ephraim, and attended him and his company for above an hour. Sometimes it appeared globular, or like the flame of a candle, at others it spread to such a degree as to involve the whole country in a pale inoffensiv.e light, then contracted itself, and. suddenly disappeared, but in less than a minute it would appear again; sometimes, running swiftly along, it would expand itself at certain intervals over more than two or three acres of the adjacent mountains. The atmosphere from the beginning of the evening had been remarkably thick and hazy; and the dew, as they felt it on the bridles of their horses, was very clammy and unctuous Lights resembling the ignis fatuus are sometimes observed at at sea, skipping about the masts and rigging of ships; and Dr. Shaw informs us, that he has seen these in such weather as that just mentioned, when he saw the ignis fatuus in Palestine. Similar appearances have been observed in various other situations; and we are told of one which appeared about the bed of a woman in Milan, surrounding it, as well as her body, entirely. This light fled from the hand which approached; but was at length entirely dispersed by the motion of the air.