We have among us several minor illusions, which are only less imposing because more familiar; and though often occurring, few are recorded with scientific accuracy. The phosphorescence of the marshes, the ignis fatuus, Will o’Wisp, Jack o’ the Lanthorn, or Friar Rush, and the corpse-candles, are mere luminous exhalations, strained into the marvellous by the vulgar, and thus set down as heralds of mortality. The dancing-light of luminous flies has been termed the green light of death; and, if you wish for more, Astrophel, read the “Armorican Magazine” of John Wesley, or the quaint volume of Burton, and thereabouts where he writes in this fashion: “The thickness of the aire may cause such effects, or any object not well discerned in the dark, fear and phantasie will suspect to be a ghost or devil. Glowwormes, firedrakes, meteors, ignis fatuus, which Plinius calls Castor and Pollux, with many such that appear in moorish grounds, about church-yards, moist valleys, or where battles have been fought, the causes of which read in Goclenius, Velcurius, Finkius, &c.”
The Parhelia, or mock suns, are produced by the reflection of the sun’s light on a frozen cloud. How readily these phenomena are magnified you may learn from ancient and modern records. In 1223 four suns were seen of crimson, inclosed in a wide circle of crystal colour. This is natural: but then comes the miracle. In the same year two giant dragons were seen in the air, flapping their monstrous wings and engaging in single combat, until they both fell into the sea and were drowned! Then, in 1104, there were seen four white circles rolled around the sun: and in 1688, two suns and a reversed rainbow appeared at Bishop’s Lavington, in Wiltshire: and in February, 1647, there is an account and sketch of three suns, and an inverted rainbow, which Baxter terms “Binorum Pareliorum Φαινομενον.” And because there were two lunar and one solar eclipses in 1652, it was called, as Lily records, “Annus tenebrum,” or “the dark year.”
The Corona, or halo around the sun, moon, and stars, is easily illustrated by the zone formed by placing, during a frost, a lighted candle in a cloud of steam or vapour.
The Aurora Borealis is arctic electricity, and is beautifully imitated by the passage of an electric flash through an exhausted glass cylinder.
The rainbow is a combination of natural prisms breaking the light into colours; and it may be seen in the cloud, or in the spray of the ocean, or in the beautiful cascades of Schaffhausen, Niagara, or Terni, or indeed in any foaming spray on which the meridian sunbeams fall, or even in the dewy grass, lying, as it were, on the ground.
When the sun shines on a cloud, there is always a bow produced visible to all who are placed at the proper angle. The lunar rainbow is achromatic, or destitute of colour, because reflected light is not easily refracted into colour. In a brilliant sunset the floods of light around him often indicate the gradation of prismatic colouring.
Cast. In some waterfalls I have seen the Iris form a complete circle; as in the Velino at Terni, and in others, especially in Ionia and Italy. A perfect illusion is produced, for the bow seems to approach the spectator and then recede, as if Juno were sending her messenger on some special mission. There are many minds which would yield with delight to this conviction, and such probably was the illusion of Benvenuto Cellini—was it not? “This resplendent light is to be seen over my shadow till two o’clock in the afternoon, and it appears to the greatest advantage when the grass is moist with dew. It is likewise visible in the evening at sunset. This phenomenon I took notice of when I was at Paris, because the air is exceedingly clear in that climate, so that I could distinguish it there much plainer than in Italy, where the moists are much more frequent, &c.” A consciousness of superior talent, and probably the homage which was paid him even by the members of the holy conclave, were the springs of this flattering vision.
Ida. The beauty of these must light up even the fancy of a child, yet a holier feeling will ever inspire a Christian philosopher, when the bow is seen in the cloud, for it was the sign of the covenant. There is, indeed, something in the glories of the firmament which never fails to elevate my own thoughts, and I can readily sympathise with the Spanish religionists of the fifteenth century, and with the North Americans, who gaze upon the beautiful constellation of the “Southern Cross,” insulated as it is from all other stars in its own dark space; in solemn belief that it is the great symbolical banner held out by the Deity in approval of their faith.
Ev. The “Fata Morgana,” in the straits of Reggio, presents a perfect scene of enchantment; when the shouts of “Morgana, Morgana,” echo from rock and mountain, as the wondering people flock in crowds to the shore. During this splendid illusion, gigantic columns, and cloud-capt towers, and gorgeous palaces, and solemn temples, are floating on the verge of the horizon, and sometimes beneath this picture of a city, on the very bosom of the water, a fainter spectrum may be seen, which is a reflected image of the other. These spectra are usually colourless, but if certain watery vapours are floating in the air, they are beautifully fringed with the three primitive colours of the prism. Such also is the illusion of the Calenture, or sylvan scenes of the ocean.
Cast. Let us seek these wonders of the waters, Astrophel; perchance we might, in some enchanted hour, see even beneath yon Severn flood the grotto of Sabrina, with its green and silver weeds, its purple shells and arborescent corallines; and, if we dive into the depths of the sea, might we not light on the palace of Amphitrite, and, while the Nereids and Tritons were mourning over the desolation of a shipwreck, hear the echo of some Ariel’s song “full fathom five,” undulating through the water; or realise the overwhelming of Maha-Velipoor, in the curse of Kehama: