And primitive man is much more subject than we are to hallucinations of the sort that are due to terror, and are not wholly fantastic, but result from a fantastic interpretation of some genuine sense stimulus. The traveller Park met two negroes on horseback; they fled from him at a gallop in extreme terror, and meeting his followers in the course of their flight reported that they had seen him dressed in the floating robes of some redoubtable spirit. One of them affirmed that at sight of Park he had felt himself enveloped in a breath of cold air from heaven, which was like a jet of cold water. Suppress the word spirit in this passage, which implies a pre-existing belief in the soul, and you will perceive how hallucinations due to terror may well give birth to beliefs all the more tenacious for the element of truth they contain. [28] Mr. H. Russell, the explorer of the Pyrenees, remarks the fantastic effects produced by the moonlight in the mountains. As the moonlight replaced the previous shadow on the faces and the angles of the rocks, he says, in an account of the ascension of the peak of Eriste, they seemed so plainly to move that once he mistook one of them for a bear and cocked the revolver at his side. The same explorer remarks also the surprising transformations which natural objects undergo at nightfall and at daybreak. At dawn, he says, there is a sort of universal shiver which seems to animate everything; the sound of the neighbouring cascade changed frequently; at break of day, after having groaned and thundered alternately, it begins to scold. For in the morning in the mountains, he says, sounds gain magnitude, they swell, and torrents in especial lift their voices as if angry; with the arrival of the day the air becomes sonorous and sound carries farther. He has experienced this, he says, frequently, but does not understand the cause.—_Alpine Club_, 1887. [Sidenote: Dreams.]