These spirits are not mischievous, unless they are insulted and laughed at; for then they fall into an ill humor, and throw things at those who offend them. One of these genii, who had been addressed in injurious terms by a miner, twisted his neck and placed his head the hind part before. The miner did not die, but remained all his life with his neck twisted and awry. George Agricola,[278] who has treated very learnedly on mines, metals, and the manner of extracting them from the bowels of the earth, mentions two or three sorts of spirits which appear in mines. Some are very small, and resemble dwarfs or pygmies; the others are like old men dressed like miners, having their shirts tucked up, and a leathern apron round their loins; others perform, or seem to perform, what they see others do, are very gay, do no harm to any one, but from all their labors nothing real results. In other mines are seen dangerous spirits, who ill-use the workmen, hunt them away, and sometimes kill them, and thus constrain them to forsake mines which are very rich and abundant. For instance, at Anneberg, in a mine called Crown of Rose, a spirit in the shape of a spirited, snorting horse, killed twelve miners, and obliged those who worked the mine to abandon the undertaking, though it brought them in a great deal. In another mine, called St. Gregory, in Siveberg, there appeared a spirit whose head was covered with a black hood, and he seized a miner, raised him up to a considerable height, then let him fall, and hurt him extremely. Olaus Magnus[279] says that, in Sweden and other northern countries, they saw formerly familiar spirits, which, under the form of men or women, waited on certain persons. He speaks of certain nymphs dwelling in caverns and in the depths of the forest, who announce things to come; some are good, others bad; they appear and speak to those who consult them. Travelers and shepherds also often see during the night divers phantoms which burn the spot where they appear, so that henceforward neither grass nor verdure are seen there. He says that the people of Finland, before their conversion to Christianity, sold the winds to sailors, giving them a string with three knots, and warning them that by untying the first knot they would have a gentle and favorable wind, at the second knot a stronger wind, and at the third knot a violent and dangerous gale. He says, moreover, that the Bothnians, striking on an anvil hard blows with a hammer, upon a frog or a serpent of brass, fall down in a swoon, and during this swoon they learn what passes in very distant places. But all those things have more relation to magic than to familiar spirits; and if what is said about them be true, it must be ascribed to the evil spirit.