Bausch enumerates and rejects a number of explanations to account for the supposed presence of the _ætites_ in the nests of eagles. One theory was that these stones served to give stability to the nest, and enabled it better to resist the assaults of the wind; others asserted that the coolness of the stones lowered the unduly high temperature of the eggs and of the parent bird’s body; others again were inclined to attribute to them a mysterious formative and vivifying power exerted on the eggs, or else a talismanic power protecting these from injury. While rejecting all these notions, as we have stated, and indeed denying the truth of the assertion that such stones were ever found in eagles’ nests, Bausch cites the authority of St. Jerome, in his commentary on Isaiah, chap. lxvi, that the amethyst had been found with the young of the eagle, being placed with them in the nest to protect them from venomous creatures.[363] That the “eagle-stones” were not always hollow is shown by a specimen owned in the eighteenth century by the English family Postlethwayte. This was solid, and had been cut into the shape of a heart, a hole being pierced at the upper end so that the stone could be worn suspended. In a curious letter written April 25, 1742, by Martha Postlethwayte, sister of Sir Thomas Gooch, who successively presided over the episcopal sees of Bristol, Norwich and Ely, to her daughter Barbara Kerrick, the writer advises her correspondent, in order to avoid a repetition of former misadventures, to “wear the eagle-stone and take Mrs. Stone’s receit,” and adds: “I hope it may have good effect and make me a good grandmother.” The result was favorable, and must naturally have affirmed the faith in the powers of the stone.[364] An inventory of the furniture, plate, jewels, etc., of Charles V of France, made in 1379,[365] describes two stones preserved in a case of cypress-wood which the king always carried about with him. One of these was called the “holy stone” and aided women in childbirth. This was probably an “eagle-stone.” It was set in gold and the setting was adorned with four pearls, six emeralds and two balas-rubies. The other stone, which cured the gout, was an engraved gem bearing the figure of a king and an inscription in Hebrew characters. This description suggests one of the Gnostic gems so common in the early Christian centuries. The gem was suspended from a silver cord, so that it could be worn on the neck, or perhaps attached to some other part of the body. We find in the _comptes royaux_ of 1420 an electuary composed of powdered precious stones, for the cure of the infirmities of Isabel of Bavaria, who was fifty years old and had been for several years obese and a valetudinarian.[366]