Nor was such a belief even in Europe, and in comparatively modern times, confined to the uneducated. On the contrary, Mercati,[251] physician to Clement VIII., at the end of the sixteenth |63| century, appears to have been the first to maintain that what were regarded as thunderbolts were the arms of a primitive people unacquainted with the use of bronze or iron. Helwing[252] at Königsberg in 1717 showed the artificial character of the so-called thunderbolts, and in France, De Jussieu in 1723, and Mahudel,[253] about 1734, reproduced Mercati’s view to the Académie des Inscriptions. In our own country, Dr. Plot, in his “History of Staffordshire”[254] (1686), also recognized the true character of these relics; and, citing an axe of stone made of speckled flint ground to an edge, says that either the Britons or Romans, or both, made use of such axes; and adds that “how they might be fastened to a helve may be seen in the Museum Ashmoleanum, where there are several Indian ones of the like kind fitted up in the same order as when formerly used.” Dr. Plot’s views were not, however, accepted by all his countrymen, for in the _Philosophical Transactions of the Royal Society_,[255] we find Dr. Lister regarding unmistakeable stone weapons as having been fashioned naturally and without any artifice. Some of the old German[256] authors have written long dissertations about these stone hatchets and axes under the name of Cerauniæ, and given representations of various forms, which were known as _Malleus fulmineus_, _Cuneus fulminis_, Donnerstein, Strahlhammer, &c. Aldrovandus says that these stones are usually about five inches long and three wide, of a substance like flint, some so hard that a file will not touch them. About the centre of gravity of the stone is usually a hole an inch in diameter, quite round. They all imitate in form a hammer, a wedge, or an axe, or some such instrument, with a hole to receive a haft, so that some think them not to be thunderbolts, but iron implements petrified by time. But many explode such an opinion, and relate how such stones have been found under trees and houses struck by lightning; and assert that trustworthy persons were present, and saw them dug out, after the lightning had struck.[257] Kentmann informs us how, in the month of May, 1561, there was dug out at Torgau such a bolt projected by |64| thunder. It was five inches long, and of a stone harder than basalt, which in some parts of Germany was used instead of anvils. He also relates how near Jülich another stone was driven by thunder through an enormous oak, and was then dug up. Aldrovandus gives a highly philosophical view as to the formation of these stones. He regards them as due to an admixture of a certain exhalation of thunder and lightning with metallic matter, chiefly in dark clouds, which is coagulated by the circumfused moisture and conglutinated into a mass (like flour with water), and subsequently indurated by heat, like a brick.