But let us return to the passage from the _Natural Questions_ and Adelard’s insinuation--slightly satirical no doubt, but also in part serious--that he has fathered new scientific notions of his own upon the Arabs. There is reason to think that he was not the only one to do this. Not only were superstitious and comparatively worthless treatises which were composed in the medieval period attributed to Aristotle and other famous authors, but this was also the case with works of real value. Also the number is suspiciously large of works of which the lost originals were supposedly by Greek or Arabian authors but which are extant only in later Latin “translations.” [Sidenote: Illustrated from the history of alchemy.] This point may be specifically illustrated for the moment from the researches of Berthelot among alchemistic manuscripts, which have demonstrated that Latin alchemy of the thirteenth century was less superstitious and more scientific than in previous periods, whether among the ancient Greeks or more recent Arabs. He found but one treatise in Arabic which contained precise and minute details about chemical substances and operations. As a rule the Arabian alchemists wrote “theoretical works full of allegories and declamation.” For a long time several works, important in the history of chemistry as well as of alchemy, were regarded as Latin translations of the Arab, Geber. But Berthelot discovered the Arabic manuscripts of the real Geber, which turned out to be of little value and largely copied from Greek authors. On the other hand, the Latin works which had gone under Geber’s name were produced in the thirteenth and fourteenth centuries by men who seem, like Adelard of Bath, to have preferred to ascribe their own ideas to the Arabs. Let us examine for a moment with Berthelot[49] the chief of these Latin treatises. It is a “a systematic work, very well arranged. Its modest method of exposition” differs greatly from “the vague and excessive promises of the real Geber.” Much of the book possesses “a truly scientific character” and “shows the state of chemical knowledge with a precision of thought and expression unknown to previous authors.” As for Adelard’s new ideas, we may not regard them as so novel as they seemed to him, nor estimate them so highly in comparison with ancient Greek science as Berthelot did medieval compared with Greek alchemy--much of Adelard’s thought may be derived by him from those ancient writings in which he claims to have read so widely--but they were probably as new to Adelard’s Latin contemporaries as they were to himself. [Sidenote: Science and religion.]