The alchemical discoveries and writings ascribed to Aristotle are often associated in some way with Alexander the Great as well. In one manuscript John of Spain’s translation of the _Secret of Secrets_ is followed by a description of the virtues and compositions of four stones “which Aristotle sent to Alexander the Great.”[781] It seems obvious that these are philosopher’s stones and not natural gems. The _Liber ignium_ of Marcus Grecus, composed in the thirteenth or early fourteenth century, ascribes to Aristotle the discovery of two marvelous kinds of fires. One, which he discovered while traveling with Alexander the king, will burn for a year without cessation. The other, in the composition of which observance of the dog-days is requisite, “Aristotle asserts will last for nine years.”[782] A collection of chemical experiments by a Nicholas, of whom we shall have more to say in a later chapter, gives “a fire which Aristotle discovered with Alexander for obscure places.”[783] A letter of Aristotle to Alexander in a collection of alchemical tracts is hardly worth noting, as it is only seven lines long, but it is interesting to observe that it cites Aristotle’s _Meteorology_.[784] Perhaps by a mistake one or two alchemical treatises are ascribed to Alexander rather than Aristotle.[785] [Sidenote: Aristotle and astrology.] Aristotle’s genuine works give even more encouragement to the pretensions of astrology than to those of alchemy. His opinion that the four elements were insufficient to explain natural phenomena and his theory of a fifth essence were favorable to the belief in occult virtue and the influence of the stars upon inferior objects. In his work on generation[786] he held that the elements alone were mere tools without a workman; the missing agent is supplied by the revolution of the heavens. In the twelfth book of the _Metaphysics_ he described the stars and planets as eternal and acting as intermediaries between the prime Mover and inferior beings. Thus they are the direct causes of all life and action in our world. Charles Jourdain regarded the introduction of the _Metaphysics_ into western Europe at the opening of the thirteenth century as a principal cause for the great prevalence of astrology from that time on, the other main cause being the translation of Arabian astrological treatises.[787] Jourdain did not duly appreciate the great hold which astrology already had in the twelfth century, but it is nevertheless true that in the new Aristotle astrology found further support. [Sidenote: Astrology and magic in the _Theology_ and _De pomo_ of Aristotle.]