make and compound a certaine medicine, which is called _Elixir_, the which when it is cast upon mettals or imperfect bodies, doth fully perfect them in the verie projection.”[48] He also believed in Astrology; but, nevertheless, he was entirely opposed to many of the magical and superstitious notions held at the time, and his tract, _De Secretis Operibus Artis et Naturæ, et de Nullitate Magiæ_, was an endeavour to prove that many so-called “miracles” could be brought about simply by the aid of natural science. Roger Bacon was a firm supporter of the Sulphur-Mercury theory: he says: “. . . the natural principles in the mynes, are _Argent-vive_, and _Sulphur_. All mettals and minerals, whereof there be sundrie and divers kinds, are begotten of these two: but I must tel you, that nature alwaies intendeth and striveth to the perfection of Gold: but many accidents coming between, change the metalls. . . . For according to the puritie and impuritie of the two aforesaide principles, _Argent-vive_ and _Sulphur_, pure, and impure mettals are ingendred.”[49] He expresses surprise that any should employ animal and vegetable substances in their attempts to prepare the Stone, a practice common to some alchemists but warmly criticised by others. He says: “Nothing may be mingled with mettalls which hath not beene made or sprung from them, it remaineth cleane inough, that no strange thing which hath not his originall from these two [viz., sulphur and mercury], is able to perfect them, or to make a chaunge and new transmutation of them: so that it is to be wondered at, that any wise man should set his mind upon living creatures, or vegetables which are far off, when there be minerals to bee found nigh enough: neither may we in any wise thinke, that any of the Philosophers placed the Art in the said remote things, except it were by way of comparison.”[50] The one process necessary for the preparation of the Stone, he tells us, is “continuall concoction” in the fire, which is the method that “God hath given to nature.”[51] He died about 1294. [46] ERNST VON MEYER: _A History of Chemistry_ (translated by Dr. McGowan, 1906), p. 35. [47] See ROGER BACON’S _Discovery of Miracles_, chaps. vi. and xi. [48] ROGER BACON: _The Mirror of Alchimy_ (1597), p. 1. [49] _Ibid._ p. 2. [50] ROGER BACON: _The Mirror of Alchimy_ (1597), p. 4. [51] _Ibid._ p. 9. Arnold de Villanova (12--?-1310?). § =37.= The date and birthplace of =Arnold de Villanova=, or Villeneuve, are both uncertain. He studied medicine at Paris, and in the latter part of the thirteenth century practised professionally in Barcelona. To avoid persecution at the hands of the Inquisition, he was obliged to leave Spain, and ultimately found safety with Frederick II. in Sicily. He was famous not only as an alchemist, but also as a skilful physician. He died (it is thought in a shipwreck) about 1310-1313. Raymond Lully (1235?-1315).