Whether the statement appearing in the manuscript under his name, that Michael Scot worked on this recipe, be true or not, one would not envy the task of the modern chemist who was called upon to compound the prescription. The basic idea of alchemy which, since the discovery of radium, is looked upon with some favour by certain advanced scientists, that all metals are reducible to a single substance, and therefore theoretically interchangeable, does not seem to find much place in this curious prescription, which suggests the idea of what we should call to-day a gold-substitute, rather than the genuine metal itself, in spite of the fact that we are told that the gold in question would prove “as good as what comes from Arabia.” The greatest work of Scot as translator was his reproduction in Latin of the commentary of Averroes on the _De Anima_ of Aristotle. This book, which expounded views on theological problems which were the reverse of orthodox, was long held back from publication by Scot’s patron, the Emperor Frederick, who hesitated to incur obloquy, and in especial the hostility of the Pope by reason of its publication. Friction, however, between the Papal See and the Emperor became so acute in the end that it appeared useless to attempt to placate papal bigotry further, and the publication in question was thus finally given to the world. The study of the writings of Averroes had indeed taken very strong hold on Scot’s imagination, and if the story may be accepted as authentic, he even went so far as to attempt to evoke the spirit of the great Arabian, presumably with a view to securing his assistance in the work which he had in hand. There is nothing intrinsically improbable in the supposition that Scott practised or experimented in such methods of evocation. Averroes had only been dead some twenty years when Scot was in Spain, and holding the views he did, he may well have thought that the philosopher’s spirit had not passed so far from the physical plane that some form of necromantic conjuration of his conscious personality would be ineffectual. Here, as elsewhere, it seems impossible to draw the line between record of fact and that fabric of legend and tradition which has been woven round the story of his life.