7. _De Magia Mathematica._--Merely a collection of excerpts from writers on Magic--Tritemius, Agrippa, Pietro Di Abano, the (Pseudo-) Albertus Magnus. (Noroff MSS. The title is that of the Italian editors.) 8. _De Rerum Principiis et Elementis et Causis._--(Noroff MSS. The writing was begun on the 16th of March 1590, in Helmstadt, by Besler, to Bruno's dictation.) It contains the theory of the natural and material elements or principles of things--light and fire, wind or air, water or vapour or darkness, and earth or the dry, with their "forms," time and place--leaving the metaphysical and the immaterial principles (spirit and soul) for consideration elsewhere. It is not of great scientific value. Bruno makes use of abstract terms even more readily than Aristotle (e.g. "_lux seminaliter est ubique, et in tenebris_," p. 514). The chief aim of the work is to illustrate the magical applications of the different elements[154] (cf. pp. 516, 525, etc.). Its value mainly lies in the light it throws on Bruno's atomic theory, and on one or two other minor points of his philosophy--the harmony, co-ordination, and sympathy between all natural things, the doctrines of liberty and necessity, etc. 9. _De Medicina Lulliana, partim ex mathematicis, partim ex physicis principiis educta._--Written immediately after the above (_de rerum principiis_), to which it occasionally refers: merely a collection of abstracts from works of Lully on medicine, as a practical application of the system of magic contained in the three previous writings. It is accordingly of the astrological type of mediæval medicine. 10. _De Vinculis in genere._ Noroff MSS.--A first sketch in Bruno's own hand, dating probably from Frankfort; and a later, much more detailed, in Besler's, copied at Padua. It in a sense completes the tractates on Magic, by dealing with "attraction" in general, of which the attractions and sympathies of natural and mathematical magic are special cases. As it stands, however (for neither sketch is finished: Bruno's covers wider ground than Besler's, the latter breaks off abruptly before the natural end is reached), it is a psychological essay on the human passions, and more especially on human love, from a purely objective, matter-of-fact standpoint. In it the most grossly material and the highest spiritual sources of love are placed side by side; and to love, including self-love, are reduced all passions, all effects, even _hate_, which is an outcome, a reversion of love. PART II PHILOSOPHY OF BRUNO CHAPTER I THE SOURCES OF THE PHILOSOPHY [Sidenote: Aristotle's rejection of mathematical method.] [Sidenote: His treatment of the earlier Greeks.]