Furthermore, Ostwald takes into consideration the tempo of the intellectual pulse of inspiration to divide the main types of great men into a classical and a romantic category: this classification cannot, however, be applied to Einstein. He is decidedly classical, in so far as his work seems calculated to serve later generations as a classical foundation for all mechanical investigations of the macrocosm of the heavens and the microcosm of atoms. On the other hand, his versatility, the mobility and resource of his highly imaginative mind, stamp him as a romantic spirit. His delight in teaching would also assign him to this category, for in the case of many classical spirits there is a decided aversion to imparting instruction. So that, although we might well be able to speak of a synthesis of these two forms, it seems better to estimate Einstein, not in the light of a ready scheme, but rather as a type of which he is the unique representative. * * * * * * * * Just as the external contour of his life is on the whole regular and unbroken, so also his inner life is attuned to simplicity. Nowhere, it might almost be said, do we observe a break, a spasmodic turn, or a sudden intensification. Although he has grasped and suggested so many problems, he himself presents no psychological riddle, and we meet with no singularities in analysing his personality. It has already been remarked several times that Art plays a part in his life. What I learned from him himself about his affection for music coincides exactly with what observation clearly discloses. The expression of his countenance when he is listening to music is a sufficient indication of the resonances induced in him. He is confessedly a classicist, and a sincere devotee of the revelations of Bach, Haydn, and Mozart. What fascinates and enraptures him above all is that which is directed inwards, which is contemplative and erected on a religious basis. The simple masterful flow in musical development and invention is all-important for him. The architectonic structure that we marvel at in Bach, the Gothic tendency towards heavenly heights, perhaps calls up in him sensations that emanate from his hidden wealth of constructive mathematical ideas. It seems to me that this possibility is not unworthy of remark. It suggests a reason for the fact that he gives himself up only unwillingly to the nervous strain of drama directed at emotional upheaval. He does not gladly overstep the boundary that separates the simple from the psychologically subtle, and whenever his desire to understand art requires him to venture beyond it, his appreciation is not accompanied by genuine pleasure. His subjectivity does not fix this boundary in accordance with the ordinary rules of concert æsthetics, which are actually not rules at all, but only changeable valuations and crystallizations of the feelings of certain groups of people. He gives