treating light among the French, with its molécules de lumière, and in general with their fixed idea of reducing everything in nature to mere mechanical effects. Lastly, the great individual diversity of intelligence we are speaking about shows itself excellently in the degrees of the clearness of understanding, and accordingly in the distinctness of the whole thinking. To one man that is to understand which to another is only in some degree to observe; the one is already done and at the goal while the other is only at the beginning; to the one that is the solution which to the other is only the problem. This depends on the quality of thought and knowledge, which was already referred to above. As in rooms the degree of light varies, so does it in minds. We can detect this quality of the whole thought as soon as we have read only a few pages of an author. For in doing so we have been obliged to understand both with his understanding and in his sense; and there fore before we know all that he has thought we see already how he thinks, what is the formal nature, the texture of his thinking, which remains the same in everything about which he thinks, and whose expression is the train of thought and the style. In this we feel at once the pace, the flexibleness and lightness, even indeed the soaring power of his mind; or, on the contrary, its dulness, formality, lameness and leaden quality. For, as language is the expression of the mind of a nation, style is the more immediate expression of the mind of an author than even his physiognomy. We throw a book aside when we observe that in it we enter an obscurer region than our own, unless we have to learn from it mere facts, not thoughts. Apart from mere facts, only that author will afford us profit whose understanding is keener and clearer than our own, who forwards our thinking instead of hindering it, like the dull mind that will force us to keep pace with the toad-like course of its thought; thus that author with whose mind it gives
