CHAP. IX.] ABERDEEN. 259 



tests and controversies, the mention of these facts will 

 be a sufficient caution against taking the lowest 

 estimate of Maxwell's teaching powers ; and in after 

 years " at Cambridge, where his class consisted of 

 picked students," we have good authority for say- 

 ing " his lectures were listened to with an atten- 

 tion and pleasure similar to that with which his 

 books are now read." But at this earlier time there 

 were certainly drawbacks, of which he himself was 

 imperfectly conscious. Between his students' ignor- 

 ance and his vast knowledge, it was difficult to find a 

 common measure. The advice which he once gave a 

 friend whose duty it was to preach to a country 

 congregation, "Why don't you give it them thinner ?" 

 must often have been applicable to himself. Another 

 hindrance lay in the very richness of his imagination, 

 and the swiftness of his wit. The ideas with which 

 his mind was teeming were perpetually intersecting, 

 and their interferences, like those of the waves s of 

 light, made " dark bands " in the place of colour, 

 to the unassisted eye. Illustrations of ignotum per 

 ignotius, or of the abstruse by some unobserved pro- 

 perty of the familiar, were multiplied with dazzling 

 rapidity. Then the spirit of indirectness and paradox, 

 though he was aware of its dangers, would often take 

 possession of him against his will, and either from 

 shyness, or momentary excitement, or the despair 

 of making himself understood, would land him in 

 " chaotic statements," breaking off with some quirk 

 of ironical humour. Add to this his occasional hesi- 

 tation, his shortsightedness, and the long years of 



