BIOGRAPHICAL MEMORANDA 



view of the Witte Singel, a local canal. Later they moved to an archi- 

 tecturally interesting, old-fashioned house on the Heerengracht. Finally, 

 to the delight of father Kluyver, the family acquired a very modern, 

 sunny, and colourful mansion at the Hoge Rijndijk; it was from here 

 that the children gradually dispersed. 



Kluyver died in Leiden, at the age of 72, on December 3, 1932, 

 four years to a day after his wife. He was an exceptionally thorough 

 mathematician, imbued with the contributions of the great mathe- 

 maticians of the past, from whose works he often borrowed illustrative 

 examples. When lecturing he was wont to cover blackboard after 

 blackboard with beautifully regular letters and signs, without ever 

 wavering. He was a stately, imposing figure, with a wittily ironic 

 gleam in his grey eyes that caused many students rather to fear him. 

 He was a splendid speaker and the address on 'The Steady Evolution 

 of Mathematics' which, as Rector Magnificus, he delivered on Febru- 

 ary 8, 1 9 10, in the main auditorium of Leiden University, remains in 

 my opinion the most beautiful paper on mathematics for laymen. 



It was after the Easter holidays in 1904 that I first set eyes on Albert 

 Jan. He occupied a front row seat in the fourth grade classroom of the 

 Leiden High School ; a slender, blond boy, but recently graduated to 

 'long pants'. Invariably he knew everything, and never failed a quiz; 

 but he was in no way a braggart, rather did he appear timid and 

 bashful. 



Not till after the summer holidays, when we had frankly expressed 

 our delight at meeting again, did we begin regularly to study together 

 for the final examinations. Mostly we worked in his room which we 

 had virtually converted into a laboratory for practicing chemistry. 

 Nearly every evening was concluded by a brief visit to the living 

 room. Like all living-rooms in those days, this was a simply furnished 

 apartment, with a rectangular table in the centre over which hung 

 the lamp; there were no low little tables or cosy nooks. During the 

 winter Albert Jan did his homework at that table in the family circle ; 

 his powers of concentration made him immune to distraction. On rare 

 occasions, when upstairs we got stuck in a mathematical problem, we 

 mustered up enough courage to ask the professor how it should be 

 tackled. Usually he was engaged in reading a book or newspaper, and, 

 almost without looking up or listening to us, he would then sketch 



