A don of Magdalen College, Oxford, was asked by an American friend how long it would take to raise, in America, a lawn like the famous lawn of Magdalen College. “I do not know,” said the don, “but it took us over two centuries to do it here in Oxford.” Niven implied, of course, that it will take much more than two centuries to create at any American college that atmosphere which surrounded me at the Trinity College quadrangle on that memorable Sunday evening. It was the mysterious charm of that atmosphere which held me chained to Cambridge in spite of the fact that I did not believe that the Cambridge tripos method of laying a foundation in mathematical physics was fitting my particular case. Students shift from university to university in continental Europe, migrating to places where they are attracted by the reputations of teachers who happen to be there. I went to Cambridge because I thought that Maxwell was there. But at Cambridge, and at Oxford too, it was not only the teacher who was there but also the teachers who had lived there during generations long past who determined the choice made by ambitious students. The great teachers in the mathematical sciences when I was there were Lord Rayleigh, the successor of Maxwell; John Crouch Adams, who, with Leverrier in France, shared in the great distinction of calculating from the perturbations in the orbit of Uranus the position of the still unknown planet Neptune; George Gabriel Stokes, the greatest mathematical physicist in Europe at that time, and the occupant of the professorial chair once held by great Newton. But that which brought the students in mathematical sciences to Cambridge was not only the lustre of the reputations of these great professors, but also the existence at Cambridge of a historical educational policy, to the development of which many great Cambridge mathematicians of generations long past had made lasting contributions. The mathematical tripos was the most concrete expression of this traditional policy.