underlie it, the oceans that toss upon it, the atmosphere that surrounds it. The other roved not widely, but keeping to his lenses and calculations, penetrated perhaps more profoundly. Helmholtz, a well-born youth, began his career as a surgeon in the Prussian army, and his service there, no doubt, contributed to the manly carriage for which he was conspicuous. He married a lady of a noble house of Wuertemberg, and moved in an environment conducive to courtly manners. Heidelberg, like the German universities in general well understood that ability in its teachers, and not a pompous architectural display, makes a great institution. Its buildings were scattered and unpretending. Helmholtz had a lecture-room and laboratory apart, in a structure modern and graceful, but modest in its appeal. Here he discoursed to reverent throngs in tones never loud or confident. It is for wiseacres and charlatans to declaim and domineer. The masters are deferential in the presence of the sublimities and of the intelligences they are striving to enlighten. In Germany I saw the great lights of science from afar, coming into relations of intimacy only with one or two _privat-docents_, young men struggling precariously for a foothold. One such striver I came to know well, a young man gifted but physically crippled, who, being anxious to get up his English, as I was to get up my German, entered with me into an arrangement to converse in these alternately. We were about on a par in our knowledge or ignorance of the speech not native to us, and helped each other merrily out of the pitfalls into which we stumbled, according as English or German ruled the time. I was aghast to find that I had been telling my new German acquaintances that while a married man, I had _deserted_ and _cast off_ my wife and little boy in America, when I meant to say only that I had left them behind during my temporary sojourn. A treacherous inseparable prefix had imparted to my "leaving them" an unlooked-for emphasis. The laugh for the moment was on me, but only for the moment. A little later Knopff was telling me of the old manuscripts in the library illuminated gorgeously by "de pious and skilful monkeys of de Middle Ages." He was a bright fellow, and I have hoped I might encounter his name in some honourable connection. If he survived it was as one of the _unbekannt_, an affix very dreadful to young aspirants for university honours. As regards the men who, during the past seventy-five years have so greatly widened our scientific knowledge, I have had contact with those of Germany only for brief periods, and in the outer circle. As to their American brethren, fate has been more kind to me. I have sat as a pupil at the feet of the most eminent, and with some I have stood in the bond of friendship.