I held the attention of so
potent a Prospero.

In those days the name of Kirchoff was coupled always with that of
an associate, the chemist Bunsen, when there was mention of
spectrum-analysis; and in my time at Heidelberg, Bunsen was at hand
and I became as familiar with his figure as with Kirchoff. In frame
Bunsen was of the burly burgomaster type not rare among the Teutons,
and as I saw him in his laboratory to which I sometimes gained access
through students of his, he moved about in some kind of informal
_schlafrock_ or working dress of ample dimensions, with his
large head crowned by a peculiar cap. On the tables within the spaces
flickered numerously the "Bunsen burners," his invention, and it
was easy to fancy as one saw him, surrounded by the large company of
reverent disciples, that you were in the presence of the hierophant
of some abstruse and mysterious cult, in whose honour waved the many
lambent flames. I think he was unmarried, without domestic ties, and
lived almost night and day among his crucibles and retorts, devoted to
his science and pupils toward whom he showed a regard almost fatherly.
In his lecture-room, in more formal dress he was less picturesque, but
still a man to arouse deep interest. He was in the front rank of the
chemists of all time, and I suppose had equal merit with Kirchoff in
the momentous discovery in which their names are linked.

There was, however, at this time in Heidelberg a scientist probably
of greater prestige than even these, whose contemporary influence was
more dominant, and whose repute is now, and likely to be hereafter
more prevailing. In my walks in a certain quiet street, I sometimes
met a man who made an unusual impression of dignity and power. He
had the bearing of a leader of men in whatever sphere he might move,
massive and well-statured, his dress not obtrusive but carefully
appointed, with an eye and face to command. His manner was courteous,
not domineering, and I wondered who the able, high-bred gentleman
might be, for he carried all that in his air as he passed along the
street. It was the illustrious Helmholtz, then in his best years,
with great achievements behind him and before. His researches in many
fields were profound and far extending. I suppose his genius was
at its best when dealing with the pervasive imponderable ether that
extends out from the earth into the vast planetary spaces in whose
vibrations are conditioned the phenomena of light. No