by
few, if any, so often repeated. I have myself more than once benefited
by his determination, quite spontaneously shown, that justice should be
done in the apportionment of credit; and I have with admiration watched
like actions of his in other cases: cases in which no consideration of
nationality or of creed interfered in the least with his insistence on
equitable distribution of honors.

"In this undertaking to fight for those who were unfairly dealt with, he
displayed in another direction that very conspicuous trait which, as
displayed in his Alpine feats, has made him to many persons chiefly
known: I mean courage, passing very often into daring. And here let me,
in closing this little sketch, indicate certain mischiefs which this
trait brought upon him. Courage grows by success. The demonstrated
ability to deal with dangers produces readiness to meet more dangers,
and is self-justifying where the muscular power and the nerve habitually
prove adequate. But the resulting habit of mind is apt to influence
conduct in other spheres, where muscular power and nerve are of no
avail--is apt to cause the daring of dangers which are not to be met by
strength of limb or by skill. Nature as externally presented by
precipice ice-slopes and crevasses may be dared by one who is adequately
endowed; but Nature, as internally represented in the form of physical
constitution, may not be thus dared with impunity. Prompted by high
motives, John Tyndall tended too much to disregard the protests of his
body.

"Over-application in Germany caused absolute sleeplessness, at one time,
I think he told me, for more than a week; and this, with kindred
transgressions, brought on that insomnia by which his after-life was
troubled, and by which his power for work was diminished; for, as I have
heard him say, a sound night's sleep was followed by a marked exaltation
of faculty.

"And then, in later life, came the daring which, by its results, brought
his active career to a close. He conscientiously desired to fulfil an
engagement to lecture at the British Institution, and was not deterred
by fear of consequences.

"He gave the lecture, notwithstanding the protest which for days before
his system had been making. The result was a serious illness,
threatening, as he thought at one time, a fatal result; and
notwithstanding a year's furlough for the recovery of health, he was
eventually obliged to resign his position. But for this defiance of
Na