130                                       EIGHTH  LECTURE.

laws which retain their meaning for all investigators and for
all times, and to discover these invariants is always the real
endeavor of physical research. We shall work further in this
direction in order to leave behind for our successors where pos¬
sible—lasting results. For if, while engaged in body and mind
in patient and often modest individual endeavor, one thought
strengthens and supports us, it is this, that we in physics work,
not for the day only and for immediate results, but, so to speak,
for eternity.

I thank you heartily for the encouragement which you have
given me. I thank you no less for the patience with which you
have followed my lectures to the end, and I trust that it may be
possible for many among you to furnish in the direction indicated
much valuable service to our beloved science.