volume, dealing with the "Watchers of the Sky," began to take definite
shape during what was to me an unforgettable experience--the night I
was privileged to spend on a summit of the Sierra Madre Mountains,
when the first trial was made of the new 100-inch telescope. The
prologue to this volume attempts to give a picture of that night, and
to elucidate my own purpose.

The first tale in this volume plunges into the middle of things, with
the revolution brought about by Copernicus; but, within the tale,
partly by means of an incidental lyric, there is an attempt to give a
bird's-eye view of what had gone before. The torch then passes to
Tycho Brahe, who, driven into exile with his tables of the stars, at
the very point of death hands them over to a young man named Kepler.
Kepler, with their help, arrives at his own great laws, and
corresponds with Galileo--the intensely human drama of whose life I
have endeavoured to depict with more historical accuracy than can be
attributed to much of the poetic literature that has gathered around
his name. Too many writers have succumbed to the temptation of the
cry, "e pur si muove!" It is, of course, rejected by every reliable
historian, and was first attributed to Galileo a hundred years after
his death. M. Ponsard, in his play on the subject, succumbed to the
extent of making his final scene end with Galileo "frappant du pied la
terre," and crying, "pourtant elle tourne." Galileo's recantation was
a far more subtle and tragically complicated affair than that. Even
Landor succumbed to the easy method of making him display his entirely
legendary scars to Milton. If these familiar pictures are not to be
found in my poem, it may be well for me to assure the hasty reader
that it is because I have endeavoured to present a more just picture.
I have tried to suggest the complications of motive in this section by
a series of letters passing between the characters chiefly concerned.