"Necessarily so, because I can only lead you to my discovery step by
step," replied the other steadily. "I wish you to be thoroughly prepared
for anything that may happen, so that you can deal intelligently with
results that might otherwise overwhelm you."

"Overwhelm--?" faltered his listener.

"_Might_, I said. Note carefully my use of words, for they are accurately
chosen. Before I can tell you all I must submit you, for your own sake,
to certain tests--chiefly to the test of Alteration of Form by Sound. It
is somewhat--er--alarming, I believe, the first time. You must be
thoroughly accustomed to these astonishing results before we dare to
approach the final Experiment; so that you will not tremble. For there
can be no rehearsal. The great Experiment can only be made once ... and I
must be as sure as possible that you will feel no terror in the face of
the Unknown."


IV

Spinrobin listened breathlessly. He hesitated a moment after the other
stopped speaking, then slewed round on his slippery chair and faced him.

"I can understand," he began, "why you want imagination, but you spoke of
courage too? I mean,--is there any immediate cause for alarm? Any
personal danger, for instance, _now_?" For the clergyman's weighty
sentences had made him realize in a new sense the loneliness of his
situation here among these desolate hills. He would appreciate some
assurance that his life was not to be trifled with before he lost the
power to withdraw if he wished to do so.