I was silent, for I could not deny that that conviction had come to me.

"Henceforth, when you recover from the confusion or anger which now
disturbs your impressions, you will be prepared to listen to my
explanations and my recital in a spirit far different from that with which
you would have received them before you were subjected to the experiment,
which, allow me to remind you, you invited and defied. You will now, I
trust, be fitted to become my confidant and my assistant; you will advise
with me how, for the sake of humanity, we should act together against the
incarnate lie, the anomalous prodigy which glides through the crowd in the
image of joyous beauty. For the present I quit you. I have an
engagement, on worldly affairs, in the town this night. I am staying at
L----, which I shall leave for Derval Court tomorrow evening. Come to me
there the day after to-morrow, at any hour that may suit you the best.
Adieu!"

Here Sir Philip Derval rose and left the room. I made no effort to
detain him. My mind was too occupied in striving to recompose itself and
account for the phenomena that had scared it, and for the strength of the
impressions it still retained.

I sought to find natural and accountable causes for effects so abnormal.

Lord Bacon suggests that the ointments with which witches anointed
themselves might have had the effect of stopping the pores and congesting
the rain, and thus impressing the sleep of the unhappy dupes of their own
imagination with dreams so vivid that, on waking, they were firmly
convinced that they had been borne through the air to the Sabbat.