e ground floor with Weber, Mazeroux, and Don Luis Perenna.

Their expectations were disappointed; and this was M. Desmalions's fault.
In spite of the express opinion of Don Luis, who deprecated the
experiment as useless, the Prefect had decided not to turn off the
electric light, so that he might see if the light would prevent the
miracle. Under these conditions no letter could appear, and no letter did
appear. The miracle, whether a conjuring trick or a criminal's device,
needed the kindly aid of the darkness.

There were therefore ten days lost, always presuming that the diabolical
postman would dare to repeat his attempt and produce the third
mysterious letter.

* * * * *

On the fifteenth of May the wait was renewed, while the same crowd
gathered outside, an anxious, breathless crowd, stirred by the least
sound and keeping an impressive silence, with eyes gazing upon the
Fauvilles' house.

This time the light was put out, but the Prefect of Police kept his hand
on the electric switch. Ten times, twenty times, he unexpectedly turned
on the light. There was nothing on the table. What had aroused his
attention was the creaking of a piece of furniture or a movement made by
one of the men with him.

Suddenly they all uttered an exclamation. Something unusual, a rustling
noise, had interrupted the silence.

M. Desmalions at once switched on the light. He gave a cry. A letter lay
not on the table, but beside it, on the floor, on the carpet.

Mazeroux made the sign of the cross. The inspectors were as pale as
death.

M. Desmalions looked at Don Luis, who nodded his head without a word.

They inspected the condition of the locks and bolts. Nothing had moved.

That day again, the contents of the letter made some amends for the
really extraordinary manner of its delivery. It completely dispelled
all the doubts that still enshrouded the double murder on the
Boulevard Suchet.

Again signed by the engineer, written throughout by himself, on the
eighth of February, with no visible address, it said:

"No, my dear friend, I will not allow myself to be killed like a sheep
led to the slaughter. I shall defend myself, I shall fight to the last
moment. Things have changed lately. I have proofs now, undeniable proofs.
I possess letters that have passed between them. And I know that they
still love each other as they did at the start, that they want to marry,
and that they will let nothing st