ule. In that position he remained for
about a minute.

"Well?" I asked him when he got up.

"Oh! nothing very important,--a drop of blood," he replied, turning
towards Daddy Jacques as he spoke. "While you were washing the
laboratory and this vestibule, was the vestibule window open?" he asked.

"No, Monsieur, it was closed; but after I had done washing the floor, I
lit some charcoal for Monsieur in the laboratory furnace, and, as I lit
it with old newspapers, it smoked, so I opened both the windows in the
laboratory and this one, to make a current of air; then I shut those in
the laboratory and left this one open when I went out. When I
returned to the pavilion, this window had been closed and Monsieur and
Mademoiselle were already at work in the laboratory."

"Monsieur or Mademoiselle Stangerson had, no doubt, shut it?"

"No doubt."

"You did not ask them?"

After a close scrutiny of the little lavatory and of the staircase
leading up to the attic, Rouletabille--to whom we seemed no longer to
exist--entered the laboratory. I followed him. It was, I confess, in
a state of great excitement. Robert Darzac lost none of my friend's
movements. As for me, my eyes were drawn at once to the door of
The Yellow Room. It was closed and, as I immediately saw, partially
shattered and out of commission.

My friend, who went about his work methodically, silently studied
the room in which we were. It was large and well-lighted. Two big
windows--almost bays--were protected by strong iron bars and looked out
upon a wide extent of country. Through an opening in the forest, they
commanded a wonderful view through the length of the valley and across
the plain to the large town which could be clearly seen in fair weather.
To-day, however, a mist hung over the ground--and blood in that room!

The whole of one side of the laboratory was taken up with a large
chimney, crucibles, ovens, and such implements as are needed for
chemical experiments; tables, loaded with phials, papers, reports,
an electrical machine,--an apparatus, as Monsieur Darzac informed me,
employed by Professor Stangerson to demonstrate the Dissociation of
Matter under the action of solar light--and other scientific implements.

Along the walls were cabinets, plain or glass-fronted, through which
were visible microscopes, special photographic apparatus, and a large
quantity of crystals.

Rouletabille, who was ferreting in the chimney, put his fingers into one
of