“Inside,” I heard John Silence cry, and the Colonel followed him through the door, while I was just quick enough at their heels to hear him add, “the smoke’s the worst part of it.  There’s no fire yet, I think.”

And, true enough, there was no fire.  The interior was thick with smoke, but it speedily cleared and not a single bucket was used upon the floor or walls.  The air was stifling, the heat fearful.

“There’s precious little to burn in here; it’s all stone,” the Colonel exclaimed, coughing.  But the doctor was pointing to the wooden covers of the great cauldron in which the clothes were washed, and we saw that these were smouldering and charred.  And when we sprinkled half a bucket of water on them the surrounding bricks hissed and fizzed and sent up clouds of steam.  Through the open door and windows this passed out with the rest of the smoke, and we three stood there on the brick floor staring at the spot and wondering, each in our own fashion, how in the name of natural law the place could have caught fire or smoked at all.  And each was silent—­myself from sheer incapacity and befuddlement, the Colonel from the quiet pluck that faces all things yet speaks little, and John Silence from the intense mental grappling with this latest manifestation of a profound problem that called for concentration of thought rather than for any words.

There was really nothing to say.  The facts were indisputable.

Colonel Wragge was the first to utter.

“My sister,” he said briefly, and moved off.  In the yard I heard him sending the frightened servants about their business in an excellently matter-of-fact voice, scolding some one roundly for making such a big fire and letting the flues get over-heated, and paying no heed to the stammering reply that no fire had been lit there for several days.  Then he dispatched a groom on horseback for the local doctor.

Then Dr. Silence turned and looked at me.  The absolute control he possessed, not only over the outward expression of emotion by gesture, change of colour, light in the eyes, and so forth, but also, as I well knew, over its very birth in his heart, the masklike face of the dead he could assume at will, made it extremely difficult to know at any given moment what was at work in his inner consciousness.  But now, when he turned and looked at me, there was no sphinx-expression there, but rather the keen triumphant face of a man who had solved a dangerous and complicated problem, and saw his way to a clean victory.

“Now do you guess?” he asked quietly, as though it were the simplest matter in the world, and ignorance were impossible.

I could only stare stupidly and remain silent.  He glanced down at the charred cauldron-lids, and traced a figure in the air with his finger.  But I was too excited, or too mortified, or still too dazed, perhaps, to see what it was he outlined, or what it was he meant to convey.  I could only go on staring and shaking my puzzled head.