In a few moments the four men passed out of the laboratory, while I, as I had done below, remained behind for a moment.

I stood before the furnace peering into the ashes.

I saw there something which they had overlooked, or, if they had seen it, could convey nothing to them.

Among those grey ashes lay a black horn overcoat button!

This I snatched up and transferred to my pocket.

Had that bottle of acid been purposely smashed in order to dispel any unpleasant odour arising from the furnace?

I longed to throw myself upon my knees and examine those ashes, but, alas! I dare not.

So I was compelled to follow my companions, rigid and speechless.