“Mr Langton has already told me how he met you—when he believed there were burglars in our house in Sussex Place,” she said, with a brightening smile.

“Yes,” I replied. “I—well, I was put there on guard, but Mr Langton’s suspicions fortunately proved to be unfounded.”

“Ah!” she said, with just the slightest suspicion of a sigh. “I’m glad of that—very glad!”

“The reason of my visit, Miss Greer, is,” I explained after a brief pause, “to ask you whether you are aware of the whereabouts of my friend, your father?” And I fixed my eyes straight upon hers.

“My father went to Scotland,” she replied, without wavering. “At present he’s in Germany. The last I heard of him was three days ago, when he was in Strassburg.”

“He wrote to you?” I gasped, staring at her in amazement that this ready lie should be upon her lips.

She noted my surprise, and said:

“Yes, why shouldn’t he?”

What reply could I give? Could I tell her that the Professor, her father, had been cruelly done to death, and his body cremated in his own experimental furnace? Had I not given my word of honour to that weird will-o’-the-wisp, Kershaw Kirk, that I would preserve silence? Besides, my only thought was for my own dear wife, whose face now rose ever before me.

“Well,” I stammered. “I—well—I believed that you were unaware of his whereabouts, Miss Greer. At least, I understood so from your father’s butler, Antonio.”