"And that is what killed poor Boris," said the Major, as he watched the eddying whirls of smoke which settled and rested upon the surface of the gas. "Exactly," I said, "and probably Ashton as well. His skull was fractured, it is true, but the divisional surgeon at the inquest reported, you may remember, that the fracture was not sufficient of itself to have caused instant death. It was ten minutes or more, I should say, from the time I was first awakened by Ashton's cry, until we finally broke in the door and reached his side. By that time he had suffocated. The gas, as no doubt you know, is not a poisonous one, but containing no oxygen which the lungs can take up, acts very much the same as water would if breathed into the lungs."
Muriel looked at me with admiring eyes. I did not tell her that my father had intended me to be, like himself, an engineer, and that I had taken a pretty thorough technical course before adopting art as a profession. And, after all, the simple explanations I had made were known to almost every schoolboy with a little knowledge of chemistry or physics.
"I believe your explanation of Mr. Ashton's death is the correct one, Mr. Morgan," said McQuade, and he said it ungrudgingly. "But how, after all, did the missing emerald come to be found in the cake of soap?"
"Undoubtedly Ashton put it there," I replied. "He realized the enormous value of the thing and feared that some attempt might be made to take it from him. His hiding place for the jewel was certainly an ingenious one, and you will remember that you and your men searched the room thoroughly on more than one occasion without finding it."
McQuade looked a bit sheepish at this. He walked over to the chandelier and examined its ugly-looking spike with deep interest. It was stained with dried blood and a few bits of hair still clung to it, but whether Ashton's or my own, we could of course not tell. There seemed nothing further that we could do, and, as McQuade said he intended going into Exeter immediately after luncheon to make his report, and have the authorities make an examination into the cause of the collection of the carbonic-acid gas in the room, as well as the stains of blood, etc., upon the point of the chandelier, I suggested that I accompany him, as I wanted to get my wound dressed without delay.