CHAPTER IX
THE TWILIGHT SLEEP
As I entered the laboratory I saw before him a peculiar, telescope-like instrument, at one end of which, in a jar of oxygen, something was burning with a brilliant, penetrating flame.
He paused in his work and I hastened to tell him of the peculiar experience I had had in the forenoon. But he said nothing, even at the significant actions of Dr. Preston.
"How about those things you found in the maid's room?" I asked at length. "Do they explain Rawaruska's death?"
"The trouble with them," he replied, thoughtfully shaking his head, "is that the effects of such things last only for a short time. They might have been used at first—but there was something used afterward."
"Something afterward?" I repeated, keenly interested, and fingering the telescope-like arrangement curiously. "What's this?"
"One of the new quartz lens spectroscopes used by Dr. Dobbie of the English Government laboratories," he answered briefly. "I think chemists, police officials, coroners and physicians are going to find it most valuable. You see, by throwing the ultra-violet part of the spectrum from a source of light as I obtain from the sparking of iron in oxygen through the lenses of a quartz spectroscope, the lines of many dangerous drugs, especially of the alkaloids, can be distinctly and quickly located in the spectrum. Each drug produces a characteristic kind of line. We use a quartz lens because glass cuts off the ultra-violet rays. Why, even the most minute particle of poison can be detected in this revolutionary fashion."
He had resumed squinting through the spectroscope.
"Well," I asked, "do you find anything there?"