'All we want now is the lamps.'" I tried placing the electric lights on, or close to, the protuberances.

But the glow never came to the stone.

So the conviction grew on me that there were special lamps made for the purpose.

If we could find them, a step on the road to solving the mystery should be gained.
"'But what about the lamps ?' I asked.

'Where are they?
When are we to discover them?
How are we to know them if we do find them?
What--" "He stopped me at once: "'One thing at a time!' he said quietly.