rather a complicated thing, with an inner compartment over which was a hollow cover, opening along one rim. That, I conjectured, was designed to hold some chemical compound or salt. There were many minor openings, too, each guarded by a similar hollow door. My business was with the heavy top cover.
"'It should shut and open softly, gently,' explained the Professor. 'So. Not with-a-grating-sound-to-be-accompanied,' he added, with his curious effect of linked phraseology.
"Half a day's work fixed it. The lid would stand open of itself until tipped at a considerable angle, when it would fall and lock. Only on the outer shell was there a lock: that one was a good bit of craftsmanship.
"'So, Percy, my boy,' said the doctor kindly. 'That will with-sufficient- safety guard our treasure. When we obtain it, Percy. When it entirely-finished-and-completed shall be.'
"'And when will that be?' I asked.
"'God knows,' he said cheerfully. 'It progresses.'
"Whenever I went strolling at night, he would produce his curious lights. Sometimes they were fairly startling. One fact I made out by accident, looking down from a high place. They did not project from the laboratory. He always worked in the open when the light was to be produced. Once the experiment took a serious turn. The lights had flickered and gone. Dr. Schermerhorn had returned to his laboratory. I came up the arroyo as he flung the door open and rushed out. He was a grotesque figure, clad in
