It was an even hour before the time appointed for Tarbell’s return when Maxwell joined the chemistry expert at the table in the Topaz café where they usually sat when they could dine together.

At the unfolding of the napkins Sprague said: “I’ve found your germ, Dick, and things are beginning to develop. What do you think of that?”—passing a bit of dingy coarse-fibred paper across the table.

Maxwell opened the paper and read the ill-spelled type-written note it bore.

“Mr. Spraig:

“Weer onto you with both feet. keep youre fingers out ov the geers or maybe youll git em mashed.

“A well-Wishur.”

“Where did that come from?” asked the superintendent, plainly amused.

“It was pushed under the door of my room upstairs about half an hour ago. The man who left it was short, thick-set, smooth-shaven, and he wore a pepper-and-salt suit and a slouch hat. Also, his breath smelled of whiskey.”

“You expect me to recognize the description?”

“I didn’t know but you might.”