"I suppose," puts in Mr. Robert, "that some golf enthusiast might have taken it into his head to practice a shot from somewhere in the neighborhood."

"That's logical," admits Old Hickory, "but from where did he shoot? We are nineteen stories above the sidewalk, remember. I never saw a player who could loft a ball to that height."

Which gives me an idea. "What if it was some golf nut who'd gone out on a roof?" I asks.

"Thank you, Torchy," says Old Hickory. "From a roof, of course. I should have made that deduction myself within the next half hour. The fellow must be swinging away on the top of some nearby building. Let's see if we can locate him."

Nobody could, though. Plenty of roofs in sight, from five to ten stories lower than the Corrugated buildin', but no mashie maniac in evidence. And while they're scoutin' around I takes another squint at the ball.

"Say, Mr. Ellins," I calls out, "if it was shot from a roof how do you dope out this grass stain on it?"

"Eh?" says Old Hickory. "Grass stain! Must be an old one. No, by the green turban of Hafiz, it's perfectly fresh! Even a bit of moist earth where the fellow took a divot. Young man, that knocks out your roof practice theory. Now how in the name of the Secret Seven could this happen? The nearest turf is in the park, across Broadway. But no golfer would be reckless enough to try out a shot from there. Besides, this came from a southerly direction. Well, son, what have you to offer?"

"Me?" says I, stallin' around a bit and lookin' surprised. "Oh, I didn't know I'd been assigned to the case of the mysterious golf ball."

"You have," says Old Hickory. "You seem to be so clever in deducing things and the rest of us so stupid. Here take another look at the ball. I presume that if you had a magnifying glass you could tell where it came from and what the man looked like who hit it. Eh?"

"Oh, sure!" says I, grinnin'. "That is, in an hour or so."