“What’s the domestic situation there?”
“The professor, as you probably know, resigned his chair some ten years ago. Since then he’s been living in West 75th Street, near the Drive. He took his brother’s child—a girl of fifteen—to live with him. She’s around twenty-five now. Then there’s his protégé, Sigurd Arnesson, who was a classmate of mine at college. The professor adopted him during his junior year. Arnesson is now about forty, an instructor in mathematics at Columbia. He came to this country from Norway when he was three, and was left an orphan five years later. He’s something of a mathematical genius, and Dillard evidently saw the makings of a great physicist in him and adopted him.”
“I’ve heard of Arnesson,” nodded Vance. “He recently published some modifications of Mie’s theory on the electrodynamics of moving bodies. . . . And do these three—Dillard, Arnesson and the girl—live alone?”
“With two servants. Dillard appears to have a very comfortable income. They’re not very much alone, however. The house is a kind of shrine for mathematicians, and quite a cénacle has developed. Moreover, the girl, who has always gone in for outdoor sports, has her own little social set. I’ve been at the house several times, and there have always been visitors about—either a serious student or two of the abstract sciences up-stairs in the library, or some noisy young people in the drawing-room below.”
“And Robin?”
“He belonged to Belle Dillard’s set—an oldish young society man who held several archery records. . . .”
“Yes, I know. I just looked up the name in this book on archery. A Mr. J. C. Robin seems to have made the high scores in several recent championship meets. And I noted, too, that a Mr. Sperling has been the runner-up in several large archery tournaments.—Is Miss Dillard an archer as well?”
“Yes, quite an enthusiast. In fact, she organized the Riverside Archery Club. Its permanent ranges are at Sperling’s home in Scarsdale; but Miss Dillard has rigged up a practice range in the side yard of the professor’s 75th-Street house. It was on this range that Robin was killed.”
“Ah! And, as you say, the last person known to have been with him was Sperling. Where is our sparrow now?”
“I don’t know. He was with Robin shortly before the tragedy; but when the body was found he had disappeared. I imagine Heath will have news on that point.”