“How do you fix the exact day?” Mantell questioned perplexedly.
“By the character of the imprints and the condition of the near greensward, to which they frequently stepped,” Nick explained. “We had a hard rain eleven days ago, and have had none since then.”
“I remember.”
“A hard rain would completely obliterate such imprints from the soil of a flower bed,” Nick went on. “These, then, must have been formed since the storm. The depth and irregular character of them, however, show that the soil must have been very soft and muddy, as if very soon after the rain. This appears, too, in that when they stepped to the greensward they left many traces of the soil clinging to their soles. I feel perfectly safe in saying that they were there the night after the storm.”
Mantell’s face had taken on a more serious expression.
“By Jove, you have reminded me of something, Carter,” he said gravely.
“What is that?”
“It was on the day following that storm that I received Vandyke’s letter, and I read it aloud that evening to my wife and parents. We were here in the library. I begin to think your deductions are correct.”
“I am very sure of it,” Nick declared, smiling a bit oddly.
“But who could have been spying upon us, or playing the eavesdropper?”