They saw the figure of Locke cross one of the shed windows toward a door. And just then Ashton-Kirk stumbled rather heavily against Haines; the lantern dropped to the ground and was extinguished.
"I beg your pardon," said the investigator in a rueful tone; then he began to rub his shins. "That was rather hard, whatever it was."
The door of the building opened and Locke appeared; his great bald head shone in the light that streamed after him; and it was thrust forward as he strove to penetrate the darkness ahead.
"He feels the vibrations of those buzzers," Haines told them, "and knows right away when anyone wants to get in."
He began fumbling with the lantern as Locke disappeared; but Ashton-Kirk said to him:
"You need not light that. We can see very well. And, on second thought, you need not wait, either. We can introduce ourselves to Professor Locke without troubling you further."
"Thank you, sir," said the man, vastly relieved. "They all have queer dispositions, you see, and I don't like to trouble them."
At once Haines made his way back along the path by which they had approached; some distance away they saw him kindle his lantern, and then watched the yellow spark as it glanced fitfully away across the grounds.
The cottage and work-shop of Professor Locke appeared to be set back some little distance from what Haines had called the county road; a grove of tall trees thickened the shadows all about, and it was into these trees that the professor had gone.
"The buzzer must have the button that sounds it attached to a gate opening upon the road," said Pendleton.