However, when he saw him, small and far away on a hilltop, stooping, studying and moving here and there, the big man manifested some interest.

“Hello!” said he; “what’s this?”

Cautiously he made his way toward the spot, moving along fences and keeping trees between himself and the other where it was possible. Finally he was able to make out the man and his doings with little difficulty.

The saffron-coloured one had a glass in his hand and was examining the hole of an oak tree which grew on the crest of the hill.

“Same tree I stood under last night when I watched the fellow in the rolling chair,” murmured Bat. “Wonder what he finds wrong with it?”

From the tree the yellow man fell to carefully noting the dried stems of some stunted bushes; then he studied something here and there upon the ground, sometimes using the glass, but more often not.

“If I didn’t have a first-class reason for suspecting invalids,” said Mr. Scanlon, “I’d say this fellow was a botanist—maybe hunting a plant which, when cooked, would have some sort of a discouraging effect on the liver.”

He watched the man for some time; carefully the saffron-hued one went from place to place, from tree to tree, from one clump of dried brush to another. Gradually he moved down one hill and up the side of another. From the top of this a good view was to be had of Schwartzberg through the trees, and stationing himself behind one of these, the stranger looked long and searchingly toward the castle.

Kretz was not to be seen upon the walls; but at one of the windows Bat made out a woman’s figure. Apparently the saffron-hued man also saw her; but apparently he desired a better view. So taking a field-glass from a case which hung at his side, he trained it upon the window.

He spent some little time in watching the woman; then putting the glass away he moved along a road that ran between the hills at a sharp angle from Schwartzberg. Much interested, Bat followed. Again the stranger turned sharply, this time toward the river. And now Scanlon understood his movements.