yellow envelope
had been on the table, and more than once his mind had wandered from the
lessons he was preparing to speculate on the possible tidings wrapped
up in that sealed packet. Not that a telegram was an unheard-of event in
the family. No, his father received many; most of them, however, went to
the Boston office, and the boy could not imagine what this one was doing
at their Cambridge home.

The moment his father entered the house Donald handed him the envelope
and Mr. Clark quickly stripped it open; yet even though it now lay
spread out before him the mystery it contained appeared to be unsolved.
It was seldom that Donald asked questions, nevertheless he found himself
wondering and wondering what it was that had brought that odd little
wrinkle into his father's forehead. Donald understood that wrinkle; he
had seen it many times and knew it never came unless some question arose
to which it was difficult to frame an answer. As his father and he had
lived alone together ever since he could remember they had grown to know
each other very well, and had become the best of friends. It therefore
followed that when one worried, both worried.

As the boy looked on, his father glanced up suddenly and caught sight
of the anxiety mirrored in his face. The man smiled kindly.

"I can find no answer to this riddle, Don," he said. "Listen! Perhaps
you can help me. A few days ago I received word from Crescent Ranch that
Johnson, our manager, had been thrown from his horse while out on the
range and so badly hurt that he will never again be able to continue his
work with us. They have taken him to the hospital at Glen City. The
letter came from Tom Thornton, the head herder at the ranch. Thornton
assured me that everything was going well, and that there was not the
slightest need for me to come to Idaho."

Donald listened.

"Well, to-day I received this telegram. It is neither from Johnson nor
Thornton. It reads:

"'You would do well to visit Crescent Ranch,' and it is signed--'Sandy
McCulloch.'"

"Who is Sandy McCulloch?" asked Donald.

"That's the puzzle! I do not know. I never heard of any such person in
my life--not that I remember. Evidently, though, he knows enough about
me to know that I own that sheep ranch, and to think that I ought to go
out there and see it. I do not understand it at all. What do you make of
it, son?"

Donald thought carefully.

"Do you suppose anything is wrong on the ranch?"

"No, in