"It may mean a good deal," he answered. "I hope, however, that no harm has come to Silas Keene; yet I am at a loss to understand why he remains away so long."

"He promised to return?"

"Yes."

For some moments a silence fell between mother and son, broken at length by a second ring at the bell.

"We seem to have visitors in plenty," uttered the young engineer, as he went again to the door.

On the step stood a small boy.

"Well, my little man."

"A letter for you, sir," and the lad placed an envelope in the hand of the engineer.

Would wonders never cease?

"Wait a moment."