“I’m mighty sorry that you have to leave us, Butzow,” said Barney’s partner.  “It’s bad enough to lose you, but I’m afraid it will mean the loss of Barney, too.  He’s been hunting for some excuse to get back to Lutha, and with you there and a war in sight I’m afraid nothing can hold him.”

“I don’t know but that it may be just as well for my friends here that I leave,” said Butzow seriously.  “I did not tell you, Barney, all there is in this letter”—­he tapped his breastpocket, where the foreign-looking envelope reposed with its contents.

Custer looked at him inquiringly.

“Besides saying that war between Austria and Serbia seems unavoidable and that Lutha doubtless will be drawn into it, my informant warns me that Leopold had sent emissaries to America to search for you, Barney, and myself.  What his purpose may be my friend does not know, but he warns us to be upon our guard.  Von der Tann wants me to return to Lutha.  He has promised to protect me, and with the country in danger there is nothing else for me to do.  I must go.”

“I wish I could go with you,” said Barney.  “If it wasn’t for this dinged old mill I would; but Bert wants to go away this summer, and as I have been away most of the time for the past two years, it’s up to me to stay.”

As the three men talked the afternoon wore on.  Heavy clouds gathered in the sky; a storm was brewing.  Outside, a man, skulking behind a box car on the siding, watched the entrance through which the three had gone.  He watched the workmen, and as quitting time came and he saw them leaving for their homes he moved more restlessly, transferring the package which he held from one hand to another many times, yet always gingerly.

At last all had left.  The man started from behind the box car, only to jump back as the watchman appeared around the end of one of the buildings.  He watched the guardian of the property make his rounds; he saw him enter his office, and then he crept forward toward the building, holding his queer package in his right hand.

In the office the watchman came upon the three friends.  At sight of him they looked at one another in surprise.

“Why, what time is it?” exclaimed Custer, and as he looked at his watch he rose with a laugh.  “Late to dinner again,” he cried.  “Come on, we’ll go out this other way.”  And with a cheery good night to the watchman Barney and his friends hastened from the building.

Upon the opposite side the stranger approached the doorway to the mill.  The rain was falling in blinding sheets.  Ominously the thunder roared.  Vivid flashes of lightning shot the heavens.  The watchman, coming suddenly from the doorway, his hat brim pulled low over his eyes, passed within a couple of paces of the stranger without seeing him.

Five minutes later there was a blinding glare accompanied by a deafening roar.  It was as though nature had marshaled all her forces in one mighty, devastating effort.  At the same instant the walls of the great mill burst asunder, a nebulous mass of burning gas shot heavenward, and then the flames settled down to complete the destruction of the ruin.