Coming into possession of a torn map, they work out its solution and discover a rich mine of tourmalines, those gems that are famous in the State of Maine, and are valuable both as jewels and as parts of electrical apparatus.
As they plan to return to their work as Rangers, they are asked by Mr. Boone to aid him in unraveling the mystery of the trouble at his summer logging camp.
Again they find LeBlanc is mixed up in the theft of the timber, and after a half a dozen narrow escapes from disaster, meet with success. LeBlanc makes a mad dash for freedom and succeeds in swimming to meet a motor boat containing some of his friends, including his brother, Baptiste, who is just as great a villain as Jean.
In several of their adventures they have put to good use a wireless telephone outfit given them by Mr. Graham in gratitude for the double rescue of his little daughter, Patty.
In the preceding volume Dick called for help when the timber thieves had besieged the camp and captured the men loyal to Mr. Boone. Through the machinations of Barrows, the camp manager, much of the timber had been stolen, and enough harm done to seriously hinder Boone from keeping his contracts to deliver a certain supply of lumber at a set date.
Thanks to the boys’ work, however, the plot was nipped before it had gotten too far, and so we meet them now in the camp office after order has been restored, and the men are working doubly hard to aid their employer.
Just one more thing must be explained, and that is the mystery that entered Dick’s life when he was a mere child. His father, a friend of Garry’s father, had been professor of botany at an Eastern university. Dick’s mother died when he was a baby. One day Professor Wallace fell from his horse and received an injury that made him lose his memory. Before he could be operated upon he escaped from the hospital, in delirium, and had not been heard of from that day.
Out of sincere friendship for his old schoolmate, Mr. Boone had taken Dick into his home and, after formally adopting him, brought him up as he did his own son, Garry.
Now to return to the boys, who are just finishing their letters.
“Who is all that mail for you from?” quizzed Phil, as he spied Garry finishing his third letter.