What is the purpose of the trip that John takes chapter 7 write evidence

In Chapter Seven, we learn that winning the bet allows John to pay off his debts and to journey east with his partners for a fabled lost mine. Buck leads a team of six dogs 70 miles up the Yukon. John Thornton is unafraid of the wild, so he hunts for their food each day, always certain that it will eventually appear. Buck is very happy as they trek through the wilderness, fishing, hunting and unthinking of time. For two years they wander, seeking an ancient cabin and a mythical mine. They never find the mind, but in the spring of teh second year they find a "shallow placer in a broad valley where the gold showed like yellow butter across the bottom of the washing-pan."

When Buck earned sixteen hundred dollars in five minutes for John Thornton, he made it possible for his master to pay off certain debts and to journey with his partners into the East after a fabled lost mine, the history of which was as old as the history of the country.

Buck earns 1600 dollars for Thornton and it allows him to pay off many debts he had. It also let's them take a trip to find a mine full of gold where "no living man had looted this treasure house, and the dead were dead."