The Purchase of the North Pole

The gun club of "From the Earth to the Moon" and "Around the Moon" returns after a long retirement. "The Purchase of the North Pole" brings back the three explorers who have come up with a new engineering project. If they fire a huge enough cannon, they can achieve displacement of the Earth's rotation axis. They seem to have a secret motive and we are left to wonder what they expect to achieve. Why are they not willing to give up on their plan? Have they made a huge mistake? Let's hope it's not too late to save the world from the damage one gun club can cause.