They have bribed you.
I see the whole of it.

Tell me the truth, and you shall have five shillings." The driver looked over the marshes as if he had never received such an offer before.

Five shillings for a falsehood would have seemed the proper thing, and have called for a balance of considerations, and made a demand upon his energies.

But to earn five shillings by the truth had never fallen to his luck before; and he turned to me, because I smiled, and he said, "Will you taste the water, miss ?" "Bless me!" cried the Major, "now I never thought of that.

Common people have such ways about things they are used to! I might have stood here for a month, and never have thought of that way to settle it.
Ridiculously simple.