So they had recourse to artifice, and invited an eminent medical man to their house as a visitor.
And then under the guise of a friendly chat, the doctor took his observations.
But the peculiar ailment, if ailment it could be called, of Isaac Mole, completely baffled the man of science at first.
It was only in a casual conversation that, being an observing man, he discovered the real truth.
"Our patient wants a roving commission," said the physician to himself.
And then he communicated his own convictions to old Jack.
"I scarcely believe it possible, doctor," said Jack.
But the doctor was positive.
"Nothing will do him any good but to get on the move; I'm as sure of that as I am that he has no physical ailment."
"What's to be done then?" demanded Harkaway. "He can't travel alone."