He's not your passenger:" to hear him grunt out: "What's the matter--lost your pedals ?" Harris, in his early married days, made much trouble for himself on one occasion, owing to this impossibility of knowing what the person behind is doing.

He was riding with his wife through Holland.

The roads were stony, and the machine jumped a good deal.
"Sit tight," said Harris, without turning his head.
What Mrs.Harris thought he said was, "Jump off." Why she should have thought he said "Jump off," when he said "Sit tight," neither of them can explain.
Mrs.Harris puts it in this way, "If you had said, 'Sit tight,' why should I have jumped off ?" Harris puts it, "If I had wanted you to jump off, why should I have said 'Sit tight!' ?" The bitterness is past, but they argue about the matter to this day.
Be the explanation what it may, however, nothing alters the fact that Mrs.Harris did jump off, while Harris pedalled away hard, under the impression she was still behind him.

It appears that at first she thought he was riding up the hill merely to show off.

They were both young in those days, and he used to do that sort of thing.