Einstein's Chauffer

This is a true life anecdote about Albert Einstein, and his theory of relativity.
After having propounded his famous theory, Albert Einstein would tour the various Universities in the United States, delivering lectures wherever he went. He was always accompanied by his faithful chauffer, Harry, who would attend each of these lectures while seated in the back row. One fine day, after Einstein had finished a lecture and was coming out of the auditorium into his vehicle, Harry addresses him and says, "Professor Einstein, I've heard your lecture on Relativity so many times, that if I were ever given the opportunity, I would be able to deliver it to perfection myself!"
"Very well," replied Einstein, "I'm going to Dartmouth next week. They don't know me there. You can deliver the lecture as Einstein, and I'll take your place as Harry."
And so it went to be... Harry delivered the lecture to perfection, without a word out of place, while Einstein sat in the back row playing "chauffer", and enjoying a snooze for a change.
Just as Harry was descending from the podium, however, one of the research assistants intercepted him, and began to ask him a question on the theory of relativity, one that involved a lot of complex calculations and equations. Harry replied to the assistant, "The answer to this question is very simple. In fact, it's so simple, that I'm going to let my chauffer answer it!"