I risk dipping too often into the well of the life of François Arago, but this evening during my lecture I had to share an anecdote from his autobiography, and thought it was worth sharing here as well!

At the end of 1803, Arago entered the Polytechnic School at the age of 17 with the intention of becoming an artilleryman.  The science and math-based curriculum was challenging, but the students were generally up to the challenge.  More so apparently, in some cases, than the professors running the class.  From Arago’s autobiography:

When a professor has lost consideration, without which it is impossible for him to do well, they allow themselves to insult him to an incredible extent. Of this I will cite a single specimen.

A pupil, M. Leboullenger, met one evening in company this same M. Hassenfratz, and had a discussion with him. When he re-entered the school in the morning, he mentioned this circumstance to us. ” Be on your guard,” said one of our comrades to him; “you will be interrogated this evening. Play with caution, for the professor has certainly prepared some great difficulties so as to cause laughter at your expense.”

Our anticipations were not mistaken. Scarcely had the pupils arrived in the amphitheatre, when M. Hassenfratz called to M. Leboullenger, who came to the board.

“M. Leboullenger,” said the professor to him, “you have seen the moon?” “No, sir.” “How, sir! you say that you have never seen the moon?” “I can only repeat my answer – no, sir.” Beside himself, and seeing his prey escape him, by means of this unexpected answer, M. Hassenfratz addressed himself to the inspector charged with the observance of order that day, and said to him, “Sir, there is M. Leboullenger who pretends never to have seen the moon.” “What would you wish me to do?” stoically replied M. Le Brun. Repulsed on this side, the professor turned once more towards M. Leboullenger, who remained calm and earnest in the midst of the unspeakable amusement of the whole amphitheatre, and cried out with undisguised anger, “You persist in maintaining that you have never seen the moon?” “Sir,” returned the pupil, “I should deceive you if I told you that I had not heard it spoken of, but I have never seen it.”  “Sir, return to your place.”

After this scene, M. Hassenfratz was but a professor in name; his teaching could no longer be of any use.

I mentioned this anecdote in class today because the class was catching a lot of my mistakes on the board and was otherwise quite engaged in what I was talking about!  After they caught the third or fourth error, I noted that I was worried that I was losing their respect, and shared Arago’s story.  It was a great lecture, though — I had a lot of fun and the class and I laughed a lot!