There are countless beautiful encounters in this world, and perhaps the most touching one is the encounter between Lavoisier, the “father of modern chemistry”, and his wife Marie. They worked together to create scientific miracles. It is no exaggeration to say that without them, there might not be a discipline of chemistry. However, when we open the PEP chemistry textbook and see the portrait of Lavoisier, we may be a little confused: Why does Lavoisier, holding a quill, neither look down at the paper nor look ahead, but turns his head? Looking to the right? In fact, this portrait is called “Portrait of Mr. and Mrs. Lavoisier”, but Mary beside…