Xia Huai'an stood in the largest square of Huaxia Academy, facing over a thousand selected students and teachers, and delivered a loud public lecture on electromagnetism.
"All things in the universe are divided into yin and yang! Yin and yang give rise to and restrain one another!" Xia Huai'an's opening words made pedants like Zhao Henian nod inwardly. Today, Xia Huai'an had invited them to attend a lecture on natural philosophy, claiming he had opened up a new branch of learning. At first, they had found it eccentric, but upon hearing this theory of yin and yang, they felt considerably more at ease.
Xia Huai'an continued, "Electricity is one of the fundamental attributes of all things. Electricity is also divided into yin and yang; negative charge is yin electricity, and positive charge is yang electricity. Like charges repel each other, and opposite charges attract each other."
Chapter 132