How did Isaac start his teaching?

Strangely, perhaps, for someone whom we regard as defining the fundamental laws of the universe, Newton started by talking about light.

Newton had long been interested in the colours in rainbows and had also noticed the colours in white light when grinding the lenses for his telescope. He observed that the edge of every lens is a small prism. He bought a prism in Downham market and then in his rooms he performed his famous experiment to show that white light is not white light at all -that it is a mixture of colours: red, orange, yellow, green, blue, indigo and violet. He was also able to recombine these colours into white light with a second prism.