Because of Diamond, I have had to begin much of the work afresh. I will not, however, rid myself of her, nor even punish her. She knew not what she was doing, and that which she did was for my protection and for love of my person. Her place remains at my side or against my feet when I lie abed.

The Synthesis consists in assuming the Causes discovered and established as Principles, and by them explaining the Phænomena proceeding from them, and proving the Explanations.

My Design in this Book is not to explain the Properties of Light by Hypotheses, but to propose and prove them by Reason and Experiments: In order to which, I shall premise the following Definitions and Axioms.

God is able to create particles of matter of several sizes and figures and perhaps of different densities and forces, and thereby to vary the laws of nature, and make worlds of several sorts in several parts of the Universe.

The great ocean of truth lay all undiscovered before me.

To every action there is always opposed an equal reaction.

Truth is ever to be found in the simplicity, and not in the multiplicity and confusion of things.