Those who draw their sustenance from science are blessed. It is for me to only derive an occasional pleasure. This is nothing worthy of conceit, but I am indeed touched by the joys. This book is an ode to such joys, a digest of my collections from various sources.
I did not imitate the skeptics who doubt only for doubting's sake, and pretend to be always undecided; on the contrary, my whole intention was to arrive at a certainty, and to dig away the drift and the sand until I reached the rock or the clay beneath.