X^1. HOW IT WORKS *** Produced by Jon Richfield FRAGMENTS OF SCIENCE: A SERIES OF DETACHED ESSAYS, ADDRESSES, AND REVIEWS. BY JOHN TYNDALL, F.R.S. Printed By Spottiswoode AND CO. 1879. All rights reserved. PREFACE TO THE SIXTH EDITION. VOL. II. I. REFLECTIONS ON PRAYER AND NATURAL LAW.