That Christian believer must either have a very imperfect view of the spirit of his own faith, or a very narrow conception of the evidences and the effect of its teachings, who imagines that the freest spirit of scientific inquiry, or the most penetrating insight into the secrets of matter or of spirit can have any other consequence than to strengthen and brighten the evidence for Christian truth. N. P. YALE COLLEGE, _May_, 1872. ------------------------------------------------------------------------ PUBLISHERS’ NOTE TO SECOND EDITION. The five lectures embodied in this First Series of Half Hours with Modern Scientists were first published as Nos. I.—V. of the University Scientific Series. In this series the publishers have aimed to give to the public in a cheap pamphlet form, the advance thought in the Scientific world. The intrinsic value of these lectures has created a very general desire to have them put in a permanent form. They therefore have brought them out in this style. Each five succeeding numbers of this celebrated series will be printed and bound in uniform style with this volume, and be designated as second series, third series, and so on. Henceforth it will be the design of the publishers to give preference to those lectures and essays of American scientists which contain original research and discovery, rather than to reprinting from European sources. The lectures in the second series will be (1) On Natural Selection as Applied to Man, by Alfred Russel Wallace; (2) three profoundly interesting lectures on Spectrum Analysis, by Profs. Roscoe, Huggins, and Lockyer; (3) the Sun and its Different Atmospheres, a lecture by Prof. C. A. Young, Ph.D., of Dartmouth College; (4) the Earth a great Magnet, by Prof. A. M. Mayer, Ph.D., of Stevens Institute; and (5) the Mysteries of the Voice and Ear, by Prof. Ogden N. Rood, of Columbia College. The last three lectures contain many original discoveries and brilliant experiments, and are finely illustrated. ------------------------------------------------------------------------ ────────────── _ON THE PHYSICAL BASIS OF LIFE._ ────────────── ------------------------------------------------------------------------ INTRODUCTION.