CONTENTS. 
PART I. 
I. On the Electromotive Properties of the Leaf of Dioncea in the Excited and Unexcited 
States. By J. Buedon-Sandeeson, M.D., F.R.S., Professor of Physiology in 
University College, London .. page 1 
II. Lucifer: a Study in Morphology. By W. K. Brooks, Associate in Biology and 
Director of the Chesapeake Zoological Laboratory of the Johns Hopkins 
University, Baltimore, Md., U.S.A. Communicated by Professor Huxley, 
Sec. R.S .... 57 
III. On the Structure and Development of the Skull in Sturgeons (Acipenser rutlienus 
and A. sturio). By William Kitchen Pakkee, F.R.S. . 139 
IV. On the Stresses caused in the Lnterior of the Earth by the Weight of Continents 
and Mountains. By G. H. Daewin, F.R.S. . 187 
V. Experimental Determination of the Velocity of White and of Coloured Light. By 
James Young, LL.D., F.R.S., and Professor G. Foebes.231 
VI. The Bakeeian Lectuee. — Action of Free Molecules on Radiant Heat, and its 
Conversion thereby into Sound . By John Tyndall, F.R.S. . 291 
Index to Part L. 
355 
