CONTENTS 
OF VOL. 144. 
I. On the Vibrations and Tones produced by the Contact of Bodies having different 
Temperatures. By John Tyndall, Ph.D., F.R.S., Member of the Royal 
Society of Haarlem , and Professor of Natural Philosophy in the Royal Insti- 
tution page 1 
II. Theory of the Reciprocal Action between the Solar Rays and the different Media 
by ivhich they are ref ected, refracted, or absorbed ; in the course of which various 
optical laws and phenomena are elucidated and explained. By Joseph Power, 
M.A., Fellow of Clare Hall, and Librarian of the University of Cambridge : 
Member of the Cambridge Philosophical and Antiquarian Societies, and Founda- 
tion Fellow of the Society of Northern Antiquaries at Copenhagen. Communi- 
cated by the Rev. J. Cape, F.R.S 11 
III. On some of the Products of the Decomposition of Nitrotoluy lie Acid. By Henry 
M. Noad, Ph.D., Lecturer on Chemistry at St. George’s Hospital ... 43 
IV. Researches on the Geometrical Properties of Elliptic Integrals. By the Rev. 
James Booth, LL.D., F.R.S. 8$c 53 
V. On a Class of Differential Equations, including those ivhich occur in Dynamical 
Problems. — Part I. By W. F. Donkin, M.A., F.R.S., F.R.A.S., Savilian 
Professor of Astronomy in the University of Oxford 71 
VI. On the Geometrical Representation of the Expansive Action of Heat, and the 
Theory of Thermo-dynamic Engines. By William John Macquorn Hankine, 
C.E., F.R.SS. Lond. and Edin. 8$c 115 
VII. The Bakerian Lecture. — On Osmotic Force. By Thomas Graham, F.R.S., 
$c 177 
VIII. Researches on the Impregnation of the Ovum in the Amphibia ; and on the early 
Stages of Development of the Embryo. ( Third Series.) By the late George 
Newport, F.R.S., F.L.S. &;c. Selected and arranged from the Authors MSS., 
by George Viner Ellis, Professor of Anatomy in University College, London. 
Communicated by Sir John Forbes, 31 . D., F.R.S. 229 
