CONTENTS. 

 VOL. XXX. 



No. 200.— December 18, 1879. 



Page 



On the Secular Changes in the Elements of the Orbit of a Satellite re- 

 volving about a Tidally Distorted Planet. By G. H. Darwin, F.RS 1 



On Buff's Experiments on the Diathermancy of Air. By John Tyndall, 

 F.RS 10 



On the Photographic Spectra of Stars. By "William Huggins, D.C.L., 

 LL.D., F.RS 20 



On a New Method of Spectrum Observation. By J. Norman Lockyer, 

 F.RS 22 



Note on the Spectrum of Hydrogen. By J. Norman Lockyer, F.RS 31 



On the Capillary Electroscope. By G. Gore, LL.D., F.E.S 32 



Chemico-Electric Eelations of Metals in Solutions of Salts of Potassium. 

 By G. Gore, LL.D., F.RS 38 



On the Spontaneous Segmentation of a Liquid Annulus. By A. M. 

 Worthington, M.A 49 



On the Histology of Hydra fusca. By T. Jeffery Parker, B.Sc, Lec- 

 turer on Biology in Bedford College, London, and Demonstrator in the 

 Eoyal School of Mines. (Plate 1) 61 



January 8, 1880. 



The Bakerian Lecture. — On the Photographic Method of Mapping the 

 Least Eefrangible End of the Solar Spectrum (with a Map of the Solar 

 Spectrum from 7600 to 10750). By Captain W. de W. Abney, E.E., 

 F.RS 67 



January 15, 1880. 



On Chemical Repulsion. By Edmund J. Mills, D.Sc, F.RS , 68 



