CONTENTS. 



VOL. XXXI. 



— ~+iH* — 

 No. 206. 



Page 



Researches on the Action of Organic Substances on the Ultra-Violet Rays 

 of the Spectrum. Part III. An Examination of Essential Oils. By 

 W. N. Hartley, E.R.S.E., &c, Professor of Chemistry in the Royal 

 College of Science for Ireland, Dublin, and A. K. Huntington, F.C.S., 

 Associate of the Royal School of Mines.., 1 



Researches into the Colouring Matters of Human Urine, with an Account 

 of the Separation of Urobilin. By Chas. A. MacMunn, B.A., M.D 26 



No. 207.— November 18, 1880. 



On the Essential Properties and Chemical Character of Beryllium (Gluci- 

 num). By L. F. Nilson and Otto Pettersson '. 37 



On the Molecular Heat and Volume of the Rare Earths and their Sul- 

 phates. By L. F. Nilson and Otto Pettersson 46 



On the Absorption Spectra of Cobalt Salts. By W. J. Russell, Ph.D., 

 F.R.S., Treas. C.S., Lecturer on Chemistry at the Medical School, 

 St. Bartholomew's Hospital 51 



On the Friction of Water against Solid Surfaces of Different Degrees of 

 Roughness. By Professor W. C. Unwin, M.I.C.E., Professor of Hy- 

 draulic Engineering at the Royal Indian Engineering College 54 



November 25, 1880. 



On the Chemical Composition of Aleurone-Grains. By S. H. Vines, 

 M.A., D.Sc, Fellow of Christ's College, Cambridge 59 



On the Ossification of the Terminal Phalanges of the Digits. By F. A. 

 Dixey, B.A. (Oxon.) (Plates 1, 2) 63 



On a Sun-Spot observed August 31, 1880. By J. N. Lockyer, F.R.S 72 



On Methods of Preparing Selenium and other Substances for Photo- 

 phonic Experiments. By Professor Graham Bell 72 



