iv 



Pa & e 



On the Internal Forces of Magnetized and Dielectrically Polarized Bodies. 

 By Professor H. Helmholtz, For. Mem. R.S 40 



April 28, 1881. 



The Influence of Stress and Strain on the Action of Physical Forces. By 

 Herbert Tornlinson, B.A 41 



Lucifer : a Study in Morphology. By W. K. Brooks, Associate in Bio- 

 logy and Director of the Chesapeake Zoological Laboratory of the 

 Johns Hopkins University, Baltimore, Md., U.S. A 46 



List of Presents 48 



Influence of Voltaic Currents on the Diffusion of Liquids. By G. Gore, 

 LL.D., F.R.S 56 



Phenomena of the Capillary Electroscope. By G. Gore, LL.D., F.E.S 85 



No. 213.— May 5, 1881. 



List of Candidates for Election 104 



On the Determination of the Ohm in Absolute Measure. By Lord Ray- 

 leigh, F.R.S., and Arthur Schuster, Ph.D., F.R.S 104 



On the Structure and Development of the Skull in Sturgeons (Acipenser 

 ruthenus and A. sturio). By W. K. Parker, F.R.S 124 



On the Estimation of the Anrylolytic and Proteolytic Activity of Pan- 

 creatic Extracts. By William Roberts, M.D., F.R.S., Physician to the 

 Manchester Royal Infirmary, and Professor of Clinical Medicine in 

 Owens College 145 



May 12, 1881. 



On the Physiological Action of /3 Lutidine. By C. Greville Williams, 

 F.R.S., and W. H. Waters, B.A., Demonstrator in the Physiological 

 Laboratory, Cambridge 162 



Discussion of the Results of some Experiments with Whirled Anemo- 

 meters. By Professor G. G. Stokes, Sec. R.S. 170 



Investigations on the Spectrum of Magnesium. By G. D. Liveing, M.A., 

 F.R.S., Professor of Chemistry, and J. Dewar, M.A., F.R.S., Jack- 

 sonian Professor, University of Cambridge. (Plate 1) 189 



Note on the Reduction of the Observations of the Spectra of 100 

 Sun-spots observed at Kensington. By J. Norman Lockyer, F.R.S. 

 (Plate 2) 203 



May 19, 1881. 



On Discontinuous Phosphorescent Spectra in High Vacua. By William 



Crookes, F.R.S 206 



Molecular Magnetism. By Professor D. E. Hughes, F.R.S 213 



