PHILOSOPHICAL TRANSACTIONS. 



Contents op Part II, 1880. 



XI. Double Refraction and Dispersion in Iceland Spar : an Experimental In- 

 vestigation, with a comparison with Huyghen's Construction for the 

 Extraordinary Wave. By R. T. GtLAzebrook, M.A., Fellow of Trinity 

 College, Cambridge. 



XII. On the Normal Paraffins— Part III. By C. Schorlemmer, F.R.S., Pro- 

 fessor of Organic Chemistry in Owens College, Manchester. 



XIII. On the Motion of Two Spheres in .a Fluid. By W. M. Hicks, M.A., 

 Fellow of St. John's College, Cambridge. 



XIY. On the Organization of the Fossil Plants of the Coal-Measures. — Part X. 



Including an Examination of the supposed Radiolarians of the Car- 

 boniferous Bocks. By W. C. Williamson, F.E.S., Professor of Botany 

 in Owens College, Manchester. 

 XV. On the Relation between the Diurnal Range of Magnetic Declination and 

 Horizontal Force, as observed at the Royal Observatory, Grreen-vvich, 

 during the years 1841 to 1877, and the Period of Solar Spot Frequency. 

 By William Ellis, F.R.A.S., Superintendent of the Magnetical and 

 Meteorological Department, Royal Observatory, Greenwich. 



XVI. On the Sensitive State of Vacuum Discharges. — Part II. By William 

 Spottiswoode, D.C.L., LL.D., President of the Royal Society, and 

 J. Fletcher Mottlton, late Fellow of Christ's College, Cambridge. 

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

 least Refrangible End of the Solar Spectrum. By Captain W. de W. 

 Abney, R.E., F.R.S. 



XVIII. On the Photographic Spectra of Stars. By Wiliiam Huggins, D.C.L., 

 LL.D., F.R.S. 



XIX. On the Electromagnetic Theory of the Reflection and Refraction of Light. 

 By G-eo. Fras. Fitzgerald, M.A., Fellow of Trinity College, Dublin. 

 XX. On the Secular Changes in the Elements of the Orbit of a Satellite revolv- 

 ing about a Tidally Distorted Planet. By Gr. H. Darwin, F.R.S. 

 Index to Part II. 



PHILOSOPHICAL TRANSACTIONS. 

 Part IT, 1880, price £2. 



Extra volume (vol. 168) containing the Reports of the Naturalists attached to the 

 Transit of Venus Expeditions. Price £3. 



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