PROCEEDINGS OF SECTIONS. 



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(An asterisk (*) signifies that the title only is printed.) 



Section A.— ASTRONOMY, MATHEMATICS, AND PHYSICS. 



Page. 



1. On the Quaternion Expression for the Co-ordinates of a Screw 



Reciprocal to five given Screws. By Sir Robert Ball ... ... 52 



2. Variable Stars of Long Period. By Professor E. C. Pickering ... 57 



3. Note on a Geometrical Illustration of the Convergence of the 



Geometrical Series. By Professor H. S. Carslaw ... .. 58 



4. On Certain Surface and Volimie Integrals of an Ellipsoid. Part II. 



By Evelyn G. Hogg 58 



5. On the Symmedian Point of a Triangle. By Evelyn Hogg ... ... 61 



6. Theory of the Alternate Current Generator. By Thos. R. Lyle ... 66 



7. Experiments on the Behaviour of Iron under Periodic Magnetizing 



Forces. By Professor T. R. Lyle 93 



8. Photographs of Arc Spectra of Metals under High Pressure. By 



W. Geoffrey Duffield 107 



9. International Solar Research. By W. Geoffrey Duffield ... ... 110 



10. Polar Lines in Arc Spectra. By W. Geoffrey DufReld ... ... Ill 



11. Elastic Solid Ether, with Two Moduli, Satisfying MacCullagh's 



Crystalline Optical Conditions." By Professor A. Macaulay ... 112 



12. On the Radium Content of Certain Igneous Rocks from the Sub- 



Antarctic Islands of New Zealand.* By C. Coleridge Farr and 



D. C. H. Florance 112 



13. Recent Experiments on the Viscosity of Water.* By Richard 



Hosking 112 



14. The Spectrum of Silver Given by a Carbon-Tube Furnace.* By W. 



G. Duffield 112 



15. The Laws of Mobility and Diffusion of the Ions formed in Gaseous 



Media. By E. M. Wellisch Il2 



16. The Theory of the Small Ion in Air.* By W. Sutherland 113 



17. The Bleeck-Love Electric Battery.* By W. A. Bleeck 113 



18. On Some Observations with Selenium Cells.* By 0. U. Vonwiller 113 



19. The Electrodeless Discharge in Mercury Vapour.* By S. G. Lusby 113 



20. A Note on the Electron Theory of the Carbon Arc* By Professor 



J. A. Pollock 113 



21. The Scattering of Beta Rays.* By J. P. V. Madsen 113 



22. The Scattering of X Rays.* By Professor W. H. Bragg 113 



23. Short Notes on — I. Taylor's Theorem, and — II. Envelopes.* By 



Professor E. J. Nanson ... ... ... ... ... ... ... 113 



24. Universal Radio-Activity. New Experiments without Radium.* By 



J. W. H. Hullett 113 



25. The Teaching of Mathematics." By R. H. Roe 113 



26. The Proof of Projection of Certain Types of Geometrical Theorems.* 



By H. Tomkys 113 



Section B.— CHEMISTRY. 



1. The Alkaloids of the Pukatea. By Bernard C. Aston ... ... 121 



2. Notes on Dipping Fluids. By J. C. Briinnich 129 



3. Euphorbia Pilulifera. By John Lunn ... ... ... ...\ ... 134 



4. Local Manufacture of Carbide of Calcium and Calcium Cyanimide. 



By E. Kilburn Scott 135 



