VI CONTENTS OF VOL. XXVII. FOURTH SERIES. 



Page 



Mr. J. Croll on the Influence of the Tidal Wave on the Earth's 

 Rotation, and on the Acceleration of the Moon's Mean 

 Motion 285 



Prof. Maxwell on the Calculation of the Equilibrium and StifF- 

 ness of Frames , 294 



Proceedings of the Royal Institution : — 



Prof. J. A. Wauklyn on the Synthesis of Organic Bodies. 299 



Further Remarks on the Telescopic Appearance of the Exterior 

 Envelope of the Sun, and of its Spots, by the Rev.W. R. Dawes. 306 



On the Hypothesis of Molecular Vortices, by W. J. Macquorn 

 Rankine, F.R.S 313 



On the Deflection of the Magnetic Needle by the Secondary 

 Currents of the Leyden Battery, by P. Riess 313 



On a New British Mineral, by Prof. N. S. Maskelyne „ 316 



New Investigation on the Position of the Optic Centre of the 

 Eye, and Determination of the Refractive Values of the dif- 

 ferent Media, by M. Girard-Teulon 316 



On the Geometry of my Eighth Decimal Approximation to the 

 Circular Circumference, by S. M. Drach, F.R.A.S. ...... 318 



On Albert Durer's Heptagon-chord. — Second Notice, by S. M. 

 Drach, F.R.A.S. 320 



NUMBER CLXXXIIL— MAY. 



Prof. Frankland on the Physical Cause of the Glacial Epoch . . 321 

 Mr. C. K. Akin on a New Method for the Direct Determination 



of the Specific Heat of Gases under Constant Volume 341 



Mr. J. Croll on the Nature of Heat Vibrations 346 



Mr. J. J. Waterston on Liquid Expansion. (With a Plate.) . . 348 

 Dr. A.W.Williamson on the Dynamics of the Galvanic Battery. 353 

 Dr. Hargreave on Differential Equations of the First Order . . 355 



Prof. Magnus on the Constitution of the Sun 376 



Captain J. Mitchell on the Duration of the Combustion of Fuses 



under different Atmospheric Pressures 379 



Mr. J. Croll on the Cause of the Cooling Effect produced on 



Solids by Tension 380 



Proceedings of the Royal Society : — 



Prof. J. A. Wanklyn on the Distillation of Mixtures 382 



Mr. C. K. Akin on Thermo-electric Currents of the Rit- 



terian Species 383 



Mr. C. Chambers on the Nature of the Sun's Magnetic 



Action upon the Earth 384 



Mr. H. E. Roscoe on the Measurement of the Chemical 



Brightness of various portions of the Sun's Disc .... 384 

 Mr. J. Hicks on an Improved Mercurial Barometer .... 386 

 Proceedings of the Royal Institution : — 



Prof. G. G. Stokes on the Discrimination of Organic Bodies 

 by their Optical Properties 388 



