CONTENTS op N° 246.— Fifth Series. 





XXXY. On the Properties of a Mixture of Liquids. By 

 R. A. Lehfeldt, B.A., B.Sc, Demonstrator at Firth College, 

 Sheffield page 397 



XXXVI. An Improved Calorimeter for the Application of the 

 Method of Mixtures. By F. A. Waterman 413 



XXXVII. The Viscosity of Mixed Gases. By William 

 Sutherland 421 



XXXVIII. The Thermal Unit. By E. H. Griffiths, M.A., 

 F.R.S., Sidney Sussex College, Cambridge. (Plates VI. & VII.) . . 431 



XXXIX. On the Pressures of Saturation of Oxygen. By 

 Thaddetts Estreioher 454 



XL. On a Simple Geometrical Construction for finding the 

 Intensity of Illumination at any Point of a Plane due to a Small 

 Source of Light symmetrical about an Axis perpendicular to that 

 Plane. By Charles H. Lees, D.Sc 463 



XLI. On Helium and its place in the Natural Classification 

 of Elementary Substances. By Henry Wilde, F.R.S. (Plate 

 VIII.) 466 



XLII. Self-recorded Breaks in the Properties of Solutions. By 

 Spencer Umfreyille Pickering, F.R.S 472 



XLIII. Intelligence and Miscellaneous Articles : — 



Measurements with Alternating Currents of High Frequency, 

 by Dr. Josef Tuma 476 



*** It is requested that all Communications for this Work may be addressed, 

 post-paid, to the Care of Messrs. Taylor and Francis, Printing Office, Red 

 J^TpTi Tinurt. Fleet Street, London. 



