INDEX 
TO THE 
PHILOSOPHICAL TRANSACTIONS 
Series A, Vol. 217. 
B. 
Bakkla (0. G.). On X-rays and the Theory of Radiation, 315. 
C. 
Chapman (S). On the Kinetic Theory of a Gas. Part II.—A Composite Monatomic Gas : Diffusion, "Viscosity, and Thermal 
Conduction, 115. 
Cbookes (Sir W.). On the Photographic Spectra of Meteorites, 411. 
D. 
Doodson (A. T.). See Pboddman, Doodson and Kennedy. 
E. 
Electromagnetic 'wave, theory of diffraction of, by perfectly conducting sphere (Pbotjdman and others), 279. 
Equilibrium of rotating liquid mass, instability of pear-shaped figure of (Jeans), 1. 
G. 
Gag —diffusion, viscosity, thermal conduction of monatomic (Chapman), 115. 
H. 
Haloes, genesis of pleochroic (Jody), 51. 
Hioks (W. M.). A Critical Study of Spectral Series. Part IV.—The Structure of Spark Spectra, 361. 
J. 
Jeans (J. H.). On the Instability of the Pear-shaped Figure of Equilibrium of a Rotating Mass of Liquid, 1. 
Joey (J.). The Genesis of Pleochroic Haloes, 51. 
3 R 
VOL. CCXVII. —A. 
Published December 31, 1918. 
