VUl 



PLATES 



PAGE 



Thermal Expansion of Ice (Figs. 1, 2) 254 



Morteratsch Grotto (Figs. 3, 4, 5) 263, 264 



View of San Antonio after Rainless Years, and after a Storm 



(Figs. 6a, 6b) 273 ^ 



Rock on Chilian Coast (Fig. 7) 274 



Charts of Tuberculosis... 284 



Figure illustrating Distance of Stars (Figs. 1-4) 308 



Portrait of Sir James Dewar in the Laboratory 354 



Photographs of Sun-Spots (Figs. 1-4, 6) 622, 626 



Tower Telescope on Mount Wilson ... ... ... ... 624 



Interior of Pasadena Laboratory 627 



Sun-Spot Spectra 628 



Siliceous Spicules in Sponges (Figs. 1, 2) 650 



Panama Canal — Photographs, Maps, etc. ... 688, 690, 694 



Problems of Helium and Radium (Figs. 1-5) ... ... ... 724 



Photographs of Sand (Figs. 1-6) 742 



Sand Electrical Machine (Fig. 7) 744 



Sand Pihng, etc. (Figs. 8-11) 746, 748, 750 



Crystal Structure (Figs. 2-5) 826,832 



Photo-Telegraphic Apparatus ... ... ... ... ... 836 



Drawings Transmitted by Telautograph (Plates II.-III.) ... 840 



Atmosphere of the Sun (Plates I.-IV.) .^ ... 902 



Light Reactions at Low Temperatures (Plates I. -V.) 928 



