THE PROGRESSIVE SCIENCE SERIES 



THE STARS 



A Study of the Universe 



By PROFESSOR SIMON NEWCOMB 



With Illustrations. 6s. net 



Professor Newcomb gives in this book a fascinating account of the wonder- 

 ful advances of our generation in the knowledge of the fixed stars. In its 

 preparation he has had the assistance of a number of friends and colleagues, 

 who have supplied him with the material necessary to the presentation of 

 their latest researches. 



CONTENTS 



Review of Recent Progress — Magnitudes of the Stars — Constellations and 

 Star-names — Cataloguing and numbering the Stars — The Spectra of the 

 Stars — Proper Motions of the Stars— Variable Stars — New Stars — The Paral- 

 laxes of the Stars — Systems of Stars — Nebula; — Constitution of the Stars — 

 Stellar Evolution— The Structure of the Heavens— Apparent Distribution of 

 the Stars in the Sky— The Clustering of the Stars — The Structure of the 

 Milky Way — The Progression in the Number of Stars as the Brightness 

 diminishes — Statistical Studies of Proper Motions — The Distribution of the 

 Stars in Space. 



THE SOLAR SYSTEM 



A Study of Recent Observations 



By CHARLES LANE POOR 



Professor of Astronomy in Columbia University 



6s. net 



The tides and tidal evolution, subjects but briefly treated in most astrono- 

 mical works, are given considerable space in the present volume, and Mars 

 and the so-called Martian canals, about which so much has been written, are 

 somewhat fully dealt with. 



CONTENTS 



The Moon— The Earth as an Astronomical Body — Tides and Tidal Evolution 

 — The Distance of the Sun — The Physical Characteristics of the Sun — The 

 Sun's Light and Heat — The Motions of the Planets — The Inner Planets : 

 Mercury and Venus — Mars — Has Mars Canals? — The Outer Planets— Satel- 

 lite Systems — Comets and Meteors — The Evolution of the Solar System. 



