New and Variable Stars [358]
Distance of the Stars [364]
Proper Motion of the Stars [365]
Chemical and Physical Constitution of the Stars [371]
III. Nebulæ [373]
Classification of Nebulæ [373]
Irregular Nebulæ [376]
Spiral Nebulæ [384]
The Nebular Hypothesis [391]
IV. The Structure of the Stellar Universe [396]