II. ON FORCE, AND THE RELATIONS BETWEEN FORCE AND 23 MATTER III. ATOMIC THEORY, ANALYSIS AND SYNTHESIS OF MATTER, 93 UTILITY OF WASTE SUBSTANCES—COAL-TAR COLOURS, ETC. IV. THE SOLAR SPECTRUM, SPECTRUM ANALYSIS, SPECTRA OF 129 GASES AND VOLATILIZED MATTER, INVERSION OF COLOURED LINES, CONSTITUTION OF SUN AND STARS PART II. VEGETABLE ORGANISMS. I. MICROSCOPIC STRUCTURE OF THE VEGETABLE WORLD 167 II. ALGÆ 179 III. FUNGI 260 IV. LICHENS 298 V. CHARACEÆ 312 VI. HEPATICÆ, OR LIVERWORTS 316 VII. MUSCI, OR MOSSES 323 VIII. FILICES, OR FERNS 335 IX. EQUISETACEÆ, OR HORSETAILS 367 X. MARSILEACEÆ, OR RHIZOSPERMÆ 371 XI. LYCOPODIACEÆ, OR CLUB MOSSES 373 XII. GENERAL STRUCTURE OF FLOWERING PLANTS 378 XIII. MONOCOTYLEDONOUS, OR ENDOGENOUS PLANTS 383 XIV. DICOTYLEDONOUS, OR EXOGENOUS PLANTS 404 ILLUSTRATIONS TO THE FIRST VOLUME. (_The Author is indebted to the works of Dr. Carpenter, Rev. M. J. Berkeley, Mr. Gosse, and Mr. Darwin, for the larger part of these Illustrations._) FIG. PAGE 89. Eucyrtidium cranoides _frontispiece_ 1. Form of stratified discharge in a vacuum tube 79 2. Form of stratified discharge in a vacuum tube, as 81 affected by an electro-magnet 3. Development of Ulva 171 4. Vertical section of the cuticle of Iris germanica 173 5. Longitudinal section of stem of Italian reed 176 6. Palmoglœa macrococca 182 7. Protococcus pluvialis 184 8. Volvox globator 189 9. Various species of Staurastrum 192 10. Economy of Closterium Lunula 193 11. Diatoma vulgare and Grammatophora serpentina 197 12. Biddulphia pulchella 198 13. Pleurosigma angulatum 199 14. Actinocyclus undulatus 200