he finds corresponds to the line marked 2796 on Kirchhoff's map, and not, as was supposed, identical with Fraunhofer's line G.

At the end of the volume will be found a tolerably complete List of Memoirs forming the literature on the subject.

My thanks are due to Mr. J. D. Cooper and Mr. Collings for the very great care which they have bestowed upon the illustrations, and especially upon the difficult task of reproducing Kirchhoff's maps in four tints.

MANCHESTER, April 1869.

H. E. R.

CONTENTS.

LECTURE I-APOTHECARIES' HALL, MAY 2, 1868.

INTRODUCTION. -NEWTON'S DISCOVERY OF THE COMPOSITION OF WHITE

LIGHT, 1675.-PROPERTIES OF SUN LIGHT.-HEATING RAYS.-LUMI-

NOUS RAYS.-CHEMICALLY ACTIVE RAYS. THE SOLAR SPECTRUM.-

POSITION OF MAXIMA.-ILLUSTRATIONS OF THESE RADIATIONS.-

MEANS OF OBTAINING A PURE SPECTRUM.- -FRAUNHOFER'S LINES.-

PLANET AND MOON LIGHT.-STAR LIGHT

Page

26

APPENDIX B.-BURNING MAGNESIUM WIRE A SOURCE OF LIGHT FOR

PHOTOGRAPHIC PURPOSES

36

APPENDIX C.-ON THE CHEMICAL ACTION OF THE CONSTITUENT PARTS

OF SOLAR LIGHT

38

LECTURE II.-MAY 9, 1868.

CONTINUOUS SPECTRUM OF INCANDESCENT SOLIDS.-EFFECT OF INCREASE

OF HEAT. BROKEN SPECTRA OF GLOWING GASES. APPLICATION

TO CHEMICAL ANALYSIS.-SPECTRA OF THE ELEMENTARY BODIES.---

CONSTRUCTION OF

SPECTROSCOPES.-MEANS OF OBTAINING SUB-

STANCES IN THE STATE OF GLOWING GAS.-EXAMINATION OF THE

SPECTRA OF COLOURED FLAMES.-SPECTRA OF THE METALS OF THE

ALKALIES AND ALKALINE EARTHS.-DELICACY OF THE SPECTRUM

ANALYTICAL METHOD

.

APPENDIX A.-KIRCHHOFF AND BUNSEN:

44

DESCRIPTION OF THE SPECTRUM

REACTIONS OF THE SALTS OF THE ALKALIES AND ALKALINE EARTHIS 68

APPENDIX B.--BUNSEN AND KIRCHHOFF ON THE MODE OF USING A SPEC-

APPENDIX C.-BUNSEN ON A METHOD OF MAPPING SPECTRA

88

LECTURE III.-MAY 16, 1868.

HISTORICAL SKETCH.-TALBOT, HERSCHEL, BUNSEN, AND KIRCHHOFF.—

DISCOVERY OF NEW ELEMENTS BY MEANS OF SPECTRUM ANALYSIS.-

CESIUM, RUBIDIUM, THALLIUM, INDIUM.-THEIR HISTORY AND PRO-

PERTIES.-KNOWLEDGE OF DISTRIBUTION AND OCCURRENCE OF OTHER

ELEMENTS. SPECTRA OF THE NON-METALLIC ELEMENTS, HYDROGEN,

NITROGEN, ETC. APPLICATION OF SPECTRUM ANALYSIS TO STEEL-

MAKING

Page

90

APPENDIX A.--SPECTRUM REACTIONS OF THE RUBIDIUM AND CESIUM

APPENDIX C.-ON THE SPECTRUM OF THE BESSEMER FLAME

APPENDIX D.-IGNITED GASES UNDER CERTAIN CIRCUMSTANCES GIVE

CONTINUOUS SPECTRA.-COMBUSTION OF HYDROGEN IN OXYGEN

APPENDIX E. DESCRIPTION OF THE SPECTRA OF THE GASES AND NON-

METALLIC ELEMENTS

LECTURE IV.-MAY 23, 1868.

130

SPECTRA OF THE HEAVY METALS. EXAMINATION OF THE LIGHT OF THE

ELECTRIC DISCHARGE.--VOLATILIZATION OF METALS IN THE ELEC-

TRIC ARC. KIRCHHOFF AND HUGGINS' MAPS OF THE METALLIC

LINES. ACTION OF INCREASE OF TEMPERATURE ON THE SPECTRA.-

SPECTRA OF COMPOUND BODIES. ABSORPTION SPECTRA OF BLOOD

AND OTHER COLOURED LIQUIDS.-APPLICATION TO THE MICROSCOPE 134

APPENDIX A.-ON THE SPECTRA OF SOME OF THE CHEMICAL ELEMENTS. 157

APPENDIX B. ON THE EFFECT OF INCREASED TEMPERATURE UPON

THE NATURE OF THE LIGHT EMITTED BY THE VAPOUR OF CERTAIN

METALS, OR METALLIC COMPOUNDS

. . 172

APPENDIX C.-ON THE SPECTRA OF ERBIUM AND DIDYMIUM COMPOUNDS. 175

APPENDIX D. DESCRIPTION OF THE MICRO-SPECTROSCOPE

177

LECTURE V.-MAY 30, 1868.

Page

SOLAR

FOUNDATION OF SOLAR AND STELLAR CHEMISTRY.-EXAMINATION OF THE

SPECTRUM.-FRAUNHOFER, 1814. KIRCHHOFF, 1861. — COIN-

CIDENCE OF DARK SOLAR LINES WITH BRIGHT METALLIC LINES.-

REVERSION OF THE BRIGHT SODIUM LINES. KIRCHHOFF'S EXPLANA-

TION. CONSTITUENTS OF THE SOLAR ATMOSPHERE. PHYSICAL CON-

STITUTION OF THE SUN.-PLANET AND MOON LIGHT.

APPENDIX A.- LOCKYER'S AND JANSSEN'S DISCOVERIES RESPECTING THE

180

. . 210

APPENDIX B.--EXTRACTS FROM THE REPORT OF THE COUNCIL OF THE

ROYAL ASTRONOMICAL SOCIETY TO THE FORTY-NINTH ANNUAL

APPENDIX C.-. ANGSTRÖM, RECHERCHES SUR LE SPECTRE NORMAL DU

SOLEIL .

LECTURE VI.-JUNE 6, 1868.

215

STARS.

-

STELLAR CHEMISTRY.-HUGGINS AND MILLER.--SPECTRA OF THE FIXED

DIFFICULTIES OF OBSERVATION. -METHODS EMPLOYED.-

VARIABLE STARS. DOUBLE STARS.--TEMPORARY BRIGHT STARS.

NEBULE.COMETS.-CONCLUSION

APPENDIX A.- EXTRACT FROM A MEMOIR "ON THE SPECTRA OF SOME OF

THE FIXED STARS (HUGGINS AND MILLER).

APPENDIX B.-—“ON THE SPECTRUM OF MARS, WITH SOME REMARKS ON

257

266

66

-"ON THE SPECTRA OF VARIABLE STARS

APPENDIX D.- FURTHER OBSERVATIONS ON THE SPECTRA OF SOME OF

THE STARS AND NEBULÆ, WITH AN ATTEMPT TO DETERMINE THERE-

FROM WHETHER THESE BODIES ARE MOVING TOWARDS OR FROM THE

EARTH; ALSO OBSERVATIONS ON THE SPECTRA OF THE SUN AND OF

COMET II. 1868 " (HUGGINS)

272