CONTENTS OF THE APPENDIX. XJ 



CHAPTER XV. 



ON THE DECOMPOSITION OF CARBONIC ACID GAS AXD THE ALKALINE CARBONATES BY TKE LIGHT OF THE STTJt, 



AND ON THE TITHONOTYPE. 



Dr. Daubenv's Experiments. Importance of the Subject. Decomposition in the Prismatic Spectrum. De- 

 composition under Absorbent Media. Decomposition is due to Light. Disturbing Causes. Analysis of 

 Gas evolved. Decomposition of Saline Bodies. Production of Nitrogen. Disappearance of Oxygen. 

 Character of Chlorophyl. 



Tithonotypes in Copper. Detithonizing Power of Gases ........ Page 175 



CHAPTER XVI. 



DESCRIPTION OF THE TITHONOMETER, AN INSTRUMENT FOR MEASURING THE CHEMICAL FORCE OF THE DJDIGO- 



T1THO.MC E--. 



The Instrument consists of a Mixture of Chlorine and Hydrogen. It is acted upon by Lamp Light, an Elec- 

 tric Spark at a Distance, <tc. Chlorine and Hydrogen unite in Proportion to the Amount of Light. Mode 

 of measuring out known Quantities of Rays. The Maximum of Action is in the Indigo Space. Construc- 

 tion of the Instrument. Theoretical Conditions of Equilibrium. Preliminary Adjustment. Method of 

 continuous Observation. Method of interrupted Observation. Remarkable Contraction and Expansion 187 



CHAPTER XVII. 



ON TITHONIZED CHLORINE. 



Description of the Experiment. The Change in the Chlorine is not Transient. There are two Stages in 

 the Phenomenon. Rays are absorbed in producing this Change. It is the Indigo Ray which is absorbed. 

 The Action is positive from End to End of the Spectrum. The Indigo Ray forms Muriatic Acid, as 

 well as produces the Preliminary Tithonization. Change in other Elementary Bodies. Verification of 

 the preceding Results with the Tithonometer .......... 198 



CHAPTER XVIII. 



FARTHER CONSIDERATIONS ON THE EXISTENCE OF A FOURTH IMPONDERABLE. 



Defects of former Evidence. A new Photometer. Measures of the Light transmitted by Coloured Solutions. 



Explosion of Chlorine and Hydrogen by a distant Electric Spark. Absorptive Action of Media. 

 The Absorptive Action on Light and the Tilhonic Rays follows different Laws. 

 Opacity of Glass for Phosphoric Rays. Determination of the Refrangibility of the Phosphoric Rays of an 



Electric Spark. Refrangibiliiy of the same Rays in the Voltaic Arc of Flame. Professor Henry's Ex- 



perime: 

 These Facts serve to prove that there are more than three Imponderables 205 



