XJV CONTENTS. 



CHAPTER VII. 



THE PHYSICAL THEORY OP ENDOSMOSIS. 



Relation of Endosmosis to Capillary Attraction. Cases of reported Decompositions. Can be pro- 

 duced by Inorganic Masses, and therefore not due to Vitality. Water made to wet Mercury. 

 Voltaic Battery controls Capillary Attraction. Action of Inorganic Tissues. Water passes 

 through excesively small Pores. Hydraulic Currents. Deposites produced by Endosmotic Cur- 

 rents. Apparent Decomposition of Metallic Salts by Membranes. True Theory of it. General 

 Conclusion that Endosmosis is nothing more than common Capillary Attraction, and never occa- 

 sions true Decompositions . . . - 1 '. .;"".- . . . . . Page 57 



CHAPTER VIII. 



ON THE USE OF A SECONDARY WIRE AS A MEASURE OF THE RELATIVE TENSION OF ELECTRIC CURRENTS. 



Object of the Memoir. Action of a Secondary Wire. Description of the Torsion Galvanometer. 

 Resistance of the Secondary Wire under Variations of Tension. Condition of the Current never 

 changes. Tension rises with Length of Wire and with Distance of Plates. Relation between 

 Quantity and Tension. Theory of Tension of the Voltaic Battery. Known Methods of increas- 

 ing Tension of Currents. General Law. Case of Thermo-Electricity and Machine Electricity. 

 Voltaic Spark before contact in Vacua . . . . . . . .73 



CHAPTER IX. 



ON THE ELECTROMOTIVE POWER OF HEAT. 



Object of the Memoir. Experimental Arrangement to determine the Electromotive Power. Tem- 

 peratures calculated from Quantities of Electricity. Increase of Tension with Increase of Tem- 

 perature. Depends on increased Resistance to Conduction. Quantity of Electricity independent 

 of heated Surface. In Thermo-electric Piles, the Quantity of Electricity proportional to the Num- 

 ber of Pairs. Best Forms of Construction of Thermo-electric Pairs . . . . .90 



CHAPTER X. 



EXPERIMENTS ON THE CHEMICAL ACTION OF SOLAR LIGHT. 



Action of Absorbent Media. Ideal Coloration of the Chemical Rays. Specific Absorption. Col- 

 orific Absorption. 'Calorific Absorption. Specific Absorption of the Chemical Rays. Effect of 

 Yellow Solutions. 



Decomposition of Carbonic Acid by Leaves. Penetration of Dimensions in Gases. Decomposition 

 of Carbonic Acid under various coloured Media. Gas from Leaves contains Nitrogen. Chem- 

 ical Rays of different Colours. Identity of Volume in the absorbed and evolved Gas. Cause of 

 the Decomposition. 



Ritter's Experiments of the Non-oxygenation of Phosphorus. 



Decomposition of the Salts of Silver. Prismatic Spectrum on Bromide of Silver. Interference of 

 Chemical Rays. Salts decomposed by Light. Moonlight and Artificial Flames are inactive. 



Of Perihelion Motions. Dew of Water and Mercury. Iodine. Chloride of Gold. Non-deposition 

 on a Glass Plate. Current Action.^Action of Flame. Action of Metal Screens. Protecting 

 Action of a Metal Ring. Is there Electricity in the Solar Ray ? 



Cause of the Green Colour of Leaves. Plants grow in Lights of various Colours. Seeds also ger- 

 minate in Red, Yellow, and Blue Light. Chemical Rays of different Colours . . . 99 



Note added to the foregoing Chapter. 



AN ACCOUNT Of SOME EXPERIMENTS MADE IN THE SOUTH OF VIRGINIA ON THE LIGHT OP THE SUN 133 



