TABLE OF CONTENTS. yn 



Relation of Forests to Rain-fall, 70; Adirondack State Park and Rain-fall, 

 84 ; Line of Perpetual Snow, 85 ; Rain-gauges at Sea, 73 ; AVater-spouts and 

 Cyclones, 107 ; Unvarying Course of Cirrus Clouds, 68 ; Poey's Classifica- 

 tion of Clouds, 86 ; Formation of Clouds, 89; Altitude of Clouds, 102; Mete- 

 oric Dust in Snow, 209 ; Hair Hygrometer versus Psychrometer, 115. 



Instruments : Carrying Thermometers, 74 ; Hair Hygrometer and Psy- 

 chrometer, 115; New Barometer, 116. 



C. PHYSICS '. . (xxxvi) 125 



General : Becquerel's Electro-capillary Pile, 125 ; Relation between Elec- 

 tricity and Heat, 126; Electricity and Capillarity, 165; Tension of Vapors 

 from Solids and Liquids, 144 ; Hinrichs' Theory of INIolecules, 164 ; Atomic 

 Theory, 169 ; Diffusion of Carbonic Acid, 166 ; Dialysis of Vegetable Cuti- 

 cles, 164 ; Dynamical Theory of Gases, 165 ; Theory of Rupert's Drops, 168 ; 

 Mechanical Principles of Flying, 172 ; Vibration of Cords, 177. 



Hydrodynamics : Recent Researches in Hydraulics, 145 ; Flow of Water 

 in Rivers and Canals, 167. 



Sound : Mayer's Discoveries in Acoustics, 129 ; New Method of Analy- 

 sis of Composite Sounds, 156 ; Harmonic Echoes, 163 ; Acoustics of Large 

 Rooms, 176 ; Vibration of Cords, 177 ; Lissajous' Phonoptometer, 142. 



Light : Sensibility of Selenium to Light, 127 ; New Determination of 

 Velocity, 128 ; Polarization by Reflection, 141 ; Rotation of Plane of Polar- 

 ization under Magnetic Influences, 148 ; Spectral Phenomena : New Spec- 

 troscope Micrometer, 136 ; Spectra of Simple and Compound Bodies, 153 ; 

 for Solar Spectroscopy, see Astroxo^iy, the Sun ; Nature of Sunlight, 137 ; 

 Actinic Power of Sunlight, 175 ; Intensity of Fraunhofer Lines, 174 ; Irra- 

 diation, 141; Dififraction Gratings, 154; Mechanical Combination of Colors, 

 155; Optical Telegraphy, 161; Effect of Light on Electric Currents, 150 ; 

 Blue Color of the Sky, 230; Double -image Micrometer, 136; Power of 

 Small Telescopes, 152. 



Heat : Best P^^rometer, 142; Solar Heat Reflected from Lake Geneva, 155. 



Electricity : Telegraphic Longitudes, 18 ; Signal Telegraphy and the 

 Herring Fi3her}^ 73 ; Telegraphic Line to Australia, 125 ; Spontaneous Elec- 

 tric Currents, 126 ; Electricity of Glycerine, 133 ; of Crystals, 133 ; Dissipa- 

 tion of Electricity in Gases, 134 ; Silent Dissipation of Electricity, 173 ; Nat- 

 ure of Electricity, 140; Electric Condensation, 150; Electric Current as Af- 

 fected by Light, 150 ; Effect of Galvanic Currents on Metallic Conductors, 

 151 ; Relation of Electricity to Capillarity, 166. See also Telegraphs, under 

 Engineering and Mechanics, and A tmospheric Electricity, under Mete- 

 orology. 



Magnetism : Protection of Ships' Compasses, 138 ; Ships' Magnetism, 

 146 ; Magneto-Electric Induction, 139 ; Best Condition for Electro-Magnets, 

 147 ; Influence of Magnetic Power of Steel on its Temper, 148. See also 

 Terrestrial Magnetism, under Terrestrial, Physics. 



D. CHEMISTRY AND METALLURGY (xxxvii) 179 



The Elements and their Simpler Combinations : Selenium, Sensibility 

 to Light, 127 ; Gold in Sea-water, 180 ; Antimony, Explosive, 181 ; Indium, 

 Position of, 188 ; Copper in Green Feathers of Parrot, 188 : in Turacine, 190 ; 

 Phosphorus, Action in Coal on Iron, 189 ; Amorphous Red Phosphorus, 182; 



