TABLE OF CONTENTS.* 



PEEFACE Page iii 



GENERAL SUMMARY OF PROGRESS xvii 



A. MATHEMATICS AND ASTRONOMY 1 



ASTRONOMY. 

 The Sun: Eclipse of December, 1870, 3; Corona, 1,2; Protuberances, G, 

 12 ; Spots, 7 ; Explosion in, 12 ; Period of Rotation, 13 ; Temperature, 6. 

 The Stars : Parallax of, 10. The Planets s Erato, 13 ; New Asteroids, 15 ; 

 Transit of Venus in 1874, 14. The Moon : Mass of, 9. Comets : Tele- 

 scopic, 14; Nature of, 15; Spectrum of Encke's, 17. Meteorites, 11, 18. 

 Nebulae, 8. The Aurora, 10. Zodiacal Light, 37. 



B. TERRESTRIAL PHYSICS AND METEOROLOGY 10 



TERRESTRIAL PHYSICS. 



Water-courses, 19. Lakes : Blue Color of, 38. Tides, 20 ; Action on the 

 Earth, 21 ; Influence of atmospheric Pressure on, 37. Gravity of the Earth, 

 22 ; Pendulum Experiment in India, 39. 



METEOROLOGY. 

 The Atmosphere in general : Ozone, 22; Climate of Peru, 24 ; of Michi- 

 gan, 35 ; Influence of Trees, 25 ; Influence of the Moon, 36. Winds : Pre- 

 diction of Gales, 31 ; Winds of the North Atlantic, 33 , Calm in Storms, 31. 

 Pressure : Influencing Tides, 37 ; Determination of Heights, 34. Tem- 

 perature ; Cycles of, 26 ; Waves of, 27 , of the Air at different Heights, 27 ; 

 - of the Earth at different Depths, 27 ; Cold on Mount Washington, 32 ; 



. Freezing of Water, 29 ; Radiation, 37 ; in Mount Cenis Tunnel, 27, 37. 

 Moisture : Rain-fall, 22, 29 ; Variation with Altitude, 30 ; Formation of 

 Clouds, 24 ; New Form of Clouds, 30 ; Direct Condensation by Glaciers, 25 ; 

 Hail, 36 ; Insects in Hailstones, 218 -, Storms, 23, 35. Instruments : Ther- 

 mometer, 28; Barometer, 35; Weathercock, 31. Observations: Smith- 

 sonian Institution, 27 ; Storm-signal Sendee, 32 ; Station at the Azores, 34. 



C. ELECTRICITY, LIGHT, HEAT, AND SOUND 41 



ELECTRICITY AND MAGNETISM. 

 Magnetism : Curves, 41 ; Action on Gases, 50. Electricity of the Atmos- 

 phere, 43 ; Opposite Currents, 50. Apparatus : Batteries, 41, 42 ; Amal- 

 gam, 43. 



* In the arrangement of articles in the body of the work, it was found difficult to 

 place them iu systematic sequence. The effort has been made in the Table of Con- 

 tents to rectify any misplacement of paragraphs, so as to bring together those most 

 nearly related, and in proper order. 



