INDEX. C 



Dechen (Berghauptmann von), remarks on the maars, p. 231, and on the pumice, 

 p. 234, of the Eifel district, Note 314. 



Decennial period of the solar spots and of the magnetic variations, pp. 81 and 89, 

 and Note 73. 



Deception Island, p. 331. 



Declination, magnetic, first marked on the chart of Andrea Bianco, 1436, p. 55 ; 

 line of no, determined by Columbus in 1492, p. 5558 ; first map of, by Alonzo 

 de Santa Cruz in 1530, p. 56; existence of four lines of no, stated by Acosta 

 in 1589, p. 57; Halley's chart of (1702), p. 61; diurnal variation of, first 

 observed by Graham, in London, in 1722, p. 126; described, p. 127135; 

 discussed, p. 496; present distribution of the, lines, p. 144. 



Demavend, p. 335, Note 480. 



Density of the earth, p. 3133 and 449. 



Deville (Charles St. Claire), p. 420, Notes 602, 604. 



Diamaguetism, p. 50. 



Diaphragm of Dicearchus, Note 567. 



Disturbances, magnetic, p. 135, and 485495. 



Dome-shaped trachytic-mountains, p. 226. 



Douglas (David), p. 73. 



Due, p. 72. 



Duperrey, p. 67 ; magnetic equator, p. 110. 



Dupetit-Thouars, p. 67. 



Earth, figure of, p. 1831 and 453484, Notes 710 ; density of, p. 31 and 449, 

 and Notes 2528 ; temperature of, p. 3448 and Notes 3150; internal heat 

 of, Note 234 ; ideas of the ancients on the form of, Note 23 ; thickness of 

 crust of, p. 418, Notes 234 and 574. 



Earthquakes, p. 166184 and Notes 230254 ; nature of the first impulse in 

 earthquake movements, p. 169; velocity of propagation of, p. 179; question 

 of whether they affect the condition of terrestrial magnetism, p. 123 125 ; 

 Riobamba, p. 172173; Lisbon, p. 179, Note 251. 



Ehrenberg, infusoria in the Eifel, p. 235236. 



Eifel, maars and ancient volcanoes in the, p. 229236, 425, and 445, Notes 

 314319, 511. 



Elburuz, p. 341. 



Elevation-craters see Craters. 



Elliot, magnetic determinations, p. Ill, 149. 



Ellipticity of the earth, p. 18-31 and 453484. 



Encke, on the diurnal variation of the Declination, Note 154. 



Erebus, Mount, p. 247 and Note 355. 



Erman, magnetic observations, p. 72, 95, 100, 125, and 148149 j volcanoes in 

 Kamtschatka, p. 343348, and Notes 349 and 352. 



Etna, p. 223, 243, 250, 259, and 425, Notes 605 and 606. 



Eruption, cones of, p. 302. 



Eruptions, remarkable submarine volcanic, p. 215 and 331. 



Etymological discussions on the Pithecusae, Note 385. 



Euboea, earthquake and emission of lava in the Island of, p. 182 and 224. 



Faraday, on the magnetism of oxygen, p. 50 and 87 ; magnetic induction currents, 

 p. 75, 83, 91, 105, and Note 75. 



Felspar, glassy, p. 439. 



Fissures, pouring forth of lava and basalts from, p. 223, 259, 308, 384, and Note 

 306; volcanoes elevated over, p. 259; Italian, p. 260; American, p. 261 

 264, 268-269, 276, 289, 299, 388 j Java and Sumatra, p. 279, 282 ; continent 



VOL. IV. m 



