Index. 297 



its axis to the axis of its orbit, 331 mensuration of the 

 earth, and way in which this was accomplished, ib. the 

 earth found to be not a perfect sphere, 335 methods of 

 ascertaining the longitude at sea, 338 general view of the 

 materials of which this globe is composed ; and different 

 hypotheses on the subject, ii. 171 to 175. See also Tides. 



Earth's surface, extent of the, i. 67' 



Earths, simple substances in chemistry, ii. 30. 55 lect 

 ture on, 170 definition of earthy and stony substances, 

 ib. different classes of them; remarks on each, and 

 on their distribution, 171 10,197. 



Earthquakes, phenomena of, i. 6. 



Eclipse, the expected of 1820 and 1847 determined, ii. 

 27. 



Eclipses, lecture on, ii. 18 of the moon, ib. of the 

 sun, 22 returns of eclipses as influenced by the nodes, 

 24, 25 principles of foretelling eclipses, 26 par- 

 ticular points and phases to be noticed in eclipses, 28 

 explanation of the term digits, 2Q eclipses of the 

 satellites of Jupiter, ib. 



Ecliptic, explanation of this term, i. 268. advantages of 

 the inclination of the axis of the earth to the, ii. 1, 2. 



Effervescence of ammonia and sulphuric acid, ii. 88 

 by marble and muriatic acid, 89. 



Efflorescence of salts, process of, ii. 134. 



Elective attraction, or affinity explained, ii. Ql. 



Electrical attraction, phenomenon of, i. 11. 



Electrical kite employed by Dr. Franklin, i. 1 14. 



Electricity, lectures on, i. 96. 109 nature of the elec- 

 tric fluid, 90 principal phsenomena of electricity, 97 

 first discoveries in electricity, 98 experiments on 

 bodies capable of being excited to, og machines used 

 in, explained, 102 experiments with them, 104 

 invention of the Leyden phial, 106 discovery and 

 explanation of the difference between positive and nega- 

 tive electricity, ill experiment of the electrical 

 belis, 112 account of the electrometer, 113 effects 

 of electricity on animals and vege;ables, 113, 1 14. ex- 

 planation of the phenomena of thunder and lightning, 

 114 electricity and galvanism are essentially the 

 same, 127 electrical mineral and animals, ib. 

 electricity a method of producing heat for chemical 

 purposes, ii. 112. 



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