KEY AND INDEX 



1, 41; conceptions concern- 

 ing the earth, sky, etc., 1, 42; 

 the recognition of the pulse, 

 1,51; practical mathematics, 

 1, 52; science as science was 

 unknown, 1, 55. 



Egyptian seasons, three in num- 

 ber, 1, 36. 



Egyptian temples, oriented with 

 reference to the point at which 

 the sun rises on the day of 

 the summer solstice, 1, 34. 



Eighteenth-Century Medicine, 

 Chapter VII, 4, 182. 



Eleatic School, founded by 

 Xenophanes, 1, 114. 



Electricity, Progress in, from 

 Gilbert and Von Guericke to 

 Franklin, Chapter XIV, 2, 

 259. 



Electricity and Magnetism, The 

 Modern Development of, 

 Chapter VII, 3, 229. 



Electricity, Oersted's experi- 

 ments with suspended mag- 

 netic needle, 3, 236; its rela- 

 tion to magnetism, 3, 238; 

 the discovery of the principles 

 of electro-dynamics, 3, 239; 

 the first electro-magnet, ibid.; 

 experiments of Michael Fara- 

 day, 3, 243; the first storage 

 battery, 3, 246; Seebecle's 

 battery, 3, 247; the "Hertz- 

 ian Waves," now used in wire- 

 less telegraphy, 3, 247; Pro- 

 fessor Thompson and the 

 nature of, 5, 92; relation of 

 gases to the conduction of, 

 ibid.; atomic character of, 6, 

 96; regarded as a form of 

 matter, 5, 97; Age of, 6, 15; 

 general chapter on, 6, 148; 

 theories as to what it is, 6, 

 149; multiform uses of, in 

 every -day life, 6, 149; Ben- 

 jamin Franklin's one-fluid 

 theory of, 6, 150; two-fluid 

 theory of, 6, 151; name de- 

 rived from Latin word elec- 

 trunt, 6, 152; derivation of 

 the idea that it is a "fluid," 

 6, 153; modem views of, 6, 

 153; studies of Rumford, 



Young, Fresnel, and Davy, 

 leading up to modern theories, 

 6, 154; most recent views as 

 to the nature, 6, 155; cur- 

 rents of, simply aggregations 

 of free electrons, 6, 156; how 

 it is developed, 6, 159; 

 statical and dynamical, 6, 

 1 60; generation of, by walk- 

 ing on a wool carpet in cold 

 weather, 6, 160; amount gen- 

 erated by lightning, 6, 161; 

 the static machine, 6, 161; 

 the work of the dynamical 

 current, 6, 162; voltaic cell 

 for generating, 6, 163; the- 

 ories ol electrical action, 

 6, 165; practical uses of, 6, 

 1 68; current of, used for pro- 

 ducing heat, 6, 169; dynamos 

 for generating, 6, 174; mech- 

 anism of its production by the 

 dynamo, 6, 181; amount 



r crated at Niagara Falls, 

 [89; transmission of, from 

 Niagara Falls, 6, 194; loss 

 in transmission of, as esti- 

 mated by Siemens, 6, 195; 

 transmission of, at Niagara by 

 recent methods, 6, 197; "step 

 up" and "step-down" trans- 

 formers, 6, 198; high 

 and low voltage, 6, 199; 

 Ruhmkorff coil, the construc- 

 tion of, 6, 199; traction en- 

 gines used in mining, 6, 257; 

 engine invented by W. M. 

 Schlessinger, 6, 257; in coal- 

 mining, 6, 266; electric light- 

 ing of mines, 6, 269; obtain- 

 ing nitrogen from the air by 

 the use of, 6, 307; and high 

 temperatures, 6, 313; the 

 discovery of, 8, 4- 

 Electric light, Sir Humphry- 

 Davy's experiments with, 3, 

 234; first ever invented, by 

 Sir Humphry Davy, 6, 220; 

 first practical application of, 

 in France, 1849, 6, 222; the 

 improved arc light, 6, 226; 

 Chas. F. Brush's invention of 

 arc light, 6, 226; some recent 

 types of arc lights, 6, 227; 



[I 7 6] 



