KEY AND INDEX 



detecting and measuring the 

 parallax of a star, 3 , 6 1 . 



Henry III, French King, his use 

 of extraordinary ruffs, 9, 65. 



Henry VIII, probably intro- 

 duced knitted stockings into 

 England, 9, 68. 



Henry, Joseph, his experiments 

 with electric magnets, 3, 239; 

 8, 16; his early studies of 

 electro-magnetic induction, 6, 

 175; his construction of elec- 

 tro-magnets, 6, 177. 



Henry the Navigator of Portu- 

 gal, his physicians credited 

 with inventing or introduc- 

 ing the astrolabe, 7, 19. 



Henson, his studies of the lift- 

 ing-power of plane surfaces, 7, 

 246. 



Heraclides first to point out the 

 value of opium in certain 

 diseases, 1, 196. 



Hero, or Heron, a pupil of Ctesi- 

 bius, 1, 243; an explicit 

 champion of the molecular 

 theory of matter, 1, 245; his 

 experiments with water and 

 gases, 1, 246; his experiments 

 with heated air to produce 

 motor power, 1, 247- his ex- 

 periments with air under pres- 

 sure, 1, 248; his steam engine, 

 1, 250; the inventor of the 

 penny-in-the-slot machine, 1, 

 251; studied phenomena of 

 suction, 6, 64; described 

 and perhaps invented mech- 

 anism to show that heat could 

 do mechanical work, 6, 82. 



Herodotus, his visit to Babylon, 

 1 57. J 93J refers to the use 

 of skins in writing, 8, no. 



Herophilus, his records are the 

 first we have of the dissection 

 of the human body, 1, 194; 

 handed condemned criminals 

 over to the medical profession 

 to be operated on, 1, 195. 



Herschel, John, in collaboration 

 with James South he dis- 

 covered many double stars, 3, 

 58; his improvements of the 

 microscope, 4, in. 



Herschel, William, his positive 



enius for sidereal discovery, 

 , 19; discovered the planet 

 Uranus, 3, 20; conceived the 

 universe to be a vast galaxy 

 of suns held to one centre, 3, 

 22; thinks that all the suns 

 are "well supplied with in- 

 habitants," 3, 23; theory 

 of the Milky Way, 3, 24; 

 thought all the suns of a sys- 

 tem would be drawn together 

 and destroyed by impact, 3, 

 26; suggests that the planets 

 Ceres and Pallas be called 

 asteroids, 3, 41; discovered 

 that certain fixed stars have 

 changed their relative posi- 

 tions, 3, 57. 



Hertz, Dr. Heinrich, discovered 

 the method now used in wire- 

 less telegraphy, 3, 247; his 

 electro-magnetic theory of 

 light, 3, 280; produced elec- 

 tromagnetic waves, 6, 154; 

 discovery of "Hertzian" 

 waves, 8, 52. 



Hevelius, Johannes, advanced 

 astronomy by his accurate 

 description of the face and 

 the spots of the moon, 8,3. 



Hesse, G. Emil, description of 

 the Svea caloric engine, 6, 145. 



Hewitt, Peter Cooper, his in- 

 vention of the mercury- vapor 

 light, 6, 236. 



High temperatures, obtained by 

 electricity, 6, 314; obtained 

 by explosion of cordite in 

 closed chamber, 6, 315. 



Highway of the Waters, The, 

 Chapter II, 7, 56. 



Hildanes, Fabricius, German 

 surgeon, 2, 183. 



Hinrichs, Professor Gustav. 

 draws attention to "law of 

 octaves," 4, 67. 



Hipparchus, demonstrated the 

 eccentricity of the sun's seem- 

 ing orbit, 1, 234; his theory, 

 though incorrect, absolutely 

 consistent with all the facts of 

 a correct observation of the 

 sun's eccentricity, 1, 235; his 



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