GENERAL INDEX 



he received a prize of twenty 

 thousand pounds sterling from 

 the British Government, 7, 



Hartley, Dr. David, his famous 

 vibration theory, 4, 268. 



Harvey, From Paracelsus to, 

 Chapter VII, 2, 156. 



Harvey, William, life of, 2, 169; 

 his discovery of the circula- 

 tion of the blood, 2, 171-178. 



Hatchet, principle of, 6, 54. 



Hauksbee, Francis, his mercu- 

 rial fountain, 2, 2 59 ; discovery 

 of "induction," 2, 259-262; 

 early experiments with the 

 telephone, 8, 67. 



Hauron, Ducos du, his simple 

 method of color-photography, 

 8, 241. 



Hautefeuille, attempted to make 

 practical use of the power set 

 free by the explosion of gun- 

 powder, 6, 134. 



Heat, Count Rumford's experi- 

 ments with, 3, 209; Hum- 

 phry Davy's independent de- 

 monstration that labor may 

 be transformed into, 3, 255; 

 Sadi Carnot expresses belief 

 in the quantitative relation 

 between work and, 3, 255; 

 James Prescott Joule demon- 

 strated the mechanical equiv- 

 alent of, 3, 256; Colding, 

 Mayer, and Helmholtz inde- 

 pendently discover the same 

 principle, 3, 257; Dr. Mayer's 

 own account of his discovery, 

 3, 259; Joule's paper on, 1843, 

 3, 269; James David Forbes 

 showed that radiant heat 

 resembles light in its confor- 

 mation to laws of polarization 

 and double refraction, 3, 275; 

 studies of heat by Professor 

 William Thomson (later Lord 

 Kelvin) led to the develop- 

 ment of the doctrine of the 

 dissipation of energy, 3, 276; 

 the old theory of "imponder- 

 ables" finally substituted by 

 the theory of an all-pervading 

 ether, 3, 281; explained as 



due to the vibrations of the 

 particles of matter, 3, 294; 

 studies of, by Clausius, Clerk- 

 Maxwell, and others, led to 

 the development of the ki- 

 netic theory of gases, 3, 295; 

 absence of, causes liquefaction 

 of gases, 3, 304; low-tem- 



rature researches in detail, 

 . 3 8 -7 2 ; principle that heat 

 can do mechanical work by 

 generating steam shown by 

 Hero or Ctesibius, 6,82; gen- 

 eration of, by electricity, 6, 

 169. 



Heat and Light, Modern The- 

 ories of, Chapter VI, 3, 206. 



Heating, the problem of, in 

 ancient and mediaeval dwell- 

 ings, 9, 150; in skyscrapers, 

 9, i 66. 



Heaviside, A. W., experimented 

 with parallel telegraph lines, 

 8, 51- 



Heidenham, Dr. Rudolf, on the 

 phenomena of hypnotism, 4, 

 269. 



Heliocentric theory, as pro- 

 pounded by Aristarchus in 

 the third century B.C., 1, 

 212; as demonstrated by 

 Copernicus in the fifteenth 

 century A.D., 2, 54. 



Hellenistic Period, Greek Science 

 of the Alexandrian or, Chap- 

 ter IX, 1, 189. 



Helmholtz, Hermann von, his 

 theory of solar energy, 3, 

 65; renounced all claim to 

 the discovery of the conser- 

 vation of energy in favor of 

 Mayer, 3, 269; found that a 

 vortex whirl once established 

 in a frictionless medium must 

 go on forever, 3, 290; his 

 measurement of speed of 

 nervous impulses, 4, 262; ex- 

 planation of the continued 

 heat of the sun, 6, 207; con- 

 cluded that man would never 

 be able to fly by his own 

 power alone, 7, 278. 



Henderson, Thomas, his work 

 at the Cape of Good Hope in 



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