BIOGRAPHICAL INDEX 



Harvey, William, ii, 169. Born at Folkestone, 

 England, April, 1578; died at Hempstead, Essex, 

 June 3, 1657. An English physician, famous as 

 the discoverer of the circulation of the blood. 

 His experiments to demonstrate his theory were 

 made upon serpents, and his demonstrations 

 were such that his conclusions were accepted al- 

 most immediately by scientists all over the civil- 

 ized world. 



Hauksbee, Francis, ii, 259. English physicist, 

 one of the early experimenters with electricity. 

 Through experiments with a whirling globe 

 from which the air had been exhausted, and 

 with a barometer and rubbed glass rods he 

 produced a glow which he found to be electrical. 

 He also discovered the important property of 

 electricity known as "induction" by revolving 

 two cylinders placed about an inch apart. 



Helmholtz, Hermann Ludwig Ferdinand von, 

 iii, 280. Born at Potsdam, Aug. 31, 1821; died 

 at Berlin, Sept. 8, 1894. German physiologist 

 and physicist. At the age of twenty-two he was 

 military physician at Potsdam. Later was Pro- 

 fessor of Anatomy and Physiology at Bonn, 

 Professor of Physiology at Heidelberg, and Pro- 

 fessor of Physics at Berlin. In 1851 he invented 

 the ophthalmoscope an instrument invaluable 

 to oculists for examining the internal structures 

 of the eye. He formulated an electro-magnetic 

 theory of light, which was shown to be correct 

 by the experiments and discoveries of his pupil, 

 Heinrich Hertz. 



Henderson, Thomas, iii, 61. Astronomer 

 Royal of Scotland. He was one of the first as- 

 tronomers to detect and measure the parallax of 



