turned to medicine. Was Professor of Anatomy 

 at Bologna. By an accident he discovered the 

 existence of the galvanic current, which led to 

 the invention of the voltaic cell and all that has 

 developed from it. 



Gauss, Karl Friedrich. Born at Brunswick, 

 1777; died at Gottingen, 1855. German mathe- 

 matician, one of the most brilliant of modern 

 times. Born in poverty, but was educated at 

 Gottingen. Invented a method of calculating 

 positions of heavenly bodies in order to redis- 

 cover the lost planet Ceres. Devoted latter part 

 of life to geodesy and the mathematical theory 

 of electricity. Developed the theory of least 

 squares. 



Gay-Lussac, Joseph Louis, iv, 41. Born at 

 Saint-Leonard le Noblat, 1778; died at Paris, 

 1850. French chemist and physicist. Studied at 

 Paris. Became assistant to Berthollet at the 

 Government chemical works. Made balloon as- 

 cent to ascertain whether magnetic force existed 

 above the earth. With Humboldt he announced 

 the exact composition of water (1804), which 

 led to the discovery by Gay-Lussac in 1808 of 

 the important law of volumes. 1809, became 

 Professor of Chemistry at ficole Polytechnique. 

 Discovered a better way than electrolysis for 

 producing potassium. 



Geber, ii, 20. Died about 1776. An Arabian 

 chemist. He discovered sulphuric, nitric, and ni- 

 tromuriatic acids, thus greatly increasing the 

 possibilities of chemical experiment. He is cred- 

 ited with writing about five hundred works. Of 

 these "Testamentum," "De Inventions Vintatis," 

 "Liber Fornacum," "Summa Perfectionis," "De 



