the age. Their purpose was to correct and 

 replace the Ptolemaic planetary tables, which 

 were full of errors. 



Alhazen (full name, Abu AH Al-Hasan Ibn 

 Alhasan), ii, 18. Born at Bassora cir. 965; died 

 at Cairo cir. 1039. Arabian physicist and natu- 

 ralist. Wrote important work on Optics. Fa- 

 mous for the geometrical problem bearing his 

 name. 



Amici, Giovanni Battista, iv, 112. Born at 

 Modena, 1786; died at Florence, 1864. Italian 

 astronomer, director of the Florence Observa- 

 tory. He designed and constructed many valu- 

 able astronomical and physical instruments. 

 Was also interested in botany. 



Ampere, Andre, iii, 239, iv, 43. Born at Lyons, 

 1775; died at Marseilles, 1836. French mathe- 

 matician, physicist and naturalist. Taught in 

 several places, and finally with great distinction 

 at the fecole Polytechnique, Paris. Science is 

 most indebted to him for his researches in elec- 

 tricity and magnetism. Invented the astatic 

 needle. Showed identity between magnetism 

 and electricity. Showed attraction and repul- 

 sion in parallel conductors of electricity, with 

 currents flowing in same or opposite direction. 

 The unit of strength in electric current is named 

 after him. 



Anaxagoras, i, 240. Born in Ionia cir. 500 

 B.C.; died at Lampsacus, 428. Taught at 

 Athens. The last Greek philosopher of the 

 Ionian school. His great service to the world 

 was that he turned philosophy from thought 

 about things to thought in itself.. He defined a 

 new principle, Mind as acting on matter, which 



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