CONTENTS. 



PART II. 



SCIENCE OF THE MIDDLE AGES. 



: 



CHAPTER VI. 



SCIENCE OF THE ARABS. 



PAGE 



Dark Ages of Europe Taking of Alexandria by the Arabs, and 

 burning of the Library The Arabs, checked in their conquests 

 by Charles Martel, settle down to Science The Nestorians 

 and Jews translate Greek Works on Science Universities of the 

 Arabs Chemistry first studied by the Arabs Alchemy, or the 

 attempt to make Gold Hermes the first Alchemist Hermeti- 

 cally-sealed Tubes Gases and Vapours called * Spirits ' by the 

 Arabs The use of this Word retained by us . . . 39 



CHAPTER VII. 



SCIENCE OF THE ARABS (CONTINUED). 



Geber, or Djafer, the founder of Chemistry His Explanation of 

 Distillation Of Sublimation Discovers that some Metals in- 

 crease in weight when heated Discovers strong Acids Nitric 

 Acid Sulphuric Acid Discovery of Sal-Ammoniac by the 

 Arabs Arabs mix up Astronomy with Astrology Albateg- 

 nuis calculates the Length of the Year Mohammed Ben Musa, 

 first writer on Algebra Uses the Indian Numerals Gerbert 

 introduces them into Europe Alhazen's discoveries in Optics 

 His Explanation why only one image of each object reaches the 

 Brain His discovery of Refraction, and of its effect on the light 

 of the Sun, Moon, and Stars His discovery of the magnifying 

 power of rounded glasses ....... 43 



CHAPTER VIII. 

 SCIENCE OF THE MIDDLE AGES IN EUROPE. 



Roger Bacon His 'Opus Majus' His Explanation of the Rain- 

 bowHe makes Gunpowder Studies Gases Proves a Candle 

 will not burn without Air His Description of a Telescope 

 Speaks of Ships going without Sails Flavio Gioja invents the 



