CONTENTS, xi 



PART II. 



SCIENCE OF THE MIDDLE AGES. 



CHAPTER VI. 



SCIENCE OF THE ARABS. 



PAGB 



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 VIIL 



SCIENCE OF THE MIDDLE AGES IN EUROPE. 



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

 bow - He 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 



