KEY AND INDEX 



of lever that was well known to the ancients, but Archimedes 

 brought it to its highest state of perfection. See "Wheels and 

 Pulleys," Vol. VI, p. 32. 



Pump. A machine for raising liquids or extracting gases. 

 The common form is the piston pump, but there are also centri- 

 fugal, rotary, electric pumps. For the invention of the air- 

 pump, see "Mariotte and Von Guericke," Vol. II, p. 210. For the 

 development of steam pumps, see "The Story of the Steam 



k Engine," Vol. VI, p. 79. For pumps run by hot-air engines, see 

 "Gas and Oil Engines," Vol. VI, p. 132. For electric pumps, 

 see "Electric Mining Pumps," Vol. VI, p. 263. 

 Quadrant. An old form of sextant (q.v.). 

 Quinine. An alkaline substance obtained from the bark of 

 trees of the cinchona genus. The bark of these trees was in- 

 troduced as a medicine in 1640. 



Rabies. A germ-produced disease affecting certain animals, 

 especially dogs, from which hydrophobia is communicated. 

 Pasteur discovered a preventive inoculation for this disease. 

 See "Aims and Objects of the Pasteur Institute," Vol. V, p. 182. 



Radio-activity. The property possessed by certain substances 

 of spontaneously and continuously emitting penetrating rays 

 capable of passing through bodies opaque to ordinary light. 

 It was discovered by M. Henri Becquerel in 1896. See "Radio- 

 activity," Vol. V, p. 97. 



Radiolarians. Creatures of microscopic size found in the mud 

 )f the ocean bottom, etc. Prof. Ernst Haeckel discovered, named, 

 and described more than 4,000 new species, obtained from a 

 few ounces of mud. See "Ernst Haeckel and the New Zoology," 

 Vol. V, p. 153- 



Radium. A new element discovered by Professor and Mme. 

 Curie in 1898, which possesses remarkable powers of radiation. 

 See "Radio-activity," Vol. V, p. 97. 



Refrigerator Machines. Mechanisms for producing very low 

 temperatures, used for liquefying gases, such as hydrogen, air, 

 :tc. See "The Royal Institution and Low Temperature Re- 

 searches," Vol. V, p. 38. 



Respiration. The process of taking in oxygen and giving off 

 carbon dioxide by the respiratory organs of animals. In man 

 and the higher animals this function is performed by the lungs. 



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