KEY AND INDEX 



first demonstrated by Benjamin Franklin's classical experiments 

 with kite and key, made about the middle of the eighteenth 

 century. See "Benjamin Franklin," Vol. II, p. 286. 



Lime-light. A light produced by heating a block of lime to 

 incandescence with a blast of oxygen or gas. 



Liquefaction of Gases. Reducing gases, such as oxygen, 

 hydrogen, air, etc., to a liquid state. See "Low Temperature 

 Researches," Vol. V, p. 29. 



Liquefied Air. See "Liquefaction of Gases" of the present 

 index. 



Liquid Fuel. The term given to the various oils, usually crude 

 petroleum, which have come into use recently as fuel for loco- 

 motives, steamships, etc. See "Liquid Fuel," Vol. VII, p. 90. 



Lithography. The process of reproducing pictures from an 

 etched surface of stone. The process was invented by Alois 

 Sanfelder early in the nineteenth century. See "The Reproduc- 

 tion of Illustrations," Vol. VIII, p. 184. 



Locomotive. The traction vehicle perfected, but not invented, 

 by George Stephenson. The earliest locomotives were those of 

 Cugnot and Trevithick. Locomotives were used in collieries 

 for a good many years before Stephenson made his memorable 

 demonstration with the Rocket in 1829. See "The Steam Loco- 

 motive," Vol. VII, p. 119. 



Log. An apparatus for measuring the speed of ships. Orig- 

 inally this consisted of a log or block of wood attached to a 

 knotted rope. This log was dropped into the water astern, 

 and the speed of the ship was estimated from the number of 

 knots that ran through the fingers while a half-minute sand- 

 glass was emptying. The modern log revolves in the water, 

 and records speed on a clock-like dial. See "Sailing by Dead 

 Reckoning," Vol. VII, p. 14. 



Longitude. Distance east or west of an arbitrarily selected 

 meridian (as that of Greenwich, or that of Washington), as 

 measured in degrees, minutes, and seconds of arc. The mariner 

 determines his longitude by means of observation of sun or 

 stars, in connection with the time record furnished by chrono- 

 meter. See "The Development of the Sextant," Vol. VII, p. 18. 



Loom. An apparatus for weaving cloth. The primitive hand 

 loom had been used from remotest antiquity. The power loom 

 was the invention of the British clergyman, Dr. Edmund Cart- 

 wright (1784). See "The Manufacture of Textiles," Vol. IX, 

 P 43- 



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