KEY AND INDEX 







trie current is generated in a coil of insulated wire wound about 

 another coil, through which a current generated in the usual 

 way is passed. The familiar Faradic current is thus induced. 

 For a description of the discovery of induction, see "Progress in 

 Electricity from Gilbert and Von Guericke to Franklin," Vol. 

 II, p. 259. For Faraday's experiments, see Vol. Ill, p. 240. 



Inorganic Matter. Mineral compounds of whatever character 

 that have been developed or compounded without the aid or 

 interposition of living organisms, vegetable or animal. 



Interference of Light. The collision of one wave of light 

 (etherial undulation) with another in such a way as to obstruct 

 the wave, causing darkness. Studies of interference led Young 

 to the elaboration of the undulatory theory of light. See 

 "Thomas Young and the Wave Theory of Light," Vol. Ill, 

 p. 215. 



Isomerism. A word coined by the chemist Berzelius to in- 

 dicate the fact, demonstrated in 1823 by Liebig and Wohlen, 

 that two substances exhibiting different physical properties 

 may have precisely the same chemical composition. See "Or- 

 ganic Chemistry and the Idea of the Molecule," Vol. IV, p. 53. 



Julian Calendar. The reformed calendar of Julius Caesar, 

 which adopted the Alexandrian expedient of introducing an ad- 

 ditional day every fourth (leap) year. For comparison of this 

 calendar and with that of the ancient Egyptian calendar, see 

 "Astronomical Science," Vol. I, p. 33. 



Kinematograph. See Chrono-photography, Vol. VIII, p. 248. 



Kinetic Theory (of gases). The theory that a gas consists 

 of molecules in a state of agitation, describing a "free path" of 

 relatively great length between successive impacts with other 

 molecules. See Vol. Ill, p. 295. 



Knitting Machinery. A machine for knitting stockings was 

 invented by a Scottish clergyman, William Lee, in 1589; a de- 

 velopment that permitted the knitting of a ribbed surface was 

 introduced by Jedediah Strutt in 1758; and the circular knitter 

 (producing a seamless stocking) was perfected by Peter Claussen 

 in 1845. See "Lace Making and Knitting Machinery," Vol. IX, 



P- 55- 



Krupp Steel. An alloy steel, containing nickel, which adds 

 to its hardness and gives it great value for armoring ships. See 

 "The Age of Steel," Vol. VI, p. 295. 



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