LOGIC 



3486 



LOK 



LOGIC, loj'ik, is pure reasoning, and to be 

 logical is to argue reasonably upon a basis of 

 fact in behalf of truth. Reasoning is the 

 process by which conclusions regarding certain 

 things are reached from what is already known 

 about them. There are two processes, induc- 

 tion and deduction, by which these conclusions 

 may be reached. 



By induction a number of related facts about 

 a certain thing are drawn in and put under a 

 general law or truth. For instance, from the 

 fact that heat expands iron, gold and platinum, 

 the general conclusion is that heat expands all 

 metals. 



By deduction a particular conclusion about a 

 certain thing is reached by drawing out facts 

 from a knowledge of the class to which it be- 

 longs. Thus : 



All animals with four legs are quadrupeds. 

 The horse has four legs. 



. Therefore, the horse is a quadruped. 



The expression of an argument in this for- 

 mal way is called a syllogism. Aristotle, a 

 Greek philosopher (384-322 B. c.), originated the 

 deductive form of reasoning. 



LOG 'WOOD, the most important dyewood 

 known, so named because it is exported in logs. 

 It is the red heartwood of a tree found in 

 Mexico, Central America and some parts of the 

 West Indies. The best logwood comes from 

 Jamaica, Honduras and Santo Domingo, the 

 Campeachy supply, formerly considered the 

 best, is now almost exhausted. The texture is 

 firm and the wood is heavy enough to sink in 

 water; the color is a dark blood-red, which be- 

 comes almost black after long exposure. The 

 infusion of the wood is also blood-red, which is 

 readily yielded to boiling water. The shades 

 produced vary from red to black; acids change 

 it to the lighter shades, and alkalies to the 

 darker hues. It is largely used for producing 

 blacks on silk and wool and in the manufac- 

 ture of ink. Medicinally it acts as a mild as- 

 tringent, but it is now little used by physicians. 



LOHENGRIN, lo 'en grin, the hero of the 

 German version of the legend of the knight 

 of the swan. Besides the German, the legend 

 has an English and a French version. The 

 story is founded on two common themes of 

 folklore, the changing of human beings into 

 swans and the wife whose inquisitiveness re- 

 sults in disaster. The fable has been followed 

 closely by Richard Wagner in his opera Lohen- 

 grin. The German story appears in the last 

 stanzas of Wolfram von Eschenbach's Parzi- 

 \al, in which Loherangrin, Parzifal's son. was 



sent from the castle of the Grail to help the 

 young Duchess of Brabant. He arrives in a 

 boat drawn by a swan, rescues the duchess from 

 captivity and marries her. She begs him to 

 tell her the story of his origin, which he does, 

 after which he is forced to return to the Grail, 

 by the terms of his vow. The widely-popular 

 Lohengrin Wedding March, played at count- 

 less wedding ceremonies every year, is taken 

 from Wagner's opera. 



LOIRE, Iwahr, in Roman times called the 

 LIGER, is the longest river of France, having a 

 total length of 620 miles and a drainage basin 

 almost equal to one-fourth the area of the 

 country. It rises in the Cevennes Mountains 

 4,500 feet above the sea, and flows in a north- 

 erly, then in a westerly direction, dividing 

 France into two nearly equal parts, and empty- 

 ing into the Bay of Biscay at Saint-Nazaire. 

 Navigation on the Loire is attended with diffi- 

 culties. In the wet season melting snows and 

 heavy rains so increase the volume of the river 

 that floods are of not infrequent occurrence, 

 and during the period of summer drought it 

 shrinks to an insignificant stream of sandbars 

 and shallows. 



Its estuary has been dredged to accommo- 

 date ocean vessels; dikes and embankments 

 have been constructed at various points to con- 

 trol the floods, and a canal 125 miles in length 

 has been built along the river to provide a 

 reservoir for the overflow. Its utility has been 

 further increased by canals connecting it with 

 the Saone and the Seine, and by a canal be- 

 tween Roanne and Briare, the latter running 

 parallel with it for 160 miles. The city of 

 Nantes, thirty-seven miles from its mouth, is 

 joined to the harbor of Brest by still another 

 artificial channel. 



LOK, lohk, or LOKI, lo' ke, in mythological 

 legends of Northern Europe, was the spirit of 

 strife and evil. Although a wicked deity and 

 the embodiment of evil, he was supposed to be 

 a very handsome, fascinating god. He shrewdly 

 planned the death of Balder, when Frigga had 

 induced all objects not to injure him. The 

 mistletoe not being included, Loki made it 

 into an arrow and gave it to the blind Hoder, 

 who shot it at random. The dart struck Balder 

 and killed him. Subsequently Loki was bound 

 with ten chains and will continue chained, so 

 the legend runs, until the twilight of the gods 

 appears, when he will break his fetters; then 

 the heavens will disappear, the earth will be 

 submerged by the sea, and fire will consume the 

 elements. Loki was considered far more clever 





