EXPERIMENT 



3O5O 



EXPLORATION 



Experiment.' Testing a pro- 

 visionally adopted theory by facts. 

 The great progress of natural 

 science in modern times has been 

 chiefly due to the systematic em- 

 ployment of experiment. Ancient 

 philosophers and inquirers had a 

 contempt for this method, which 

 first received due recognition by 

 Francis Bacon in his Novum 

 Organum, 1620. An experiment 

 may be defined as an observation 

 which can be repeated, varied, and 

 explained. 



Experimental Farm. Farm 

 at which science is applied to the 

 processes of agriculture, and the 

 results tabulated for reference and 

 publication. The best known and 

 oldest of English experimental 

 farms is that founded by Sir John 

 Lawes at Rothamsted in 1843. 

 He succeeded to the estate in 1834, 

 and from the first carried out cer- 

 tain experiments ; but it was not 

 until 1843 that he obtained the 

 assistance of Dr. Gilbert, and 

 began his famous systematic ex- 

 periments. Since that pioneer 

 work, the great agricultural socie- 

 ties started other stations such as 

 that at Woburn, and of Pum- 

 pherston in Scotland. The oldest 

 French station was founded by 

 Boussingault at Bechelbronn in 

 Alsace. Most governments have 

 established similar agricultural 

 research institutions, among them 

 being several in Canada. See Agri- 

 culture ; Crops ; Farm. 



Expert (Lat. expertus, tried). 

 Term used by English lawyers to 

 describe one who has special skill 

 in and knowledge of a trade or 

 profession. A surgeon, an archi- 

 tect, a builder, a chemist, for 

 example, are experts in surgery, 

 building, and chemistry. Experts 

 are often called to give their 

 opinions in technical cases. 



Exploder. Term designating 

 (a) the priming employed in high- 

 explosive shell, and (6) the electric 

 machine for firing blasting charges 

 fitted with electric detonators. 



(a) The high-explosive charge 

 employed in a shell is always 

 in a very dense condition in 

 order to reduce its sensitivity, 

 utilise the greatest possible weight 

 in the limited space, and prevent 

 movement owing to the shock of 

 discharge when the projectile is 

 fired. High explosives in a dense 

 condition cannot readily be de- 

 tonated by fulminate of mercury 

 or other initiators, and in order to 

 build up sufficient violence it is 

 necessary to interpose a quantity 

 of loose or lightly compressed high 

 explosive between the detonator 

 in the fuze and the bursting 

 charge. This priming may be 

 confined in a gaine (q.v.), or 



placed in a bag, or merely loosely 

 stemmed into a cylindrical cavity in 

 the bursting charge just below the 

 fuze, and is termed the exploder. 

 The high explosive employed in ex- 

 ploders is usually trinitrotoluene, 

 tetryl, picric acid or picric pow- 

 der. See Ammunition; Explosives; 

 Shell. 



(6) Exploders for firing blasting 

 charges occasionally utilise current 

 from a set of accumulators passed 

 through an induction coil, but 

 the more usual machines are of 

 the magneto type, a sectional illus- 

 tration of such a machine being 

 shown. It consists essentially of a 

 double-wound armature, A, which 

 can be rotated between the poles 

 of the horseshoe magnet, B, 

 through the free wheel pinion, C, 

 which is actuated by the rack, hav- 

 ing a hand grip, D, at its upper end. 

 The free wheel ensures that the 

 armature does not rotate as the 

 handle is pulled up, but only when 

 it is pushed down and the current 

 is normally short-circuited by the 

 switch, E. When the rack reaches 

 the bottom of its stroke, and the 

 armature is revolving at maximum 

 speed, the rack opens switch, E, 



Exploder. Sectional diagram of 



magneto exploder. For explanation 



see text 



and the whole of the current 

 passes to the main leads secured 

 by the wing-nuts shown on the 

 left, and thus to the detonators. 

 A machine of this type weighs 

 som3 16 lb., and is capable of 

 simultaneously firing up to 100 

 charges if desired. 



Exploitation (old Fr. esploit, 

 profit). Stage in the life of a mine 

 when ore is extracted and sold, the 

 previous stages being prospecting 

 and development. During the 

 earlier periods the money expended 



is regarded as capital invested in 

 the business ; during exploitation 

 the revenue from sales is regarded 

 partly as return of the capital 

 expended and the interest thereon. 

 See Mining ; Prospecting. 



Exploits. River of Newfound- 

 land. The longest river in the 

 island, it rises in the hills of Long 

 Range and flows right across in a 

 N.E. direction. It passes through 

 a well-wooded district which sup- 

 plies timber for the pulp mills, and 

 on it is the town of Grand Falls. 

 It empties itself into the Bay of 

 Exploits, having drained about 

 4,000 sq. m. Its length is about 

 160 m., and it is navigable by 

 steamers for 12 m. 



Exploration (Lat. explorare, 

 to search out). Literally, any 

 kind of discovery, but the word is 

 applied specially to discovering 

 and making known the hitherto 

 unknown parts of the world. 

 There was little in the way of 

 exploration from the time of the 

 Greeks to almost the end of the 

 Middle Ages. 



In the 13th century something 

 became known about China, and 

 Marco Polo may fairly be ranked as 

 a pioneer of exploration. It was, 

 however, towards the end of the 

 15th century that the great dis- 

 coveries were made that gave a re- 

 markable impetus to the work of 

 the explorer. In 1492 Columbus 

 reached the W. Indies; in 1497 

 Vasco da Gama rounded the Cape 

 of Good Hope, and reached India ; 

 while about those years notable 

 voyages were undertaken by Bar- 

 tholomew Diaz, the Cabots, and 

 others. Newfoundland was dis- 

 covered ; Cabral reached Brazil ; 

 Balboa saw the Pacific. From 

 these discoveries followed the ex- 

 ploration of America. In the N. 

 the lead was taken by Frenchmen, 

 La Salle being one of their greatest 

 names, and in the S. by the Span- 

 iards and Portuguese. Gradually 

 the nature and extent of the two 

 continents were made known ; 

 the Amazon and the Mississippi 

 were discovered and then explored, 

 while the secrets of the wonderful 

 Aztec civilization were revealed. 



In the 18th century Australia 

 was discovered by Captain Cook, 

 although the Dutch Tasman had 

 some time before found Tasmania 

 and New Zealand. Early in the 

 19th century the continent was ex- 

 plored by Oxley, Sturt, Eyre, and 

 a host of others. More and more 

 was becoming known of Asia, 

 although it was long before its 

 central area was explored by 

 Hedin and others, the final stage 

 being the en try in to Lhasa, 1904. 

 In the 19th century, too, came the 

 exploration of Africa, the work of 



