242 



SCIENTIFIC THOUGHT. 



14. 

 Plucker. 



discouragement and neglect being thrown in the way of 

 the growth of new ideas. Plucker of Bonn laboured for 

 many years on the union of the geometrical and analytical 

 methods in the treatment of geometry ; but he found so 

 little appreciation that he abandoned his investigations, 

 and only resumed them when in after-years a similar line 

 of thought was independently developed in England. 1 



Transverse Vibrations, which the 

 Academy had recommended to be 

 printed : " We are sorry to observe 

 that this recommendation has not 

 yet been acted upon, and that this 

 important memoir, to the regret 

 and disappointment of men of sci- 

 ence throughout Europe, remains 

 yet unpublished " (' Ency. Metrop.,' 

 article "Light"). A full account 

 of the opposition and difficulties 

 which both Young and Fresnel 

 had to encounter will be found in 

 Whewell's ' History of the Induc- 

 tive Sciences,' vol. ii. In earlier 

 times Reaumur seems to have ex- 

 ercised a similar tyranny in the 

 Academy of Sciences ; see Maury, 

 ' Les Academies d'autref ois, ' vol. i. 

 pp. 280, 123 ; also Huxley, 'Critiques 

 and Addresses,' 1890, p. 112, &c. 



'Julius Plucker (1801-68), pro- 

 fessor at Bonn, equally known in 

 England by his scientific co-opera- 

 tion with Faraday and by that 

 with Cay ley and Salmon, worked 

 both in physics and geometry on 

 independent lines. In the latter 

 especially he brought about that 

 union of purely geometrical and 

 algebraic methods which has be- 

 come so fruitful in the development 

 of modern geometry and modern 

 algebra. He had two periods of 

 original geometrical work. The 

 first began in 1826 (the year of 

 the revival of mathematics in Ger- 

 many), and closed in 1846. His 

 mathematical researches were little 

 noticed in his own country, where- 

 as in France, and still more in 



England, his name was well known. 

 After having published in 1846 a 

 ' System of Geometry,' which con- 

 tained his former results in a more 

 methodical form, he dropped his 

 mathematical researches for twenty 

 years, during which time he devoted 

 himself to physical investigations of 

 great originality. By these, if he 

 had not been a personal friend, he 

 might almost have been called a 

 rival of Faraday (G. Chrystal in 

 'Ency. Brit.') During a visit to 

 England in 1864 he was agree- 

 ably surprised to meet with ap- 

 preciative interest from English 

 geometricians, who had independ- 

 ently worked on the same lines as 

 he had done twenty years earlier. 

 He was thus induced to resume his 

 favourite studies, and to develop an 

 idea which had already been expres- 

 sed in his last-named work of 1846. 

 This led to a new fundamental con- 

 ception of geometrical forms, in 

 which not the point but the line 

 is the element of space. He was 

 not spared to complete this line- 

 geometry, but after his death his 

 pupils found sufficient material to 

 put his researches into a systematic 

 form under the title, 'Neue Geo- 

 metric des Raumes, gegriindet auf 

 die Betrachtung der geraden Linie 

 als Raumelement ' (Leipzig, 1868 

 and 1869). See Clebsch on Julius 

 Pliicker, Gottingen, 1872. A very 

 appreciative notice of Pliicker, by 

 George Chrystal, will be found in 

 the 9th edition of the ' Encyclopae- 

 dia Britannica.' 



