November ii, 191 5] 



NATURE 



291 



Imperial Colleg^e of Science and Technology are 

 clue. 



In 1 90 1 Rucker was induced to accept the prin- 

 cipalship of the reorganised University of London. 

 He had been a member of the old senate since 

 [I890, and had acquired an intimate knowledge 

 )f the working of the University, its aims, and 

 )mewhat divergent policy. In undertaking the 

 >rincipalship he undoubtedly entered upon the 

 lost difficult and most arduous position he was 

 *ver called upon to fill. To a man of less courage, 

 tact, and patience his situation would at times 

 lave been intolerable. He had very definite views, 

 )ased upon knowledge and a ripe experience of 

 le true functions of a great metropolitan Univer- 

 sity, and had on several occasions, both in speech 

 ind in writing, given public utterance to them, 

 lut as a man of affairs, accustomed to the con- 

 ict of discordant aims and the clash of vested 

 iterests, no one knew better how often in this 

 iperfect world the better is the enemy of the 

 No one was more ready to appreciate the 

 ferength of an opponent's position or to realise 

 le value of compromise, and his sympathy, his 

 ;nse of fairness, his unfailing courtesy, and his 

 :ill in diplomacy constantly enabled him to get 

 best out of a compromise. To his intimate 

 pends he had communicated his intention of 

 'signing his position when he should have 

 jached his three-score years. During the seven 

 ;ars he held it he had the satisfaction of bring- 

 about the incorporation, as constituent parts 

 the University, of the two leading London 

 )lleges, with the consequent strengthening of the 

 Iternal side. He gave up his office to the great 

 ;Tet of all who served with or under him, and 

 ith a unanimity in expression of good-will, 

 steem, and friendship from all sections which 

 greatly touched him at the time, and of which 

 he had a grateful recollection. 



Rucker was elected into the Royal Society in 

 1S84, was a member of council in 1887-89, and 

 again in 1894, when he became one of the secre- 

 taries. No man ever filled that office with greater 

 acceptance. During the five years he held it he 

 brought to the exercise of its duties the same 

 habits of industry and the same mental and per- 

 sonal characteristics that had marked his dis- 

 charge of every position he had undertaken. 



In i8gi he became treasurer of the British 

 Association, in 1898 a trustee, and in 1901 presi- 

 dent. He took an active share in the formation 

 of the Physical Society, served on its council, 

 and was its president in 1893-95. 



Rucker, as might be supposed, was frequently 

 (ailed upon to serve upon Royal Commissions and 

 Departmental Committees, and much of his time 

 and energy was spent in such public service. 

 He was a member of the Royal Commission on 

 Irish Universities in 1906; on the University of 

 Belfast Commission in 1908, in which year he was 

 also placed on the Carnegie Trust for the Scottish 

 Universities. He was a member of the Board of 

 Trade Committee on Sight Tests in 1910, and of 

 the Royal Commission of the 185 1 Exhibition in 

 191 1. He acted as deputy chairman of Lord 

 NO. 2402, VOL. 96] 



Rayleigh's Committee which led to the founda- 

 tion of the National Physical Laboratory; he 

 served on its governing body, and, so long as 

 the state of his health permitted, took an active 

 interest in its development. 



Rucker's list of scientific papers is compara- 

 tively short, and it cannot be said that he has left 

 any marked impression upon British physics. 

 There can be no question, however, that he pos- 

 sessed all the essential attributes of a successful 

 investigator. But, as it happened, circumstances, 

 not always of his choosing, placed him in positions 

 in which his time, energy, and mental powers 

 were practically wholly absorbed by matters un- 

 connected, or at most only indirectly connected, 

 with physical inquiry. At the same time he was 

 keenly interested in the progress of science, and 

 was an omnivorous reader of contemporary 

 scientific literature. It was easy to engage his 

 attention and to excite his interest in any pro- 

 blem which he thought his knowledge or mathe- 

 matical ability might possibly elucidate. Some 

 of his early papers were joint productions on 

 subjects of physical chemistry contributed by us to 

 the Journal of the Chemical Society. On one 

 occasion he was induced to address the society on 

 the Range of Molecular Forces (published in the 

 Transactions for 1888), in which he incidentally 

 gave an account of the joint work of Prof. Reinold 

 and himself on "The Properties of Liquid-films" 

 (Phil. Trans., 1881 and 1886). 



But Rucker's chief contribution to science was 

 his share — and it was by far the more important 

 share — ^in the Magnetic Survey of the British 

 Isles for the epochs 1886 and 1891, the results 

 of which were published in their final form in 1896 

 as a separate volume (vol. clxxxviii) of the Philo- 

 sophical Transactions. Space precludes any at- 

 tempt to tell the story of how the Survey 

 originated and how Riicker was induced to take 

 an active interest in Terrestrial Magnetism. 

 He showed himself an excellent observer, and 

 became very expert in the use of the Kew pattern 

 of magnetometer in the field, where, in a variable 

 climate like ours, it is frequently necessary to be 

 prompt as well as accurate. He organised the 

 whole of the tedious work of reduction, checking, 

 and tabulation, and upon him fell the chief burden 

 of putting together the outcome of our discus- 

 sions of the results. The first memoir was made 

 the Bakerian Lecture for 1889, and the Society 

 indicated its high appreciation of Rucker's work 

 by recommending him for a Royal Medal in 1891. 

 It is but just to him to say that the memoir in 

 which he embodied the results of our joint labours, 

 extending over some fourteen years, marks a new 

 departure in work of this kind, and that its in- 

 fluence is plainly evident in similar surveys which 

 have been subsequently carried out in various- 

 parts of the world. 



Rucker was married twice. His first wife was 

 Marian, daughter of Dr. J. D. Heaton, F.R.C.P., 

 the first chairman of council of the Yorkshire 

 College. She died in 1878, leaving a daughter, 

 now Mrs. Reginald Hooker. His second wife, 

 whom he married in 1892, is Thereza, daughter 



