28 



NATURE 



[March 8, 19 17 



inferior quality. '\.\\it more the situation is con- 

 sidered, the, more imperative appears the need to 

 cultivate every rod of fertile ground. Unless the 

 omens are false, and whether peace come soon or 

 no, all the vegetable produce that can be raised 

 will be sorely needed. F. K. 



PROF. GA^rON DARBOUX, For. Mem. R.S. 



BY the recent death of the permanent secre- 

 tary of the Academy of Sciences of the 

 Institute of France, mathematical science, and all 

 that it stands for in the evolution of human pro- 

 gress, has suffered a grievous loss. Of dark 

 complexion and large build, which were a con- 

 tinual reminder of his southern Provencal origin, 

 and of the exquisite courtesy which marks the 

 French man of learning at his best, Prof. 

 Darboux was no stranger in this country. Those 

 who were present in December, 1907, at the great 

 concourse which followed the remains of Lord 

 Kelvin to his tomb adjacent to that of Sir Isaac 

 Newton in Westminster Abbey will remember the 

 striking Pgure who, in the uniform of the Insti- 

 tute of France, represented the sister nation 

 among the bearers of the pall. Already in those 

 early days of the Entente France made a point to 

 send of her best — Becquerel," Darboux, Lippmann 

 — to represent her in our national mourning for 

 a man of science whose work had united so hap- 

 pily the genius of the two nations. Later, at the 

 London meeting of the International Association 

 of Academies in 191 2, Darboux was naturally 

 prominent as one of the French representatives ; 

 and, though even then showing signs of failing 

 health, he contributed notably as usual, by his 

 tact and moderation and sympathy, to the success- 

 ful issue of business not always easy to negotiate. 



Jean Gaston Darboux ^ was born at Nimes on 

 August 13, 1842, in a house which had once been 

 a chapel of the cathedral. He lost his father at 

 seven years of age ; and he and his only brother 

 were educated under the anxious care of their 

 mother at the local lycee, attending as demi-pen- 

 sionnaires, as was not unusual in those days, from 

 six o'clock in the morning until eight in the even- 

 ing. He passed on to the more special classes 

 of the lycee of Montpelier in 1859, and in 1861 he 

 headed the lists for admission both to the Ecole 

 Polytechnique and to the Ecole Normale. Of 

 these, true to his desire to devote himself to the 

 profession of teaching, he chose the latter^ 

 thereby setting a fashion followed in later years 

 by other illustrious men who came out high on 

 both lists. His mother w^ent specially to Paris in 

 order to introduce him to Pasteur, then the scien- 

 tific director of the school. 



At the Ecole Normale his bent was towards 

 geometry, and he found time for minute study of 

 the classical works of Monge, Gauss, Poncelet, 

 Dupih, Lame, and Jacobi. In 1864 his own 

 studies on orthogonal surfaces had already borne 

 fruit in the Cotnptes rendus, and in 1866 he sus- 



' Use has been made for these facts of a monograph on M. Darboux 

 published by M. E. Lebon in 1910. 



NO. 2471, VOL. 99] 



tained a memoir " Sur les surfaces orthogonales " 

 as a thesis at the Sorbonne for the doctorate in 

 mathematical science. He then plunged into 

 teaching, to which he had been looking forward, 

 collaborating with Joseph Bertrand in mathemati- 

 cal physics at the College de France, and with 

 Bouquet at the Lycee Louis le Grand ; but he also 

 found time to elaborate two of his principal 

 memoirs, both published in 1870, one on partial 

 differential equations of the second order, the 

 other the famous treatise, " Sur une classe 

 remarquable des courbes et des surfaces 

 algebriques. " In the latter work was developed 

 the theory of cyclides, so named after the special 

 cyclide surface of Dupin, a study which had been' 

 initiated by Moutard and envisaged under more 

 general forms by Kummer. The Irish mathe- 

 matician Casey published about the same time, 

 and in the main independently, several very 

 elegant and elaborate memoirs on the same topic, 

 developed by more purely geometrical methods ; 

 and the fascination of their results and the beauty 

 of the processes attracted great attention to the 

 subject in this country during the succeeding 

 years. It u-as another instance of the affinity of 

 the Irish school of mathematics to the French 

 school, on which it had for long been consciously 

 modelled. Near the end of his life Darboux re- 

 turned to this subject and prepared an extended 

 edition of his earlier work. 



From 1873 to 1878 he assisted Liouville, then 

 of advanced years and in bad health, in the chair 

 of rational mechanics at the Sorbonne ; and some 

 of the fruits of this course are preserved in the 

 elegant and valuable notes, in his best geometrical 

 vein, that he appended to an edition of 

 Desf)eyrous's "Cours de Mecanique." 



Darboux finally entered upon his life-work in 

 1880 in the professorship of Geometric superieure 

 which had been founded at the Sorbonne for 

 Chasles in 1846. As part of the activities of this 

 chair he elaborated the great treatise on in- 

 finitesimal geometry, the "Theorie generale des 

 Surfaces," which came out in four volumes 

 between 1887 and 1896. This constitutes his 

 chief expository work ; into it much of his own 

 previous researches is condensed; and, as usual 

 with the French treatises on analysis, it ramifies 

 into adjoining domains, such as general 

 dynamics, whenever the methods of his exposi- 

 tion are adapted to illuminate such cognate 

 theories. 



He was elected a member of the Academic des 

 Sciences in 1884, and there he gained the highest 

 mark of the esteem and appreciation of his col- 

 leagues in being chosen as Secretaire perpetuel 

 in 1900. The efficiency and charm with which 

 he executed the delicate duties of that office have 

 been universally recognised. He held honorary 

 rank in the Universities, amongst others, of Cam- 

 bridge and Christiania and Kasan. He was 

 elected a foreign honorary member of the Royal 

 Society in 1900, and last autumn, just in time, 

 he received the award of its Sylvester medal. 



Joseph Larmor. 



