502 



NATURE 



[October 20, 1910 



nected with the growth of the University and its 

 colleges, as well as of Eton College. Four years 

 later, in 1890, "The Life and Letters of Adam Sedg- 

 wick" was published by J. VV. Clark, in collabora- 

 tion with Prof. T. McKenny Hughes. 



As an antiquary, Clark was specially concerned with 

 libraries, and he was an acknowledged master in 

 matters relating to their furniture and fittings. Some 

 of his results in this line of investigation were pub- 

 lished in iqoi, under the title of "The Care of Books." 

 His interest in libraries took a practical shape in the 

 work he devoted to the L^niversity library, as shown, 

 for instance, bv his success in raising, within the last 

 few years, a sum of 20,000!. in order to place the 

 finances of that institution on a more satisfactory 

 basis. The Fitzwilliam Museum is another institu- 

 tion to which Clark devoted much of his time, and to 

 which he rendered innumerable services. He was a 

 member of the, council of the Cambridge .Antiquarian 

 ■Society for fortv-nine years, and he read more than 

 fifty papers at meetings of the society. 



As a zoologist, Clark's principal interests were con- 

 nected with marine mammals, as is exemplified by the 

 fine collections of Cetacea, Sirenia, and Pinnipedia 

 •vhich he inade for the museum of zoology. His best- 

 known zoological publications refer to these groups of 

 animals, and special reference must be made to his 

 papers on eared seals, published in the Proceedings 

 of the Zoological Society in 1873 to 1884. 



During the last nineteen years of his life, Clark 

 was fullv occupied by the duties devolving on him as 

 registrary of the L'niversity. In this capacity his 

 extraordinary knowledge of the early history of Cam- 

 bridge and of its forms and ceremonials, his ability 

 in the care and publication of documents, and his 

 acquaintance with procedure were all of the greatest 

 service to the L'niversity. 



It is ditTlcult to speak dispassionately of Clark's 

 singularly attractive personality, and of the ready 

 sympathy he showed with all sorts and conditions of 

 men. 



.\dvancing years did not take from him the capacity 

 of making new friends, many of whom were chosen 

 from among the younger members of the University. 

 " Gracious and apt to win the youngest heart. 

 Yet keep the oldest true ! " 



These words, written of him by his friend, Mr. 

 k. C. Benson, will express the affectionate regard 

 felt for him by many with whom his loss leaves a 

 blank that cannot be filled. Sidney F. H.\rmer. 



PROF MAURICE LEVY. 

 T N N.wuRE of last week the death was announced 

 ■'• of M. Maurice L^vy, sometime inspector-general 

 of the Ponts et Chausses, and professor at the College 

 de France. An interesting account of Levy's investi- 

 gations in pure and applied mathematics and 

 mechanics is given by M. femile Picard in an address 

 to the .Acad^mie des Sciences, read on October 3 

 (Comt>lcs rcndiis, cli., 14). 



In infinitesimal geometry. Levy obtained the doc- 

 torate in 1867, for an essay on orthogonal coordinates 

 embodying several new and important results. His 

 investigations in this subject also included the study 

 i>f spiral surfaces. His treatise on graphical statics, 

 of which the first edition appeared in 1874, practically 

 initiated the study of this important branch of applied 

 mathematics in France. The notes at the end of the 

 first edition really constitute original papers on the 

 tension of elastic rods, and on the systems of maxi- 

 mum strength with given amount of material; in them 

 the author discusses the advantages of structures 

 without superfluous connections. A second and en- 



NO. 2138, VOL. 84] 



larged edition appeared in due course, and the com- 

 pletion of a third edition has been unfortunately cut 

 short by Levy's recent death. 



The subject of elasticity occupied a large share — 

 perhaps the main_ share — of Levy's attention. After 

 he entered the Ecole polytechnique in 1856, at the 

 age of eighteen, he indicated a new and simple method 

 of investigating the resistance of continuous beams. 

 The problems presented by systems, one of the dimen- 

 sions of which is small compared with the others, 

 greatly interested him, and a long memoir was pub- 

 lished by him on the flexure of elastic plates. M. 

 Picard speaks in high terms of the ingenuity and 

 ability displayed in this essay, while remarking that 

 a more complete solution of the difficulties occurring' 

 in this problem is to be sought elsewhere. 



\ second problem in elasticity was afforded by the 

 stability of rods or prisms under end-thrust, and Levy 

 extended the investigation from straight to circular 

 rods, obtaining extremely interesting conditions of 

 stability by means of an analysis involving elliptic 

 functions. To M. Levy is assigned the credit also of 

 obtaining for the first time the general equations for 

 ductile bodies strained beyond the limits of elasticity, 

 thus responding to the question put by Saint Venant, 

 arising out of Tresca's experiments. 



Hydrodynamics formed the subject of Levy's second 

 paper, dealing with rectilinear vortex motion. In 

 this, the author took a leaf out of Cauchv's theory 

 of optical dispersion in his application of the higher 

 differential coefficients in studying the mutual action 

 of two vortices. 



A development of a more practical character was 

 M. Levy's investigation of the equilibrium of earth 

 and the strength of masonry supporting walls. Start- 

 ing with the laws of friction, L^vy found the differen- 

 tial equation of the lines of rupture in limiting equili- 

 brium, and showed that, contrary to Coulomb's results, 

 the surfaces of rupture for a prismatic mass of earth 

 are not in all cases planes parallel to the edges of the 

 prism. 



It will thus be seen that M. Levy played an im- 

 portant part in applying analytical methods to the 

 solution of problems of practical interest, and his 

 works constitute a heritage from which workers in 

 aoplied science cannot fail to benefit greatly. 



NOTES. 



The I'ouncil of the Royal Scottish Geographical Society 

 has resolved to award the society's medal to Prof. James 

 Geikie, F.R.S., for his numerous contributions to geo- 

 graphical research and his great services to the society ; 

 and the Livingstone gold medal to Sir John Murray, 

 K.C.B., F.R.S., in recognition of his oceanographical 

 work, and more particularly in commemoration of the 

 completion of the bathymetrical survey of Scottish fresh- 

 water lochs. 



We regret to see the announcement of the death, on 

 October 14, of Dr. Sydney Ringer, F.R.S., at seventy-six 

 years of age. 



According to a Reuter message from Santiago de Chile, 

 official returns show that the world's consumption of 

 nitrate during the past year amounted to 43,996,966 

 quintals, an increase of 8,000,000 quintals as compared 

 with the previous twelve months. 



Prof. How.\rd C. Bl'tler, of Princeton, has just re- 

 turned to that University with an encouraging report of 

 the archaeological expedition he has been directing at 

 Sardis, in Asia Minor. The discoveries include a part of 

 the pavement of the ancient city, and the substructure of 

 a large temple of the fourth century B.C. In the necro- 



