256 



NA TURE 



[July t2, 1900 



heating nor by shock. On account of its great stability towards 

 oxidising agents, the author suggests the formula CgHg.N j NH 

 as being the most probable. 



The additions to the Zoological Society's Gardens during the 

 past week include two Tigers {^Felis iigris, <J , ? ) from India, 

 presented by H.H. the Maharani Regent of Mysore ; a Black- 

 eared Marmoset (ZTa/a/^ yac^/^?<j) from South-east Brazil, pre- 

 sented by Mrs. G. L. Bagnell ; a Pine Marten {Mustela marles), 

 British, presented by Mr, C. G. Beale ; a Common Squirrel 

 (Sciurtts vulgaris), British, presented by Mr. Cecil Slade ; a 

 Yellow-cheeked Amazon {Chrysotis autumnalis) from Honduras, 

 presented by Mr. S. Rankings ; two Crimson-crowned Weaver 

 Birds {Euplecies Jlammiceps) from West Africa, presented by 

 Mrs. Charles Green ; a Sharp-nosed Crocodile ( Crocodilus 

 cataphractus) from West Africa, presented by Mr. J. A. Robb ; 

 a Four-lined Snake (^Coluber quatuorlineatus), European, pre- 

 sented by Mr. W, R. Temple ; four Natterjack Toads {Bujo 

 calamiia), European, presented by Mr. Stanley S. Flower ; two 

 Great Wallaroos {Macropus robustus, 6 , 9 ) from South 

 Australia, three Wrinkled Terrapins (CArysemys scripta rugosa) 

 from the West Indies, deposited ; an Adanson's Sternothere 

 (Sternothoerus adansoni), a Common Chamreleon {Chamaeleon 

 vulgaris) from the Soudan, received in exchange ; a Burrhel 

 Wild Sheep {Ovis burrhel)^ two Black-backed Gulls (^Larus 

 marinus), a Herring Gull {Larus argentatus'), bred in the 

 Gardens. 



Erratum.— We are asked to state that in the report of Prof. 

 S. Young's paper, read before the Physical Society on June 22, 

 on the Law of Cailletet and Mathias, the words " i per cent." 

 (p. 215, col. I, line 3) should be "o'l per cent." The o was 

 omitted from the report sent to us. 



OUR ASTRONOMICAL COLUMN. 



Comet Giacobini (1900 a).— Several observations have 

 been made of this comet since its conjunction with the sun, 

 but it is reported as faint. The following positions are an 

 abridgment from the Ephemeris by Herr Ristenpart in Astro- 

 nomische Nachrichteii, No. 3636. 



Ephemeris for 12/t. Berlin Mean Time. 

 I90O- R.A. Decl. 



July 12 

 14 

 16 

 18 

 20 

 22 

 24 

 26 

 28 

 30 



R.A. 



h. m. s. 



22 29 5 



12 29 



21 55 5 



37 4 



18 42 



21 O 16 

 20 42 2 

 24 19 

 20 7 20 

 19 51 16 



-f 46 25-9 



46 50-9 



47 5'i 

 47 7-1 

 46 55 9 

 46 30-8 

 45 51-8 

 45 o-o 

 43 56-4 



+ 42 42-4 



The comet attains its maximum north declination on the i8th, 

 to the north-west of a Cygni, afterwards travelling in a south- 

 westerly direction through Cygnus and Lyra. 



WALTER PERCY S LADEN 

 gY the death of Walter Percy Sladen, the world has lost one 

 of the most lovable of men, and science an earnest devotee 

 —a worker content to spare no effort could he but discover the 

 truth. 



Sladen was born on June 30, 1849, at Meerelough House, 

 near Halifax, Yorkshire, and was educated at Hipperholme 

 Grammar School, and afterwards at Marlborough under Dean 

 Bradley. He came of an old Yorkshire family, who have -been 

 niuch respected for many generations ; and ease and refinement 

 of manner were among his marked characteristics, while the 

 charm of his address endeared him to all with whom he came in 

 contact. 



NO. 1602, VOL. 62I 



He never attended a regular academic course of instruction 

 in the branch of science in which he became eminent; his 

 elementary training was self-acquired, and his leaning towards 

 zoology innate. The definitive choice of the Echinoderma as 

 the object of his life's work was of his own seeking, after much 

 consideration ; and in this he showed great force of character 

 and a power of self-reliance which there was reason earlier to 

 believe he possessed, for even before he entered Marl- 

 borough he evinced an unusual predisposition towards science, 

 in founding for his boy friends a scientific society devoted more 

 especially to the study of astronomy, in connection with which 

 he became known among them as the " Astronomer Royal." 

 Little did he think that he would in later life become for ten 

 years a secretary of a leading scientific society, and that for 

 eighteen he would conduct the affairs of a zoological research 

 committee, as he did in his capacity as Secretary to the British 

 Association Table of the Naples Station. 



Sladen's scientific work, so far as his published memoirs and 

 papers are concerned, extended over a period of seventeen years, 

 1877 to 1893. Of these there are thirty-four in all — twenty-one 

 from his own hand, thirteen in conjunction with his intimate 

 friend and adviser, the late Prof. Martin Duncan. Beyond 

 these there stand to his record certain bibliographical notices 

 and miscellanea. Of the thirty-four published works, fifteen of 

 which he was sole, and four of which he was joint author, deal 

 with the starfishes ; and of the remaining fifteen, nine were con- 

 joint, and devoted, with the exception of two, to fossil forms. 

 Conspicuous among these are reports upon the collections made 

 by the Geological Survey of India ; and among those which he 

 alone produced are Parts i. and ii. of the second volume of the 

 Palseontographical Society's Memoirs on the Fossil Echinoder- 

 mata, which were his last published works. They deal with the 

 Cretaceous Asteroids, and appeared in the Society's volumes 

 for 1890 and 1893. His first three papers deal with the 

 remarkable creature Astrophiura, whose generic name is self- 

 explanatory. The first, a brief description, was published in 

 \.\\& Proceedings of the Royal Society for 1878; the other two, 

 each containing a Latin diagnosis, in the Zoologischer Anzeiger 

 and Annals and Magazine of Natural History, the year follow- 

 ing. His remaining papers appeared in the Annals and the 

 Journal of the Linnean Society, the publications of the Royal 

 Society of Edinburgh, and elsewhere. They mostly deal with 

 whole collections, and include reports on those, made in the 

 Arctic Region in 1875-1876, on those of the Alert, Knight 

 Errant and Triton, as also those made in the Faroe Channel, 

 the Korean Sea, and the Mergui Archipelago. In each 

 Sladen produced good results, as in the discovery of genera, 

 such as Micraster and Rhegaster; and what more natural, 

 therefore, than that he should have been entrusted with the 

 working out of the Asteroids collected by H.M.S. Challengery 

 the report upon which was the crowning achievement of ihis 

 life. ' 



This magnificent work of 900 pp., with its accompanying 

 atlas of 118 plates, ranks among the most masterly and 

 exhaustive of the Challenger volumes. Before taking it 

 seriously in hand, Sladen visited every museum in Europe (with 

 one exception) which was known to contain starfishes of im- 

 portance ; and, as pointed out by the editor in its preface, it is 

 a monograph of the whole group. The labour involved in its 

 production was prodigious ; and its interest is enhanced by the 

 fact that the bulk of it was written between the hours of 9 p.m. 

 and those of early morning, often after a day's occupation with 

 other affairs. The extension of the family Pterasteridae and the 

 great addition to our knowledge of the deep-sea forms are its- 

 most salient characters ; but we know not which to admire most,, 

 the body of the work, with its laborious descriptions of individual 

 forms, or the supplemental part, in which there is given a list 

 of every known species, with a record of its bathymetric distri- 

 bution. Elementary student and expert stand alike indebted to 

 him for this monumental work, indispensable to progress in the 

 knowledge of the subject with which it deals. Generic names 

 like Benthaster and Marsipasler are sufficiently significant in 

 themselves. Proceeding to classification, Sladen made good use 

 of the marginal and ambulacral plates, and his subdivision into 

 the sub-classes Euasteroidea and Palaeasteroidea, with the 

 ordinal divisions to which he was led, has withstood the test of 

 time and become the adopted classification of the better text- 

 books, as for example those of Lang and Gregory. In this his 

 influence on the progress of science will live, and it is a matter 

 of profound gratification that only a short time before his death. 



