2l8 



NATURE 



[October 14, 1920 



eyes of many Diptcra, and the amazing- iridescent 

 hairs of a mammal, the Cape Golden Mole, 

 Chrysochloris aurea, 5 (Fig. i), showing the fine 

 imbricated scales, 1. In addition there are the 

 brilliant setae of the "sea-mouse," a marine 



worm (Aphrodite aculeata). In plants not many 

 iridescent structures are found, with the exception 

 of the beautiful Pteridophyte, Selaginella Wilde- 

 novii, which glistens with a very strong blue and 

 purple metallic sheen. 



Obituary. 



Arthur Sidgwick as Naturai.isi. 



THE admirable notice of the late Arthur 

 Sidgwick in the Times of September 28 de- 

 scribes him as "naturalist," as well as "scholar " 

 and "politician." It is a true and just descrip- 

 tion. The love of natural history developed early, 

 and was always one of the strong- and essential 

 elements in his intellectual life. 



Sidgwick was twenty-seven, and had been a 

 master at his old school — ^Rugby — for three years, 

 when Wallace's article "On Mimicry and other 

 Protective Resemblances among Animals " a{)- 

 peared in the IVestminster Review for July, 1867, 

 and it had the same effect upon him as, in its later 

 form, reprinted in the " Essays on Natural Selec- 

 tion," it had ,on the present writer. A few 

 months after reading it, Sidgwick, on November 9, 

 read his paper " On Protective Resemblances 

 among Insects " before the Rugby School Natural 

 History Society (pp. 23-26 of the report for 1867), 

 in which he not only gave an admirable review of 

 the article, but was also able to draw on his own 

 past experience as a naturalist for illustrations. 

 There is one slip in his reference to Wallace's 

 account of Bates's epoch-making paper, for he 

 sp)oke of the Heliconidae and their Leptalis mimics 

 as "white," whereas they are brightly coloured, 

 while the Leptalis, abandoning an ancestral 

 white, have become brightly coloured also. 



Among Sidgwick 's original observations in the 

 paper, the following are quoted by Wallace in 

 his revised essay (p. 45 of the 1875 edition) : — 



I myself have more than once mistaken Cilix com- 

 pressa, a little white and grey moth, for a piece of 

 bird's dung dropped upon a leaf, and vice versa the 

 dung for the moth. Bryophila glandifera and perla 

 are the very image of the mortar walls on which fhcv 

 rest ; and only this summer, in Switzerland, I amused 

 myself for some time in watching a moth, probably 

 Larentia triptinctaria, fluttering about quite close to 

 me, and then alighting on a wall of the stone of the 

 district, which it so exactly matched as to be quite 

 invisible a couple of yards off. 



Observations of this kind were far from well 

 known in those days, only a few years after the 

 appearance of the "Origin of Species." 



Sidgwick was a man of strong opinions ; what 

 he believed he believed intensely. Yet, with all 

 this, he was exceptionally modest. I recall a later 

 paper of his on the same subject as the earlier, 

 read before the recently established Oxfordshire 

 Natural History Society. In the discussion some 

 criticisms were passed upon the relative value of 

 the destructive agencies of which he had spoken. 

 He accepted the remarks of much younger 

 NO. 2659, VOL. 106] 



members with perfect kindliness, and ended by 

 saying that he hoped "to do better next time." 



These memories lead naturally to thoughts of 

 his simplicity, and with it his delightful and in- 

 fectious boyishness. One came in to ask for his 

 ever-ready help in coining some scientific term, 

 and found him testing his latest toy, a little type- 

 writer, and then everything must give way to a 

 race between the player and the writer — the latter 

 much handicapped by the banging of the 

 machine ; or a simple form of billiard table had 

 displaced the heaps of books, and a game must 

 be played ; or a chunk of marzipan emerged and 

 must be shared. 



Sidgwick 's sympathy with the aims of science 

 in university life was not bounded by his love of 

 natural history. In the conflicts which often arose, 

 and w^ere bound to arise, between the old, which 

 is really modern, and the new, which is a return 

 to the ancient ways, Sidgwick always supported 

 science. I never knew an exception in the years 

 when we were closely associated. 



Among the notices and memories of .Arthur 

 Sidgwick I have seen, there has been no refer- 

 ence to the two volumes of "School Homilies," 

 addressed, from 1870 onwards, to the boys in 

 Canon J. M. Wilson's House at Rugby. The 

 addresses deal, as Canon Wilson says in his 

 introduction, " with apparently commonplace sub- 

 jects, but they lifted every subject out of the 

 commonplace." They should be read by everyone 

 who wishes to know the man and all that he stood 

 for. E. B. P. 



By the death of M. Louis Ducos du Hauron 

 we lose one of the foremost pioneers in the photo- 

 graphy of colour. M. du Hauron was born on 

 December 8, 1837, and died on August 31 last. 

 La Nature of September 25 publishes a portrait 

 taken in 1877, and the British Journal of Photo- 

 graphy, Colour Supplement, of October i gives 

 the portrait by which he is generally known, 

 taken evidently some years after the other, and 

 a useful chronology of his work. It seems that 

 he began the study of luminous sensations in 1859, 

 and that by 1862 he had worked out a method of 

 colour photography by means of three colour 

 filters and complementary printing ; but his chief 

 contributions to the subject are contained in two 

 small volumes, which, unfortunately, are now 

 very rare — "Les Couleurs en Photographic : Solu- 

 tion du Problfeme," published in i86g, and "Les 

 Couleurs en Photographic et en particulier 

 I'H^liochromie au Charbon," published in the fol- 

 lowing year. In these publications he enunciated 



