June 1, 1895.] 



KNOWLEDGE 



129 



Cases of mimicry are really of the same class as protective 

 colours, but would be incomprehensible but for our know- 

 ledge of warning colours. Insects possessing warning 

 colours are, as we have seen, nauseous and unpalatable 

 to the animals which pursue them as prey ; they, therefore, 

 advertise themselves by their bright colours so as to be 

 easily recognized and so escape destruction. Hence it is 

 plain that other edible insects, if they have colours and 

 markings resembhng those of the nauseous ones closely 

 enough to be mistaken for them, may benefit by the 

 resemblance, and escape. 



A large number of these cases are now known in which 

 an edible butterfly mimicks an inedible and nauseous one, 

 protected by its warning colours, so closely, that in many 

 cases they would be considered members of the same 

 species. This resemblance may be so close as to deceive 

 the butterflies themselves, and the male of the mimicking 

 butterfly has been seen pursuing the female of the 

 mimicked species, unaware of his mistake till he got very 

 close to her. 



The colours of animals and plants, of which those of 

 butterflies are some of the most important, forms in fact 

 one of the most interesting and delightful branches of 

 natural history, and furnish us with many problems, with 

 which the above remarks deal only too briefly. 



Scftnct Notts. 



Dr. Deninger, of Dresden, has prepared carbon mono- 

 sulphide CS pure for the first time, and finds that, instead 

 of being as described in the text-books, an amorphous red 

 solid, it is really a colourless gas. He pi'epared it by 

 heating dry sulphide of sodium with chloroform, or, 

 preferably, iodoform, in sealed tubes to 180° C. The 

 gaseous products were made to bubble through aqueous 

 caustic potash, which absorbed the sulphuretted hydrogen, 

 and the carbon monosulphide passed through unabsorbed. 

 By acting upon carbon disulphide with sodium, in the 

 presence of some aniline, the new gas was also obtained. 

 It is colourless, and easily condensable to a clear liquid, 

 which, however, rapidly evaporates. It burns in air with 

 a bluish flame to form COo and SO,. It is extremely 

 explosive, and was only with some considerable difficulty 

 analyzed and found to have a composition equal to CS. 



M. Berthelot's experiments on the absorption of argon 

 by benzene are very interesting, and exhibit argon in a 

 new light. The fact that the greenish-yellow phospho- 

 rescence of this mixture is very like that of the aurora 

 borealis indicates a probable explanation of this hitherto 

 unexplained natural phenomenon. 



»^ I 



Some years ago the Dutch chemist, Lobry de Bruyn, 

 isolated pure anhydrous hydroxylamine by a somewhat 

 peculiar reaction, and the happy idea recently struck him 

 of applying the same process to the isolation of hydrazine 

 N„H^. Hydrazine has never been obtained fi-ee from 

 water, but always as the hydrate N^H^. H.^O ; indeed, so 

 strong was this attraction for water that its discoverer 

 Curtius recently asserted that its isolation was, he felt 

 convinced, impossible, though he thought the gas N„H^ 

 might in some cases be momentarily liberated. However, 

 de Bruyn, by acting on sodium methylate with hydrazine 

 hydrochloride in methyl alcohol and then fractionally 

 distilling the products, obtained pure hydrazine as a colour- 

 less liquid of fairly high boiling point and freezing at i" C. 

 It is really very stable, but hisses with water and, of course, 

 fumes vigorously in moist air. The halogens all react 

 violently with it, as also does sulphur. 



In a recent number of the American Chemical Journal, 

 there is an interesting paper by H. N. Stokes on some 

 nitro-chlorides of phosphorus. Dr. Gladstone, some years 

 ago, by the action of pentachloride of phosphorus on 

 ammonium chloride obtained the substance (PNCl.,),. 

 Stokes has by the same process obtained also the corre- 

 sponding acid (PN(OH).,),. This substance (PNCl,)^ 

 crystallizes in enormous crystals of unlimited size, and 

 exhibits a remarkable repugnance to being wetted by- 

 water, upon which the crystals consequently float. They 

 have a pleasant odour, but after some time the odour 

 produces a very painful difiiculty in breathing. 



For many years the actual existence of the original 

 manuscript of the " Natural History of Selborne " was 

 known to but a few people. At the death of Gilbert 

 White it had remained with Benjamin White, his brother, 

 the publisher of the original edition of 1789. From him 

 it descended to his son Benjamin, who in turn passed it 

 on to his son, the Eev. Glyd White. The Eev. Glyd 

 White bequeathed it to Mr. A. Holte White, on the dis- 

 persal of whose estate it for the first time reached the 

 auction room on Friday, April 26th, 1895. Messrs. 

 Sotheby, the auctioneers, had been unable even to suggest 

 its value, and it had been considered beforehand whether 

 it would be well to dispose of it privately to the Selborne 

 Society, who were willing to ofl'er £'50. There were but 

 twenty people in the sale-room at the time, and the bidding 

 remained entirely with some three or four individual.?. 

 Bidding started with an amount of no less than two 

 hundred guineas, which was at once capped by one of two 

 hundred and ten guineas, and eventually the manuscript 

 was knocked down to Messrs. Pearson & Co., of Pall Mall 

 Place, for two hundred and eighty guineas. The manu- 

 script was in a capital state of preservation. This is the 

 more remarkable, as it had been lying, for some time, 

 treated almost as lumber, in a box in an old outhouse. 

 Great care was manifest on every page on the part of the 

 author. No haste showed itself. The regularity of the 

 handwriting, careful and precise ; the straightness of the 

 hnes, the apparent absence of haste in the preparation of 

 the letters, all betokened the leisurely and careful habits 

 of the writer. 



At a recent meeting of the Victoria Institute, Sir George 



Stokes, Bart., F.R.S., took the chair, and papers by 



Sir .J. W. Dawson, C.M.G., F.R.S., Profs. E. Hull, 



F.E.S., Parker and Dunns, the Eev. G. Whidborne and 



Mr. J. Slater, F.C.S., were read, upon the questions in 



regard to natural selection and evolution treated by 



Prof. Huxley in his recent address on " The Past 



and Present.'' It was pointed out that, as regards the 



Darwinian hypothesis of evolution, all naturalists admitted 



that it was as yet insuflicient to account for man's place in 



nature, in fact was only a working hypothesis, and 



although one might recognize how magnificent in such 



master hands as those of Prof. Huxley had been the 



results of scientific methods, yet even he confessed to have 



met with mutual contradictions and intrinsic weaknesses 



in the hypothesis. 



— ^-^-* — 



One of the most remarkable botanical achievements of 

 this century has been obtained by Prof. Emery E. 

 Smith, of Cahfornia, who, by experiments in cross- 

 fertilization, has succeeded in producing an entirely new 

 violet, highly scented, and of great beauty. In size the 

 flower covers an American silver dollar. Its colour is a 

 clear violet purple, which does not fade. The fragrance 

 is very powerful. 



