November 3, 1892 



NATURE 



line lye resembled that of an alkaline solution of impure 

 alizarin. 



These experiments lead to the conclusion that the red colour 

 of the fabric was produced by dyeing with some kind of madder, 

 either wild or cultivated, the fabric having been previously 

 treated with a mixed aluminous and ferric mordant, and then 

 probably oiled — that it was, in fact really a kind of Turkey 

 red. 



Maroon. — The dull chestnut colour of this fabric presented a 

 striking contrast to the bright red of the preceding. Its consti- 

 tution was, however, similar. Having treated it in the same 

 way as the other, I found that the colouring matter must have 

 been derived from madder ; fatty matter was also present, but 

 the mordant contained a larger proportion of ferric oxide, a 

 fact which sufficiently explains the brown tint of the dyed 

 fabric. 



Purple. — The fabric in which this colour was seen was made 

 up of a pale yellow warp, and a weft of a dull purple or claret 

 colour. The latter colour was found to be due to an intimate 

 mixture of red and blue, for the threads, on examination under 

 the microscope, were seen to consist partly of red, partly of 

 blue fibres, the former predominating. The two sets of fibres 

 had, of course, been mixed before spinning. The blue fibres 

 were certainly dyed with indigo, the red probably with madder. 



Black. — The colour of the black fabric, like that of the green, 

 was a compound of two colours, one overlying the other. 

 Under the microscope the individual threads appeared grey. 

 On treatment with a mixture of alcohol and hydrochloric acid 

 they changed colour, a yellow liquid being obtained, while the 

 fabric itself now appeared blue, and after washing and drying 

 yielded indigo by appropriate treatment. The yellow alcoholic 

 licyiid was found to contain purpurin. The colour may be sup- 

 posed to have been produced in the following manner : — The 

 woollen fabric having first been dyed blue was mordanted, to 

 use a modern phrase, and then dyed with madder, the two 

 colours together producing the effect of black. 



Edward Schunck. 



SCIENTIFIC SERIALS. 



In the Botanical Gazette for July, August, and September, 

 there are several papers of general interest. Mr, G. A. Rex 

 presents a further contribution to our knowledge of the Myxo- 

 mycetes in an account of the genus Linhladia. — Mr. D. T. 

 McDougal gives a detailed account of the morphology and 

 anatomy of the tendrils of Passiflora ccerulea. — Mr. M. B. 

 Thomas describes and figures an apparatus for determining the 

 periodicity of root-pressure in plants. — Mr. C. L. Holtzman has 

 a short paper on the Apical growth of the stem and the develop- 

 ment of the sporange in Botrychium virginianum, his obser- 

 vations favouring the view that the Ophioglossaceas are a more 

 primitive form than the typical Filices, — Mr. A. F. Foerste con- 

 tinues his observations on the Relation of autumn to spring- 

 blossoming plants. — Mr. Charles Robertson gives a further 

 instalment of his series of papers on Flowers and insects. — A 

 brief report is given of the botanical papers read at the recent 

 meeting of the American Association for the Advancement of 

 Science. 



In the Journal of Botany for September and October, no less 

 than four new species are added to the British flora and to 

 science — Hieracium hibernicuvi, H. duriceps, and H. Bread- 

 albanense, by Mr. F. T. Hanbury ; and Ranunculus petiolaris 

 (sect. Flammula). by "Rev. E. S. Marshall. — F^ev. W. Moyle 

 Rogers continues his Essay at a key to British Rubi ; Mr. E. G. 

 Baker his Synopsis of genera and species of Malveae ; and Mr. 

 W. A. Clarke his First Records of British Flowering Plants. 



Bulletin of the New York Mathematical Society. Vol. ii. 

 No. I, October, 1892. (New York.)— Prof. Cajori opens this 

 number with an interesting note on the evolution of criteria of 

 convergence (pp. l-io), in which he discusses some special and 

 general criteria furnished in the writings of Gauss, Cauchy, 

 Abel, DeMorgan, Bertrand, Kummer, and others, and notices 

 specially the remarkable advance made by Pringsheim {Math. 

 Ann. vol. xxxv.). — Dr. A. Martin calls attention (pp. 10- Cl) to 

 a slip in Bill's "Short History of Mathematics " (p. 102), the 

 probable origin of which is accounted for by. Mr. Ball. — There 



NO. i2or, VOL. 47] 



is a slight review of Chapman's "Elementary Course in the 

 Theory of Equations " (pp. 11-12), and the rest of the issue is 

 taken up with the usual list of new publications and notes. In 

 these last Dr. Martin points out a curious error in the Royal 

 Society " Catalogue of Scientific Papers," vol. ix. ( :874-l883), 

 where, of the papers accredited, on p. 790, to Ezekiel Brown 

 Elliott, Nos. 5-11, 14-17 should be assigned to Mr. Edwin 

 Bailey Elliott, of Oxford, and not to the late Mr. Ezekiel Brown 

 Elliott, of America, to whom Nos. 4, 12, 13 are rightly 

 attributed. 



In the Bullettino of the Botanical Society of Italy, we find 

 in addition to papers of more local interest, a further com- 

 munication from Sig. Macchiati on the Cultivation of diatoms, 

 in which he states that the presence of infusoria and of diatoms 

 in the water is mutually beneficial to one another, while the 

 most destructive enemies of the latter are bacteria. — A paper 

 by Sig. Piccioli on the Biological relations between plants and 

 snails, is chiefly devoted to the protective contrivances found in 

 the former against the attacks of the latter, the most important 

 of which are of a cfiemical nature — tannm, latex, oleiferous 

 glands, and poisonous salts such as calcium oxalate : mechanical 

 means of protection, such as hairs and a comparatively thick 

 cuticle, play a subordinate part. — In a further communication by 

 Prof. Arcangeli on the Cultivation of Cynomorium coccineum, 

 he states that he does not find such an intimate parasitism with 

 its host as is the case with the Rafilesiaceae and the Balano- 

 phoracese. 



SOCIETIES AND ACADEMIES. 



Paris. 



Academy of Sciences, October 24. — M. de Lacaze- 

 Duthiers in the chair. — Researches on the fixation of atmo- 

 spheric nitrogen by microbes, by M. Berthelot. The investiga- 

 tion was made in order to elucidate the mechanism of the 

 fixation of atmospheric nitrogen. It appears that the presence 

 of green vegetable material is not essential to the process. The 

 colourless bacteria are able to absorb nitrogen when supplied 

 with humic acid only as nutriment. The assimilation takes 

 place more readily with natural than with artificial humic acid, 

 probably because the former contains more nitrogen- In 

 experiments with hermetically sealed cultivations it was found 

 that the gain of nitrogen by the organic material under cultiva- 

 tion was 6 or 9 per cent, in excess of that supplied by the 

 humic acid, the difference being derived from the enclosed air. 

 With an occasional stream of dust-laden air this was brought up 

 to 30 per cent. — Coloured photographs of the spectrum on 

 albumen and bichromated gelatine, by M. G. Lippmann. 

 Albumenized and gelatinized plates soaked in bichromate of pot- 

 ash may be employed for photographing in colours. They are used 

 like silver-salt |)lates, being placed so that the mercury is in 

 contact with the film. The colours will appear immediately 

 after immersion in water, which develops and also fixes the 

 image. It disappears on drying, but reappears as soon as the 

 plate is soaked. The colours are very brilliant, and visible at 

 all angles. Those of gelatine plates are brought out by simple 

 breathing. The theory is analogous to that of silver plates, the 

 maxima and minima of interference producing hygroscopic and 

 non-hygroscopic layers with varying refractive indices. — The 

 irrigation canals of the Rhone, by M. Chambrelent. — A new 

 apparatus, the schiseophone, serving the purpose of exploring 

 the internal structure of metallic masses by means of an electro- 

 mechanical process, by M. de Place. The apparatus consists 

 of a microphone and an induction sonometer. To the micro- 

 phone is attached a rod of hard steel, kept oscillating once or 

 twice per second, and striking each time against the casting or 

 other mass of metal under investigation. The sonometer, con- 

 sisting of two coils movable towards or away from each other 

 along a divided scale, with a telephone connected with one of 

 the coils, is placed in another room, and joined by wires to the 

 microphone. The coils being so adjusted that the tapping is 

 scarcely perceptible at the sonometer, the casting is moved so 

 as to expose various portions to the impacts. If the thickness 

 be uniform, any flaw or fissure will be at once indicated by a 

 change in the sound. — Observations of the comet Barnard 

 (D 1892), made at the Paris Observatory, by M. G. Bigourdan. 



