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Standards may be sent to Sevres by post or railway (at the cost and risk of the owner); or still better, they may be delivered and removed from the Bureau by the owner or his agent. certificate of verification will be given when the standards are ready for removal. In any application to the director the denomination of the standard, or the description of the instrument, should be stated, and the nature and extent of the verification demanded.
The committee will verify metric standards of length of one, two, three, and four metres, or subdivisions of the standard metre, if made in metal or some durable stone. Line-measures should have their graduations so fine as to be well observed with a microscopic power of sixty diameters; and end-measures should have their terminal surfaces sufficiently adjusted and polished so as accurately to define the length of the bar. Measures of mass may be made also of metal or some durable stone, but each must be in one piece without handles, grooves, or adjusting holes. For thermometers and barometers special regulations are issued, which may be obtained at a small charge from MM. Gauthier-Villars, 55, Quai des Grand Augustins, Paris.
The fees on verification of measures of length vary from 60 to 400 francs, according, of course, to the extent of the verification demanded; for metric weights from 20 to 120 francs; and for thermometers and barometers from 10 to 80 francs.
What should be the true equivalent length of the yard measure in terms of the metre, may appear to some to be almost a trifling matter-because the measurement in dispute, or probable error of the equivalent at present adopted in this country, amounts only to o'0008 inch. It is, however, a fact that so small a difference as o'0008 in this equivalent would not only he felt in scientific researches but also in practical work. Messrs. Comstock and Tittman, of the United Coast Survey, as well as Dr. Peters, of Germany, and the Director of the International Committee, have found that the equivalent length of the metre (39 37c8 inches) as ascertained by Kater and Arago, in 1818, is inaccurate, to the extent of o'0008 inch, and that the true equivalent ought to be nearly 39 3700 inches. This latter value will, we have no doubt, be ultimately recognized in scientific work.
In the field of electrical measurements, we find that Dr. Guillaume is continuing his investigations as to the measurement of temperature by electrical methods; and as to the variations of mercurial standards of resistance, a work originally begun at the Bureau, by Dr. Benoît, in connection with the standard ohm. It would not appear that mercurial thermometers can be superseded for ordinary measurements of temperature, but that measurement by resistances may afford useful results in determining the temperature of a given mass or space, as the whole length of a column of mercury. Dr. Guillaume gives an account of his work on mercurial standards in the Procès-Verbaux recently issued (page 183).
During the past year Commandant Defforges, of the Geographical service of the French army, has been undertaking at the Bureau an inquiry into the effect of the force of gravity at the latitude of Breteuil, by means of a seconds pendulum and apparatus constructed by Brunner. M. Defforges found that at Breteuil (longitude east of Paris o°131, latitude north 54'260, and altitude 70'4 metres) G = 9.80991 m.
We cannot conclude this glance at the recent work of the International Committee without expressing an opinion that the scientific success of their work and the accuracy of its record, owe much to the energy and watchful care of the new president, Dr. Foerster, and the secretary of the committee, Dr. A. Hirsch.
NOTES ON SOME ANCIENT DYES.1
THE fragments of ancient dyed fabrics which I have examined
I owe to the kindness of Mr. R. D. Darbishire. They are specimens from a lot found by Mr. Flinders Petrie in a tomb at Garob, Lower Egypt, supposed to date from 400-500 A.D. They were used apparently for filling the mummy cases where required, not strictly speaking as grave clothes. My object in examining them was to ascertain, if possible, what were the materials employed in producing the various colours seen on
1 Reprinted from "Memoirs and Proceedings of the Manchester Literary and Philosophical Society," 1891-92 (Fourth Series, vol. 5, No. 2).
Blue. The colour of the fabric was a dull medium blue. Oa treatment with hot caustic lye a great part of the wool dissolved. The residue, which was dark blue, having been filtered of, washed and dried, was treated with boiling aniline, to which I it communicated a bright blue colour. The blue solution | having been filtered boiling, deposited on cooling a quantity of blue crystalline scales, which, after being filtered off, washes with alcohol and dried, were found to consist of indigo blue. On being treated in a tube they gave a sublimate of regular crystal, || blue by transmitted, copper-coloured by reflected, light; they dissolved in concentrated sulphuric acid, giving a blue solution, and the solution in aniline showed the absorption spectrum of indigo blue. It is evident, therefore, that indigo in some form or other was the material used in dyeing this colour.
Yellow. The colour of the patches dyed yellow was so evidently faded, and showed so little intensity, as to make it very uncertain whether analysis would lead to any precise result; the examination was therefore omitted.
Green. Of the material dyed this colour, I had but a small quantity, but it was sufficient to allow of some conclusion regard. ing the means whereby the colour was produced. On being treated for some days with dilute hydrochloric acid it imparted to the latter a deep yellow colour. The portion left by the acid, after being washed and dried, yielded indigo blue on treatment with boiling aniline. It is probable, therefore, that the colour was produced by first dyeing the fabric with indigo, then treating with some mordant, such as alum, and, lastly, dyeing with some yellow colouring matter, most likely of vegetable origin. With the small quantity of material at my disposal, I found it impossible to ascertain the nature of the yellow colouring matter employed.
Red. This was the most pronounced, and at the same time the most interesting, of the colours examined. The colour of the fabric was a full deep red. It might be called a Turkey red; the dye, in fact, proved on examination to be a kind of Turkey red as having the characteristic properties of tha: dye.
On being burnt, the fabric left a considerable quantity of ast consisting of calcium sulphate, alumina, aluminium phosphate, ferric oxide, and silica. A large portion of this ash no doute represents the mordant employed in producing the colour. On treatment with hot dilute hydrochloric acid, the fabric lost its re colour and became yellow. After removal of the acid by washing with water, and pressing between blotting paper, treatment with boiling alcohol deprived the wool of the greater part of the yellow colour, a faint tinge only being left. The deep yellow alcoholic liquid obtained left on evaporation a reddish-brown amorphous residue. This, on being treated with a boiling solution of alum, dissolved in part, yielding a pink fluorescent liquid, which had exactly the same colour, and showed precisely the same absorption bands as a solution of purpurin from madder in alum liquor. On adding hydrochloric acid to the pink soletion and heating, the colouring matter was precipitated in orange-coloured flocks, the liquid becoming almost colourless. The flocks after being filtered off and washed with water dissolved easily in boiling alcohol, yielding a yellow solution, which, on spontaneous evaporation, lett a quantity of dark yellow needles arranged in rosettes. These needles dissolved in caustic alkali, giving a cherry-red solution, which showed the absorption bands of purpurin. The solution, on exposure to air and light.
Some of the precipitated colouring matter, on being employed in the usual way for dyeing a bit of calico to which various mordants had been applied, yielded colours exactly like those obtained with purpurin from madder, i.c., the alumina mordan gave a bright red, the iron mordant dull purple to black tints. The matter left undissolved, after repeated treatment will boiling alum liquor, was still highly coloured. It dissolver easily in alcohol, the solution leaving on evaporation a brown amorphous residue, which remained soft even after long stand ing. This residue consisted for the most part of fatty matter, but it also contained some colouring matter insoluble in alum liquor. That this colouring matter was alizarin seemed pro bable, since the colour which the mixture imparted to alka
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 constitution 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
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, 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 liquid was found to contain purpurin. The colour may be supposed 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.
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 Myxomycetes in an account of the genus Linbladia.-Mr. D. T. McDougal gives a detailed account of the morphology and anatomy of the tendrils of Passiflora cærulea.-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 development of the sporange in Botrychium virginianum, his observations favouring the view that the Ophioglossaceæ are a more primitive form than the typical Filices.-Mr. A. F. Foerste continues his observations on the Relation of autumn to springblossoming 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 hibernicum, H. duriceps, and H. Breadalbanense, by Mr. F. J. Hanbury; and Ranunculus petiolaris (sect. Flammula) by Rev. E. S. Marshall.-Rev. W. Moyle Rogers continues his Essay at a key to British Rubi; Mr. E. G. Baker his Synopsis of genera and species of Malveæ; and Mr. W. A. Clarke his First Records of British Flowering Plants.
Bulletin of the New York Mathematical Society. Vol. ii. No. 1, October, 1892. (New York.)-Prof. Cajori opens this number with an interesting note on the evolution of criteria of convergence (pp. 1-10), 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. 10-11) to a slip in Ball's "Short History of Mathematics" (p. 102), the probable origin of which is accounted for by Mr. Ball.-There
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. these last Dr. Martin points out a curious error in the Royal Society "Catalogue of Scientific Papers," vol. ix. (:874-1883), 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 communication from Sig. Macchiati on the Cultivation of diatoms, in the water is mutually beneficial to one another, while the in which he states that the presence of infusoria and of diatoms 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 chemical nature-tannin, 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 Rafflesiaceæ and the Balanophoraceæ.
SOCIETIES AND ACADEMIES.
Academy of Sciences, October 24.-M. de LacazeDuthiers in the chair.-Researches on the fixation of atmospheric nitrogen by microbes, by M. Berthelot. The investigation 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 nitrogenexperiments with hermetically sealed cultivations it was found that the gain of nitrogen by the organic material under cultivation 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 potash may be employed for photographing in colours. They are used like silver-salt plates, 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 electromechanical process, by M. de Place. The apparatus consists of a microphone and an induction sonometer. To the microphone 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, consisting 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.
-Elements of the comet Barnard, of October 12, 1892, by M. L. Schulhof. On the algebraic integrals of the differential equation of the first order, by M. L. Autonne.-On centres of geodesic curvature, by M. Th. Caronnet.-On Pfaffs problem, by M. A. J. Stodolkievitz.-Sunspots and magnetic disturbances in 1892, by M. Ricco.-On considerations of homogeneity in physics; reply to M. Clavenad, by M. Vaschy.-Verification of parallelism of optic axes in uniaxial crystalline plates, by M. Bernard Brunhes.-On a photoptometric photometer, for the measurement of feeble illuminations, by M. Charles Henry. This is based upon the constancy of the phosphorescent sulphide of zinc. Its law of loss of brilliance being determined, it may be used for measuring very feeble illuminations, such as distant artificial light or the general luminosity of the sky due to the stars. The decrease of light after the first 900 seconds being given by 5 (185) = const., it is easy to calculate the luminosity at any instant. In the instrument in question there are two screens of ground glass, one of which is illuminated by the phosphorescent sulphide, brought to its maximum glow at a certain time by burning magnesium ribbon, the other exposed to the source of light. It is then only necessary to wait till both the screens are equally illuminated, and to note the time.-On the dissociation of chrome alum, by MM. H. Baubigny and E. Pechard.-On the temperatures of maximum density of aqueous solutions, by M. L. de Coppet. On some double salts of quinine, by M. E. Grimaux. On the thermal value of the three functions of orthophosphoric acid, and on its constitution, by M. de Forcrand. -Preparation and properties of fibroine, by M. Leo Vignon.Regeneration of the so-called sporangial form in the diatoms, by M. P. Miquel.-On the hematozoaria of cold-blooded vertebrates, by M. Alphonse Labbé.-Influence of coloured light on the development of animals, by M. E. Yung.-On the mode of fixation of the hexapod parasitic larvæ of the acarians, by M. S. Jourdain. -The cavern of Brassempouy, by M. Edouard Piette. Discovery of a skeleton of Elephas meridionalis in the basaltic ashes of the volcano of Senèze, by M. Marcellin Boule. -Vegetable prints of the Dover boring, by M. R. Zeiller.
Meteorological Society, October 11.-Prof. von Bezold, president, in the chair.-Dr. Berson reported on an interesting relationship which he had discovered between insolation and temperature. Since it has not yet been possible to determine accurately the absorption due to the atmosphere, the speaker had calculated the insolation at the external limit of the atmosphere, which admits of rigid mathematical treatment, both for the whole year and for the months of January and July. The mean of insolation for the whole year was found to lie at the thirtieth degrees of northerly and southerly latitude, so that the zone between these parallels, or about 60 per cent. of the whole external surface, receives more insolation than the mean, whereas the two polar caps, or the remaining 40 per cent., receive less. A similar calculation of the annual temperature gave the mean as at latitude 38° N. and 35° S., giving as before 60 per cent. of the surface with the temperature above the mean, and 40 per cent. below. In January 61 35 per cent. of the surface experienced an insolation above the mean and 60 per cent. a temperature above the mean, while in July the percentages were respectively 6137 and 61 33.-Dr. Zenker gave a short account of a research on the relationship between temperature and insolation on the earth's surface. He had accurately calculated the relationship both for regions comprising land only and water only, and arrived at some interesting conclusions as to the theoretical temperatures at various latitudes of continents and oceans.
Physical Society, October 21.-Prof. Kundt, president, in the chair.-Dr. Jäger gave an account of the measurements he had made, in conjunction with Dr. Kreischgauer, of the temperature-coefficient of electric conductivity of mercury. Dr. Arons demonstrated an arc-light between mercurial electrodes in vacuo. It yielded a dazzling white light, which was steady at the anode but flickered and jumped at the cathode: its intensity approximated to that of an ordinary carbon arclight. The heat given off by it was but slight so that the tube could be held in the hand; the temperature was highest at the cathode. Attempts were made to determine the resistance of the arc, but without result. It was found by the use of a telephone that the current is discontinuous. A spectroscopic investigation of the light revealed a lime-spectrum showing very
BOOKS and SERIALS RECEIVED.
Books. The Great World's Farm: S. Gaye (Seeley).-The Zoological Record, 1891 (Gurney and Jackson).-Castorologia, or the History and Traditions of the Canadian Beaver: H. T. Martin (Stanford) -Transac tions of the Royal Society of Edinburgh, vol. xxxvi. Parts 2 and 3 (Edinburgh)-Les Alpes Françaises: A. Falsan (Paris, Baillière) -Calendar of the University College of Wales, Aberystwith. 189-93 (Manchester, Cornish).-London Birds and other Sketches, revised edition: T. D. Pigott (Porter). Contents and Index of the First Twenty Volumes of the Memoirs of the Geological Survey of India. 1859-83: W. The bald (Calcutta).Memoirs of the Geological Survey of India; Index to the Genera and Species described in the Paleontologia Indica, up to the Year 1891: W. Theobald (Calcutta).-Star Atlas: Dr. H. J. Klein, translated. &c., by E McClure, new edition (S. P.C.K.).-City and Guilds of London Institute Programme of Technological Examinations, 1892-93 (London). -Appareils d'Essai à froid et à chaud des Moteurs à Vapeur: M. Dudebout (Paris, Gauthier-Villars).-Canon Torpilles et Cuirasse: A Croneau (Paris, Gauthier-Villars).-Ostwald's Klassiker der Exakten Wissenschaften, Nos. 31 37 (Leipzig, Engelmann).-Gesammelte Abhandlungen über PflanzenPhysiologie. Erster Band: J. Sachs (Leipzig, Engelmann).—On the American Iron Trade and its Progress during Sixteen Years: Sir L. Bell (Ballantyne). Universal Atlas, Part 20 (Cassell).
SERIALS. The Physical Society of London, Proceedings, vol. xi. Part 4 (Taylor and Francis).—Botanical Gazette, October (Bloomington, Indiana) -Traité Encyclopédique de Photographie, Premier Supplement A. quat. fasc.: C. Fabre (Paris, Gauthier-Villars).-Zeitschrift für Wissenschaftliche Zoologie, liv. Band, 4 Heft (Williams and Norgate).-Morphologisches Jahrbuch, xix. Band, i Heft (Williams and Norgate).
Letters to the Editor:
Nova Auriga.-H. F. Newall
On the Need of a New Geometrical Term-“Conju-
The Photography of an Image by Reflection.-Frede-
Induction and Deduction.-Edward T. Dixon
Bell's Idea of a New Anatomy of the Brain.-Jas. B.
Photographic Dry Plates.-Arthur E. Brown
GEOLOGICAL SOCIETY, at 8.-A Sketch of the Geology of the Iron, Gold, and Copper Districts of Michigan: Prof. M. E. Wadsworth.-The GoldQuartz Deposits of Pahang (Malay Peninsula): H. M. Becher.-The Pambula Gold Deposits: F. D. Power.
THURSDAY, NOVEMBER IC. MATHEMATICAL SOCIETY, at 8.-Presidential Address. -Some Properties of Homogeneous Isobaric Functions: E B. Elliott, F.R.S.-On Certain General Limitations affecting Hyper-magic Squares: S. Roberts, F.R.S.A Group of In-triangles of a given Triangle: R. Tucker.-Note on Secondary Tucker Circles: J. Griffiths.
INSTITUTION OF ELECTRICAL ENGINEERS, at 8.-The Problems of Commercial Electrolysis: James Swinburne
INSTITUTION OF CIVIL ENGINEERS.-Students' Visits to Tottenham and Forest Oate Railway. (Train from Liverpool Street at 9.58 a. m.)
FRIDAY, NOVEMBER 11.
PHYSICAL SOCIETY, at 5.- Continued Discussion of the Papers by Mr. Williams and Mr. Sutherland, Dimensions of Physical Quantities, and Molecular Forces.
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