July 26, 1894] 



NA rURE 



;ii 



crater, or to any wandering of the luminous area, a? is seen with 



a long, unsteady arc, but to the refraction of the light by heated 



vapour. All experiments, such as enclosing the arc in a smill 



chamber of transparent mica, or the use of magnets, or an air 



\ blast, have failed to produce any effect. A distortion of the 



' image of the crater while the patch revolves, has been looked 



for, but nothing distinguishable from changes of luminosity has 



been seen. 



' An unexpected difficulty is thus introduced in the use of the 



I arc as a standard of light, and one which may interfere with its 



use under some circumstances as a steady and continuous source 



of light. The author is further examining this phenomenon, 



with the view of ascertaining its nature, and of finding practical 



conditions under which it is absent or negligable. 



j "On the Viscosity of Water as determined by Mr. J. B. 

 Hannay, by means of his Microrheometer." By Robert E. 

 Bamett. 



In a paper entitled "On the Microrheometer," published in 

 the I'hil. Trans, for 1879, Mr. Hannay described an apparatus 

 ' which he devised for measuring the rate of flow of liquids 

 I through a capillary tube, and gave the times of flow of water 

 at various temperatures, and of certain aqueous salt-solutions 

 which he had observed by its means. The capillary was 21 mm. 

 ! long, and 00938 mm. in diameter ; the bulb had a capacity of 

 I 4'053 <^<^> '"'' 'he pressure employed was that of I metre of 

 water at 20". In order to compare the results with tnose of 

 other observers, the author has converted the measurements of 

 time of flow recorded by Mr. Hannay for water into viscosity- 

 coefficients by means of the formula : — 



_ vr^pt _ Vp 

 ^ ' ^8VT SirTt' 



The figures thus obtained are given in tabular form, and on 

 comparison with the results given by Poiseuille, Slotte, Sprung, 

 aud Thorpe and Rodger, are seen to yield discordant 

 I values for the viscosity of water. Not only is the value 

 I at 0° far below that of any known liquid, but it diminishes 

 so rapidly that at 6" and above it is a minus ijuantity. This 

 I paradiixical result is due to the fact that Mr. Hannay's experi- 

 mental figures are inconsistent. It is physically impossible to 

 i iss such a volume of water under the stated pressure through a 

 illary tube of the dimensions given, in the times recorded. At 

 for instance, the time of flow required under these condi- 

 uuns would be about 4600 seconds, instead of 131 '3 seconds, as 

 I stated. The author has attempted in several ways to account 

 fir the discrepancy, but without success. 



"On the Singular Solutions of Simultaneous Ordinary 

 ilerential Equations and the Theory of Congruencies." By 

 I rof. A. C. Dixon, 



Paris. 



Academy of Sciences, July 16. — M. Lcewy in the chair. — 

 New researches on chromium, by M. Henri Moissan. Chro- 

 mium has been prepared in large quantity by means of the 

 electric furnace. Pure chromium has the density 692 at 20° C. 

 It is more infusible than platinum, and has, apparently, no action 

 on a magnetic needle. It is practically unacted on in moist air, 

 but burns at 2000' C. in oxygen. It readily combines with 

 silicon and carbon, to form very hard compounds ; the sdicide 

 scratches the ruby. The pure metal is not nearly so hard, and 

 readily takes a fine polish. It is hardly attacked by acids, 

 resisting aqua regia, and is not acted on by fused potash, though 

 oxidised by fused potassium nitrate or chlorate. — On the two 

 ourang outangs which have recently died at Paris, by M. A. 

 Milne- Edwards. — On the mechanism of the murmurings caused 

 by the passage of air in tubes ; determination of the moment 

 when a soundless flow, transformed instantaneously into a 

 murmuring flow, becomes sonorous in the different points of the 

 tube, by M. A. Chauveau. — On the necessity for ostriches, and 

 most birds, to swallow hard bodies which remain in the pyloric 

 region of the stomach, and which play the part, as regards foods, 

 ol masticatory organs, by M. C. Sappey. — On dimcthylamido- 

 benzoylben/.aic acid, diethylamidobenziylbenzoic ai;id, and 

 dimelhylanilinephthalein, by .M.\I. A. Haller and A. Guyot. — 

 Note on some biological variations of Pncumohactilus liqiu- 

 faciens Ivjis, the miciobe of contagious peripneumonia of caitle, 

 by M. S. Arloing. The author descrioes a non-liquefying 



NO. I 291, VOL. 50] 



variety of this microbe, and shows that it is not an independent 

 species. — Studies on central actions : general laws relative to the 

 effect of media, by M. F. P. Le Roux. — On interferences due to 

 mean difference of path, by M. Georges Meslin. — Direct auto- 

 graphic record of the form of periodic currents by means of the 

 electrochemical method, by M. P. Janet. A battery of fifteen 

 steel styles, connected with fifteen points of the circuit taken, 

 so that the difference of potential between consecutive points 

 was about four volts, gave traces on prepared paper which 

 indicated the characteristics of the discharge through the cir- 

 cuit. — Coefficient of self-induction of n equal and equidistant 

 parallel threads of which the sections are distributed on a 

 circumference, by M. Ch. Eug. Guye. The coefficients cal- 

 culated for two selected definite systems by means of a formula 

 quoted agree with the experimental values within about one 

 per cent. — On the equation of discharges, by M. R. Swynge- 

 dauw. — Separation and estimation of tin and antimony in an 

 alloy, by >I. Mengin. The oxides are obtained as usual by 

 means of nitric acid acting on the alloy of tin and antimony, 

 and the metal antimony is reduced therefrom by means of a 

 plate of pure tin and hydrochloric acid, and weighed separately. 

 — On rotatory powers variable with the temperature ; a reply 

 to M. Colson, by M. A. Le Bel. —Synthesis of mesoxalic acid 

 and bismuth mesoxalate, by M. H. Causse. The acid has been 

 obtained by oxidation of glycerine by means of nitric acid in 

 presence of bismuth nitrate. Insoluble bismuth mesoxalate is 

 formed and, by virtue of its insolul)ility, the mesoxalic acid is 

 removed from the field of action and escapes further oxidation. — 

 Contribution to the study of some amidoacids obtained by the 

 condensation of vegetable proteid substances, by M. E. Fleurent. 

 On some derivatives of the propylamines, by M. F. Chancel. 

 The preparation and properties are described of the compounds 

 (i) propylpropylideneamine, (2) monopropylacetamide, (3) 

 dipropylacetamide, and (4) tetrapropylurea. — On some points 

 in the anatomy of the ourang-outang, by MM. J. Deniker and 

 R. Boulart. — On the male genital apparatus of the ourang- 

 outang (Simla satyrus, L ), by M. E. de Pousargues. — On the 

 osteology of the ourang-outang, by M. P. Delisle. — Researches 

 on the excitability of rigid muscles and on the causes of the dis- 

 appearance of cadaveric rigidity, by M. J. Tissot. The author 

 shows that the relaxation ot the cadaveric rigidity of muscles is 

 not due to putrefaction, which only sets in after the rigidity dis- 

 appears. — Physiological mechanism of egg-laying among 

 Oithopterous insects of the family of the Acridii. The rolt of 

 the air as a mechanical agent, and multiple functions of the 

 genital apparatus, by -M. J. Kunckel d'Herculais. — Conditions 

 of the development of /iotigeol (Exobasidiurn vilis) on the 

 leaves of the vine, by M. Albert Renault.— On a parasite of the 

 vine, Aureobasidium vilis, by MM. P. Viala and G. Boyer. — 

 On the carved ivories from the Quaternary station of Brassempouy 

 (Landes), by M.M. Ed. Piette and J. de Laporterie. .\n account 

 of five statuettes or parts of statuettes of human figures, found 

 among cinders and numerous bones of the rhinoceros, mammoth, 

 aurochs, horse, and hyjena. — On the Constantinople earthquake. 

 An extract from a letter from M. Moureaux to M. Mascart. 



AMSTERD.4M. 



Royal Academy of Sciences, June 30. — Prof, van der 

 Waals in the chair. — Prof. Behrens, Delft, gave some particu- 

 lars concerning the detection of alkaloids by microchemical 

 methods. A good method must give slides, showing the alka- 

 loids pure or well crystallised combinations, from which the 

 pure alkaloid can be set free by simple and trustworthy reactions. 

 Such >lides can be kept any time a., .locuments for comparing 

 with standard slides arui further experiments, while the colour- 

 tests incurrent use generally destroy the alkaloid. Volatile alka- 

 loids are the most easy to isolate. Thus, from 0'3 mgr. of tea, and 

 from I mgr. of coffee, by extraction with limewaterand with alco- 

 hol, and subsequent sublimation, characteristic needles of theine 

 were obtained without any difficulty. Cocoa must be extr.acted 

 with weak acetic acid. After purifying with acetate of lead and 

 concentrating, the liquid is dried with an excess of sodium car- 

 bonate, and sublimed at 300" C. Powdery theobromine is 

 obtained, giving characteristic prisms with silver nitrate, and, 

 later on, needles, resembling theine, more volatile than theo- 

 bromine and more soluble in water. Their angle of extinction is 

 0°, and their chloromercurate is easily soluble. For theine, angle 

 of extinction 45°, chloromercurate thrown down as long needles. 



