2o6 



NATURE 



[December 28, 1893 



with the star-chart. Your thesis, which you have prepared 

 according to our course of higher mathematics, with an 

 assiduity that we could not ignore, is the first that a lady has 

 presented and successfully sustained before our Faculty to obtain 

 the degree of Doctor of Mathematical Sciences. You have 

 worked in a deserving manner, and the Faculty has unani- 

 mously decided to declare you worthy of the grade of Doctor." 



M. Marey has accepted the Presidency of the French Photo- 

 graphic Society, in sijccession to Dr. Janssen, who has retired 

 after completing his full term of office— three years. 



The British Medical Journal says that a branch of the 

 Pasteur Institute will be established atAlgiers next year. 



The death is announced of Dr. E. Lellmann, Professor of 

 Chemistry at Giessen University. 



We regret to announce that Prof. A. Sprenger, the celebrated 

 orientalist, died on December 19, at the age of seventy-five. 



Mr. W. L. H. Duckworth has been elected to a N atural 

 Science Fellowship at Jesus College, Cambridge. The new 

 Fellow took a First Class in both parts of the Natural Science 

 Tripos (1892-93), attaining distinction in Human Anatomy and 

 Anthropology, and has published several papers on points con- 

 nected with these sciences. His election is creditable both to 

 his College and to the rising School of Anthropology which 

 Prof, Macalister has founded in Cambridge. 



The University Correspondent says that the late Mr. 

 Alexander Low Bruce, son-in-law of Dr. Livingstone, the ex- 

 plorer, has left ;^3,ooo for the purpose of founding a Chair of 

 Public Health in the University of Edinburgh. 



The Franklin InUitnte has awarded the following John 

 Scott Legacy Medals and Premiums : — Mr. J. B. Edson, for his 

 invention of a pressure-recording gauge ; Mr. N. W. Perry, 

 for his system of series electric traction for railways ; Mr. J. T. 

 Wilkin, for a method and apparatus for generating cycloidal sur- 

 faces ; Mr. W. F. C. Morsell, for an application of polarised 

 light to the systematic study of colour and crystal patterns for 

 design, and Mr. F. Shuman, for his machine and process for 

 embedding wire-netting in glass. 



The report of the Meteorological Council for the year ending 

 March 31, 1893, which has recently been issued, contains an 

 account of the progress in the various discussions in hand. In 

 the branch of ocean meteorology, much valuable information 

 has been added to the current charts for the Atlantic, Pacific, 

 and Indian oceans, from the log-books of H.M. ships, and from 

 data furnished by Foreign Governments. The latter observa- 

 tions are mostly for the Pacific Ocean, where they are compara- 

 tively scarce. For another investigation, the district between 

 the Cape of Good Hope and New Zealand, all available data 

 have been dealt with in the construction of monthly charts of 

 the various elements, and the council have decided thai the 

 next district to be discussed shall be the South Atlantic. The 

 work in the branch of weather telegraphy and forecasts con- 

 tinues to increase ; comparisons of the results of forecasts 

 issued during the hay harvest season, and of those regularly 

 issued at night for the morning newspapers, show respectively 

 a success of 88 and 79 per cent., taking an average of all 

 districts, but for some localities the success was considerably 

 higher. The work included under the climatology of the 

 British Isles is steadily continued, and among the various 

 investigations may be mentioned a discussion of the results of 

 the harmonic analysis of the daily curves for temperature at 

 the observatories, which has been laid before the Royal Society 

 by General R. Strachey, chairman of the council, and of which 

 an abstract is given in the report. Among the miscellaneous 



NO. 1261, VOL. 49] 



subjects we notice a description of a proposed new form of 

 pressure gauge, which is the outcome of the investigations on 

 wind measurements that have been carried out by Mr. W. H. 

 Dines ;*and, also, that the council have commenced the regular 

 tabulation of the hourly values of sunshine for seven observa- 

 tories, since the year 188 1. The results of an inquiry into fog 

 observations, by Mr. Scott, for the years 1875-90, have been 

 published by the Royal Meteorological Society. 



At the meeting of the French Meterological Society on 

 December 5, M. Angot stated that while investigating the 

 diurnal range of the amount o f cloud at Paris, and represent- 

 ing it by a harmonic series, he had found that the semi-diurna 

 period showed a range absolutely opposite to that of the 

 diurnal variation of the barometer, so that the miximum of 

 the semi-diurnal period in the amount of cloud corresponded 

 to the minimum of pressure, and vice versa. W e agree with 

 I\L Angot that it would be interesting to find whether the 

 same relation holds for other places, in v/hich case a proof 

 would be given of the influence of the diurnal variation of the 

 barometer upon the amount of cloud. 



A DIFFERENTIAL method of determining the refractive index 

 of solutions to which the interferential refractometer is not 

 adapted, is described by W, Hallwachs in the current number 

 of Wiedeinann''s Annalen. The former instrument is only ap- 

 plicable to measurements of differences of refractive power 

 between very dilute solutions and their solvents. For higher 

 concentrations the prism method has been generally used. But 

 between these degrees of concentration and the former there 

 lies a long series of solutions to which neither method is well 

 suited. For these, Mr. Hallwachs has adopted the following 

 arrangement. A beam of sodium light falls upon a plane- 

 parallel plate of glass at an incidence of nearly a right angle, 

 and is refracted into the glass and out on the other side, thus 

 only skimming the surface on one side. The glass plate divides 

 the solution from the solvent, and stands at right angles to another 

 vertical plane- parallel plate, the two forming a combination 

 in the form of a T. The beam traverses the solution and the 

 second plate, and emergence at an angle with the first plate, 

 which is read by a scale and micrometer. For differences of 

 refractive index of o'ooi, 0*005, '^nd oT the angles were in one 

 case 6°, 13°, and 63° respectively, where with a prism of 60° 

 they would only have been 0-15°, o"8°, and 16°, In practice, 

 the beam was first sent from the medium into the solution, and 

 then from the solution into the medium, thus eliminating any 

 errors in the position of the plates. The difference of refractive 

 index was equal to the square of the sine of the angle of emer- 

 gence divided by the sum of the two refractive indices. It was 

 found that the molecular refractive index of the substance is 

 decidedly affected by changes in concentration, accompanied by 

 changes of molecular volume, while the specific refractive power 

 of the substances is, curiously enough, very little disturbed. 

 It appears that the effects of dissociation chiefly influence the 

 density. 



For some weeks there have been appearing in the Electrician 

 accounts of devices for compensating the effects of hys- 

 teresis of the iron which is used in measuring instruments. The 

 current number of that journal contains a short account, by 

 Messrs. Field and Walker, of some experiments they have made, 

 at Prof. Perry's suggestion, with this object in view. The 

 principle of the method employed is to place a piece of hard 

 magnet steel as a shunt between the poles of the electromagnet 

 used in the instrument. When the magnetised current is pass- 

 ing, some of the lines of force pass through this shunt. When 

 the current is broken, the lines of force in the air gap, due to the 

 residual magnetism in the electromagnet and in the hard steel, 

 will be in opposite directions, and by suitably proportioning the 



