262 



NA TURE 



[January 16, 1896 



At the annual meeting of the Incorporated Association of 

 Headmasters of Secondary Schools, held on January 8, two 

 resolutions were passed with regard to science teaching, which 

 it is to be hoped may bear fruit in the form of an improved 

 method in many of our schools. At the previous annual meeting 

 a discussion had taken place on the subject ; and as a result of 

 this a memorial was sent, in July of last year, to the authorities 

 controlling the Local examinations of Oxford and Cambridge 

 Universities, setting forth the desire that " examining bodies 

 should encourage a more rational method of teaching science " by 

 framing the syllabuses on different lines. A committee was also 

 appointed to consider the subject, and this committee, consisting 

 of men possessed of considerable experience in science teaching 

 in secondary schools, has now presented its report. They 

 agree with all scientific educationists in saying that a large 

 proportion of the time given to science in schools should be 

 occupied by the pupils in performing actual measurements 

 themselves, and that the object should be to impart not only 

 information but chiefly the knowledge of method, and with this 

 object in view, that the instruction should be given in strictly 

 logical order. To serve as a basis of discussion with the 

 University authorities, the committee has put forth an admirable 

 syllabus, which includes the more fundamental portions of physics 

 and chemistry, and (an important point) which indicates what 

 experiments can easily be performed by beginners. The 

 syllabus represents a practical scheme of elementary science 

 which will be appreciated by teachers, and which cannot be too 

 widely adopted. It indicates the manner in which the study of 

 science in schools may be made of true educational value, and in 

 the interests of science it is to be hoped that examining bodies 

 will give it full consideration. Examinations at present 

 dominate our educational system, and it is almost hopeless to 

 attempt to introduce into schools a scheme of instruction 

 that does follow the lines laid down by examiners. But if 

 a syllabus is rational, the teaching which follows it will possess 

 good features. If, therefore, the logical syllabus drawn up by 

 the Committee of the Headmasters' Association be adopted by 

 the Delegacy for Local examinations of Oxford and Cambridge, 

 an important step will have been taken in the advance of 

 scientific education in this country. 



SCIENTIFIC SERIALS. 



Ajnerican Journal of Science, December 1895. — How to 

 find the key-note of auditoriums, by E. Cutter. If a speaker 

 uses the key-note of his auditorium, the audience shows by 

 attitude and attention that it hears what is said. The speaker 

 speaks with ease, and feels his voice impinge upon the farthest 

 walls. The key-note may be found by means of a siren, or by 

 singing, and observing which note resounds most powerfully. 

 The paper contains practical hints of some value to public 

 speakers, but is unscientific in tone and substance. — Stratigraphy 

 of the Kansas coal-measures, by Erasmus Haworth. The 

 different formations lie one above the other in regular order, 

 similar to the order found in other parts of the world. The 

 general character of the shales throughout the whole of the coal- 

 measures is such that they must have been deposited, in the 

 main, in shallow water, probably ocean-water, as evidenced by 

 the frequency of ripple-marks and other physical properties. 

 The coastal area must have progressed westward as geological 

 time advanced. The thickness of the Kansas coal-measures 

 cannot be much less than 2500 feet. — Igneous rocks of Yogo 

 Peak, Montana, by W. H. Weed and L. V. Pirsson. Yogo 

 Peak is composed of a core or stock of massive, granular, 

 igneous rock, composed chiefly of augite and orthoclase. The 

 mass shows a progressive differentiation along its east and west 

 axis, with a continual increase in the ferromagnesian elements 

 over the felspathic ones. — A new alkali mineral, by Warren M. 

 Foote. This mineral, named Northupite, after its discoverer, 

 crystallises in regular octahedra, whose diameters rarely reach 

 I centimetre. It is brittle, shows uneven fracture, and a hard- 

 ness of 3-5 to 4. In powdering the mineral a foetid odour is 

 distinctly perceptible. It is easily fusible before the blowpipe, 

 and its analysis indicates it to be a double chloride and carbonate 

 of .sodium and magnesium, with traces of phosphoric acid, 

 silica, iron, calcium, and organic matter. It was found in the 

 neighbourhood of the Borax Lake, California. — On the affinities 

 and classification of the Dinosaurian reptiles, by O. C. Marsh. 

 Twelve restorations of Dinosaurs are given, and a relation is 

 traced between them and the Crocodilians, 



Wiedemann's Annalen der Physik und Chetnie, No. 12. — 

 On the origin of frictional electricity, by C. Christiansen, 

 Differences of potential created by contact between two metals 

 were investigated by means of "drop electrodes," one terminal 

 of the electrometer being connected with the upper reservoir ot 

 mercury, and the other with the lower, in which plates of a 

 different metal were immersed. The gas through which the 

 drops fall is of considerable influence. Platinum becomes more 

 positive in hydrogen, and more negative in oxygen. Other 

 metals become more negative in hydrogen. ^Dielectric constants 

 of mixtures and solutions, by Ludwig Silberstein. Given two 

 perfect insulators, like benzol and phenylethylacetate, which 

 mix in all proportions and do not contract in the process, the 

 specific inductive capacity of the mixture may be found by 

 taking the sum of the products of the two separate volumes into 

 their specific inductive capacities and dividing by the total 

 volume. This proposition was experimentally proved by 

 Nernst's method, with induction coil and telephone. — On the 

 passage of electricity through gases, by A. Paalzon and F. 

 Neesen. This is the continuation of a highly-interesting paper 

 on various obscure phenomena connected with discharge tubes. 

 The medium in which the discharge tubes were immersed had a 

 decided influence upon them. Immersion in water or alcohol 

 extinguished the glow. This was not due to condensation, 

 since the total current was diminished, and extinction took some 

 time to set in. Electrification of the outer surface of the tube, 

 or discharge of it by a*flame or other means, or the approach of 

 a charged piece of sealing-wax — in short, any motion of 

 electricity in the neighbourhood, favoured the internal discharge. 

 — Movable light phenomena in rarefied gases, caused by electric 

 oscillations, by J. Ebster and H. Geitel. In a discharge tube 

 surrounded by a conducting ring put to earth, and touching 

 another conductor connected with a strong induction coil, a 

 pencil of bluish light is formed at a vacuum of o"oi to O'ooi mm. 

 of mercury, ending in an intense green phosphorescent patch 

 next the conductor, tapering as it passes through the ring, and 

 ending somewhere in the gas space. The approach of a 

 conductor or a magnet makes the pencil assume various shapes 

 and positions. 



SOCIETIES AND ACADEMIES. 



London. 



Royal Society, November 21, 1895. — "On the Variable 

 Stars of the S Cephei Class." By J. Norman Lockyer, C.B.,. 

 F.R.S. 



Prof. E. C. Pickering, in his classification of the variable 

 stars, which is based on a study of the light curves (Amer. 

 Acad. Proc, vol. xvi. p. 17), recognises two classes of variables 

 having short periods. His Class IV. includes those variables, 

 exemplified by 5 Cephei and /S Lyras, in which the light changes 

 are not of very great range, and continue throughout the period. 

 Class V. comprises those like Algol in which there is a temporary 

 reduction of light at minimum, produced by the eclipse ot 

 the bright star by a relatively dark companion ; this explanation 

 has since been established by spectroscopic investigations, which 

 have shown that there is no change in the spectrum at minimum, 

 and that there is an orbital movement of corresponding period. 



Excluding /8 Lyr^, which, as shown in the paper, is spectro- 

 scopically different from the others so far examined, it will be 

 convenient to refer to the remaining variables of Pickering's 

 Class IV. as those of the 5 Cephei class, and it is with some of 

 these that the present paper is concerned. 



The available spectroscopic data with regard to the 5 Cephei 

 class were very meagre, and I therefore determined to investi- 

 gate the spectra photographically, so far as the means at my 

 disposal would permit. Five stars were studied, namely^ 

 T) Aquilis, C Geminorum, 5 Cephei, T Vulpeculte, and S Sagittse. 



Five very definite results have been arrived at :— 



( 1 ) The spectra of the five variables of this class which have 

 been photographed are practically identical. 



(2) The five variables in question are stars of increasing 

 temperature. 



(3) There is a general weakening of the continuous spectrum, 

 as the light of the star decreases. 



(4) There are no indications of bright-line radiation at the 

 positions occupied by the lines of hydrogen or helium at any 

 part of the period in the case of these variables. 



(5) There is no visible doubUng of the lines in any of the 

 photographs. 



NO. 1368, VOL. 53] 



