214 



NATURE 



[May 4, 191 6 



tific teaching. Personally, Mr. Crook thinks, there 

 should be a practical room in every school, and that 

 the elements of the physical sciences should be learnt 

 from experiments performed by the children them- 

 selves. VVe must, however, he continued, take care 

 that practical science does not become too dominant 

 in our primary schools. What is needed is the scien- 

 tific spirit, which should, and must, direct the teaching 

 of all subjects, not omitting the essentials of formal 

 English, so that our children may proceed to sound 

 judgments by accurate reasoning upon clearly viewed 

 facts. The difficulty will be to determine exactly 

 which sciences shall be attempted. Much of the so- 

 called nature-study now attempted gets no further 

 scientifically than the stage of classification, and is 

 rather destructive of nature than instructive in scien- 

 tific principles. To secure this extension or addition 

 of scientific teaching the requisite time can be found 

 in two ways : first, by the scrapping of some of the 

 subjects or parts of the subjects now taught, and 

 secondly, by the extension of the school age to fifteen. 

 On the former of these two, it must be obvious to 

 all that it is now more than ever necessary that our 

 antiquated system of weights and measures should 

 go, and that some simplification of our spelling and 

 handwriting should, at least, be considered. The 

 number of rules still taught in arithmetic could easily 

 and with advantage be curtailed, and long and useless 

 mechanical problems should be omitted. 



SOCIETIES AND ACADEMIES. 

 London. 

 Physical Society, March 24. — Prof. C. Vernon Boys, 

 president, in the chair. — D. Owen : The laws of varia- 

 tion of resistance with voltage at a rectifying contact 

 of two solid conductors, with application to the electric 

 wave detector. The paper contains an account of an 

 investigation the primary object of which was to 

 determine the nature of the physical actions occurring 

 at a rectifying contact. Resistance characteristics are 

 given for various contacts, some including a mineral, 

 some in which both elements are metals. It is shown 

 that a specific characteristic may be drawn for any 

 given pair of materials. The experimental results are 

 in accordance with the view that the actions are 

 thermo-electric, the main determining factors being 

 the thermo-electric power and the temperature- 

 coefficient of electric resistance. Based on the law of 

 constancy of the voltage-coefficient, calculations are 

 given showing the best value of the resistance of the 

 telephone in a wireless receiving circuit in which the 

 contact detector is employed. The influence of a 

 polarising voltage is also traced. The use of the com- 

 bination of rectifier with a direct-current galvanometer 

 as indicator of the balance point in an alternating- 

 current bridge is examined, and it is shown that the 

 minimum detectable alternating voltage cannot be re- 

 duced much below a millivolt.— Dr. T. Barratt : The 

 electrical capacity of gold-leaf electroscopes. A gold- 

 leaf electroscope is frequently used to compare exceed- 

 ingly small ionisation currents. For this purpose it is 

 much more sensitive than a quadrant electrometer. 

 If the capacity of the electroscope is known, then the 

 absolute value in amperes of the ionisation current can 

 be deduced. A method is described for measuring the 

 capacity of a gold-leaf electroscope, the method depend- 

 ing on sharing the charge of a parallel plate air con- 

 denser of measurable capacity as many times as neces- 

 sary, and deducing the capacity of the electroscope from 

 the observed drop of potential. The method gives 

 consistent results when the experimental conditions are 

 widely varied. The amount of deflection of the leaf 

 appears to have little influence on the result. 



NO. 2427, VOL. 97] 



Zoological Society, April 18. — Dr. S. F. Harmer, vice- 

 president, in the chair.— Major H, M. Evans : The 

 poison organ of the sting-ray {Trygon pastinaca). It 

 has been observed for centuries that the wounds pro- 

 duced by the serrated spine growing from the base 

 of the whip-like tail of the sting-ray produced very 

 severe injuries and pain and inflammation, which 

 could not be accounted for by the laceration of the 

 wounds alone. Dr. Antonio Porta in 1905 described 

 a gland in the groove lying medially to the rows of 

 teeth on either side, which he stated is similar to the 

 gland found in Scorpaena. Major Evans's researches 

 do not confirm Porta's description In all particulars. 

 The examination of a series of sections shows a gland 

 of a different type from that, found in the weevers, 

 Scorpaena, etc. The points emphasised are : — (I) The 

 origin of the gland from a special epithelial structure 

 at the base of the spine ; (li) the arrangement of folli- 

 cles discharging their secretion by ducts or canals, 

 communicating with the exterior by means of nipples 

 or filaments; (iil) the arrangement of these nipples at 

 the base of the teeth ; (Iv) the presence of muscular 

 fibres surrounding the main canals, which are instru- 

 mental In discharging the venom. — R. I. Pocock : The 

 external characters of the mongooses (Mungotldae). 

 The paper dealt principally with the ears, feet, and 

 anal sac. Reasons were given for restoring the 

 generic names Arlela for Crossarchus fasciatus and 

 Atllax for Mungos paludinosus. It was also shown 

 that the mongooses differ from other VIverrldae in the 

 structure of the ears, and that the type of ear in 

 Suricata Is different from that of all other genera of 

 the family. 



Paris. 

 Academy of Sciences, April 17. — M. Camille Jordan In 

 the chair. — The president announced the death of M. 

 Jules Gosselet, non-resident member, and M. A. 

 Lacroix gave an account of his life work. — G. 

 Lemoine : The catalysis of hydrogen peroxide In a 

 heterogeneous medium. First part : general considera- 

 tions, experiments with mercury. The catalysis of 

 hydrogen peroxide is a surface phenomenon, since it 

 process with rapidity in contact with a layer of silver 

 only 00002 mm. thick. A repetition of Bredig's ex- 

 periments with strong solutions of the peroxide showed 

 that a red oxide of mercury is temporarily formed. 

 Yellow mercuric oxide and hydrogen peroxide react 

 with violence, giving mercury and water with an 

 Intermediate production of the suboxide of mercury. — 

 A. Blondel : The llrruting perception of light signals 

 produced by rotating beams of small divergence, and 

 an apparatus for the comparison of the brilliancy of 

 light of short duration giving the same quantity of 

 light In different times. — M. Yersin was elected a 

 correspondant for the section of medicine and surgery 

 in succession to the late Ernst von Leydn. — H. 

 Arctowski : The Influence of the earth on the frequency 

 and the mean heliographic latitude of sun-spots. 

 References are given to earlier work on this subject, 

 and the problem reconsidered on the basis of the data 

 of A. Wolfer for the years 1852 to 1913, and of the 

 Greenwich observations. The diagram from the aver- 

 ages Illustrates the annual variation of the mean lati- 

 tude of the spots, and shows that the amnlltude 

 of this variation amounts to at least 4°. — M. _de 

 Broglie : The highly penetrating radiations belonging 

 to the K series of tungsten and the spectra of the 

 X-rays of the heavv metals. The tuni?sten anti- 

 kathode spectrum of tungsten In the Coolldge tube, 

 j using a rotating crystal of sodium chloride, contains 

 ! a eroup with wave-lengths 2.032-10-' cm. and 

 I 1.76810-' cm. These radiations are the most pene- 

 j trating yet discovered as emitted by X-ray bulbs.— -V. 

 Dauzire': The formation of a cellular network during 



