January 5, 191 1] 



NATURE 



327 



exile, and consequent lack of stimulus, is almost inevit- 

 able. Important as are our publications, it is even more 

 through our monthly meetings and the promotion of 

 personal intercourse that the society can help in its 

 m-imary duty of the advancement of natural knowledge in 

 South Africa. 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE. 



The discussions at a conference of teachers in rural 

 schools, held in London «n December 28, 19 10, under the 

 auspices of the National Union of Teachers, showed that 

 teachers are recognising more fully the desirability of 

 making the education in elementary schools in countn. 

 districts so far as possible of a practical kind, which will 

 train the children for agricultural and other country 

 avocations in later life. A resolution was adopted 

 unanimously urging that, wherever possible, some teach- 

 ing in handicraft and housecraft should be given to 

 children in rural schools, and that, where necessary and 

 practicable, centres for instruction in these subjects should 

 be formed. It was suggested during the discussion that 

 central school farms might be established, where practical 

 work on the land could be carried on by boys drafted 

 from neighbouring schools. It was recognised, also, that 

 actual work in a garden abounds in opportunities for the 

 best lessons in observation, attention to detail, never 

 putting off until to-morrow what ought to be done to-day, 

 as well as the cultivation of the virtues more commonly 

 associated with the moral instruction lesson. Another 

 resolution, unanimously carried, deplored the continuance 

 of the partial exemption system, and declared that the 

 time has arrived when no child shall be either partially 

 or totally exempt from attendance at school before four- 

 teen years of age. .'\ discussion on continuation schools 

 in rural districts revealed some diversity of opinion, but 

 the meeting eventually decided that, having regard to the 

 impossibility of satisfactorily organising and coordinating 

 continuation work in rural districts, where children are 

 at present allowed to secure partial exemption from school 

 attendance at the early age of eleven or twelve for the 

 purpose of employment, no exemption, either partial or 

 whole-time, from day-school attendance should be granted 

 until the age of fourteen years is attained, all wage- 

 earning child labour out of school hours under the age 

 of fourteen should be forbidden by law, and these con- 

 ditions having been secured, a system of compulsory 

 attendance at continuation schools or other suitable educa- 

 tional institutions from the age of fourteen to eighteen, 

 accompanied by provisions which should safeguard young 

 people against undue physical or mental overstrain, should 

 be an integral part of a national sj-stem of education. 



SOCIETIES AND ACADEMIES. 

 Dublin. 

 Royal Dublin Society, December 20, 1910. — Mr. R. 

 Lloyd Praeger in the chair. — Dr. J. H. Pollok : The 



vacuum-tube spectra of the vapours of some metals and 

 metallic chlorides (part i.). By the use of a new form of 

 vacuum tube, made entirely of quartz, which the author 

 has recently devised, he can readily obtain photographs of 

 the whole of the vacuum-tube spectra of the vapours of 

 metals and metallic chlorides. In the present paper the 

 author gives a description of the quartz vacuum tube and 

 photographs of the spectra of the vapours of mercury, 

 nc, cadmium, arsenic, and antimony, tc^ether with 

 otographs of the spectra of their chlorides, under vary- 

 ing conditions. The vapours of the metals and their com- 

 pounds, so far examined, show substantially the same line 

 spectrum in the vacuum tube that they do when metallic 

 electrodes are sparked in air. When a condenser is intro- 

 duced in the circuit, the metal and its compound show 

 precisely the same change of spectrum, which would seem 

 to indicate that the changes take place in the vibratin;^ 

 atom. If a large amount of vapour of the chloride is 

 jwesent without a condenser, bands are seen in addition 

 to the line spectrum of the metal, and these appear to be 

 due to the particular compound present, and must there- 

 fore be connected with the vibrations of the molecule. 



NO. 2149, VOL. 85] 



— Dr. G, H. Pethybridgre : Considerations and experi- 

 ments on the infection of potato plants with the blight- 

 fungus (Phytophthora infestans) by means of mycelium 

 derived direct from the planted tubers. The theory recently 

 advocated by Massee, that the potato crop becomes 

 attacked with the " blight," not by means of the " spores " 

 of P. infestans, but by means of the mycelium of this 

 fungus, which, after lying dormant for a long period, 

 passes from the planted tubers into the nearly full-grown 

 stalks, is criticised, and it is pointed out how difficult it 

 is to reconcile this mode of infection with the well-known 

 facts of the disease. It is shown that, owing to the 

 absence of controls, the experimental evidence on which 

 the theory is based is quite worthless. -'\ repetition of the 

 experiments, carried out by the author with the necessary 

 controls, gave results exactly the opposite to those on 

 which the theory is based. — Rev. H. C. Browne : Some 

 suggested improvement in epicyclic variable gears. The 

 improvement applies specially to the modern bicycle, and 

 consists in effecting the complete separation of the epicyclic 

 train from all the moving parts on the middle speed, so 

 that the friction is reduced to the same amount as if the 

 machine were a single-geared machine, i.e. so that there 

 is no movement except that of the ball races at each end 

 of the axle. The high and low speeds are also improved 

 by getting rid of all friction due to over-running pawls or 

 the unnecessary rubbing of parts. The middle speed is 

 produced directly by the engagement of the driving member 

 with the hub, the epicyclic train being completely detached 

 and in no contact with any of the moving parts. The 

 linking up of the gear train with the drive for the high 

 and low speeds is effected in a simple manner by the use 

 of spring trigger pawls. Some care has been given to the 

 construction of the epicyclic train so that it may be a 

 proper mechanical unit in itself instead of being a some- 

 what loose assemblage of wheels. With this object, the 

 wheels of the train are provided with friction discs reach- 

 ing to the pitch lines, and the friction between the elements 

 of the train is thereby reduced to rolling friction. 



Paris. 

 Academy of Sciences, December 27, 1910. — M. !^mile 

 Picard in the chair. — A. Gaillot : The analytical theory 

 and tables of motion of Jupiter, by Le Verrier. Additions 

 and rectifications. These tables represent with sufficient 

 exactitude the observations made between 1750 and 1869. 

 From 1870, the comparison of the observed and calculated 

 positions shows increasing discrepancies. The tables for 

 Jupiter have now been recalculated, and the results com- 

 pared with observations for the period 1750 to 1906-7. — 

 Paul Sabatier : A method for causing two substances to 

 react in the electric arc. The method described by M. 

 Salmon in a recent note (December 5) was anticipated 

 by the author in 1899. — W. Kilian and M. Gig:noux : 

 .An attempt to coordinate the levels of the pebble beds and 

 terraces of the Bas-Dauphin6. — The perpetual secretary 

 announced the death of Armand Sabatier, correspondant 

 for the section of anatomy and zoolt^)-. — ^J. Guillaume : 

 Observations of the sun made at the Observaton.- of Lyons 

 during the third quarter of 19 10. Observations were 

 possible on sixty-four days during the quarter. Three 

 tables of the results are given, showing number of spots, 

 their distribution in latitude, and the distribution of the 

 faculae in latitude. — Maurice Servant : The transforma- 

 tions of surfaces applicable to surfaces of the second 

 degree. — T. Lalesco : Left-handed symmetrical nuclei. — 

 G. Ko«<ralew8ki : The formulae of Frenet in functional 

 space. — L. Zoretti : The equations of motion of a viscous 

 fluid. — G. de Proszynski : The application of the gyro- 

 scope and of compressed air to taking kinematographic 

 views. The gyroscope is driven by compressed air, and 

 is attached to the camera in such a manner as to suppress 

 or deaden small vibrations. — Jean Becquerel : The 

 positive magneto-optic effect presented by the phosphor- 

 escence bands of rubies and emeralds, and the relations 

 between emission and absorption in a magnetic field. — 

 J. Thovert : Photometry and the utilisation of coloured 

 sources of light. A description of a new empirical spectro- 

 photometric method. — Daniel Berthelot and Henry 

 Gaudechon : The principal tvpes of photolysis of organic 

 compounds by the ultra-violet rays. The photolvsis of 



