August 13, 1908J 



NA rURE 



i59 



ment of Science, at the meeting held last week at Clermont 

 Ferrand. From a summary given by the Paris corre- 

 spondent of the Times, we learn that Prof. Appell defines 

 the man of science, not as "the man who knows," but 

 as a man who " combines with his knowledge scientific 

 activity, that is to say, a curiosity always alert, indefatig- 

 able patience, and,' above all, initiative and again 

 initiative." French instruction, he pointed out, was not 

 generally calculated to develop the latter. The examina- 

 tion system was a trial of memory, not of real knowledge, 

 observation, and experience. The evil extends from the 

 primary schools to the upper special schools, and nothing 

 is more necessarv than to begin to oppose this tendency. 

 Prof. .Appell's solution would be to utilise universities for 

 scientific education and to substitute for the technical 

 schools, which are now virtually closed to many tempera- 

 ments that might develop scientific capacities — even a 

 Claude Bernard failed to pass his examination for the 

 medical faculty — open schools in which the selection would 

 lake place from among the pupils according to the results 

 of their work for the entire year. He would substitute for 

 the two or three years now passed in the Lyc^e to prepare 

 for the entrance into the upper special schools a course of 

 scientific training immerlintelv after the close of secondai y 

 studies. Prof, .^ppell developed an elaborate system of 

 re-organisation of the universities involving a complete 

 change in the curriculum of the Sorbonne and in the 

 administration of the Museum of Natural History. He 

 would not, however, in any way- alter the character of the 

 College de France. 



The Board of Education has issued (Cd. 4184) regula- 

 tions for the training of teachers for secondary schools. 

 Funds have long been available for the purpose of assist- 

 ing the training of elementarv-school teachers, but there 

 has hitherto been little official recognition of the necessity 

 of making some systematic provision for the professional 

 training of men and women intending to teach in secondary 

 schools. Now, however, a Parliamentary grant of 5000/. 

 has been made available from the Exchequer for this pur- 

 pose, and the regulations under which the fund will be 

 dispensed are of great interest. The Board has decided 

 that the course of training must be taken after graduation 

 or its equivalent, and be confined to purely professional 

 work. It is to be an indispensable condition for recogni- 

 tion as an efficient training college that there shall be 

 access for the students, under proper conditions, to 

 secondary schools which are thoroughly suitable for 

 demonstration and practice, and not less than one-half of 

 the staff must have been successful teachers for a reason- 

 able time in secondary schools. Grants will be paid to 

 colleges, in which tfie number of recognised students is 

 not less than ten, at the rate of 100!. in respect of every 

 complete group of five recognised students, subject to the 

 condition that the grant does not exceed one-half of the 

 total sum paid for salaries on account of services in train- 

 ing the students. It is satisfactory to find so complete 

 an appreciation of the imperative need that the staff re- 

 sponsible for the training of secondary-school teachers must 

 possess high academic qualifications, and be, in addition, 

 experienced and successful teachers. There has been in 

 the past an uneasy feeling that much of the training avail- 

 :Me for secondary-school teachers was divorced too com- 

 pletely fronq schoolroom practice and over much concerned 

 w'th theoretical and historical matters, and these regula- 

 tions of the Board of Education will serve to inspire 

 grealer confidence in the value of the training provided in 

 assisted colleges. 



SOCIETIES AND ACADEMIES. 



London. 



Royal Society, May 28. — "On the Theory of Capil- 

 larity." Bv Dr. E. T. Whittaker, F.R.S. 



The fundamental quantities in the theory of capillary 

 phenomena are the surface-tension y (expressed, say, in 

 dynes per centimetre), and the surface-energy \ (expressed 

 in ergs per square centimetre). The relation between 

 these two quantities is at once given by the thermodynamic 



NO. 2024, VOL. 78] 



equation connecting available energy with total energy ; 

 it is therefore 



-.-x + t'^I' 



(I) 



where T denotes absolute temperature. 



This equation implies that when the area of a surface of 

 separation is increased by i cm." at temperature T, the 

 external agencies do work amounting to y ergs against 

 the surface-tension : and this energy, together with a 

 further contribution of — Tdy/dT ergs which is appro- 

 priated from the heat-energy of neighbouring bodies, be- 

 comes resident in the film, giving rise to an increase of 

 \ ergs in its internal energy. 



The relation between the surface-tension and surface- 

 energy is, of course, exactly the same as the relation 

 between' the electromotive force of a voltaic cell and the 

 energy of the chemical reactions which occur in the cell. 



■ The author has deduced the values of \ which correspond 

 to Ramsay and Shield's experimental values for y, and 

 shows that they satisfy a relation which may be stated 

 as follows : — The surface-energy \ of a liquid in contact 

 with its own vapour at any temperature is proportional 

 to the product of the internal latent heat and the (absolute) 

 temperature. 



The internal latent heat is intimately connected with 

 Laplace's " intrinsic pressure " K of a liquid, and so with 

 the classical theory of capillary phenomena. 



Paris. 

 Academy of Sciences, August 3. — M. Bouquet de la 

 Grve in the chair. — A problem relating to the theory of 

 orthogonal systems and the method of the mobile 

 trihedron ; Gaston Darboux. — Contribution to the 

 dynamical study of motors : A. Witz. If, when the motor 

 has arrived at a state of steady motion, the motive power 

 is instantaneously cut off, the moving parts make a certain 

 number of revolutions with a decreasing velocity. From 

 a study of this decreasing velocity important conclusions 

 concerning the effects of friction can be obtained. The 

 application of this method to a gas engine, working a 

 dvnamo, gave an efficiency of 79 per cent., as against 

 784 per cent, obtained by using the dynamo as the motor. 

 For smaller gas engines the results were less satisfactory. 

 — The families of Lami composed of equal surfaces : J. 

 Haag. — The tendency of material systems to escape fric- 

 tion : Georges Remoundos. — Detectors for use in wire- 

 less telegraphy with points of tellurium and tellurides : 

 Edouard Branly. The tripod detectors with points of 

 tellurium or tellurides acting on polished steel belong to 

 the group of radio-conductors working by variations of 

 resisfance, and require an external electromotive force for 

 their working. The thermoelectric detectors of M. Tissot 

 belong to a different class. — The conditions and duration of 

 the auto-excitation of dynamos : M. Swyngedauw.— The 

 electric arc between a solid electrode and a liquid : G. 

 Athanasiadis. DuddcU's experiment may succeed when 

 the arc is produced between a liquid anode and a solid 

 kathode. The arc formed between an electrolyte and^ a 

 solid electrode as the kathode may be produced even with 

 an immersion of 7 cm. or more, the difference of potential 

 bfing 220 volts, and in certain cases this arc may give 

 rise to the effects of the Wehnelt interrupter, although with 

 reduced intensity. It is impossible to produce art arc 

 between a solid anode and an electrolyte even with a 

 voltage of 220 volts. — The quantitative indications furnished 

 bv dissociation spectra : silver : A. de Gramont. The 

 number and intensity of the silver lines, obtained in_ the 

 dissociation spectra of mineral conductors, bear a direct 

 and constant relation with the proportion of the met.als in 

 the specimens. Details are given of the lines for various 

 minerals and allovs containing from i per cent, to o-oooi 

 per cent, of silver, and application is made of the method 

 to the studv of argentiferous galena.— A new method of 

 preparing pure hvdrogen : M. Mauricheau-Beaupre. 

 Aluminium foil is treated with a small quantity of mercuric 

 chloride and powdered potassium cyanide. In contact with 

 water this material gives 1300 c.c. of pure hydrogen per 

 gram. Advantages are claimed for this material in aero- 

 nautics.— The realisation in vivo and in vitro of precipi- 

 tins for ovalbumen : .\ndri^ Mayer and Georges Schsefter. 



