June 23, 1904] 



NA TURE 



i9r 



departments of the schools and of the manual training 

 centres, and the standard of excellence attained may be 

 taken as proving that good results follow the correlation 

 of the instruction in science and in manual work. The 

 total number of exhibits was unusually small, and it is 

 difficult to find a reason for the inclusion among them of 

 scientific instruments obtained from manufacturers. The 

 collection of exhibits, though interesting and from some 

 points of view satisfactory, did not succeed in conveying an 

 adequate idea of the work in science accomplished in the 

 schools. The !nan of science interested in education would 

 have obtained a better general idea of the scope of the 

 science work in the council's day and evening schools had 

 typical laboratory note-bcoks and typical syllabuses of work 

 done been exhibited. There was, however, evidence enough 

 to show that the claims of science to a place in the curri- 

 culum of the public elementary schools of London itre recog- 

 nised bv the London Education Committee. 



SOCIETIES AND ACADEMIES. 

 London. 



Royal Soci. ty, lune 2.— "On the Magnetic Changes of 

 Length in .Annealed Rods of Cobalt and Nickel." By 

 Shelford Bidwell, K.R.S. 



The magnetic changes of length in annealed iron were 

 described by the author in i.Sii4 {Proc. Roy. Soc, vol. Iv. 

 p. 228). When subjected to a longitudinal field gradually 

 increasing from a small value, an ordinary iron wire is at 

 first extended, then it recovers its original length, and finally 

 becomes shorter than when unmagnetised. In annealed 

 iron the fnaximum extension is diminished, and contraction 

 begins in a weaker field, the change-of-length curve being 

 lowered. In the case of a thoroughly well annealed speci- 

 men, contraction began in a very weak field without any 

 preliminary extension. .Similar experiments have now been 

 made with cobalt and nickel. Cobalt in the ordinary con- 

 dition behaves oppositely to iron, contracting in weak fields 

 and lengthening in strong ones. It was found that a well 

 :mnealed rod of cast cobalt contracted uniformlv in fields 

 up to 13O0 units (the highest reached), the retraction curve 

 being a straight line. This confirms an observation pub- 

 lished last year in Japan by Honda and Shimizu. For a 

 specimen of rolled cobalt, however, the change-of-length 

 curve retained its general form, but was considerablv 

 lowered ; in .'i field of 1750 the ascending limb was still 

 below the axis of H and nearly parallel to it : probably, 

 therefore, there would never be any elongation, however 

 strong the field. The most noteworthy effect of annealing 

 upon the retraction curve for nickel is an increase in the 

 abruptness of its descent, which mav be due merely to 

 greater magnetic susceptibilitv. Thus it appears that well 

 annealed specimens of iron, cobalt and nickel all undergo 

 contraction when longitudinally magnetised. 



Mi»eralogicaI Society, June 7. — Dr. Hugo Miilleri 

 president, in the chair. — The Rev. Mark Fletcher con- 

 tributed a note on mispickel from Sulitjelma Mine. Norway, 

 containing about 132 per cent, of cobalt, and showing the 

 forms loilj, {012;, 'llOf. — Mr. G. K. Herbert Smith 

 exhibited a hand-refractometer of the Bertrand tvpe, in 

 which the curwilure of the focal surface had been reduced 

 by means of a correcting lens, with a consequent improve- 

 ment in the definition of the shadow edges. — Prof. H. A. 

 Miers gave an account, illustrated bv numerous lantern 

 slides, of the development of the Kimberlev Diamond Mines. 

 He traced the changes in the methods of working from the 

 first surface diggings to the time when the blue-ground 

 was brought to the edge of the pit by a " cobweb " of wire 

 ropes stretching from the numerous independent claims into 

 which the mines were split up, and showed how the in- 

 creasing difficulties involved in this method led to the final 

 consolidation of the mines under Beit and Rhodes, and to the 

 initiation of the present system of mining, which consists 

 in sinking shafts on the edge of the pit, and running cross- 

 cuts into the blue-ground. He referred finally to the recent 

 disiovery of blue-ground in the neighbourhood of Pretoria. 



Faradav Society, June 9. — Dr. J. W. Swan, prcsiden', 

 in the chair. — The electric furnace : its origin, transform- 

 ations and applications, part i. : M. .Adolphe Minet. The 



NO. 1808, VOL. 70"| 



paper discusses the growth of the furnace from the historical 

 point of view, and then proposes a new classification, which 

 is worked out in minute detail in the form of a table. .A 

 full bibliography of the electric furnace completes this 

 section of the paper. ^ — A form of porous diaphragm con- 

 venient for laboratory use : Dr. K. M. Perkin, It consists 

 of two perforated concentric porcelain cylinders packed in 

 between with brow-n paper, asbestos, or other material, de- 

 pending on the use to which the diaphragm is to be put. 

 — The hard and soft states in metals : G. T. Beilby. The 

 views advanced by the author are based on his earlier 

 observations on surface flow- in crystalline solids. The 

 evidence afforded by the micro-structure has been supple- 

 mented by observations on the other properties of metals 

 in the hard and soft states, and the view is now advanced 

 that these states are perfectly distinct phases. This is 

 shown by the mechanical, electrical, optical, and thermo- 

 chenjca! properties, as well as by the micro-structure. 



Royal Meteorological Society, June 15.— Capt. D. Wilson 

 Barker, president, in the chair. — Efi'ects of a lightning stroke 

 at Karl's Fee, Bow'ers Clifford, Essex, .\pril i^ : Rev. C. F. 

 Box. .\ thunderstorm occurred during the earlv morning 

 hours, and about 3 a.m. there was a blinding flash, lighting 

 up the whole neighbourhood for miles around, followed 

 immediately by a crashing explosion. One person stated 

 that he saw what appeared to be a cylinder, and another 

 person a ball of fire, descend and then e.xplode, " casting 

 darts" in all directions. On careful examination in day- 

 light, it was found that in an oatfield, which had recently 

 been dredged, there were three distinct sets of holes ranging 

 from q inches down to about i inch in diameter. The 

 holes, which were perfectly circular, diminished in size as 

 they went downwards, and remained so on to the perfectly 

 rounded ends at the bottom. L'pon digging sectionally 

 into the soil, which is stiff yellow clay, it was found that 

 the holes were " as clean cut as though bored with an 

 auger." .An interesting discussion followed the reading of 

 this paper. — .An instrument for determining the true direc- 

 tion and velocit\' of the wind at sea : A. Lawrence Rotch. 



Academy of Sciences, June IJ. — M. Mascart in the chair. — 

 .Muscular displacement applied to carrying a load without 

 displacement, the statical work of muscle. The comparison 

 of this internal work with the resulting expenditure of 

 energy, and influence of the magnitude of the load ; A. 

 Chauveau. Cse was made of the respiratory coefficient 

 in measuring the energy e.xpenditure, and this was found 

 to increase faster than the load sustained, although for 

 small loads these were found to be nearly proportional. — 

 The influence exercised by small variations of external 

 actions on a system affected by hysteresis and defined by 

 tw'o variables : P. Duhem. — On the property possessed by 

 a considerable number of bodies of projecting a ponderable 

 emanation spontaneousi}" and continuously : R. Blondlot. 

 — .A photographic study of the spectrum of the planet 

 Jupiter : .M. Millochau. The photographs were taken with 

 a spectrograph attached to the large telescope of the Observ- 

 atory of Meudon (S4 cm. diameter), and the spectra obtained 

 extended from the F' line to the C line, means being taken 

 to allow of a comparison of the spectra from the bands 

 with that from the other parts of the disc. The presence of 

 water vapour is clearly proved. — Remarks on the preceding 

 communication : J. Janssen. — On a class of differential 

 equations with multiform integrals : Pierre Boutroux. — 

 Energy in statical reactions : Eugfene Lebert. .A discussion 

 of the results of M. Chauveau on the " statical work " of 

 muscle. — On the index of refraction of solutions : C. 

 Cheneveau. — Contributions to the study of the n- and 

 ii|-rays : Jean Becquerel. — On the forms of high frequency 

 lighting between platinum wires of small diameter : Andr6 

 Broca and M. Turchini. — The action of the li-rays on pure 

 water: Julien Meyer. Experiments are described leading 

 to the conclusion that pure water, submitted to the action 

 of the H-ravs, becomes itself a source of H,-rays. — On the 

 measurement of the mobility of the ions in gases by a null 

 method : liug^ne Bloch. The method of MacCIelland, 

 improved by Zelenv, is modified by conversion into a null 

 method, which much extends the field of its application. — 

 The atomic weight of nitrogen : the analysis of nitrogen 



