November ii, 1915] 



NATURE 



299 



gts flux, and thus compensating for the saturation. 



his device should prove especially useful in the case 

 )f rotary converters, where the commutation is often 

 iifiicult; it will enable an increased output to be 

 >btained from a machine of a given size. 



A mathematical paper on '• Electric Oscillations 



[in Coupled Circuits " was read by Dr. Eccles and 



iMr. A. J. Makower. The special case considered 



.as that in which three paths, each containing an 



Inductance and a condenser, are connected in parallel. 



he formulae obtained were confirmed by tests in 



}0 simple special cases, viz., two tuned circuits 



)upled either by a common condenser or a common 

 Inductance. In the discussion Prof. Howe showed 



lat the two special cases dealt with experimentally 

 could be calculated in a very simple manner by a 

 Suitable choice of initial conditions. 



Prof. G. W. O. Howe then read a paper on "The 

 [Capacity of Aerials of the Umbrella Type," in which 

 the method described by the author at the Sydney 

 meeting last vear was extended to aerials of this 

 type. In the discussion Prof. Schuster pointed out 

 that the small error due to the author's assumption 

 of a uniformly distributed charge would be always 

 in the same direction. 



A note on "Earth Resistance" was read by Prof. 

 E. W. Marchant, who suggested the use of the equi- 

 valent length of a column of the earthy material, 

 which, with a cross-section equal to the surface of 

 the buried conductor, would have the same resistance 

 as the actual earth, as a criterion of the "earth." 

 Prof. Howe showed that this "equivalent length" 

 depended merely on the dimensions, and need not be 

 determined experimentally, since such measurements 

 depended on the uncertain specific resistance of the 

 soil; it could be calculated in the same way as the 

 capacity, if the conductors were surrounded bv an 

 insulating medium. Dr. Eccles pointed out the need 

 for caution in applying the continuous or low fre- 

 quency resistance to the case of a radio-telegraphic 

 aerial. 



Messrs. Lacey and Stubbings described some ex- 

 periments to determine the effect of a third harmonic 

 on the iron losses of a three-phase transformer, the 

 harmonic being due to the saturation of the cores. 

 With a triple harmonic of 48 per cent, the iron loss 

 decreased 225 per cent, on opening the neutral wire; 

 this would prevent any third harmonic in the current 

 and would remove the sine-wave constraint from the 

 magnetic flux, which would consequently reach a 

 lower maximum value. 



Prof. E. Wilson gave further information about ^ 

 number of aluminium alloys, which have been ex- 

 posed on the roof in London for many years, and 

 on which he has reported on previous occasions. 



Saturday, September 11. — Mr. T. H. Brigg- de- 

 scribed a new method of attaching horses to vehicles, 

 the principle of which is that the shafts are forced 

 upward by a spring, thus relieving the horse of a 

 part of his own weight when travelling on an easv 

 road. As soon as the road becomes more difficult, 

 owing, say, to an up gradient, the increased pull on 

 the traces overcomes the spring and exerts a down- 

 ward force on the shafts, enabling the horse to obtain 

 the necessary adhesion on the road. 



The report of the committee on complex stress 

 distribution was read by Prof. Coker. It consisted 

 mainly of a comparison of the behaviour of a sample 

 of miid steel when subjected to steady and alternating 

 stresses respectively. 



A paper on the strength of iron and steel struts 

 was read by Mr. A. Robertson. It was a record of 

 experiments on solid, free-ended, centrally-loaded 

 struts made at Manchester University. The results 



NO. 



2402, VOL. 96] 



confirmed Euler's formula, except for very short 

 struts ; the latter are discussed in detail in the paper. 



Prof. C. Batho described a new method of deter- 

 mining the torsion stresses in framed structures and 

 thin-walled prisms, especially useful in the case of 

 cantilever bridges in which the suspended span is 

 subjected to torsion, owing to unsymmetrical loading 

 on the cantilever and anchor arms. The author 

 showed the application of the method to a bridge of 

 similar design to the new Quebec bridge. 



Prof. Miles Walker described some experiments 

 made to determine whether the acceleration of one 

 mass e.\erts any force on a neighbouring mass, as 

 it should do if the analogy between the electric 

 current and the movement ot matter be perfect. The 

 results obtained were negative, although the appa- 

 ratus combined great sensitiveness with the very 

 rapid acceleration of large masses. Prof. Schuster 

 expressed regret that a paper of such physical im- 

 portance had not also been brought before Section A 

 (Physics) of the Association. 



This brought the proceedings of Section G to a 

 close. 



ANTHROPOLOGY AT THE BRITISH 

 ASSOCIATION. 



IN Section H (Anthropology) the proceedings showed 

 little departure from the normal except perhaps 

 in the small number of ethnographical papers, and in 

 the character of the discussions which, on the whole> 

 were a little less vigorous than usual, owing to the 

 absence of many who, as a rule, may be counted upon 

 to take part in the debates. The programme, how- 

 ever, showed a longer list of communications than 

 might have been expected. 



As in other sections, subjects of special interest at 

 the moment were not neglected. Indeed, the principal 

 item in the programme was a discussion which took 

 place in joint session with Section E (Geography) on 

 "Racial Distribution in the Balkans." This was 

 opened by Prof. G. Elliot Smith, who, after a lucid ex- 

 position of the geographical, ethnological, and histo- 

 rical factors which have brought about the segrega- 

 tions and disunion of the Balkan peoples, went on to 

 show that in spite of conflicting interests arising out 

 of difi'erences of history and creed, ethnological no 

 less than geographical and economic considerations 

 definitely linked together the Slovenes, Croats, and 

 Serbs as one race, whose domain included not only 

 Croatia (with Slavonia), Bosnia, Herzegovina, Mon- 

 tenegro, and most of Serbia as at present delimited, 

 but also Dalmatia, nine-tenths of Istria (excepting 

 Trieste), Carniola, and a strip of South Hungary. On 

 ethnological grounds Bulgaria had a greater right 

 than Serbia to the part of Macedonia now in occupa- 

 tion by the latter, and on racial grounds her claim to 

 the Dobrudja was more justifiable than that of 

 Rumania. Sir Arthur Evans exhibited a diagram- 

 matic map illustrating the ethnic relations between 

 the Adriatic, the Drave, and the Danube, the result 

 of many years' observations in the area which is now 

 occupied by the southern Slavs or Jugo-Slavs. Ethno- 

 logical considerations supported the argument for a 

 Jugo-Slav State. Italic preponderance was situated 

 in the lower valley of the Isonzo, at Trieste, and in 

 Istria. In Dalmatia, except in the town of Zara, the 

 Italian element amounted to about 3 per cent, only 

 of the population, the prevalence of Italian culture and 

 the use of the language for commercial purposes 

 giving a wrong impression. Sir Arthur then pointed 

 out the value of the establishment of such a state 

 in facilitating the completion of a railway, joining up 



