44: 



NA TUnii 



[August 30, 1894 



chambers, excavated in the chalk, and approached by low narrow 



passages of some length. — A paper by M. Ziborowslci, on ten 



crania from Rocheforl, is continued fiom the January to the 



February number. M. Zaborowski argues in favour of the 



primitive ethnical identity of the blondes, wherever they are 



lound in a st.ite of puriiy, whether in 



the Caucasus, in England, or in Cha- 



rente-Infcrieure.— M. Zaborowski also 



coDlribuies a paper on the circumcision 



of boys and the excision of girls as 



initiation ceremonies. He traces the 



origin of the custom in Asia .-ind Europe 



to the influence of ancient Egypt. — 



.M. de Saporta describes certain popuUr 



medical practices in Provence. In 



cases of delirium or meningitis, if the 



warm body of a recently killed pigeon 



is not available, they have recourse to 



a fried egg, which is placed, burning 



hot, on the forehead of the patient. 



M. de Saporta does not think tnat any 



supernatural virtue is attached to these 



practices. 



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the other two were attached to the edges, opposite to one 

 aroiher, and parallel to the axis of the ring. The ring was 

 inserted In a wooden case, also shown, through holes in which 

 the four tiiass rods projected. Jnsul.ated wiie for carrying the 

 magnetising current was wound over the wooden jacket. 



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SOCIETIES AND ACA- 

 DEMIES. 



LO.NDON. 



Royal Society, May 31. - " On the 



Efliect of Magnetisation upon the Di 

 roensions of Iron Rings in Directions 

 perpendicular to the .Magnetisation, and 

 upon the Volume of the Rings." IJy 

 Shelford Bidwell, F.R.S. 



A recent communication {Roy. Soc. 

 Proc. vol. Iv. p. 228) to the Society con- 

 tained an account of some experiments 

 relating to the effects of magnetisation 

 upon the dimensions of two iron rings, 

 one of which was annealed and the 

 other hardened. The rings had the 

 form of short cylinders about 6 cm. in 

 diameter, 3 cm. in height, and 04 cm. 

 in thickness. The experiments in ques- 

 tion were concerned with the circum- 

 ferential variations which took place 

 along the lines of magnetisation ; those 



10 tie here described deal with the concomitant variations 

 in the height of the cylinders (width of the rings) transversely 

 to the magnetisation. On the assumption that variations similar 

 to the latter occur at the same time in the thickness of the 



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metal, it i> po»ible to deduce the changes in the volume of the 

 ring which attend magnetisation. 



Mg. I, from a photograph, shows how the ring^ were pre- 

 pared for the experiments. Four brass rods were hard-soldered 

 to the iron, two of them being in a line with a diamclcr, while 



NO. 1296, VOL. 50] 



!■ IG 2. — '1 he curves marked " ioacitiidinnlly " rel.ilc to circiimfcrcnli.ll cli.inees, a/cwf the lines of 

 niaenctisnlion. 'those marked *' transversely " relate Co ctianges in the width, /^r/c«rt'/<«/iir/i' 

 to the magaetisation. 



For the new experiments the ring was placed in a horizontal 



position, one of the edge rods resting upon a brass socket on 



the adjustable base of tne instrument, and the other, which had 



a chisel-shaped end (not shown in the figure), actuating ti c 



lever. To counlerhalance the weight nf tin 



ring a horizontal atni, carrying a sliding 



weight, was fixed to the lower rod. 



The annealed ring will, as before, be dis- 

 tinguished as Ring I. and the hardened one 

 as Ring H. 



The changes observed in the widths nf 

 the two rings (transversely to the magnetisa- 

 tion) are indicated in the curves of Fig. 2 

 It will be seen that they are '|uile similar in 

 the two cases, little or no effect being \ir>' 

 (luced liy annealing. Under graduallv 

 asctnding forces both lings first beconi' 

 narrower, then recover their original width, 

 and ultimately become wider than when un 

 magnetised. 



.\s was shown in my last paper, the eflcct- 

 along the lines of magnetisation are very 

 different in the two rings. The annealed 

 ring (King I.) begins to contract ciicuiii 

 ferenlially with the smallest forces, ami 

 continues to contract with the large ones ; 

 while the hardened ring expands with small 

 forces and contracts with large ones. These effects are indi- 

 cated in the figure by the doited curves. 



liy combining the results of the old and of the new experi- 

 ments we can ascertain the nature of the changes produced by 

 magnetisation in the volumes of the tings. These are indicated 



