288 



THE POPULAR SCIENCE MONTHLY.— SUPPLEMENT. 



vanes rotated sometimes one way, sometimes the 

 other. 3. On connecting the negative pole of a 

 Ruhrakorf coil the results were uncertain, but the 

 positive pole caused the vanes to rotate steadily. 

 In the dark the effect was very beautiful, as the 

 dark vanes moved through a phosphorescent glow. 

 As the apparatus seemed in the course of these 

 experiments to have leaked, it was recxhausted. 

 It now acted normally, the black faces of the 

 vanes being repelled by heat and light. On 

 electrizing the wire by a Ruhmkorf coil there 

 was now no luminosity, nor did the current pass. 

 But, though the current was incapable of travers- 

 ing the one-tenth of an inch of distance between 

 the vanes and the glass, induction acted across 

 it as before. From this it is apparent that the 

 effects of attenuation of air upon discharge and 

 upon induction are not the same. When attenua- 

 tion has commenced and is increasing, the dis- 

 charge passes more and more rapidly, until it 

 becomes a glow ; but a further attenuation stops 

 the discharge entirely. On the other hand, in- 

 duction continues, and appears to be in no way 

 lessened byextreme attenuation. 



Nickeliferoua Iron- Ores. — An analysis of some 

 native iron from Brazil, made by M. Damour, 

 shows an extraordinarily high proportion of nick- 

 el, namely 38 per cent., or considerably above the 

 ordinary proportion of nickel in meteoric iron. 

 The metal, which has a very fine grain, and a 

 lustre like that of steel, exhibits the so-called 

 Widmanstattian figures when a polished surface 

 of it is acted on by an acid. Strange to say, it 

 resists for an indefinite length of time the com- 

 bined action of air and water, without showing 

 the least sign of oxidation. The results of Da- 

 mour's experiments with this iron having been 

 laid before the Paris Academy of Sciences, Bous- 

 singault remarked that, according to Berzelius, 

 meteoric iron is not oxidizable by moist air. He 

 also called attention to certain experiments he 

 himself had formerly made with a view to render- 

 ing iron unoxidizable by incorporating with it 

 nickel. Having added successively 5, 10, and 15 



per cent, of nickel, he very unexpectedly found 

 that the alloy was more oxidizable than pure iron. 

 But if 38 per cent, of nickel — the proportion 

 found in the iron from Brazil — be added, the al- 

 loy is absolutely unoxidizable. M. Stanislas Meu- 

 nier, who reports the transactions of the Acad- 

 emy for La Nature, hereupon observes that, if 

 Berzelius's proposition be true, then Boussin- 

 gault's explanation is insufficient, for in meteoric 

 irons the nickel is in the proportion of only 8 

 per cent., and of course they should be very oxi- 

 dizable. Some specimens of the Brazil iron were 

 presented to the Academy by M. Daubree. They 

 are of interest, owing to the intrusion of magnetic 

 pyrites, or pyrrhotine, which they present. These 

 specimens were broken off from great masses of 

 the iron found in the province of Santa Catarina. 

 The iron appears to be of terrestrial origin. 



Injurious Effects of High-heeled Shoes. — The 

 remarks of Dr. Onimus, of Paris, upon the in- 

 jurious effects on women, of wearing shoes with 

 high heels, are timely, and deserve to be seriously 

 considered. As the fashion goes, the heel of the 

 boots is not only high, but narrow and inclined 

 forward, so that the distance between the heel 

 and the point of the foot is lessened, and the 

 foot appears to be smaller than it really is. The 

 effect of this is to remove the weight of the body 

 from its natural support, the prominence of the 

 os calcis, and project it forward on the plantar 

 arch. Hence often acute pain in the sole of the 

 foot, and serious injuries to the anterior joints. 

 The toes, instead of the heel, first touch the 

 ground, becoming permanently flexed and pressed 

 together; partly in consequence of the narrow- 

 ness of the front part of the boot, partly in con- 

 sequence of the over-action of the flexors of the 

 toes. Other muscles are also involved ; indeed, 

 all those which are concerned in maintaining the 

 erect attitude of the body. In nervous tempera- 

 ments hysterical symptoms have been produced 

 by the pain and irritation. Grave constitutional 

 troubles are not infrequently the result of per- 

 sistence in this ridiculous fashion. 



