xi ACROSS THE BORDER 309 



is taken from it every few weeks. It may be likened 

 also to Draupnir, the ring of Odin, which, after being 

 placed by him upon the pile of his son Baldur, acquired 

 the power of dropping every ninth night eight rings of 

 equal weight with itself. 



Whatever may be the atomic changes by which the 

 energy manifested by radioactive substances can be 

 explained, we have the fact that radium salts continually 

 produce sufficient light to be observed readily in semi- 

 darkness, heat enough to be appreciably warmer than 

 other objects near them, rays which have an energetic 

 action upon photographic plates and by which radio- 

 graphs can be taken, and emissions which blister the 

 skin and produce other remarkable physiological effects. 

 It is, perhaps, fortunate that the new element is probably 

 the rarest in the universe. Pitchblende, from which 

 radium is obtained, is comparatively rare, and only 

 about one and a half grains of a radium salt can be 

 extracted from a ton of pitchblende ore. 



Rontgen rays, radium and radium emanation are all 

 now largely used by physicians, not merely as means of 

 diagnosis, but for curative purposes. Early experimenters 

 with Rontgen rays did not realise the extraordinary 

 powers of the rays to produce virulent effects upon the 

 skin long exposed to them. The X-ray burns thus caused 

 are most intractable, and usually the hand or arm badly 

 affected by them has to be removed to prevent further 

 extension or death. Odin bought for himself wisdom 

 at the price of his right eye, but it was Tyr who, among 

 all the Aesir, was held by the Norns or Fates of northern 

 myths to be worthy of the highest honour, for he sacri- 

 ficed his strong right hand not for himself but for others. 

 This is what was cheerfully done by several early workers 

 with X-rays, notably Dr. Blacker, of St. Thomas's 



