234 SCIENCE PROGRESS 



was observed, but argon only. The trace of nitrogen present 

 in this case would perhaps account for the argon, but the absence 

 of helium, which is not easily masked by argon, points to a 

 possibility that some part at least of the argon was derived from 

 the emanation. 



Work on similar lines is being carried out in silica bulbs, 

 in order specially to observe whether there is any constant 

 difference of weight in the alkali residues obtained from 

 " treated " and " untreated " solutions of copper salts and those 

 of similar elements. Incidentally, such an experiment with pure 

 water gave an unweighable residue, which did not contain 

 lithium, showing that the silica is unaffected, and that the 

 method is therefore applicable. This experiment also con- 

 firmed the production of neon. In this case the neon and 

 helium spectra were comparable in intensity, the latter being 

 somewhat stronger. The spectrum was photographed, and 

 some twenty neon lines conclusively identified. 



In considering these results it is necessary to bear in mind 

 two important considerations. Soddy and Mackenzie find that 

 traces of helium and neon can always be obtained from aluminium 

 electrodes which have been used previously with those gases, 

 and even with fresh electrodes. Strutt has found that admix- 

 ture of helium with one cubic centimetre of air, and with care, 

 with one-tenth of that amount, renders the neon spectrum visible, 

 after separation of other gases with cooled charcoal. The 

 answer to objections based on these observations seems to lie 

 in the fact that in the experiments described the amounts of 

 neon observed were not mere traces, but were in one case 

 much greater than the helium present, and in the second of 

 the same order. Again, other experiments with the same 

 spectrum tubes did not result in the production of neon, so 

 that it scarcely can come from the electrodes, although these 

 were of aluminium. There is therefore strong ground for belief 

 that neon is a disintegration product of radium emanation under 

 certain conditions, and since these are brought about by the 

 intervention of human agency, it can be regarded as a case of 

 transmutation. 



The cases for argon, and for the copper-lithium change, are 

 by no means so strong. One-tenth of a cubic centimetre of 

 air contains sufficient argon to be detected with ease spectro- 

 scopically, so that slight leakage would always result in its 



