EADIOACTIVITY. 129 



comparative ease in iron and steel, to learn their laws and to know 

 what such an investigation requires, with ever finer and more accu- 

 rate instruments we may be able to prove the existence of magnetic 

 qualities in all substances. Shall we at some future time be able to 

 do the same with radioactivity ? 



Experiments have already been made in this direction, and numer- 

 ous physicists believe that their researches lead to the conclusion that 

 all bodies are radioactive. They believe it can be proved that lead, 

 zinc, etc., send out rays by which the air is made conductive. As 

 corroboration of this, experiments are made to show that an elec- 

 troscope inclosed in lead would lose its charge more rapidly than if 

 inclosed in zinc. We must not lose sight of the fact, however, that 

 our instruments are surprisingly sensitive, and that for that reason 

 the slightest admixture of radioactive substances with those under 

 examination might cause results similar to those observed. 



I have referred to the fact that the presence of the radioactive 

 emanation in all our springs shows the Avide diffusion of radium in 

 the earth. It shows, also, how easily one substance by coming in 

 contact with another is affected by it. Elster and Geitel have now 

 found proof that the radioactive emanation is everywhere present 

 in the atmosphere, in the deepest excavations and shafts, as well as 

 on the highest elevations, and that the appreciable quantity varies 

 with rising and falling air pressure, dust, fog, rain, and snow. It 

 will be easily understood how difficult this must render experiments 

 in this direction, and how cautious one must be in reporting observa- 

 tions. From previous experiments it may be safely inferred that in 

 the metals possessing radioactivity it is thousands of times weaker 

 than in radium. It is certainly conceivable that the activity of these 

 substances may be demonstrated by other methods and that they 

 emit rays whose action has so far escaped us. Ten years ago such 

 a suggestion would have been regarded as an idle dream, but such 

 phenomena as wireless telegraphy, the Rontgen mjs, and radio- 

 activity have made us more cautious in criticism and bolder in hy- 

 pothesis. Now that we have discovered the electron, have seen that an 

 atom can subdivide into others, and have actually succeeded in observ- 

 ing one element transforming itself into another, it can not be 

 regarded amiss if we venture to look for similar phenomona in the 

 other elements. I do not hesitate to acknowledge that I class myself 

 with those whose hope takes them much farther than this, even. 



We must seek to gain power over the atomic processes, to control 

 them as we now control the molecular processes. As we can to-day 

 decompose water, and by reversing the operation can reproduce it, as 

 we have learned to create thousands of organic substances, which 

 were earlier believed to be beyond the power of man to produce, and 

 SM 1906 9 



