72 TWO NEW WORLDS 



where a long and complicated course of events is 

 crowded into a fraction of a second. 



An Inner View of Matter. In the chapter on 

 Infra-Astronomy, I sketched out the actual ap- 

 pearance of the infra- world as seen within a rarefied 

 gas, and illustrated the various phenomena of " ioni- 

 sation" by astronomical analogies. There is every 

 reason for believing that the atoms and molecules 

 of a rarefied gas appear to inhabitants of the infra- 

 world very much like what the starry heavens appear 

 to us. But when we consider the aspect of the 

 infra-world as presented with a solid or liquid 

 instead of a rarefied gas, we come to aspects with 

 which we cannot trace any analogy in our own 

 world. What would be, for instance, the internal 

 appearance of a copper wire, or a crystal of calcspar, 

 or a piece of ice ? In endeavouring to get at the 

 solution of this difficult question, we must first of 

 all obtain some insight into the constitution of the 

 " positive atom." We find by chemical experiment 

 that all known substances may be arranged in a series 

 of weights marking their atoms and determining 

 most of their properties. The series begins with 

 hydrogen, whose atomic weight is arbitrarily called 

 unity, and ends with uranium, with an atomic weight 

 of 240 units. It is found that the physical, chemical, 

 and electrical properties of the elements change 

 in regular periods as the atomic weight increases. 

 Elements of the same general properties are found 



