CONTENTS. 



Chapter I. Early Successive Stages of Efficiency of the Fog Chamber and 



Allied Results. 



DISTRIBUTION OF NUCLEI WITHIN THE FOG CHAMBER ENERGIZED BY THE 

 GAMMA-RAYS OF RADIUM, AND BY THE X-RAYS. 



Page. 



i . Introductory i 



2. Data 3 



3. Explanation 5 



4. Further experiments with radium. High exhaustions 5 



5. The same, continued. X-rays 6 



6. The same, continued. Miscellaneous tests 7 



7 . Distance effects of radium 9 



8. Cause of the minimum and the maximum 10 



9. Further experiments with radium 12 



10. Distance effect of penetrating X-radiation 12 



1 1 . General inferences (radiant fields) 13 



THE NUCLEATION OF FILTERED AIR IN RELATION TO DIFFERENT SUPER- 

 SATURATIONS OF WATER VAPOR. 



12. Successive series of results 13 



13. Effect of X-rays and gamma-rays. Data 18 



14. Persistent nuclei 18 



15. Persistent nuclei generated through tin plate 20 



16. Discussion 21 



17. More rapid exhaustion. Apparatus and data 23 



18. Remarks on the J-curves. Non-energized air 25 



19. The same, continued 26 



20. The same, continued. Action of radium 27 



21. The same, continued. Action of X-rays 27 



22. Remarks on the n-eurves. Non-energized air 27 



23. The same. Action of radium 29 



24. The same. Action of X-rays 29 



25. Remarks on the iV-curves 29 



THE NUCLEATION OF FILTERED AIR IN THE LAPSE OF TIME. 



26. Method 30 



27. Early data 30 



28. Apparatus modified 31 



29. Inferences 31 



SUMMARY OF THE RESULTS OF THE CHAPTER. 



30. Distribution of ions within the fog chamber 32 



31 . Minimum of efficient nucleation 32 



32. Persistent nuclei 32 



33. Dependence of efficiency of fog chamber on the size of the exhaust pipes. ... 33 



34. Invariable character of colloidal nucleation in the lapse of time t,^ 



VII 



