Conductivity of Air enclosed in Metallic Receivers. 313 

 Table XL 



Observation Station. 



Number of Location 



Station. 



Kemarks. 



1. The ice on Toronto Bay, , Water 10 metres 

 100 metres from the I deep. 

 E. 0. Yacht Club Wharf, i Ice, 30 cms. thick. 



2. The ice near Canoe Club 

 Wharf, Toronto Bay. 



3. The ice on Grenadier 



Pond, an inlet of Lake 

 Ontario. Station " a." 



4. The ice on Grenadier 



Pond. Station "6." 



5. At the shore of Grenadier 

 Pond. Station " c." 



Water 56 metres 



deep. 

 Tee 30 cms. thick. 



Water 2 5 metres 



deep. 

 Ice 30 cms. thick. 



Water 3'5 metres 



deep. 

 Ice 30 cms. thick. 



6. On a sand hill over- Height of hill about 

 looking Grenadier Pond, j 50 metres. Dis- 

 tance rrom shore 

 100 metres. 



7. University Lawn 'Clay soil, sodded, 



frozen and co- 

 vered with ice and 

 snow20cms.deep. 



8. University Tower 26 metres high. 



I 9. In the open on the ! Frozen clay, recent- 

 ground in the rear of ly overturned, 

 the new Physical Labo- covered with 10 

 ratory. cms. of ice & snow. 



10. A room in the basement As the building is 



of the new Physical 

 Laboratory. 



new it was sup- 

 posed to be free 

 from anj radio- 

 active contami- 

 nation. 



Value of " q" the no. 



of ions generated 



per c.c. per sec. 



Lead. 



9-2 



90 



91 

 93 



11-2 



11-4; 

 132 



153 



Zinc. Aluminium, 



i 



60 



6-55 



11T 



134 



104 



125 



found for the ionization over the water when the cylinders 

 were freshly cleaned and freshly filled with filtered air. 

 These values of S'6, 6, and 6*5 obtained for the receivers of 

 lead, zinc, and aluminium are very much lower than those 

 obtained by any other observer under any conditions, and 



