546 



Mr. P. E. Shaw on 



Table I. 



Consecutive Readings showing the constancy of the contact- 

 position under favourable conditions, and also to prove the 

 small difference that exists between "make" and "break " 

 under certain . conditions. The last column gives the dif- 

 ference, if any, roughly in terms of the unit 10~ 7 cm. 



That the readings are so very steady as a whole is due in 

 great measure to the fact that they were taken in the late 

 afternoon, when the temperature in the room was nearly 

 stationary- 



Julv 









July 











30th. 



Make. 



Break. 



Difference. 



30th. 



Make. 



Break. 



Difference. 



Time. 





40-7 



1 



-7 cm. 



Time. 





■ - 





10- 7 cm. 



5.34 



40-6 



0-1 



(10) 



6.4 



40-7 



40-6 







5 



40-9 



40-9 







5 



40 6 



40-7 







6 



409 



41-0 



01 



(5) 



6 



40-65 



40-8 



015 



(15-5) 



7 



40-85 



409 



0-05 



(10) 



7 



40-6 



40-7 



01 



(10) 



8 



40 7 



407 







8 







1 





9 



407 



40-7 







9 











40 



40-8 



40-8 







10 







1 





1 



405 



40-6 



01 



(10) 



1 







)■ Inte 



rruption. 



2 



409 



41-0 



01 



(10) 



2 











3 



41-0 



41-0 







3 











4 



407 



409 







(21) 



4 







J 





5 



41-1 



41-1 







5 



40-6 



40-7 



0-1 



(10) 



6 



4095 



40-95 







6 



40-8 



40-8 







7 



410 



41-0 







7 



40-6 



40-7 



01 



(10) 



8 



40-8 



408 







8 



40-7 



40 7 







y 



40-8 



40-8 







9 



40-65 



40-75 



01 



(10) 



50 



40-8 



408 







20 



40-7 



40-7 







l 



40-9 



40-9 







1 



40-8 



40-8 







2 



40-9 



409 







2 



40-9 



40-9 







3 



40-9 



40-9 







3 



40-8 



40-8 







4 



407 



40-7 







4 



40-5 



40-5 







5 







1 Inte 





5 



403 



40-3 







6 









rruption. 



6 



40-5 



40-5 







7 



40-7 



40-7 







7 



40-7 



40-7 







8 



40-7 



40-7 







8 



40-55 



40-55 







9 



40-7 



40-7 







9 



44-55 



40-55 







6.0 



40-8 



40-8 







30 



40-6 



40-65 



0-05 



(5) 



1 



40-7 



40-7 







1 







Inter 



ruption. 



2 



40-7 



40-7 







2 



40-9 



41-1 



0-2 



(21) 



3 



40-8 



40-8 







3 



1 



40-8 



40-8 







Thus during the whole of one hour the highest reading- 

 was 41*1, and the lowest 403, the difference being only 

 8 x 10- 6 cm. 



