462 



Mr. Morris Owen on 



the difficulty of measuring with any accuracy the area 

 rubbed. The width o£ the specimen is, however, given in 

 each case. 



Readings could not be obtained for glass with the higher 

 velocities and the greatest weight ; the specimen always 

 broke when brought into contact with the wheel under these 

 circumstances. 



Table I. 



Ebonite and Slate 



(negative electricity produced on ebonite). 



Width of specimen = 2*15 cms. 



WxlO- 6 . 



Qx. 



Q 2 . 



Q 3 - 



4035 



•59 



1-76 



1-99 



8-069 



104 



2-02 



214 



14121 



1-27 



2-08 



2-38 



24-208 



1-70 



2-24 



2-43 



40-346 



2-11 



2-40 



2-57 



53-459 



2 '25 



2-41 



2-58 



75649 



239 



2-54 



2-59 



99-857 



2 "47 



2-51 



2-56 



125074 



250 



2-58 



2-55 



156-342 



2-58 



2-57 



2-59 



202-740 



253 



2-53 



2-56 



235-018 



2-57 



2-56 



2-52 



294-528 



2-58 



255 



2-57 



Table II. 



Ebonite and Copper 



(positive electricity produced on ebonite). 



Width of specimen =1*75 cms. 



Wxl0~ 6 . 



Qr 



Q 2 . 



Qs- 



4-035 



•021 



•094 



•15 



8-069 



•066 



•13 



•23 



14-121 



•19 



•26 



•37 



24-208 



•28 



•59 



•76 



40-346 



•48 



•73 



1-07 



53-459 



•69 



1-06 



1-16 



75-649 



•89 



•93 



1-46 



99-857 



111 



1-20 



1-44 



125074 



1-09 



1-54 





156342 



1-40 



1-52 





202-740 



1-46 



1-63 





235-018 



1-61 



1-65 





294-528 



1-58 



1-61 





