Effects of Moving Charged Spheres. 



299 



The following table gives the values of the ratio of the 

 units obtained from the above readings • — 



No. 



N. 



A. 



I. 



8. 



V. 



1 



42 



55 

 55 



49 

 41 



48 



6-7 

 10-3 



90 

 11-3 



55 



70 



•00364 

 •00355 

 00355 



•00298 

 •00280 

 •00280 



26 

 31 

 31 

 29 

 15 

 15 



2-6 10 10 



26 



31 



2-9 



2-7 

 2-6 



2 



3 



4 



5 



6 













Average 



2-8 10 ;0 



These results may be taken as fairly representing all that 

 have been obtained. The agreement between theory and 

 experiment is fully as good as could be expected when all 

 the uncertain elements in the determination are taken into 

 consideration. 



These uncertain elements are : — (1) The actual charges 

 carried by the spheres and the effect of surrounding bodies, 

 especially the plate coated with tinfoil covering the lower 

 end of the magnetometer-tube. This tinfoil is cut into 

 strips about 1 millimetre in width, and its effect must be 

 small. (2) The non-uniformity of distribution of electricity 

 upon the spheres so that the charges cannot be regarded 

 accurately as concentrated at their centres. (3) Errors 

 in reading the deflexion of the needle due to outside dis- 

 turbances. 



Experiments have also been made with the direction of 

 motion of the spheres reversed. The results obtained are 

 similar in every respect to those given above, except that 

 they are reversed. Experiments using only a portion of the 

 10,000 cells of the storage-battery gave results which agree 

 fairly well with the preceding. The deflexions were too 

 small, however, to expect very close agreement. 



Jefferson Physical Laboratory, 

 Harvard University, Cambridge, Mass. 



