Effect of Electrical Convection. 

 accuracy of measurement. Hence for the two disks 



41 



A 1 C Vm 



«=4-18 lir> 



and for the single disk 



= 2-0(3 



,VNd 



D 



Below are given the mean values, determined from a series 

 o£ observations similar to that recorded in Table I., of the 

 variable quantities in the above formulae for the various 

 speeds and potentials employed. Those sets in which the 

 single disk was used are marked with a "*. 



Table II. 



1. 



2d. 



2D. 



N. 



v - 



v. 



•103x10-4 



20-5 



15-5 



994 



5690 



3-03 xlO 10 



•229 



38-8 



36-8 



25 6 



6250 



3-08 



•389 



72-9 



81-5 



49-2 



6275 



2-98 



•577 



=92-6 



83-9 



63-0 



5960 



3-00 



•792 



113-4 



115-8 



924 



6230 



2-98 



From former 



paper 



67-2 



1022 



3110 



3-00 



•0813 



20-5 



18-8 



59-4 



905 



3-0 L 



•134 



26-0 



32-7 



59 6 



2030 



3-00 



* -1005 



18-7 



220 



59-2 



2950 



304 



*-249 



83-5 



561 



57-6 



4090 



292 



* -249 



47-1 



38-1 



57-9 



5010 



2-97 



*-273 



540 



47-1 



58-4 



5900 



2-98 











Mean . 



.. 300 



Surely no more conclusive refutation of M. Cremieu's 

 criticism could be desired than that contained in the above 

 results. Such close agreement between the observed and 

 calculated effect under such varying conditions cannot be 

 ascribed to the effect of a conduction current caused by any 

 leak in the insulation, for such a current would certainly, 

 from its very nature, be independent of the speed. It is to 

 be noted, however, that the exact coincidence of the value 

 of v as determined from the above experiments with its known 

 value must be considered as an accident only, for an error of 

 at least one per cent, might readily have occurred in the 

 determination of the constants of the apparatus. 



In one of his experiments on the magnetic effect ot' a 

 rotating charged disk on a magnetic needle suspended near 



