Effect of Electrical Convection. 



205 



negatively respectively ; N and S indicate the position of the 

 handle of the reversing-switch ; C is the time required for 

 200 turns of the commutator-shaft, N x and N 2 the time re- 

 quired for 20 complete turns of the speed-counters on the 

 two disks. 



This table is a fair example of the general run of readings. 

 The large variations in the separate determinations of 2 D are 

 due to the fact that the spot of light was always unsteady 

 when the charge on the disks was being rapidly reversed, 

 oscillating over from 10 to 15 millimetres. This unsteadiness 

 was probably due to the fact that the metal case inclosing 

 the coil is not a complete shield against rapidly varying 

 charges. It will also be noticed that at times there was a 

 change of the zero. This was due to variations in the field 

 at the galvanometer due to outside causes. 



In Table IV. are given the mean values of the various 

 factors of a number of sets of determinations, taken between 



Table IV. 



No. 



B. 



I. 



II. 



S. 



V. 



C. 



W, 



2D. 



v. 



il 



208 



+ 



+ 



240 

 240 



10-52 

 10-10 



10-8 

 10-9 



99-0 

 99-4 



65-3 



58-7 



2-84 Xl0 10 

 305 



3 



f > 



- 



+ 



192 



8-51 



121 



90-6 



422 



2-90 



{i 



>> 



+ 



-t- 



214 

 210 



955 

 11-20 



12-5 

 13-5 



1021 

 102 3 



56-5 



77'8 



316 



284 



6 



>> 



+ 



- 



202 



9-81 



132 



99-1 



633 



2-82 



7 



)> 



- 



- 



174 



930 



11-7 



83-5 



363 



2 97 



(^ 



2047 



>> 



+ 



4- 



189 

 189 



10-35 

 10-83 



15-4 

 150 



976 

 776 



63-7 

 53-2 



319 

 309 



10 



>> 



- 



- 



171 



930 



13-4 



899 



410 



3-24 



11 



>» 



+ 



+ 



105 



U-40 



19-8 



86-5 



691 



3-23 



(12 



1 13 



2394 

 »> 



+ 



+ 



88 

 99 



10-41 

 1012 



191 

 176 



83-2 

 89-7 



29-2 

 338 



2-93 

 2-75 



i 14 

 115 



i> 



4- 



4- 



195 

 193 



9-56 

 9-90 



22 

 21-2 



75-6 

 823 



637 



683 



2-83 

 2 87 



(16 



117 





+ 



+ 



190 

 201 



996 



10-31 



20-6 

 208 



87-9 



78-3 



66-2 

 620 



300 



317 

















M 



ean .... 



.. 3-05 xlO 10 



