264 



Messrs Burton and Phillips, 



A measured current was then passed through the tin-foil and 

 similar readings taken, the results being given in Table II. 



Table II. 



Force on Block and Conductor carrying Current. 



Current in Foil in 



Currei 



it for Weight in Pan 



Pull due to Field 



milli-amperes 



Mag 



net in grams 



in grams 



40-7 



an 



ips. 39-054 





40-6 



8 , 



39-160 



+ •107 



40-6 



, 



39-053 



40-6 



10-2, 



39-168 



+ •115 



40-7 



, 



39-053 



40-7 



12 , 



39-170 



+ •117 



40-9 



, 



39-053 



40-8 



14-9, 



39-170 



+ •117 



40-8 



, 



59-053 



40-8 



17-4, 



39-173 



+ •121 



40-9 



, 



39-052 







, 



39-052 





Table III. 

 Calculated Values of Field. 



Current in 

 Electro- 

 magnet 



8 amps. 

 10-2,, 

 12 „ 

 14-9,, 



Pull on wood 



with no current 



through Foil 



•031 grm. 

 •038 „ 

 •043 „ 

 •051 „ 



Pull on block 

 with current 

 through Foil 



+ "107 grm. 

 + •115 „ 

 + •117 „ 

 + •117 „ 



Pull due to 



current in 



Foil 



+ "138 grm. 

 + •153 „ 

 + •160 „ 



+ •168 „ 



Strength of 

 Field, 

 lOPgjli 



10200 units 

 11300 „ 

 11790 „ 

 12360 „ 



Table III prepared from the two former tables gives in 

 column IV the force due only to the current through the foil and 



in column V the calculated values for the field, i.e. 



10P<7 

 li 



corre- 



sponding to the different values of the current through the 



