178 Profs. Richardson and Cooke on the Heat developed 



G 



so that no current flowed 



through 



the 



cells Ci, Ug on, 



galvanometer G-. The cells C l5 C 2 were then made to 

 oppose one another, and it was found, as was to be expected, 

 that when the battery between E and the sliding contact was 

 turned on there was a deflexion of the galvanometer Gr which 

 could be stopped by suitably adjusting R 4 . It was now found 

 that after putting C 2 and C 2 in series there was no deflexion 

 in the galvanometer Gr, whether the potential difference 

 between E and the sliding contact was on or off, showing 

 that the method of compensating worked satisfactorily. 



Fig. 2. 



G 



30 E 



G 



The construction of the part of the apparatus containing 

 the grid and filaments is shown in detail in figure 2. The 



