1893.] Circuits of Measurable Inductance and Capacity, $c. 11 



That this latter is only very partially due to eddy currents in the 

 iron was shown by repeating the experiment with a brass rod of 

 2 cm. diameter inserted in the coil. The curve obtained is only 

 slightly (though distinctly) different from that obtained without 

 any core. 



Experiments have also been begun on the decay of current in 

 circuits containing iron and of negligible capacity. The coil possess- 

 ing the inductance forms one arm of a Wheatstone's bridge. These 

 experiments were commenced as far back as June, 1890 ; the experi- 

 ments described above were commenced in January, 1891. Both 

 series were suspended for want of a sufficiently precise interruptor. 

 This has since been obtained, and satisfactory work has thus been 

 made possible. The investigation is only in an early stage ; but the 

 fact that at least one other observer* is already working in the same 

 field induces me to present this preliminary note in order to show the 

 independence of our work. 



* P. Janet. See ' Comptes Kendus,' vol. 115, Nos. 21 and 26 ; vol. 116, No. 8, 



