Hormell — Dielectric Constant of Paraffins. 439 



placed a number of times in order to test the accuracy with 

 which the relative positions of the coils could be reproduced. 

 In all cases the agreement of the wave lengths was very 

 satisfactory. 



Table II. 



Distance between 





centers of coils. 



Wave length 



2.34mm 



89'80 cm 



3-15 



87-25 



3-46 



84-80 



3-77 



80-20 



4-08 



76-10 



4-39 



73-05 



469 



71-15 



Table II shows the results of this experiment. It will be 

 observed that as the distance between the coils increases the 

 wave length decreases, showing that a decrease in the capacity 

 and mutual induction of the system decreases the period of 

 oscillation. 



(c) Determination of the Relative Velocities of Electrical Waves 

 along Magnetic and Non-Magnetic Wires of Different 

 Diameters. 



In this experiment the coils were 5 cm in diameter and the 

 length of the secondary was 48'5 cm . The coils were kept at 

 the same distance and the Lecher wires were changed. 





Table III. 





Kind of wire. 



Diameter of wire. 



Corrected wav< 



Copper 

 Copper 

 Copper 

 Iron 



1 . 00 mm 



2-00 

 3-40 

 1-00 



81-52 cm 

 80*84 

 80-80 

 81-70 



Iron 



1-25 



81-56 



Iron 



1-80 



80-36 



Iron 



2-60 



80-86 



Copper 

 Nickel 



1-00 

 •93 



00 00 



CO 



00 



German silv 



er 1-00 



80-88 



Brass 



1-00 



81-10 



Copper 

 Secondary 



1-00 



79-26 



Iron 







Secondary 



1-00 



79-44 



