846 Mr. R. T. Lattey on the Dielectric 



having the same external dimensions, but with a greater 

 distance between its plates. When this was filled with 



Fig. 8. 

 L 



I — TjinRp — I 



water its capacity (V) was not very different from that 

 of C . By noting the value of C, which brought the circuit 

 into tune with wave of known frequency, first with C a and 

 then with x in the circuit, the relative values of C a and x 

 could be calculated. The results are shown in Table XIII. 



Table XIII. — Capacity of Water Condenser (#), 

 taking Air Condenser as 0*465. 

 Inductance. L . L x , L 2 . L 3 . L 4 . L-. L 6 . Mean. 



\= 17-15 -5637 -537 '550 



19-2 -5602 '5540 -517 '5640 -5688 -553 



19-85 '5750 ... -5687 '5968 -580 



25-7 -5818 -5526 -567 



31-7 -5965 -5697 '5767 ,." ... "581 



33-4 -5504 -5783 -564 



35-45 -6042 



41-8 '5592 -559 



47-4 573 -573 



52-3 '566 ... -566 



Mean... -570 '569 -579 -5645 ... -5655 -5675 -568 



The only corrections applied to the above results is a small 

 one due to the conductivity of the water; the variations from 

 the general mean are only such as may be expected from 

 the probable experimental errors of the method, and show 

 no trace of any connexion with frequency. Marx 39 has 

 shown that D for water is constant between \ = 11'1 and 

 A, = 17'8 metres. 



IX. Summary. 



The methods in use for finding the dielectric constant 

 of water and of solutions are criticised, and a method is 

 described by which the necessary corrections for con- 

 ductivity may be applied. 



