of Organic Bodies, fyc, at very Loiv Temperatures. 265 



Using the 500-ohm galvanometer and an electromotive force of 

 9*88 volts we found 153 as the dielectric constant of the frozen 

 electrolyte at the temperature of liquid air. Employing the 4-ohm 

 galvanometer and 79*5 volts we found 175 as the dielectric constant. 



All the above observations were taken at the temperature of 

 liquid air and with an electromotive force frequency of 120. It is, 

 therefore, quite clear that as far as these two frozen electrolytes are 

 concerned, raising the charging voltage to a value far above that of 

 the average electromotive force of polarisation does not bring down 

 these abnormal values of the dielectric constant. On the other 

 hand, a relatively small decrease in the temperature or increase in 

 the frequency at low temperatures suffices to reduce the dielectric 

 value of these frozen hydrates very considerably.* We may, there- 

 fore, say that the contention put forward by R. Abegg that the high 

 dielectric values we have found for certain substances at the liquid 

 air temperature are really polarisation capacities, does not seem to be 

 borne out by the results of further experiment, and for the following 

 reasons : — 



(i) Because a very great increase in the charging electromotive 



force does not in any corresponding degree reduce the 

 abnormally high dielectric values of certain frozen electro- 

 lytes to much smaller values. 



(ii) Because when in the course of observations to construct a 



temperature dielectric curve, the working electromotive 

 force has been changed from a value below the counter- 

 electromotive force of polarisation to a value far above it, 

 there is no break or discontinuity in the curve of dielectric 

 value. 



(iii) Because the great difference between quite similar electro- 



lytes, such as the 10 per cent, solution of potassic and sodic 

 carbonates, in respect of dielectric constant at equally low 

 temperatures and under equal charging electromotive forces 

 is left unexplained. 



(iv) Because in the case of many substances, such as frozen 



ammonic hydrate, ice, and oxide of copper in suspension in 

 ice, at very low temperatures, we find high dielectric values 

 even though employing alternating currents of fairly high 

 frequency (350 ) . 



* The effect of increased frequency of electromotive force reversals in decreasing 

 the dielectric constant is evidently dependent upon the temperature as well as on the 

 physical state of the body. In the case of water an increase in the frequency from 

 zero to 10 6 hardly affects the dielectric constant at all. In the case of ice at 0°C. 

 the same increase in frequency reduces the dielectric constant from 80 to between 

 2 and 3. In the case of ice at — 50° C, as we have shown above, an increase in 

 frequency from 120 to 350 reduces the dielectric constant from about 60 to about 

 3-6. (December 21, 1897.) 



VOL. LXII. U 



