96 Mr. G. Udny Yule. [June 15, 



22. The Experiment. In the experiments performed hitherto, I 

 have made the abnormal part of the conductor by hanging upon the 

 wires of the long secondary sheets of tinfoil 32 cm. deep, the length 

 varying up to 10'5 m. Several observations of the electrometer 

 throws are taken without the condenser, several with the condenser 

 1 m. long, several with the condenser 2 m. long, and so forth ; check 

 observations being taken while the condenser is being shortened 

 again. Curve No. 2 is plotted with condenser lengths as abscissae, 

 and electrometer throws as ordinates ; these latter, however, being 

 reduced to the scale, electrometer throws without condenser equals 

 unity. They thus compare with the values of I//I in curve No. 1. 

 The wave-length used was KI = 9 m. 



23. It is seen that the experimental curve thus obtained agrees in 

 its general form with that plotted from theoretical considerations. 

 Exact coincidence of theory and experiment cannot at this stage be 

 expected. I have, accordingly, made no attempt to plot a curve 

 from equation (18) with values of the constants which profess to 

 exactly represent those involved in the experiment. 



24. I am aware of two chief sources of disturbances in the experi- 

 mental conditions, but have already shown that they are not of such 

 order as to invalidate the above results, which, therefore, hold good 

 as first approximations. 



25. As the present paper is only a preliminary one, intended to 

 give an outline of the theory and experiment, I will not now enlarge 

 upon the topic of disturbances. I am still engaged on these inter- 

 ference phenomena, and hope to publish a full account of the results 

 next session. 



In conclusion, I wish to express my great indebtedness to Professor 

 Hertz, both for first directing my attention to the subject of these 

 reflections, and also for his invaluable advice in the course of the 

 work. 



VI. " On Interference Phenomena in Electric Waves passing 

 through different Thicknesses of Electrolyte." By G. 

 UDNY YULE. Communicated by Professor G. CAREY 

 FOSTER, F.R.S. Received May 31, 1893. 



In the spring of 1889 Professor J. J. Thomson published* a descrip- 

 tion of some experiments made by him for comparing the resistances 

 of electrolytes to the passage of very rapidly alternating currents, the 

 method consisting in comparing the thicknesses of layers of different 

 electrolytes which were equally opaque to Hertzian radiation. During 



* ' Roy. Soc. Proc.,' vol. 45, p. 269, 1889. 



