288 Mr. J. Daniel on the Polarization upon a 



for those of much diminished sound to the maximum sensa- 

 tion in the periods of much increased sound, as given by the 

 measurements of the amplitudes of the resultant curves of 

 the smallest consonant intervals. 



In explanation of the facts and laws given in this paper I 

 have no hypothesis to offer. It appears to me that the 

 present condition of our knowledge of audition demands 

 that we should ascertain more facts relating to it before 

 we frame hypotheses on the mechanism and action of the 

 apparatus of hearing. 



Stevens Institute of Technology, 

 Hoboken, N.J. 



XXIV. A Study of the Polarization upon a Thin Metal 

 Partition in a Voltameter. — Part II. By John Daniel. * 



IN this paper two questions will be discussed : first, the 

 passage of ions through a gold-leaf partition in a volta- 

 meter ; second, the minimum current-strength at which the 

 ions are deposited visibly upon the partition for various 

 electrolytes. This will be called the " critical current." This 

 paper is a continuation of the work done last spring in Berlin 

 in the quantitative measurement of the polarization upon 

 metal partitions ranging in thickness from '0001 millim. to 

 •02 millim. for various current -strengths in a 30-per-cent. 

 H 2 S0 4 voltameter. In those experiments there was no 

 development of gas nor polarization on a gold-leaf partition 

 (•0001 millim. thick) for the highest current used, which was 

 four tenths to five tenths ampere. 



The present apparatus consists essentially of a glass volta- 

 meter vessel with platinum electrodes separated by the metal 

 partition under investigation, so that there is no path for the 

 current except through this partition ; an accurate current- 

 measurer, and a strong, steady battery. The voltameter con- 

 sists of an outer glass jar 8 centim. high, 8 centim. wide, and 

 8 centim. long ; and a glass jar 8 centim. high, 5 centim. 

 wide, and 5 centim. long, placed inside the first jar. A 

 platinum kathode suspended by a platinum wire is placed 

 inside the inner jar, and a similar electrode serves as anode in 

 the larger jar, though a copper anode was sometimes used 

 when the electrolyte was CuS0 4 . A hole 2 centim. in 

 diameter was bored in one side of the smaller jar. Glass 



* Communicated by Prof. O. J. Lodge, D.Sc, F.R.S. 



