172 Dr. 0. 11. Alder Wright on the Determination of 



early determination of the absolute value of a Jacobi resistance- 

 unit by W. Weber ; after correction they indicate a value 

 for J of 431*6 in gravitation measure, or, assuming #=981, 

 of 42-84 megalergs ; and, next, those of Joule himself, those 

 of H. F. Weber above quoted, and those of the author and 

 Mr. Rennie (Part II.), which yield the following results : — 



Value of J, the B. A. unit 

 being supposed to Ibe exactly 

 1 earth-quadrant per second. 

 Von Quintus Icilius (corrected by 1 about 43.34 mega lergs, 



H. F. Weber) J 



Joule (1867, vide § 33), the results 1 



of which investigation have been > above 42*10 „ 

 shown to be too low (§ 54) . ) 



H. F. Weber*, 42'02 x i^j? . . 41-93 „ 



Alder Wright and Bonnie (value \ aboye 41 . 96 



slightly too low) .... J 



Moreover, as stated above, H. F. Weber has calculated, from 

 Regnault's and Rontgen's experiments on the specific heats of 

 air &c, that J = 42*10 megalergs. Hence, finally, taking 

 into account all the above experiments, the most probable 

 value of J lies close to 42 megalergs, being above rather than 

 below that value. Until further authoritative determinations 

 finally settle the question as to the true values of the B.A. unit 

 and of J, the former may, as above stated, be considered to be 

 exactly 1 earth-quadrant per second, and the latter may be 

 safely taken as being 42 megalergs, most probably lying be- 

 tween 41*75 and 42*25 megalergs. In the following parts of 

 of this paper, consequently, J is taken =42 X 10 6 C.G.S. units, 

 a%J, the factor for reducing gramme-degrees to E.M.F. units 

 (volts), is taken as being =0*000105 x 42 x 10 6 =4410*0. 



General Conclusions from the results of previous experimenters, 

 and those svbsequently detailed : Statement of Theorem relative 

 to Polarization and the Nature of Electrolysis and the Amount 

 of Work done therein. 



57. It has been shown in Part I. (§§ 13-17) that the work 

 expended in decomposing an electrolyte into the "nascent" 

 products of electrolysis is not necessarily the same as that 

 performed in breaking it up into the final products of electro- 

 lysis, and that by determining (in terms of E.M.F. or other- 



* "Weber's result refers to air-thermometer temperatures, those of the 

 other experimenters to temperatures measured by the mercurial thermo- 

 meter and not reduced to air-thermometer readings. 



