88 Table 40 (continued) 



PROBABLE VALUES OF THE GENERAL PHYSICAL CONSTANTS 



F z=Ag/o.ooi 1 1800= (107.880 ±0.001 )/o.ooi 1 1800 int. coul. 

 = 96494. ± 1 int. coul., ( 1 ) 



= 96489. ±5 abs. coul. (2) 



If q=i, as adopted by the H.P., ^ = 96494 int. coul. or abs. coul., the actual 

 value adopted by Henning and Jaeger. If q = 0.99993, as adopted by the I.C.T., 

 there results F= 96487 abs. coul. The I.C.T., however, adopts F = 96500 ±10 

 abs. coul., which with its adopted value of q, leads to F — 96507 int. coul. This 

 last value requires Ag= 107.893, in direct contradiction to facts. F = 96500 

 ± 10 abs. coul. is evidently taken from Vinal and Bates, 1 and to understand the 

 seeming discrepancy, it would be necessary to examine in detail this last quoted 

 work employing the distinction between mass carried in electrolysis and mass 

 deposited (see Doctor Birge's discussion, Phys. Rev., Suppl. 1, 35, 1929). 

 Henning and Jaeger 2 make no distinction between mass carried and mass 

 deposited, writing £^ = 0.00111800 g per int. coul. It seems evident from 

 Vinal and Bouvard 3 that there are inclusions in the silver deposit, tending to 

 make E Ag too large by 4 X io~ 8 g, and F too small by 4 coulombs. There may 

 be small parasitic chemical reactions in the silver voltameter, tending to de- 

 crease the value of E Ag and hence to increase the value of F. It seemed best to 

 adopt the value of F given in eqs. ( 1 ) and (2) , but to assign to E Ag a probable 

 error of 5 X io -8 g, i.e., an error slightly greater than the measured effect of the 

 inclusions. Then 



107.880± 0.001 nnAnA 



= 96494±5 int. coul. (3) 



(1.11800±0.00005)xlO 

 =96489 ±7 abs. coul. 

 = 9648.9 ±0.7 abs. em units, 

 = (2.89270 ±0.00021) x IO 14 abs. es units. 



The electronic charge (e). — The values of a large number of important con- 

 stants depend directly on the value of the electronic charge; in most cases the 

 final probable error is due mainly to the error in e. It is desirable that it 

 be determined in many different ways, and by many different persons. The 

 situation has been the reverse. Only one precision method for the evaluation 

 of e was known, and the work had been carried out by a single individual. 

 It is very fortunate that the investigation referred to is a masterpiece. Milli- 

 kan's 4 investigations extend over more than a decade ; the latest value of e 

 was published in 191 7. The great importance of e, and because higher values 

 have recently been obtained, led Doctor Birge to investigate the matter in more 

 than usual detail. 



Millikan found that if the viscosity of air is taken as constant, in Stokes' 

 law of fall, the apparent value of e is a function of the radius of the drop and 

 of the pressure of the air. The true value of e can be found by assuming a 

 modification of Stokes' law such that his observations could be plotted as a 



1 Bur. Standards Bull., 10, 425, 1914 (p. 447). 2 H.P., 2, 502. 3 Bur. Standards Bull., 

 13, 147. I9!6. "Phys. Rev., 29, 60, 1909; 32, 342, 1911; 2, 109, 1913; Philos. Mag., 34, 1, 

 1917; 19, 209, 1910. 



Smithsonian Tables 



