50 Table 29. 



DIFFUSION. 



2 pi e-'fi dq. 

 Inverse* values of vie =\ — tt I 



log X = log (2q) + \o%\/kt. t expressed in seconds. 

 = log 5 + logV-^^- t expressed in days. 

 = log 7 + log \/kt. " " years. 



(. ^ = coefficient of diffusion.t 

 c = initial concentration. 

 V = concentration at distance x, time t. 



• Kelvin, Mathematical and Physical Papers, vol. III. p. 428 ; Becker, Am. Jour, 

 of Sci. vol. III. 1897, p. 280. t For direct values see table 33. 



Taken from unpublished manuscript of C. E. Van Orstrand. 

 Smithsonian Tables. 



