140 



TABLES 126-127. 



DIFFUSION OF GASES, VAPORS, AND METALS. 

 TABLE 126. Coefficients of Diffusion for Various Gases and Vapors. 



* Compiled for the most part from a similar table in Landolt & Bornstein's Phys. Chem. Tab. 



TABLE 127. Diffusion of Metals into Metals. 



do 



dt 



,d^v where x is the distance in direction of diffusion; v, the degree of concentration of 

 'd x i' the diffusing metal; /, the time; A, the diffusion constant = the quantity of metal 

 in grams diffusing through a sq. cm. in a day when unit difference of concentra- 

 tion (gr. per cu. cm.) is maintained between two sides of a layer one cm. thick. 



From Roberts- Austen, Philosophical Transactions, i87A, p. 383, 1896. 

 * These values are from Guthrie. 



SMITHSONIAN TABLES. 



