Hostname: page-component-78c5997874-g7gxr Total loading time: 0 Render date: 2024-11-03T05:29:47.843Z Has data issue: false hasContentIssue false

Gas and vapour movements in the soil: I. The diffusion of vapours through porous solids

Published online by Cambridge University Press:  27 March 2009

H. L. Penman
Affiliation:
Soil Physics Department, Rothamsted Experimental Station, Harpenden, Herts

Extract

The dependence of the coefficient of diffusion, D, upon the porosity, S, of a granular solid is investigated experimentally. For steady state conditions, using carbon disulphide and acetone vapours, it is shown that a curve connecting D/D0 and S can be drawn which is independent of the nature of the solid, its moisture content and, within limits, its texture. For a limited range of values of S (0·0 < S < 0·7) a good approximation is D/D0 = 0·66S and over this range the diffusion coefficients are larger than those found by Buckingham for carbon dioxide.

Investigation of the non-steady state shows that in soils the attainment of pressure equilibrium is retarded by adsorption, and it is suggested that Buckingham's low values for steady-state conditions can be attributed to premature observations of the diffusion rates; the steady state had probably not been attained when his measurements were made.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1940

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFEEENCES

Buckingham, G. (1904). Bull. U.S. Dep. Agric. no. 25.Google Scholar
Cabman, P. C. (1939). J. agric. Sci. 29, 262.Google Scholar
Chapman, S. (1928). PUl. Mag. 5, 630.Google Scholar
Higgins, J. C. & Pollard, A. G. (1937). Ann. appl. Biol. 24, 895.CrossRefGoogle Scholar
I.C.T. (International Critical Tables) (1929). 5, 62. New York.Google Scholar
Keen, B. A. (1931). The Physical Properties of the Soil, chap. 10. London.Google Scholar
Melloe, J. W. (1925 a). Comparative Treatise on Inorganic and Physical Chemistry, 6, 99. London.Google Scholar
Melloe, J. W. (1925 b). Comparative Treatise on Inorganic and Physical Chemistry, 6, 109. London.Google Scholar
Romell, L.-G. (1922). Medd. Stat. Skogsforsoks. 19, 125.Google Scholar
Smith, F. B. & Brown, P. E. (1933). Soil. Sci. 35, 413.CrossRefGoogle Scholar
Trautz, M. & Müller, W. (1935). Ann. Phys., Lpz., 22, 313.CrossRefGoogle Scholar