TITLE:
Fick’s Diffusion Experiments Revisited —Part I
AUTHORS:
Tad W. Patzek
KEYWORDS:
Salt Diffusion, Medical, Physics, Tube, Funnel, Experiment, Pogendorff Annalen
JOURNAL NAME:
Advances in Historical Studies,
Vol.3 No.4,
September
30,
2014
ABSTRACT: In this paper, we revisit Fick’s original diffusion experiments and reconstruct the geometry of his
inverted funnel. Part I demonstrates that Fick’s experimental approach was sound and measurements
were accurate despite his own claims to the contrary. Using the standard modern approach,
we predict Fick’s cylindrical tube measurements with a high degree of accuracy. We calculate that
the salt reservoir at the bottom of the inverted funnel must have been about 5 cm in height and the
unreported depth of the deepest salt concentration measurement by Fick was yet another 3 cm
above the reservoir top. We verify the latter calculation by using Fick’s own calculated concentration
profiles and show that the modern diffusion theory predicts the inverted funnel measurements
almost as well as those in the cylindrical tube. Part II is a translation of Fick’s discussion of
diffusion in liquids in the first edition of his three-volume monograph on Medical Physics published
in 1856, one year after his seminal Pogendorff Annalen paper On Diffusion.