Publication
We examine the development of instability studies in the oil industry and in soil physics, the former being far more advanced has tended to mold the latter. This had some unfortunate consequences as oil studies tended to rely heavily on Hele-Shaw cells, which provide a poor model for soils. In soil physics creation of column flow in soils has serious implications for infiltration and the transport of pollutants. It is to John Philip's credit that he recognized fairly early the practical importance of instability in soils.
Alessio Ferrari, Gianluca Speranza