Mechanical screening of soil through a shaker screen does not recover all artifacts, particularly ones smaller than 1/4 inch. In special circumstances, in feature fill situations or other places where the recovery of small items is needed, water screening is an alternative process. This water screening device is used in the laboratory or in the field to clean and examine soil samples taken from archaeological features and sites. This method, called flotation method was developed to retrieve small organic materials, such as seeds and bone fragments, as well as tiny flint chips, from archaeological deposits. The flotation method vastly improves the amount of information archaeologists can retrieve from soil samples at a site, in particular with respect to the diet and environment of past societies.
By the way, this machine is called a Flote-Tech, and as far as I am aware, it is the only manufactured flotation machine available on the market. It is a terrific piece of hardware, and built to last forever. Discussions about its efficacy have appeared in American Antiquity lately:
Hunter, Andrea A. and Brian R. Gassner 1998 Evaluation of the Flote-Tech machine-assisted flotation system. American Antiquity 63(1):143-156.
Rossen, Jack 1999 The Flote-Tech flotation machine: Messiah or mixed blessing? American Antiquity 64(2):370-372.
By the way, this machine is called a Flote-Tech, and as far as I am aware, it is the only manufactured flotation machine available on the market. It is a terrific piece of hardware, and built to last forever. Discussions about its efficacy have appeared in American Antiquity lately:
Hunter, Andrea A. and Brian R. Gassner 1998 Evaluation of the Flote-Tech machine-assisted flotation system. American Antiquity 63(1):143-156.
Rossen, Jack 1999 The Flote-Tech flotation machine: Messiah or mixed blessing? American Antiquity 64(2):370-372.
