The moisture equivalent was introduced by

The moisture equivalent was introduced by Lyman Brigg and McLane in 1910 as a measure of field capacity for fine-textured soil materials.
Moisture capacity is defined as the percentage of water that a soil can retain in opposition to a centrifugal force 1000 times that of gravity.
It is measured by saturating a sample of soil 1 cm thick, and subjecting it to a centrifugal force of 1000 times gravity for 30 min. the gravimetric water content after this treatment is its moisture equivalent.