After removing particles larger than No. 40 sieve size, prepare
a pat of moist soil with a volume of about 1/2 cubic inch.Add enough water, if necessary, to make the soil soft but not
sticky.The proper moisture content
for running the test is when tapped, the soil pat will flatten out on
hand.If the soil pat remains the
same shape, the material is too dry; if the soil pat runs between fingers, the
is too wet.
Place the pat in the
open palm of one hand and shake horizontally, striking vigorously against the other hand several
times.A positive reaction consists of
the appearance of water on the surface o f the pat which changes to
a livery consistency and becomes glossy.When the sample is squeezed between the fingers, the water and gloss disappear from the
surface, the pat stiffens and finally it cracks or crumbles.The rapidity of appearance of water during
shaking and of its disappearance during squeezing assist in identifying the character of the
fines in a soil.
Very fine clean sands
give the quickest and most distinct reaction whereas a plastic clay has no reaction.Inorganic silts, such as a typical rock
flour, shows a moderately quick reaction.