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 material 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.