Silt three grades fine, medium and coarse 0.002 mm to 0.006 mm to 0.020 mm to 0.063 mm). In actuality, silt is chemically distinct from clay, and unlike clay, grains of silt are approximately the same size in all dimensions; furthermore, their size ranges overlap. Clays are formed from thin plate-shaped particles held together by electrostatic forces, so present a cohesion. Pure silts are not cohesive. According to the U.S. Department of Agriculture Soil Texture Classification system, the sand–silt distinction is made at the 0.05 mm particle size. The USDA system has been adopted by the Food and Agriculture Organization (FAO).
Henry Classification System (CID). In the same year, the first UK fingerprint bureau was established at Scotland Yard. (Harling 1996) (Met) (Early) The Henry Classification System allows for logical categorization of ten-print fingerprint records into primary groupings based on fingerprint pattern types. This system reduces the effort necessary to search large numbers of fingerprint records by classifying fingerprint records according to gross physiological characteristics. Subsequent searches (manual or automated) utilizing granular characteristics such as minutiae are greatly simplified. The Henry Classification System is a method to classify fingerprints and exclude potential candidates. This system should NEVER be used for individualization. The Henry Classification