The British pint is about 20% larger than the American pint since the two systems are not compatible. Almost all other countries have standardized on the metric system, so the size of what may be called a pint varies depending on local custom.
It is usually measured by the depth (in mm) of the water layer that can enter the soil in one hour. An infiltration rate of 15 mm/hour means that a water layer of 15 mm on the soil surface, will take one hour to infiltrate. In dry soil, water infiltrates rapidly.
Soils are assigned to 4 hydrologic groups and 3 dual groups. Group A - high infiltration rate when wet, low runoff potential. Group B - moderate infiltration, low runoff potential. Group C - slow infiltration, higher runoff potential. Group D - very slow infiltration rate, highest runoff potential. The dual groups are A/D, B/D, and C/D. These are used for certain wet soils that can be adequately drained. The leading letter refers to the drained condition and the second letter is