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.
The infiltration rate is determined as the amount of water per surface area and time unit that penetrates the soils. The diameter of the inner ring should be approximately 50% to 70% of the diameter of the outer ring, with a minimum inner ring size of 4-inches, preferably much larger. (Bouwer, 1986).