Comparison of the imperial and US customary measurement systems metre, as 1852 metres. Traditionally, both Britain and the US used three different weight systems: troy weight for precious metals, avoirdupois weight for most other purposes and apothecaries' weight for medicines. However, apothecaries' weight has now been superseded by the metric system. One important difference is the widespread use in Britain of the stone of 14 pounds () for body weight. This unit is not used in the United States, although its influence was seen in the practice, until World War II, of selling flour by a barrel of 196 pounds (14 stone). Another difference arose when Britain abolished the
Reuse of excreta Black Soldier Fly larvae with feces. The mature flies would then be a source of protein to be included in the production of feed for chickens in South Africa. It is known that additions of fecal matter up to 20% by dried weight in clay bricks does not make a significant functional difference to bricks. A Japanese sewage treatment facility extracts precious metals from sewage sludge. This idea was also tested by the US Geological Survey (USGS) which found that the sewage sludge generated by 1 million people contained 13 million dollars worth of precious metals. Debate is ongoing about