Apothecaries' system measure precious metals and stones. (The troy pound was already declared illegal for most other uses by the Weights and Measures Act of 1878.) In the US, the metric system replaced the apothecaries' system in the United States Pharmacopoeia of 1971. Apothecaries' system The apothecaries' system or apothecaries' weights and measures is a historical system of mass and volume units that were used by physicians and apothecaries for medical recipes, and also sometimes by scientists. The English version of the system is closely related to the English troy system of weights, the pound and grain being exactly the same in
Synthesis of precious metals normal to allow used nuclear fuel to stand for about five years before reprocessing, much of this activity will decay away leaving 4.7 MBq of Rh and 5.0 MBq of Rh. If the rhodium metal was then left for 20 years after fission, the 13.3 grams of rhodium metal would contain 1.3 kBq of Rh and 500 kBq of Rh. Rhodium has the highest price of these precious metals ($25,000/kg in 2015), but the cost of the separation of the rhodium from the other metals needs to be considered. Palladium is also produced by nuclear fission in small percentages, amounting