Pennyweight is derived from the price for a hundred nails in 15th century England: the larger the nail, the higher the cost per hundred. The pennyweight also bears no relation to the weight of the American "penny" (1 cent) coin, which weighs 2.5 g (for those minted after 1982). Pennyweight A pennyweight (abbreviated dwt, from denarius weight) is a unit of mass that is equal to 24 grains, of a troy ounce, of a troy pound, approximately 0.054857 avoirdupois ounce and exactly 1.55517384 grams. In the Middle Ages, a British penny's weight was literally, as well as monetarily, of an ounce
Five Grains behavior towards the Five Grains could take on political meaning: as a protest against the overthrow of the Shang Dynasty by the Zhou, Boyi and Shuqi ostentatiously refused to eat the Five Grains. Such rejections of the grains for political reasons underwent a complex development into the concept of "bigu", the esoteric Taoist practice of achieving immortality by avoiding certain foods. By the time of written records, the development of agriculture in China had become greatly mythologized. There were various traditions regarding which of the early Chinese leaders introduced the Five Grains: Shennong (神农) ( "Divine Farmer") was a Chinese