Dollar silver. The US Mint continues to make silver $1-denomination coins, but these are not intended for general circulation. The quantity of silver chosen in 1792 to correspond to one dollar, namely, 371.25 grains of pure silver, is very close to the geometric mean of one troy pound and one pennyweight. In what follows, "dollar" will be used as a unit of mass. A troy pound being 5760 grains and a pennyweight being 240 times smaller, or 24 grains, the geometric mean is, to the nearest hundredth, 371.81 grains. This means that the ratio of a pound to a dollar (15.52)
Ancient grains quinoa, amaranth, buckwheat, and chia. Modern wheat is a hybrid descendant of three wheat species considered to be ancient grains: spelt, einkorn, and emmer. The origin of grains goes back to the Neolithic Revolution about 10,000 years ago, when prehistoric communities started to make the transition from hunter-gatherer to farmer. Modern varieties of grains have been developed over time through mutation, selective cropping, breeding and research in biotechnology. Ancient grains, however, are said to be largely unchanged from their initial domesticated varieties. Several ancient grains were worshipped and used by many ancient civilizations, from the Aztecs to the Greeks and