The stone (abbreviation st) is a unit of measure equal to 14 pounds avoirdupois (about 6.35 kg [nb 1]) used in Great Britain and Ireland for measuring human body weight. In many Northwestern European countries the stone was formerly used for trade, with a value ranging from about 5 to 40 local pounds (3 to 15 kg).
In 1882 Edison helped form the Edison Electric Illuminating Company of New York, which brought electric light to parts of Manhattan. But progress was slow. Most Americans still lit their homes with gas light and candles for another fifty years. Only in 1925 did half of all homes in the U.S. have electric power.