Weighing scale
The balance (also balance scale, beam balance and laboratory balance) was the first mass measuring instrument invented. In its traditional form, it consists of a pivoted horizontal lever with arms of equal lengththe beamand a weighing pan suspended from each arm (hence the plural name ""scales" for a weighing instrument). The unknown mass is placed in one pan and standard masses are added to the other pan until the beam is as close to equilibrium as possible. In precision balances, a more accurate determination of the mass is given by the position of a sliding mass moved along a graduated scale. Technically, a balance compares weight rather than mass, but, in a given gravitational field (such as Earth's gravity), the weight of an object is proportional to its mass, so the standard masses used with balances are usually labeled in units of mass (e.g. g or kg).
Thaddeus Fairbanks
These platform scales revolutionized weighing methods of large loads that has been in use ever since. Portable platform scales are found in almost every hardware store, physician's office, and manufacturing factory throughout the United States. The first railway track platform scale patent was granted to Fairbanks on January 13, 1857, as Patent No. 16,381. In 1916 the company was purchased by Fairbanks, Morse and Company. Ownership of the company has since changed several times, but Fairbanks Scales continue to be made in St. Johnsbury to this day.