Skip to main content
U.S. flag

An official website of the United States government

Dot gov

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Https

Secure .gov websites use HTTPS
A lock ( ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Pear Shaped Weights

Two one pound weights sitting on top of wood boxes

These weights – 1 lb troy (left) and 1 lb avoirdupois (right) – were part of a group of five weights made in England and procured by the instrument-maker, William Simms, for the United States in 1837.

Created March 30, 2017, Updated January 11, 2018