Vernier scales and other early devices for precise measurement

Vernier scales have been extensively used since the 17th century. They replaced the Nonius scale, a unpopular device due to difficulty in its fabrication and use, and they coexisted alongside other types of scales that increased measurement precision and accuracy in complementary ways. I suggest that the success of Vernier and diagonal scales is due not only to simplicity of fabrication, but also to their exploitation of visual hyperacuities. (C) 2011 American Association of Physics Teachers. [DOI: 10.1119/1.3533717]