Octagonal four blue lenses spectacles – 1830

Octagonal four blue lenses spectacles – 1830

Octagonal four blue lenses spectacles, according to Rosenthal in “Spectacles and other Vision Aids” p. 271, “In 1854, Robert Hunt of England found that sunlight passed through a plano blue lens and then, when focused on a compass needle, could magnetize the needle. No other colored lens accomplished this. Therefore, the blue lens became immensely popular in the 1800s . It was believed to have some mysterious power.”
This pair has plano (no power) blue glass lenses that fold in and out of one’s vision.