
3 6 c m
40cm
actual image size: 32cm x 28cm
Description
Spectacles have been in use in the West for at least 700 years. The earliest had convex lenses and they were worn by people with long sight, to help them focus on nearby objects. Later, concave spectacle lenses were made for people with short sight. In 1784 Benjamin Franklin (1706-1790) invented 'bifocals' - spectacles split into two parts, each with a different focal length.
Image Details
Image Ref.
10311681
© Science Museum / Science & Society Picture Library