|Jews carding cotton|
What does carding cotton mean? How is it done?
Carding is a process of taking unprocessed fibers, such as wool or cotton, and untangling, cleaning and mixing the strands.
When done manually, carding was usually done with a brush-like tool, or "card." In the 18th and 19th centuries machines were invented to card fiber.
These Jewish men, however, are using another ancient method discussed in Wikipedia:
Historian of science Joseph Needham ascribes the invention of bow-instruments used in textile technology to India. The earliest evidence for using bow-instruments for carding comes from India (2nd century CE). These carding devices, called kaman and dhunaki would loosen the texture of the fiber by the means of a vibrating string.