According to popular account, what observation inspired James Hargreaves to conceive the Spinning Jenny?
Answer
Seeing a single-spindle spinning wheel tipped over with the spindle still spinning vertically.
A popular account suggests Hargreaves was inspired around 1764 when he noticed that even when a single-spindle spinning wheel was tipped over, the spindle remained vertical while still spinning, leading him to conceive of multiple simultaneous spindles.

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