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Are all the raised areas sitting on top of the jackscrews (where used) from 170 years ago? That itself is astounding.

No the Jackscrews would have been removed for reuse after the lift.

By the way you can still buy jacks like these. They're considered safer than hydraulic jacks and are often called "house jacks":

No, as the article states they raised the buildings then built a new foundation underneath.