An early 19th-Century lacquered brass and mahogany vacuum pump, signed John Ward 79 Bishops Gate Within London, with double rack action, the gear enclosed within the bridge supported by twin columns and ball finials, with a pair of iron Magdeburg hemispheres, 2 jars and a rare pear-shaped endiometer.

細節
An early 19th-Century lacquered brass and mahogany vacuum pump, signed John Ward 79 Bishops Gate Within London, with double rack action, the gear enclosed within the bridge supported by twin columns and ball finials, with a pair of iron Magdeburg hemispheres, 2 jars and a rare pear-shaped endiometer.
See illustration (2)