Earle's pelvimeter, with parallel blades pivoted from tension spring handles with distal imperial scale, steel, circa 1850, by Wood(?)

A pelvimeter measured the pelvic diameters of pregnant women. Compression of the ebony handles opened the blades. This allowed measurements to be read off the sliding scale. This was part of a scientific attempt to identify those women most likely to experience obstructed labour. The technique is called pelvimetry. It was developed during the late 1700s by Frenchman Jean Louis Baudelocque (1746-1810). This pelvimeter was designed by Dr Earle of Birmingham. It was made by instrument maker Wood.