Uncovering the past

Julia Lawson’s gloved hand moves with short, precise strokes, each pass of her scalpel kicking up a small cloud of ancient dust and rock particles.

Little by little, she reveals a piece of history underneath the rocky crust: a 4,500-year-old bronze knife blade from the cradle of civilization.

Spread on a table before her in a lab at the University of Pennsylvania Museum of Archaeology and Anthropology are dozens of similar items — fragile bowls, arrowheads and tools from the Mesopotamian city of Ur.