Dallmeyer projection lens, late 19th century.

Eight kinds of cameras and lenses, mid to late 19th century.

Boy with hoop, opalotype, late 19th century.

X-ray experiment, late 19th-early 20th century.

Surgeon's tools and case, late 18th or early 19th century.

Josef Max Petzval, Hungarian mathematician, late 19th century.

Gold open-faced lever pocket watch, 1847.

Gold open-faced lever pocket watch, 1847.

Gold open-faced lever pocket watch, 1847.

Gold open-faced lever pocket watch, 1847.

Artificial hand in a leather glove, Europe, late 19th-20th century.

Sir Arthur Cayley, English mathematician, late 19th century.