DISSERTATIO GRADUALIS DE SPECULO USTORIO ARCHIMEDIS

First edition:11 pages, tied with cord, a good copy.

Samuel Duræus was a physicist. Born: 20 May 1718 Died: 8 July 1789. He was a professor at Uppsala University.

Duræus (Samuel) DISSERTATIO GRADUALIS DE SPECULO USTORIO ARCHIMEDIS

Translated into English, the title reads:

Samuel Duræus
Graduation Dissertation on Archimedes’ Burning Mirror

Dissertatio Gradualis: a formal dissertation presented to obtain a degree (often in philosophy, theology, or the sciences) in a university, especially in the 17th–18th centuries.

Speculum Ustorium: literally "burning mirror," meaning a concave mirror or system of mirrors that concentrates sunlight to ignite or destroy objects.

Archimedis: "of Archimedes," referring to the famous ancient Greek mathematician and engineer.

This topic comes from the famous legend that Archimedes defended Syracuse from the Romans by using a giant concave mirror (or array of mirrors) to set enemy ships on fire. Many dissertations in the early modern period debated whether this was historically true, physically possible, or only a myth.