<div class="description">
This mezzotint print portrait of Jesse Ramsden was produced by printmaker John Jones after a painting by Robert Home at the Royal Society. Ramsden (1735–1800) was an English mathematician, and an astronomical and scientific instrument maker. In both the painting and print, he sits in a chair with his right arm resting on the circular dividing engine that he built in the early 1770s. The divider produced graduated arcs for the sextants and octants that would enable British navigators to determine their positions at sea. In the background is the great astronomical circle of 1789 that Ramsden built for the observatory at Palermo, Sicily, which was used to measure apparent positions of astronomical objects.</div>
This file was contributed to Wikimedia Commons by <a href="https://en.wikipedia.org/wiki/en:Science_History_Institute" class="extiw" title="w:en:Science History Institute"><span title="library, museum, and archive in Philadelphia, United States">Science History Institute</span></a> as part of a cooperation project. The donation was facilitated by the <a href="https://en.wikipedia.org/wiki/Digital_Public_Library_of_America" class="extiw" title="w:Digital Public Library of America">Digital Public Library of America</a>, via its partner PA Digital.<span style="text-align:left">
<ul><li><a rel="nofollow" class="external text" href="https://digital.sciencehistory.org/works/4x51hj71h">Record in source catalog</a></li>
<li>DPLA identifier: <a rel="nofollow" class="external text" href="https://dp.la/item/61575209a87ac937287c241635d86e36">61575209a87ac937287c241635d86e36</a></li>
<li>Science History Institute identifier: padig:SHI-4x51hj71h</li></ul></span>