Milner's lamp. A hollow semi-cylinder, but not with a circular curve, revolved on pivots. The curve was calculated on the law that, whatever quantity of oil might be in the lamp, the position of equilibrium just brought the oil up to the edge of the cylinder, at which a bit of wick was placed. As the wick exhausted the oil, the cylinder slowly revolved about the pivots so as to keep the oil always touching the wick.
<a href="//commons.wikimedia.org/wiki/Augustus_De_Morgan" title="Augustus De Morgan">Augustus De Morgan</a>
1872
<a rel="nofollow" class="external text" href="https://www.gutenberg.org/ebooks/23100"><i>A Budget of Paradoxes, Volume I.</i></a>, available freely at <a href="https://en.wikipedia.org/wiki/Project_Gutenberg" class="extiw" title="w:Project Gutenberg">Project Gutenberg</a>