"Background Illumination" for the light microscope after J. B. Reade (1837) as described by John Queckett, 1855. Description from the original publication: <br><i>a b</i> represents the stage of the microscope in an inclined position; <i>c</i> a condensing lens placed below and on one side of the stage; <i>d</i> a lamp also placed below the stage and at some distance from it; the rays of light <i>r r r' r'</i> emanating from the lamp,are thrown obliquely upon the object <i>e</i>, and only those that are refracted by the glass, or by the object under examination, will pass through the comound body to the eye: some objects, when viewed in this way, will appear beautifully illuminated on a field of view that is nearly, if not quite, dark.
John Queckett
<ul><li>Dieter Gerlach, Geschichte der Mikroskopie. Verlag Harry Deutsch, Frankfurt am Main, Germany, 2009. <a href="//commons.wikimedia.org/wiki/Special:BookSources/978-3-8171-1781-9" title="Special:BookSources/978-3-8171-1781-9">ISBN 978-3-8171-1781-9</a>.(Accompanying CD-ROM)</li>
<li>Original Source: John Queckett, Practical Treatise on the Use of the Microscope, 1855, page 195 (in second edition). Google Books version of the second edition, 1855: <a rel="nofollow" class="external free" href="https://books.google.de/books?id=sHOanQkmpRcC&amp;hl=de&amp;pg=PA195#v=onepage&amp;q&amp;f=false">https://books.google.de/books?id=sHOanQkmpRcC&amp;hl=de&amp;pg=PA195#v=onepage&amp;q&amp;f=false</a></li></ul>