Martinus van Marum, a Dutch physical scientist, was born Mar. 20, 1750. In the early 1780s, Van Marum constructed the largest electrostatic machine in the world; it stood over ten feet tall, with spinning disks fully six feet across, and it could produce extremely long sparks. Van Marum was also the founder of Teylers Museum in Haarlem, which is one of the finest small science museums in the world, and where his electrical machine is still on display. It used to be prominently featured in the famous “Oval Room” of the museum, as we see in a painting of around 1800 (second image above). A modern photo of the Oval Room shows the generator is missing (third image above); the machine, and a lot of other early electrical apparatus, has been moved to a room devoted to early experimental equipment (fourth image above).
Van Marum wrote a two-volume book on his machine, Beschryving eener ongemeen groote electrizeer-machine (1785-87), which we have in the History of Science Collection; it has a large folding plate showing the machine (first image above), and a number of other plates which attempt to reproduce some of the spark patterns. The spark plates have the blackest backgrounds I have ever seen on any engraving–they are quite amazing to behold (fifth image above). The Teylers Museum website devotes a special page to van Marum, their first director, from which the portrait above (sixth image) was taken.
Dr. William B. Ashworth, Jr., Consultant for the History of Science, Linda Hall Library and Associate Professor, Department of History, University of Missouri-Kansas City