Fluorescent lamp began with the Geissler tube continued as even better vacuums were produced. The most famous was the evacuated tube used for scientific research by William Crookes. That tube was evacuated by the highly effective mercury vacuum pump created by Hermann Sprengel. Research conducted by Crookes and others ultimately led to the discovery of the electron in 1897 by J. J. Thomson and X-rays in 1895 by Wilhelm Roentgen. But the Crookes tube, as it came to be known, produced little light because the vacuum in it was too good and thus lacked the trace amounts of gas that are needed
Wilhelm Barthlott (Geodiversity), including migration and globalization. His Biodiversity Distribution Map has been published in numerous textbooks in addition to being the foundation for many postgraduate studies. In the framework of the BMBF-BIOTA-AFRICA project led by him, biodiversity patterns in Africa as a model continent are analyzed and potential impacts of climate change are investigated. Wilhelm Barthlott was the first botanist to use high resolution in scanning electron microscopy systematically in the research of biological surfaces since 1970. Most prominent among his results was the discovery of the self-cleaning effect of superhydrophobic micro- and nanostructured surfaces, which were technically realized with the