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
Ludwig Wilhelm Sachs "Geheimen Medizinalrat" (private medical advisor). Ludwig Wilhelm Sachs Ludwig Wilhelm Sachs (29 December 1787 in Groß-Glogau – 17 June 1848 in Königsberg) was a German physician. From 1807 studied medicine at the universities of Königsberg, Berlin and Göttingen, receiving his doctorate at the latter institution with the dissertation-thesis ""De Humorum corporis animalis vi vitali"" (1812). He later served as a physician in war-time hospitals in Königsberg, and in 1816 obtained his habilitation. In 1818 he became an associate professor at Königsberg, followed by a full professorship in 1826. In 1832 he was named director of the medical clinic, then in