Johan Wilhelm Hittorf

German chemist and physicist. Born in Bonn. After graduating from the University of Bonn, he worked as a private lecturer and assistant professor at the University of Münster, before serving as a professor at the same university from 1856 to 1879. Initially, he was involved in electrochemistry research, and based on the research of Daniel and Miller, in 1856 he established the concept of the "transportation number" (the rate at which an ion is transported) as the relative mobility rate of ions, and succeeded in measuring it. In 1858, through a debate with Clausius, he reached a view close to the free ion theory, stating that "the individual ions are not all tightly bound together as molecules." He then turned to research into gas discharges, and from 1862 to 1865 he conducted research on spectral tubes in collaboration with his mentor Plucker. Then, from 1869 to 1883, he carried out research into vacuum discharges, using the results of the technological innovations in vacuum technology of the 1860s. He confirmed that the fluorescence that appeared on the glass wall near the anode was caused by "glow rays," a type of radiation emitted from the cathode (his discovery of cathode rays), and established the foundations for research into cathode rays, including their straightness and the "substance of electric current" inside the tube.

[Shinkichi Miyashita, October 19, 2018]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

ドイツの化学者、物理学者。ボンに生まれる。ボン大学卒業後、ミュンスター大学私講師、助教授を経て、1856～1879年同大学教授。当初、電気化学研究に従事、ダニエルとミラーの研究を踏まえて、1856年イオンの相対的移動速度としての「輸率（イオンがどのくらい運ばれるかの割合）」の概念を確立し、その測定に成功した。1858年にはクラウジウスとの論争を通じて「各イオンはすべてが分子として緊密に結び付いているのではない」と自由イオン説に近い見解に到達。その後、気体放電研究に向かい、1862～1865年、師のプリュッカーと共同でスペクトル管についての研究を行い、ついで1860年代の真空技術上の技術革新の成果を用いて、1869～1883年真空放電研究を展開し、陽極付近のガラス壁に生じる蛍光は陰極から発したある種の輻射(ふくしゃ)線である「グロー光線」によることを確かめ（陰極線の発見）、その直進性や管中の「電流の実体」をなすことなど、陰極線研究の基礎を確立した。

［宮下晋吉　2018年10月19日］

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