Faraday - Michael Faraday

Japanese: ファラデー - ふぁらでー（英語表記）Michael Faraday

British chemist and physicist. Born on September 22nd in Newington Butts, a suburb of London, as the son of a blacksmith, Faraday was apprenticed to a bookseller and bookbinder in 1804 after only learning to read, write and do arithmetic. He became interested in the scientific books that were being bound, and tried out the experiments described in them. He began attending the town's scientific society in 1810, and in 1812, thanks to the arrangement of a member of the Royal Institution who was a customer at the shop, he listened to Davy's public lectures, which made him strongly desire to work in the natural sciences. That same year, after his apprenticeship ended, Faraday worked as a bookbinder in another shop, but sent Davy a letter seeking employment, attaching a carefully compiled notebook of the lectures. In March 1813, he was hired as a laboratory assistant at the Royal Institution, and in October he accompanied Davy on a two-year trip to Europe as his secretary and assistant. He returned to the UK in 1815, and became a laboratory assistant at the Royal Institution again, a laboratory director in 1825, and a professor of chemistry in 1833. He was elected a member of the Royal Society in 1824. He spent 37 years in the attic of the Royal Institution, but in 1858 he moved to Hampton Court, a mansion offered to the Queen, where he died on August 25, 1867, at the age of 76.

[Tomoko Takahashi]

Chemical Research

Faraday worked as Davy's assistant on various industrial problems brought to the Royal Institution, mainly chemical research. In 1816 he wrote his first paper on the analysis of Tuscan quicklime, and from 1819 he studied iron alloys for five years. In 1823 he succeeded in liquefying chlorine gas, and then liquefied sulfur dioxide, nitrogen dioxide, ammonia, and other gases. In 1825 he discovered benzene in a substance that had accumulated at the bottom of a gas cylinder, and showed that it was composed of carbon and hydrogen. Around this time, he worked with J. Herschel and others to improve optical glass, creating heavy glass, but the improvement itself was unsuccessful. This glass was later used in research into diamagnetism.

[Tomoko Takahashi]

Electromagnetics Research

In 1820, Oersted discovered the magnetic effect of electric current, and Ampere was formulating "Ampere's Law" regarding the interaction of electricity and magnetism. Faraday started his research into electromagnetism at a time when this field was about to make a big leap from electrostatics and magnetism to electromagnetism, which studies the interaction between electricity and magnetism. In 1821, he succeeded in an experiment of electromagnetic rotation, and after becoming convinced of the interaction between electricity and magnetism, he tackled the problem of the inverse of the magnetic effect of electric current, that is, whether electric current can be generated from magnetism. Since a steady current generates magnetism, Faraday thought that a steady current could be obtained by placing a magnet near a conductor, and in 1824, he placed a strong magnet near a conductor through which a current was passing and observed the deflection of a magnetic needle placed at a distance during rotation. However, no change was observed. Considering the conservation of energy, it is necessary to change the magnetism to obtain an induced current, but it took him seven years to realize this at a time when no such idea existed. In August 1831, he discovered that opening and closing a circuit creates an electric current in a second circuit, and in October, he discovered that moving a bar magnet in and out of a coil creates an electric current, thus discovering electromagnetic induction.

In 1833, he confirmed the identity of various electric currents, including voltaic pile electricity, thermoelectricity, animal electricity, frictional electricity, and electromagnetic induction electricity, and formulated the laws of electrolysis, which allowed for their quantification. He introduced the concepts of electrochemical equivalent and ions, considered electrolysis to be a special type of electrical conduction, and attempted to clarify its mechanism. In 1836, he confirmed that capacitance depends on the intermediate material, and criticized the so-called action at a distance theory. He introduced the concept of lines of force, which was later adopted by Maxwell, and built the foundation for the theory of action at a distance. The progress of the Industrial Revolution brought about advances in telegraph technology, and this was an era when the development of electromagnetism was required, and many scientists, including Ampere, Weber, and Gauss, were working on this issue. Faraday was one of them, and organized his experiments in a systematic way.

He achieved many notable feats, including the discovery of self-induction in 1835, the discovery of the Faraday dark space in a gas discharge in 1838, the discovery of the Faraday effect and diamagnetism in 1845, and the discovery of reglaciation in 1850.

[Tomoko Takahashi]

"The Life of Faraday" by H. Soutin, translated by Koide Akiichiro and Tamura Yasuko (1985, Tokyo Tosho)

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

Japanese:

イギリスの化学者、物理学者。9月22日、鍛冶(かじ)職人の子としてロンドン郊外のニューイントン・バッツで生まれる。読み書きと算術を習っただけで、1804年書店兼製本業の店に徒弟奉公した。製本に回される科学の本に興味をもち、本に書かれている実験を試したりした。1810年から町の科学協会に出席、1812年、店の客だった王立研究所所員の計らいでデービーの公開講座を聞き、自然科学の仕事につきたいと強く願うようになった。この年、年季の明けたファラデーは、製本職人として別の店に勤めたが、デービーにその講演を丹念にまとめたノートを添えて職を求める手紙を送った。1813年3月王立研究所の実験室助手に採用され、10月にデービーの秘書兼助手として2年間のヨーロッパ旅行に同行。1815年帰国、ふたたび王立研究所の実験室助手、1825年実験室主任、1833年化学教授となった。1824年王立協会会員に選ばれた。37年間王立研究所の屋根裏部屋で過ごしたが、1858年女王に提供されたハンプトン・コートの邸宅に移り、1867年8月25日、76歳の生涯を閉じた。

［高橋智子］

化学研究

ファラデーは、王立研究所に持ち込まれる工業上の諸問題、おもに化学的研究にデービーの助手として取り組んだ。1816年トスカナの生石灰を分析して処女論文を書き、1819年から5年間鉄の合金を研究した。1823年塩素ガスの液化に成功、ついで二酸化硫黄(いおう)、二酸化窒素、アンモニアなどを次々に液化。1825年ガスボンベの底にたまる物質中にベンゼンを発見、炭素と水素からなることを示した。このころ、J・ハーシェルらと光学ガラスの改良を手がけ、重ガラスをつくったが、改良そのものには失敗。このガラスはのちに反磁性の研究に使われた。

［高橋智子］

電磁気学研究

1820年エールステッドは電流の磁気作用を発見し、アンペールは電気磁気の相互作用に関して「アンペールの法則」を定式化しつつあった。この分野が静電気・磁気学から電気と磁気の相互作用を研究する電磁気学へと大きく飛躍しようとしていた時代にファラデーは電磁気学研究に手を染めた。1821年電磁気回転の実験に成功、電気と磁気の相互作用を確信したファラデーは、電流の磁気作用の逆、つまり磁気から電流が生じるかどうかの問題に取り組んだ。定常電流が磁気を生じることから、導線の近くに磁石を置くことで定常電流が得られると考え、1824年、電流を通した導線近くに強力な磁石を置き、回転中の離れた所に置いた磁針の振れを観察した。しかしなんの変化も認められなかった。エネルギー保存を考えれば、誘導電流を得るには磁気を変化させる必要があるが、そうした考えのなかった当時、このことを認識するのに7年を必要とした。1831年8月、回路の開閉によって第二の回路に電流が生じることを、10月、コイルの中に棒磁石を出入りさせると電流が生じることを確認、電磁誘導を発見した。

　1833年、それまで知られていたボルタ電堆(でんたい)の電気、熱電気、動物電気、摩擦電気、電磁誘導の電気など種々の電流の同一性を確認、さらに定量化を可能にする電気分解の法則を定式化した。ここで電気化学当量やイオン概念を導入、電気分解を特殊な電気伝導と考え、その機構を明らかにしようとした。1836年には電気容量が介在する物質に依存することを確かめ、いわゆる遠隔作用論を批判した。のちにマクスウェルに引き継がれる力線の概念を導入、近接作用論への基礎を築いた。産業革命の進展が電信技術の進歩をもたらし、電磁気学の発展を要請していた時代であり、アンペール、ウェーバー、ガウスら多くの科学者がこの問題に取り組んでいた。ファラデーもその一人として実験を体系的に組織したのであった。

　1835年自己誘導の発見、1838年気体放電でのファラデー暗部の発見、1845年ファラデー効果、反磁性の発見、1850年復氷の発見など多くの注目すべき業績をあげた。

［高橋智子］

『H・スーチン著、小出昭一郎・田村保子訳『ファラデーの生涯』（1985・東京図書）』