Normal Element
Historical document, translated for reference. It reflects medical knowledge of the 1920s–30s and is not medical advice.
Summary
The normal element is a standard for the international volt used in laboratory instruments to measure electromotive force and current. It comes in two types: the international normal element and the cadmium element, with the former being more stable and widely adopted.
Encyclopedia entry (1928–1936)
Normal Element, a standard for the international volt used in laboratory practice in instruments for measuring electromotive force and current, for example, in instruments for measuring pH. The distinctive feature of the normal element is the stability of electromotive force at constant pressure and temperature and the possibility of precise reproduction. There are two types of normal elements: the international normal element and the cadmium element, which is being rapidly replaced by the international one. The positive electrode of the normal element consists of mercury, and the negative electrode consists of an amalgam made of cadmium (12.5%) and mercury (87.5%). The electrolyte is a saturated solution of cadmium sulfate. The normal element was introduced as an international standard in 1908. In the USSR, normal elements are manufactured and verified at the Main Chamber of Measures and Weights in Leningrad.
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“Normal Element.” Soviet Medical Encyclopedia. English translation of Bolshaya Meditsinskaya Entsiklopediya, 1st ed. (Moscow, 1928–1936), ed. N. A. Semashko. https://sovietmedicalencyclopedia.pages.dev/article/normal-element/