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Affinity, chemical

(786 words)

Author(s): Meinel, Christoph
An early concept to explain chemical bonding, affinity described substances’ desire to bond with one another. Experiences from commercial chemical practices in the 17th century were thus brought together in a theoretical concept [5], at first explained in animistic or mechanistic terms, then from Isaac Newton onwards in terms of a substance-specific bonding “force.” Convinced of the lawful unity of nature, Newton had proposed in his  Principia mathematica scientiae naturalis (1687) that all natural phenomena should be attributable to forces of attraction and r…
Date: 2017-02-14

Chemical sciences

(6,371 words)

Author(s): Meinel, Christoph
1. Knowledge and theory1.1. IntroductionChemistry (the term may derive from the Egyptian kmt, the word for the black earth of Egypt, or from the Greek chēmeía or  chymeía, ‘art of alloying metals’) includes various procedures and bodies of knowledge concerning the manufacture, purification, and transformation of materials. Their origins lie in metallurgy, the making of dye and glass, the manufacture of medicines, and foodstuffs technology. It was synonymous at first with alchemy, and in the first centuries of the early …
Date: 2017-02-14

Chemical compound

(850 words)

Author(s): Meinel, Christoph
Along with the concept of the elements, the concept of compounds is one of the fundamental theoretical concepts of early modern chemistry. Earlier historiography sought to trace its origins back to classical atomism with its notion of temporally stable atomic constellations [2] and the theory of  minima naturalia of the high Middle Ages, the smallest qualitatively distinct particles of a substance [9]; these were brought together around 1620 in Isaac Beeckman’s concept of the  homogeneum physicum (“molecule”) [8. vol. 1] or in the 1670s in Robert Boyle’s notion…
Date: 2017-02-14

Fermentation

(752 words)

Author(s): Meinel, Christoph
Fermentation (from the Latin  fermentum; “fermentation agent”, “leaven”) is one of the oldest biotechnological methods for conserving foodstuffs and manufacturing alcoholic beverages (e.g. Beer; Wine). Today, all technical transformations of a biological substrate using microorganisms or enzymes is called fermentation, but until the 19th century, the term denoted biological reactions in the absence of air, especially alcoholic fermentation. The theory of fermentation in this period was at the heart …
Date: 2018-02-14

Combustion

(1,120 words)

Author(s): Meinel, Christoph
1. ConceptCombustion today means the exothermic oxidation of a substance, generally in reaction with oxygen. Processes that are comparable in chemical terms are the rusting of iron and the metabolic physiology of respiration. It was not until the late 18th century that it came to be understood that these very different phenomena were attributable to the same process.Meinel, Christoph2. Corpuscular explanationsAccording to the Aristotelian view, combustion was related to the element of fire. In the atomist tradition, it was associated with the postulate…
Date: 2017-02-14

Agricultural chemistry

(749 words)

Author(s): Meinel, Christoph
Since Antiquity, organic and mineral manuring has been used to improve crop yield. In the 17th century, Paracelsism gave the initial stimulus to a chemical investigation of surface soil and plant constituents. But chemical fertilization, in the form suggested during the English Revolution by the reformist circle of Samuel Hartlib [6. 384–402] or by the chemist Johann Rudolf Glauber, remained ineffective, because key questions of plant nutrition remained unanswered. While some, following Johann Baptist van Helmont (1577-1644), saw the supposed…
Date: 2017-02-14

Gas

(2,760 words)

Author(s): Meinel, Christoph | Bleidick, Dietmar
1. From vital chaos to the gas of chemists The concept that air is a weighable substance consisting of various gases gained acceptance only in the course of the 18th century. Until then it had been considered one of the four Aristotelian elements and was neither heavy nor light, as long as it remained in its natural place. In his  Ortus Medicinae (Amsterdam 1648; Ger. Aufgang der Artzney-Kunst, Sulzbach 1683), the Flemish Paracelsist Jan Baptista van Helmont conceived an alternative, vitalistic theory of matter (Vitalism), according to which all substances …
Date: 2018-02-14