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1. Scientific classification As used today, “salt” denotes a chemical compound made up of positively charged cations and negative anions. However, the theory of ionic bonding that defines the salt as a type was described only in 1915 by the German physicist Walther Kossel. Up to the 19th century, salts were identified primarily on the basis of their taste, solubility in water, and resistance to fire; on the basis of their resemblance to ordinary edible salt, they were grouped together as “salt-like substances.”While the specific differences between individual salts rem…

Experience teaches that objects and living creatures can be transformed – for example, a caterpillar can turn into a butterfly and nondescript ore into gleaming metal. Ovid’s Metamorphoses, extremely popular in the early modern period, rings the mythological and anthropological changes on this idea. In contrast to metamorphosis, in which only the form changes while identity is preserved,  transmutation in the technical chemical sense denotes a transformation that affects substance.The theoretical basis of transmutation was the Aristotelian theory of the four …

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…

1. ConceptUntil well into the early modern era, theories of matter arose within more general theories of  substance. When considering the nature of the fundamental entities of reality, ancient philosophers raised questions concerning the immutable vehicle of shifting properties and changing substances and reflected on what (if anything) can be known about it. The conception of matter as the basic stuff underlying all things is reflected in the Greek word hyle (Latin materia): literally it means the wood of a tree, from which something can be fashioned; philosophical…

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 …

1. ConceptFollowing Justus Liebig’s dismissal of the natural philosophy of the German Romantics ( Romanticism) as the “pestilence [...] of the century” [1. 29], historians likewise long imputed to the chemistry of the years around 1800 a reputation for groundless speculation. With its poetological aspects recently rediscovered by scholars of German studies [5]; [3]; [7] and its unique characteristics reconstructed by historians of scholarship [4]; [8], however, it has come to be seen today as a characteristic mode of dealing with knowledge between em…

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…

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…