Guillaume François Rouelle (; 15 September 1703 – 3 August 1770) was a French

chemist A chemist (from Greek ''chēm(ía)'' alchemy; replacing ''chymist'' from Medieval Latin ''alchemist'') is a graduated scientist trained in the study of chemistry, or an officially enrolled student in the field. Chemists study the composition of ...

and

apothecary ''Apothecary'' () is an Early Modern English, archaic English term for a medicine, medical professional who formulates and dispenses ''materia medica'' (medicine) to physicians, surgeons and patients. The modern terms ''pharmacist'' and, in Brit ...

. In 1754 he introduced the concept of a base into chemistry as a substance which reacts with an

acid An acid is a molecule or ion capable of either donating a proton (i.e. Hydron, hydrogen cation, H+), known as a Brønsted–Lowry acid–base theory, Brønsted–Lowry acid, or forming a covalent bond with an electron pair, known as a Lewis ...

to form a

salt In common usage, salt is a mineral composed primarily of sodium chloride (NaCl). When used in food, especially in granulated form, it is more formally called table salt. In the form of a natural crystalline mineral, salt is also known as r ...

. He is known as ''l'Aîné'' (the elder) to distinguish him from his younger brother, Hilaire Rouelle, who was also a chemist and known as the discoverer of

urea Urea, also called carbamide (because it is a diamide of carbonic acid), is an organic compound with chemical formula . This amide has two Amine, amino groups (–) joined by a carbonyl functional group (–C(=O)–). It is thus the simplest am ...

. Rouelle started as an apothecary. He later started a public course in his laboratory in 1738, in 1742 he was appointed experimental demonstrator of chemistry at the Jardin du Roi in Paris. he was especially influential and popular as a teacher, and taught many students among whom were

Denis Diderot Denis Diderot (; ; 5 October 171331 July 1784) was a French philosopher, art critic, and writer, best known for serving as co-founder, chief editor, and contributor to the along with Jean le Rond d'Alembert. He was a prominent figure during th ...

, Antoine-Laurent de Lavoisier,

Joseph Proust Joseph Louis Proust (26 September 1754 – 5 July 1826) was a French people, French chemist. He was best known for his discovery of the law of definite proportions in 1797, stating that chemical compounds always combine in constant proportions. ...

and

Antoine-Augustin Parmentier Antoine-Augustin Parmentier (, ; ; 12 August 1737 – 13 December 1813) was a French pharmacist and agronomist, best remembered as a vocal promoter of the potato as a food source for humans in France and throughout Europe. His many other contrib ...

. He was elected a foreign member of the

Royal Swedish Academy of Sciences The Royal Swedish Academy of Sciences () is one of the Swedish Royal Academies, royal academies of Sweden. Founded on 2 June 1739, it is an independent, non-governmental scientific organization that takes special responsibility for promoting nat ...

in 1749. In addition to his investigation of neutral salts, he published papers on the inflammation of

turpentine Turpentine (which is also called spirit of turpentine, oil of turpentine, terebenthine, terebenthene, terebinthine and, colloquially, turps) is a fluid obtainable by the distillation of resin harvested from living trees, mainly pines. Principall ...

and other essential oils by

nitric acid Nitric acid is an inorganic compound with the formula . It is a highly corrosive mineral acid. The compound is colorless, but samples tend to acquire a yellow cast over time due to decomposition into nitrogen oxide, oxides of nitrogen. Most com ...

, and the methods of

embalming Embalming is the art and science of preserving human remains by treating them with embalming chemicals in modern times to forestall decomposition. This is usually done to make the deceased suitable for viewing as part of the funeral ceremony or ...

practised in

Ancient Egypt Ancient Egypt () was a cradle of civilization concentrated along the lower reaches of the Nile River in Northeast Africa. It emerged from prehistoric Egypt around 3150BC (according to conventional Egyptian chronology), when Upper and Lower E ...

Why bases for neutral salts were called bases

The modern meaning of the word "base" and its general introduction into the chemical vocabulary are usually attributed to Rouelle, who used the term "Base" in a memoir on salts written in 1754 (see The Origin of the Term "Base" by William B. Jensen). In this paper, which was an extension of an earlier memoir on the same subject written in 1744, Rouelle pointed out that the number of known salts had increased significantly during the 17th and early 18th centuries. This was due not only to the preparation of new salts, but also to an increasing ability to distinguish between sodium and potassium compounds, and to a generalization of the concept so as to include many substances, such as the

alums An alum () is a type of chemical compound, usually a hydrated double salt, double sulfate salt (chemistry), salt of aluminium with the general chemical formula, formula , such that is a valence (chemistry), monovalent cation such as potassium ...

and vitriols (i.e.,

sulfates The sulfate or sulphate ion is a Polyatomic ion, polyatomic anion with the empirical formula . Salts, acid derivatives, and peroxides of sulfate are widely used in industry. Sulfates occur widely in everyday life. Sulfates are salt (chemistry), ...

), that had been previously excluded. In order to incorporate this extended concept of salt formation, Rouelle explicitly defined a neutral salt as the product formed by the union of an acid with any substance, be it a water-soluble alkali, a volatile alkali, an absorbent earth, a metal, or an oil, capable of serving as "a base" for the salt "by giving it a concrete or solid form".Source https://www.physicsforums.com/threads/etymology-of-base.543937/

Why bases for neutral salts were called bases

References

Further reading