Archaic Chemical Terms

Part II (C-F)

Go to Part I (A-B), Part III (G-L), Part IV (M-R), or Part V (S-Z).

Cadet's fuming liquid (Cadet's liquid): heavy brown liquid first prepared by the French chemist Louis Claude Cadet de Gassicourt. Cadet's liquid is highly toxic, smells strongly of garlic, and spontaneously bursts into flame when exposed to air. It is mainly cacodyl oxide, ((CH3)2As)2O, with other cacodyl compounds such as dicacodyl, ((CH3)2As)2). Berzelius coined the name kakodyl (later changed to cacodyl) for the dimethylarsinyl radical, (CH3)2As, from the Greek kakodes (evil-smelling) and hyle (matter). For more on Cadet's liquid and other cacodyls compounds, see this 2001 article in Organometallics.

cadmia (cadmia fornacea or fornacum): an older name for the common zinc ore calamine (q.v.); also applied to a sublimed zinc oxide and to a cobalt ore. (The element now called cadmium is often found associated with zinc.) [Agricola]

calamine: Two ores of zinc were known by this name: zinc carbonate (ZnCO3, also known as Smithsonite) and hydrous zinc silicate (Zn2SiO4.H2O). They were distinguished by Smithson in 1802, but the term continued to be applied to both ores. The silicate was sometimes distinguished as siliceous or electric calamine. calamine

calcareous earth: calcium oxide, CaO (lime, quicklime). [Black, Lavoisier]

calcareous gas: James Kier's name for what we call carbon dioxide, CO2 (fixed air) [Kier]

calces: See calx.

calcination: formation of a calx, i.e., oxidation of a metal, often by roasting. [Bacon, Black; Lavoisier 1, 2, & 3; Rey]

calomel: mercury(I) chloride, Hg2Cl2.

caloric: a postulated elastic fluid associated with heat. [Avogadro, Davy, Dalton, Lavoisier, et al.]

calx (plural calces): a powdery solid formed by roasting a metal or mineral, most often a metal oxide. [Lavoisier 1, Rey, Stahl] Sometimes used for a particular calx, namely lime.

carbolic acid: phenol, C6H5OH.

carbonic acid: formerly referred to carbon dioxide, CO2 (fixed air) [Dalton; but also Arrhenius, Maxwell, Mendeleev, Rutherford, J. J. Thomson et al.]

carbonic oxide: carbon monoxide, CO [Dalton, Gay-Lussac, Maxwell, Ramsay, T. Thomson et al.]

carburetted hydrogen: methane, CH4 [Dalton 1 & 2, Prout]

Caro's acid: permonosulfuric acid (i.e., peroxymonosulfuric acid), H2SO5, first prepared by Heinrich Caro in 1898.

Cassel yellow: lead oxychloride, PbCl2.2PbO (mineral yellow).

cassiopeium: Auer von Welsbach's name for lutetium, Lu.

cathode rays (sometimes kathode rays in 19th-century English translations): streams of electrons issuing from the cathode of an evacuated tube. They were identified as what are now called electrons late in the 19th century. [Perrin, Rutherford, J. J. Thomson 1 & 2]

Celsius scale: temperature scale devised in the early 18th century by a certain Elvius from Sweden (1710), a Christian of Lyons (1743), and the botanist Linnaeus (1740), apparently independently. Temperatures on this scale are denoted by °C. The normal freezing point of water is 0°C and the normal boiling point of water is 100°C. The scale was named after Anders Celsius who proposed a similar scale in 1742, but he designated the freezing point to be 100 and the boiling point to be 0. The modern Celsius scale is sometimes also called the Centigrade scale. (See Fahrenheit scale, Kelvin scale, Rankine scale, Réaumur scale.)

Centigrade scale: Celsius scale.

cerusa (or ceruse or cerussa): white lead, named for its resemblance to wax (κηρος).

chalk: calcium carbonate, CaCO3 (carbonate of lime, cream of lime, mild calcareous earth). [Lavoisier; Priestley; T. Thomson]. Acid of chalk is carbon dioxide, CO2 (carbonic acid, fixed air) [Lavoisier]

chamber crystals: nitrosyl sulfate, NO.HSO4, formed in lead chambers of sulfuric acid manufacture.

charcoal: either a charred carbonaceous material or its primary constituent, namely carbon. Lavoisier coined the term carbone (carbon) to distinguish the element from impure charred material; however, the distinction was not universally adopted right away--even in translation of Lavoisier's work. [Dalton 1 and 2]

chrome ...

chromic acid: chromium(VI) oxide, CrO3, or its formal hydrate, H2CrO4

chymical: Sometimes the modern term alchemical is more accurate than chemical. Similarly chymist often means alchemist. [Boyle]

Cleve's acid and salts: named for the 19th-century Swedish chemist, Per Cleve.


colcothar: iron(III) oxide, Fe2O3, by-product from sulfuric acid manufacture (Paris red) [Lavoisier]

columbium: older name for niobium, Nb.

congo ...

copperas: see vitriol. corpuscle: generally (and still) a small particle; in the late 19th and early 20th centuries, a competing name for the electron. [J. J. Thomson 1 & 2]

corneous metals: metal chlorides, particularly of silver, mercury, or tin. Because of resemblance to horn, chlorides of these metals are sometimes called horn silver, mercury, or tin.

corrosive sublimate of mercury: mercuric chloride, HgCl2. [Scheele]

Coupier's blue: azodiphenyl, C24H18N2, a blue dye.

creech: calcium sulfate, CaSO4

cresol ...

crocus: a yellow or reddish powdered calx (oxide) Crookes tube: a highly exhausted electrical discharge tube, named for William Crookes, who experimented with such tubes

crystal violet: hexamethyl-p-rosaniline hydrochloride, C25H30N3Cl, an acid-base indicator that changes from green to blue as the pH passes through 1.0.

dephlogisticated marine acid: chlorine, Cl2 (oxymuriatic acid). See marine acid. [Priestley, Scheele]

diuretic salt: potassium acetate, KC2H3O.

didymium: a mixture of praseodymium, Pr, and neodymium, Nd, believed to be an element until 1885. [Mendeleev, Newlands]

dram (drachm): See apothecary measures.

Dutch oil (Dutch liquid, Oil of the Dutch chemists): ethylene chloride, C2H4Cl2, first prepared by the action of chlorine on ethylene (hence olefiant gas) in 1794 by four Dutch chemists Johann Rudolph Deimann, Adrien Paets van Troostwyck, Anthoni Lauwerenburgh and Nicolas Bondt. [Wurtz]

earth: a metal oxide (calx); see calcareous earth, magnesian earth, siliceous earth. [Dalton, Priestley, Scheele, T. Thomson]

elastic fluid: usually a descriptive term for gas (air) [Black, Dalton, Gay-Lussac, Lavoisier, T. Thomson et al.]; however, certain elastic fluids were postulated that correspond to no actual material (caloric, ether, phlogiston). A gas is an "elastic fluid," elastic in that it is compressible in a reversible way and fluid in that it flows.


emanation: a radioactive gas (radon) produced in the decay of other radioactive elements. Specifically, thorium emanation (also thoron) is 220Rn (half life = 55 s) produced from the decay of thorium; radium emanation is 222Rn (half life = 3.8 d) produced from the decay of radium; actinium emanation (also actinon) is 219Rn (half life = 4 s). See niton and table of isotopes. [Rutherford 1 & 2, Soddy 1 & 2]

Epsom salts: magnesium sulfate, MgSO4.7H2O; see bitter salt.

ether (physics; also aether, sometimes luminiferous ether): a hypothetical elastic fluid postulated to support the transmission of light. [Clausius, Röntgen, J. J. Thomson 1 & 2]

ether (chemistry): Originally the name of a volatile compound resulting from the action of an acid on alcohol. The current meaning is an organic compound whose formula is ROR', where R and R' are alkyl or aryl groups; especially diethyl ether, C2H5OC2H5. Some ethers in the older sense include:

Ethiops (or Aethiops) mineral: mercury(I) sulfide, Hg2S, a black substance

ethyl: in addition to the hydrocarbon radical C2H5- (sometimes spelled aethyle) ...

Euchlorine: name given by Humphry Davy to a bright green gas he believed to be a compound of chlorine and oxygen; in fact, it seems to have been mixture of clorine dioxide and and chlorine. [H. Davy, J. Davy]

Everitt's salt: potassium ferrous ferrocyanide, K2Fe[Fe(CN)6], named after Thomas Everitt.

Fahrenheit scale: temperature scale devised in 1717 by D. G. Fahrenheit and denoted by °F. The normal freezing point of water is 32°F and the normal boiling point of water is 212°F. (See Celsius scale, Kelvin scale, Rankine scale, Réaumur scale.)

ferrum: Latin for iron, hence the symbol Fe

flores martiales: ferriammonium chloride, NH4FeCl4. See flowers and Mars.

flowers: a solid, often an oxide, obtained by sublimation. For example: flowers of arsenic, phosphorus, tin, and zinc [Lavoisier, Priestley] are the respective oxides, As2O3, SnO2, ZnO (also called pompholix). Flowers of antimony is antimony oxysulfide, Sb2O3.Sb2S3 (also called antimony red); flowers of sulphur, though, is simply sublimed sulfur.

fluor and fluor spar (or fluorspar): Fluor was originally applied to readily fusible minerals, particularly those containing fluorine, espeically fluorite (calcium fluoride, CaF2). Fluorspar for CaF2 dates to the late 18th century; fluorite to the 1860s.

fossil alkali: sodium carbonate (common mineral alkali, marine alkali, soda)

fulminate: a compound containing the CNO- ion, named because such compounds are explosive (from Latin, fulminare, to strike with lightning

funiculus: an invisible membrane postulated to hold up a column of mercury in the Torricellian experiment [Linus]

Go back to the previous part (A-B) of the Glossary.
Go to the next part (G-L) of the Glossary.
Back to the top of the Classic Chemistry site