British Eighteenth-Century Chemical Terms - Part 2


Dictionary Table of Contents Dictionary - Part 1 (A-H) Dictionary - Part 3 (S-Z)

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Iceland Spar (Calcite)
A particular crystal form of calcium carbonate (CaCO3).
Icy Butter
Antimony chloride (SbCl3).
To soak or saturate with a liquid.
Infernal Stone
An alkali hydroxide (NaOH, KOH). [Not to be confused with the French term pierre infernale.]
Inflammable Air
Usually hydrogen (H2), though the usage is not constant among Priestley, Watt, Lavoisier, or Berthollet. Sometimes carbon monoxide (CO).
Inflammable Air from Metals
Hydrogen (H2).
The extraction of chemical substances by soaking them in a solvent, usually water. Sometimes boiling water was poured on a mixture of substances and then allowed to cool in order to aid the extraction; but if the heat were used, the temperature could not exceed that of boiling water.
Digestion in which the heat was supplied by the sun rather than a furnace.
To thicken or condense.
Intermediate Salt of the Ley of Blood
Potassium ferrocyanide (K4Fe(CH)6).
Intermediate Salts
Usually normal salts; occasionally acid salts.
Any reagent or reactant believed to be necessary for a reaction but which does not always appear on the product.
The process of swelling up.
A preparation from the root of the South American plant Cephaelis Ipecacuanha.
Iron Ochre
A mixture of silica, clay, and various oxides of iron. In red ochre the oxide is simple Fe2O3; in yellow ochre it is Fe2O3 . H2O.
Iron Vitriol
Ferrous sulphate (FeSO4).
In the first half of the eighteenth century a gelatinous substance extracted from the air-bladders of certain fish. Later, a synonym for sheet mica.
A black pigment prepared by the calcination of ivory in a closed vessel.

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A powder from the dried roots of the Mexican plant Exogonium purga. Used as a purgative.
James' Powder
A powder prepared by Dr. Robert James (1703-1776) that was used to reduce fevers.
The coating of an object with a very dark varnish. The original varnish came from Japan, but substitutes were later found.
Jove (of Jove)
Tin, or some compound or alloy of tin.

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The plant Salsola kali or glasswort from which, oddly enough, "mineral" alkali (sodium carbonate) was extracted by calcination. Also sometimes used for crude sodium carbonate.
A fine, white clay used in the manufacture of porcelain.
Impure soda (Na2CO3) from seaweed. In Britain, the term was sometimes used for crude sodium carbonate from any source.
Kermes Mineral
A natural mixture of antimony oxide or a mixture obtained in the laboratory by the actions of potassium carbonate on antimony sulphide.

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Lac (Laque)
A relatively thick solution of a colorant or coating.
Lac Sulphuris
See milk or sulphur.
Lapis Calaminarus (Calamine)
Mineral form of Zinc Carbonate (ZnCO3)
Lapis Haematites
Hematite (Fe2O3)
Lapis Infernalis
Fixed vegetable alkali, I., potassium carbonate (K2CO3)
Lapis Philosophorum
A mixture of fused alum, vitriol, bolus, cerussa, camphor, vinegar.
Lapis Ponderous
Calcium tungstate (CaWO4)
Lapis Septicus
Potassium hydroxide (KOH)
Lapis Serpentin
A mineral chiefly characterized by the presence of hydrous magnesium silicate (Mg3Si2O5(OH)4)
See Lac.
Any medicinal preparation with opium as a primary ingredient.
Lead sulphide (PbS)
Ley of (Ox-) Blood
The lixiviate from the residue produced by igniting blood with potashes.
Ley of Soapboilers
Potassium hydroxide (KOH)
Light Carburetted Hydorgen
Marsh gas or methane (CH4)
Light Inflammable Air
Hydrogen (H2)
Lignum Nephriticum
Two distinct woods were known as lignium nephriticum: (1) the small Mexican tree or shrub Eysenhardtia polystacha and the large Philippine tree Pterocarpus indica. In the sixteenth, seventeenth, and early eighteenth centuries, cups, powders, and dried extracts of this wood were thought to have a great medicinal powers. The infusion was flourescent.
Lignum Vitae
"Tree of Life" The wood , and sometimes the resin, of several semitropical trees, but most often referring to Guaiacum.
Filing on a metal piece to reduce it to filings. Sometimes used for simply polishing an object.
Calcium oxide (CaO).
Lime, Carbonate of
Calcium carbonate (CaCO3)
Lime, Quick
Calcium oxide (CaO)
Lime, Slaked 2)
Calcium carbonate (CaCO3)
Lime Water
A solution of calcium carbonate (CaCO3)
Liquescent (Salts)
See Deliquescence.
Liquor Fumans Boyle (Spiritus Fumans Boyle)
Ammonium polysulphide ((NH4)S2; (NH4)2S5).
Liquor Fumans Libavh (Fuming Liquor of Libavius)
Stannic chloride (SnCl4).
Liquor of Flints
See Liquor Silicum.
Liquor Hoffman
A mixture of ethanol and ether.
Liquor of Liravius
See smokinf spirit of Libavius.
Liquor Silicum (Liquor of Flints)
A solution of potassium silicate (K2 SiO3). Sometimes Used for other soluble silcates.
Yellow lead oxide (PbO)
Soft, claylike substances, such as kaolin.
A blue pigment, extracted from certain lichens. It is acid sensitive, turning red in the presence of an acid. The red form turns blue again when a base is added.
Liver of Antimony
Fused antimony sulfide (Sb2S3). Usually produced from the detonation of equal parts of crude antimony and potassium nitrate.
Liver of Arsenic
Fused mixture of potassium carbonate and (white) arsenic. May have contained some potassium arsenate.
Liver of Sulphur (Hepar Sulphuris)
Produced by heating potassium carbonatee with sulphur. Not a true compund, it is a metastable mixture of potassium polysulfides and sulfate. (K2S, K2S2, K2S3, K2S4, K2S5, K2SO4)
Lixivial Salts
Salts prepared by lixiviations.
Lixiviate of Mars
Possibly a tincture of iron, of which there were many different preperations. Typically, these were solutions of salts of iron to which rectified spirit of wine(ethanol, (CH3CH2OH) was added .
Separation of soluble from unsoluble solid substances by soaking the mixture of solids and removing the resulting solution which contained the soluble material.
A solution produced by lixiviation. Sometimes used as a general synonym for "Solution"
Lixivium of Tartar
A solution of potassium carbonate (K2CO3)
Load (Load)
Any ore.
The American tree Haematoxylon Campechionum, used in dying. It produces dark shades: blacks, blues, and dark grays.
A variety of limestones.
Lunar Cornea
Fused silver chloride (AgCl).
Lunar Caustic
Fused silver nitrate (AgNO3).
Lunar Crystals
Finely divided parts of silver nitrate (AgNO3). In preparing these crystals great care was taken to use only the purest silver and nitric acid possible.
Lunar Nitre
Silver nitrate (AgNO3).

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The softening and weakening of a solid sample, even to the piont of partial decomposition, by soaking it in a liquid.
Magisterium Tartari Vitriolati
Probably potassium sulfate (K2SO4).
Magistery of (any substance)
A precipitate of any substance, i.e., a pure form of the substance which has been separated by precipitation.
Magistery of Bismuth
Basic bismuth nitrate (BiNO3 . H2O); sometimes the oxide (BiO) or even the oxychloride (BiOCl).
Magistery of Coral
Calcium carbonate (CaCO3).
Magistery of Sulfur
Precipitated milk of sulphur (S).
Any substance prepared from the basic elements of the substance without impurities. A magistry was supposed to be closer to the ideal for a substance than was usual for real chemical preparations.
Magnesium carbonate (MgCO3). [Modern magnesia = magnesium oxide (MgO)]. Some chemists called magnesium (Mg) by the name magnesia.
Magnesia Aerata
Magnesium carbonate (MgCO3).
Magnesia Alba
Magnesium carbonate (MgCO3).
Magnesia Nigra
Manganese dioxide (MnO2).
Magnesia Salita
Magnesium chloride (MgCl2).
Basic copper carbonate (CuCO3 . Cu(OH)2).
Malic Acid
An acid extracted from apples and various other fruits. Pure malic acid is C4H6O5.
Barley or other suitable grains after a preparation for brewing or distilling that usually included soaking, germination, and drying.
Manganese dioxide (MnO2). Manganese as we know it was called reglus of manganese.
Manna Mercurii
Mercurous chloride (Hg2Cl2).
A hard, crystalline, mineral form of calcium carbonate (CaCO3).
Marcasita Plumbea
Antimony (Sb).
Minerals similar in appearance or properties to iron pyrites (FeS2). Later, a general term for pyrites. Sometimes the term was used for sulfides of arsenic (As2S2, As2S3, As2S5).
See Marzipan.
Marine Acid
Hydrochloric acid (HCl).
Marine Acid Air
Hydrogen chloride (HCl).
Marine Alkali
Sodium carbonate (Na2CO3).
Marl (Marle)
A loose soil of clays and calcium carbonate (CuCO3).
Mars (of Mars)
A substance related in some way to iron.
Marsh Gas
Methane (CH4).
Martial Balls
A mixture of iron fillings (Fe) and cream of tartar (KHC4H4O6).
Martial Ethiops
Hydrated ferrosoferric oxide (Fe3O4 . xH2O).
Martial Extract
Concentrated tincture of mars. A concentrated solution, the chief component of which may have been ferrous hydroxide (Fe(OH)2).
A confection of pounded almonds, sugar, and other ingredients.
A vessel with a round bottom and long, slender neck. Used as part of several common types of distillation apparatus.
A solvent.
Mephitic (as adjective)
Noxious; poisonous or pestilential.
Mephitic Acid
Carbonic acid (H2CO3).
Mephitic Air
Carbonic acid (CO2).
Mercurius Calcinatus
Mercuric oxide (HgO).
Merc. Calcin. Nitrat
Mercuric nitrate (Hg(NO3)2).
Mercurius Corrosivus
Mercuric chloride HgCl2.
Mercuric Corrosivus Ruber
Mercuric oxide (HgO).
Mercurius Dulcis (Calomel, Mercurious Sublimatus Dulcus, Mild Mercury)
Mercurous chloride (Hg2Cl2).
Mercurius Praecipitatus Per Se
Mercuric oxide (HgO).
Mercurius Praecipitatus Ruber
Mercuric oxide (HgO).
Mercurius Solubilis Hahnemanni
Mercuric oxide (Hg2O).
Mercurius Sublimatus Dulcis (Calomel, Mercurius Dulcis, Mild Mercury)
Mercurous chloride (Hg2Cl2).
Mercurius Sublimatus Rubeus non Corrosivas
Mercuric oxide (HgO).
Mercurius Vitae
Mixture of antimony oxychloride and antimony oxides (Sb2O3; Sb2O4, Sb2O5, SbOCl). In some contexts the term may mean just antimony oxychloride (SbOCl).
Mercurius Vitae Antimonii
Mixture of antimony oxychloride and antimony oxide (Sb2O3; Sb2O5, SbOCl).
Mercury of Life
See Mercurius Vitae.
Metallic Salt
Compound of a metal and an acid.
Miasma (Miasmata)
A noxious or infectious subtle material (e.g., a vapor or exhalation) thought to be from decaying organic matter. Sometimes used for any unseen poisonous or infectious substance.
A mixed mineral form composed mostly of aluminum silicate but with silicates of other metals. Several complicated minerals are variously, and in combination, referred to as mica; e.g., biotite K(Mg, Fe)3AlFeSi3O10(OH, F)2.
Microcosmic Salt
Sodium ammonium phosphate (NaNH4HPO4 . 4H2O).
Mild Alkali
Alkalies which produce effervescence with acids; i.e., carbonates (-CO32¯)
Mild Calcareous Earth
Calcium carbonate (CaCO3).
Mild Magnesian Earth
Magnesium carbonate (MgCO3).
Mild Mercury
Mercurous chloride (Hg2Cl2).
Mild Vegetable Alkali
Potassium carbonate (K2CO3).
Milk of Lime
Calcium hydroxide (suspension) (Ca(OH)2).
Milk of Sulfur
Finely divided sulfur (S) in solution. Usually the product of the reaction between a soluble sulfide and an oxidizing acid.
Minderer's Spirit
A solution of ammonium acetate (NH4C2H3O2).
Mineral Alkali
Sodium carbonate (Na2CO3).
Mineral Anodyne of Hoffman (Liquor of Hoffman)
A mixture of ethanol and ether (C2H5OH), (CH3CH2OCH2CH3).
Mineral Crystal
Sal prunella = potassium nitrate with a small admixture of potassium sulfate (HNO3; K2SO4).
Minium (Red Lead)
Lead tetroxide (Pb3O4).
A chemical union of two or more true "elements" or "principles." Later, any substance which could be resolved into constituent parts only by chemical means. Although the term has greater philosophical complexities, it was roughly equivalent to our term "compound," but the latter is not to be considered a synonym.
Mixtura Salina
Saline mixture prepared by saturating potassium carbonate with lemon juice and adding syrup of black currants, julep.
An exhalation or vapor of a mephitic (noxious or poisonous) gas.
Mohr's Salt
Ferrous ammonium sulfate (FeSO4((NH4)2SO4 . 6H2O).
Native molybdenum sulfide (MoS2).
Any substance which fixes or holds a colorant in the material to be dyed.
To change or destroy the normal, external form or appearance of a substance.
Mosaic Gold
Stannic sulfide (SnS2).
Mucilagenous Matter
Any semisolid material that was soft, moist, and viscous.
Mundic (Mundick)
Iron pyrites (FeS2). Sometimes used for other pyrites or as a general term for pyrites.
Chlorides (-Cl¯).
Muriatic Acid
Hydrochloric acid (HCl).
Muriatic Ether
Probably impure ethyl chloride (CH3CH2Cl).

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Naples Yellow
Lead antimoniate (Pb3(SbO4)2).
Any highly inflammable, volatile, naturally occurring mixture of hydrocarbons. Also could be obtained as the "lightest" fraction in the distillation of asphalts, bitumens, and petroleum.
Natron (Natrum)
Sodium sesquicarbonate, a naturally occurring combination of sodium carbonate (Na2CO3) and sodium bicarbonate (NaHCO3) in the ratio 1:1 (Na2CO3 . NaHCO3 . 2H2O).
Neutral Arsenical Salt of Macquer
Potassium dihydrogen arsenate (KH2AsO4).
Neutral Salts
Salts resulting from the reaction of an acid and a base (hydroxide) but having no characteristics of either acid or base.
Nihil Album (sometimes just Nihil)
Flowers of zinc, zinc oxide (ZnO).
Nitrated Earths, Metals, etc.
Nitrates (-NO3).
Nitre (Common Nitre)
Potassium nitrate (KNO3).
Nitre Fixed by Tartar
A mixture of nitre and tartar left after reaction between the two.
Nitre with an earthy base
Usually calcium nitrate (Ca(NO3)2).
Nitreum (Bergman)
Nitrous acid (HNO2).
Nitro-Aerial Spirit
The hypothetical subtle substance which was though by some to be responsible for the ability to nitre to support combustion and to be a key component of detonations
Nitrous Acid
Nitrous Acid (HNO3).
Nitrous Acid Vapor (Priestly)
Nitrogen Dioxide (NO2).
Nitrous Air (Priestly)
Nitric Oxide (NO)
Nitrous Ether
Ethyl nitrite (CH3CH2NO2).
Nitrous Gas (Lavoisier)
Nitric Oxide (NO)
Nitrum Aegypticum
Sodium Carbonate (Na2CO3).
Nitrum Antimoniatum
Product containg potassium nitrate, nitrite, and antimonate.
Nitrum Commun
See commom Nitre
Nitrum Cubic
See Cubic Nitre
Nitrum Fixatum (Nitrum Fixum, Fixed Nitre)
An ofter impure preparation of potassium carbonate (K2CO3).
Nitrum Flammans
Ammonium Nitrate (NH4NO3).
Nitrum Regeneratum
Potassium nitrate (KNO3).
Nitrum Saturni
Lead Nitrate (Pb(NO3)2).
Nitrum Stibnatum
Probably anitmony nitrate (2Sb2O3 . N205).
Nitrum Sulphure Purgatum
Mixture of potassium nitrate and potassium sulfate (KNO3; K2SO4).
Nitrum Vitriolatum
Mixture of potassium nitrate and potassium bisulfate (K2SO4; KHSO4).
Non Metals
A term used by William Cullen and his students for the following group of substances; zinc (Zn), anitmony (Sb), bismuth (Bi). arsenic (As), platinum (Pt), cobalt (Co), nickel (Ni).

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A class of mineral solids which, in powdered form, were commonly used as pigments. Their colors varied from yellow to brown, including reddish hues. Chemically, the ocheres are iron oxides, or mixtures of iron oaxides, in varying states of hydration. For example red ochre is primarily Fe2O3. Silicates, carbonates, sulfates, etc. also were commonly present with these oxides.
Cerium Oxide (CeO2).
Offa Helmonth
Potassium Carbonate (K2CO3).
Any relatively insoluble, inflammable, somewhat viscous liquid.
Oil Gas
Mixture of methane, carbon monoxide, and butlylene (CH4, CO, C4H8).
Oil of Arsenic
Arsenic trichloride (AsCl3)
Oil of Chalk
Calcium chloride solution (CaCl2).
Oil Cloves
An oily substance extracted from the buds and flower stalks of the clove tree Caryophyllus aromaticus. Used as medicinal
Oil of Dippel
The insoluble, viscous fraction from decomposed animal matter that has gone through repeated distillations.
Oil of Hartshorn
A crude animal oil obtained from the destructive distillation of bones
Oil of Lime
A solution of calcium chloride (CaCl2).
Oil of Rue
The oil extracted from evergreens of the genus Ruta. Used as Medicinal
Oil Sulphur
Concentrated sulfuric acid. Sometimes the term was used fro alkaline sulphide of ammonia (NH4)2S).
Oil of Tartar
Concentrated potassium carbonate solution (K2CO3).
Oil of Tartar per Deliquium
Potassuim carbonate, which is hydroscopic, dissolved in the water which its extracts from the air.
Oil of Venus
Concentrated solution of copper nitrate (Cu(NO3)2.
Oil of Vitriol
Sulfuric Acid (H2SO4).
Oil of Wine
A hypothetical component of alcohol thought to give it its odor and inflammability
Olea Terebinthine
Olefiant Gas
Ehtylene (C2H2).
Oleum Dulce
See Oil of Wine
Oleum Suphuris per Campanum
Sufuric Acid (H2SO4) prepared by burning sufur under a bell jar and later concentrating and purifying the product by heating to drive off water and sulfur dioxide.
Oleum Succini
Concentrated succinic acid( HOOCCH2CH2COOH).
Oleum Tartar per Demiquium
See Oil of Tartar per Deliquium
Oleum Vitriol
Oil of Vitriol
arsenic trisulfide (As2S3).
Oxycarburetted Hydrogen
Water gas mixture or hydrogen (H2), carbon monoxide, (CO), and carbon dioxide (CO2).
Oxymuriatic Acid
Chlorine (Cl2).

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Potassium sulfate (K2SO4).
Calcium sulfate (CuSO4).
The operation by which gold and silver are separated from each other.
Pearl Ash
The whitest potassium carbonate (K2CO3) extracted from calcined plants. In a sense, then, pearl ash is purified potash.
Pearl White
Bismuth oxychloride [BiOCl].
A special distillation apparatus. The condensing head had two curved tubes emerging on opposite sides. These tubes led down and entered the lower section or body of the vessel; thus, the condensed liquid ran back to the heated section where it was revaporized, giving a cyclic action. The pelican was especially effective for reactions that took place in the vapor phase.
Any thin saline crust that forms on a solution.
Per Campanum
Any process carried out under a solution.
Per Deliquium
A hygroscopic salt was said to "run per deliquium" when it changed from solid to liquid by extracting water from the air.
Perlate Salt
Sodim phosphate (Na3PO4).
Spontaneous evaporation or (less often) vaporization through heating. Also used to indicate condensation of moisture on a relatively cool body.
A medcinal which promoted perspiration.
Liquid bitumens.
A white mineral solid used in the manufacture of porcelain.
An alloy of tin. Originally with up to one-fifth lead, but later bismuth and copper were substituted for lead.
Philosopher's Wool
Zinc Oxide (ZnO).
Philosophical Flowers of Vitriol
Boric acid (H3BO3).
Philosophical Foliated Earth
Potassium acetate (KC2H3O2).
Philosophical Mercury
An alchemical term signifying the property-bearing principle of chemical activity.
Philosophical Sal Ammoniac
Ammonium sulfate ((NH4)2SO4).
Philosphical Spirit of Nitre
Nitric acid prepared by distilling saltpeter with oil of vitriol (HNO3).
Philosophical Spirit of Tartar
Potassium hydrogen tartrate (KHC4H4O6) distilled with wine.
Philosophical Spirit of Vitriol
Hydrochloric acid (HCl).
Philosophical Spirit of Wine.
Spirit of wine (alcohol) concentrated by freezing (CH2CH3OH).
Philosophical Water
Aqua regia. A solution of hydrochloric and nitric acids, usually in ratios from 2:1 to 4:1 (HCl to HNO3).
A general term for any aqueous fraction of a distillation.
Phlogisticated Acid of Nitre
Nitrous acid (HNO2).
Phlogisticated Acid of Vitriol
Sulphurous acid (H2SO3).
Phlogisticated Air
Nitrogen (N2).
Phlogisticated Alkali
Potassium ferrocyanide (K4Fe(CN)6 . 3H2O).
Phlogisticated Calx of Iron
Ferrous oxide (hydroxide) (FeO).
Phlogisticated Earth of Molybdaena
The solid reduction of molybdic acid.
Phlogisticated Manganese
Manganous carbonate (MnCO3).
Phlogisticated Nitre
Impure potassium nitrite (KNO2).
Phlogisticated Nitrous Acid
Nitrous acid (HNO2).
Phlogisticated Vitriolic Acid
Sulfurous acid (H2SO3).
A hypothetical substance originally used to account for the property of inflammability. It later was made to carry many more properties and formed a central point for the theoretical beliefs of a central point for the theoretical beliefs of a number of eighteenth-century chemists.
Phlogiston Elasticum
Hydrogen (H2).
Phosphorated Iron
Ferric phosphate (FePO4).
Phosphorated Mercury
Mercuric phosphate (Hg3(PO4)2).
Phosphorated Vegetable Alkali
Potassium phosphate (K3PO4).
Sometimes used for any phosphorescent substance.
Phosphorous of Baldwin
Calcium nitrate (Ca(NO3)2).
Phosphorous of Homberg
Calcium chloride (CaCl2).
Phosphorous of Urine
As the name implies, a form of phosphorous (P) extracted from urine.
Pierre Infernale
Fused silver nitrate 3)). [Not to be confused with "Infernal Stone."]
Pinch Beck
A gold colored alloy of about five parts cooper (Cu) to one part zinc (Zn).
Pinguious (Pinguinous)
Fatty, oily
Any semisolid plastic mixture that could be applied to a a surface and then spontaneously cured or hardened. One of the oldest plasters is a mixture of slake lime (Ca(Oh)2), sand, and hair. The term also was used to refer to impure lead oleate (Pb(C18H33O2)2).
Plaster of Paris
Calcium sulfate monohydrate ((CaSO4)2 . H2O).
Platinum (Pt.), or sometimes the usually impuer form of platinum found in nature that is alloyed with other exotic metals.
Carbon (C) in the form of graphite.
Plumbum Album
Basic lead carbonate (2PbCO3 . Pb(OH)2). Sometimes the term was applied to basic lead acetate (Pb(C2H3O2) . Pb(OH)2 . H2O).
Plumbum Cinereum
Bismuth (Bi).
Plumbum Corneum (Horn Lead)
Lead chloride (PbCl2).
Plumbum Stridens
Tin (Sn)
Pertaining to subtle, rarified, or vaporous substances such as air. In modern terms, gaseous.
Pneumatic Trough
An apparatus developed over the eighteeth century from John Mayow (1641-1679) through Stephen Hales (1677-1761) to Antoine Lavoisier (1743-1794). The trough was any large pan or vat in which inverted bottles full of water could be supported. In glass tubes conducted the gases from the vessels in which the were generated outside the trough to the inverted bottle in the trough, where the gases were trapped and held.
Point of Saturation
The instant when the exact proportions of the two "saline principles" ( one from an acid, the other from a base) unite to form a perfectly neutral salt.
Flowers of zinc (ZnO).
Ponderous Spar
Barium Sulfate (BaSO4).
Pot Ash
Potassium carbonate (K2CO3).
Powder of Algaroth
Antimony oxychoride (SbOCl)
A substance serving as intermediary to separate two other substances from each other.
Praecipitate Per Se
Mercuric Oxide (HgO).
Praecipitatus Albus
Mercurous chloride (Hg2Cl2).
Praecipitatus Vigonis
Mercuric Oxide (HgO).
Precipitate of Sulfur
Precipitated milk of sulfur (S).
The phenomenon in which a solid is formed within a solution and falls to the bottom of the vessel in which the solution was contained.
Primus Metal
See Prince Rupert's Metal
Prince Rupert's Metal (Bath Metal, Primus Metal, Princes Metal)
A brass metal alloy in which the ratios of copper (Cu) to Zinc (Zn) are approximately 4 to 1.
Prince's Metal
See Prince Rupert's Metal
One of the simplest forms of matter, from which other substances are formed through combinations with other principles or other combinations of principles. Although there are similariteies to the modern term "element", the two are not truly synonymous.
Proximate Principles
Components obtained through the chemical analysis which themselves are compounds but presumed to be simpler than the original substance.
Prussian Blue
Ferric ferrocyanide (Fe4[Fe(Cn)6]3).
Prussian Acid
Hydrocyanic acid (HCN).
Pulvis Algarothi
Antimonious oxychloride (SbOCl).
Pulvis Fulminans
An explosive mixture made from potassium nitrate, potasium carbonate, and sufur.
A light porous stone of mixed silicates.
Pure Clay
Alumina. Aluminum Oxide (Al2O3).
Pure Ponderous Earth
Baryta. Barium Oxide. (BaO)
Any process in which one substance is rendered free, or relatively free, of other substance. Common methods included distillation, crystallization, and precipitation.
Originally, any mineral which could strike sparks from steel. The term was often used to refer iron pyrites (FeS2).
Pyroligneous Acid
Crude acetic acid from wood (HC2H3O2).
Pyroligneous Spirit
Methyl alcohol (CH3OH).

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Quadrangular Nitre
Sodium Nitrate (NaNO3).
The process of combining gold (Au) and silver (Ag) in the ratio 1:3. When the combination is dissolved in nitric acid, the silver is dissolved and the gold is separated, free from impurities.
A mineral whose primary component is silicon dioxide (SiO2). Its color and other aspects of its appearance depended on the impurities present.
Calcium oxide (CaO).
Mercury (Hg).
Quicksilver Calcined Per Se
Mercuric oxide (HgO).
A mixture of an essential oil and alcohol.
Quintessence of Lead
Acetone (CH3COCH3).

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Rabel's Water
The liquid obtained by macerating poppy flowers in a mixture of sulphuric acid and alcohol for some days and then filtering.
(1) Individual (fundamental) particles of viscous or rigid bodies; (2) branching or filiment-like parts of a liquid mixture.
Arsenic disulfide (As2S2).
The vessel attached to the condensing part of a distillation apparatus in order to receive the condensed products from the distillation.
Solid waste or refuse from a chemical operation, e.g., scoria.
The purifying or refining of a substance by one or (usually) more distillations.
Red Arsenic (Realgar)
Native arsenic disulphide (As2S2).
Red Bole
A red clay that contained silicates of iron and aluminum. Used as a red pigment and as a base for gilding.
Red Flowers of Antimony
Probably antimony sulfide (Sb2S5).
Red Ochre
A mineral solid approximately 95 percent red iron oxide (Fe2O3). An old and important pigment.
Red Precipitate
See Red Precipitate of Mercury.
Red Precipitate of Mercury
Impure mercuric oxide (HgO).
Red Saunders (Red Sanders)
The wood from the tree Pterocarpus santalinus, commonly called red sandlewood. Used in dyeing.
The returning of a substance to a previous or original condition; e.g., the restoring of a metal to the metallic state from its oxide.
Refractory Earths
Mineral substances that do not fuse under the action of fire.
A vessel at the top or head of some stills that is surrounded by or filled with cold water to condense any vapors in tubes or vessels within it.
Regenerated Marine Salt
Potassium chloride (KCl).
Regenerated Sea Salt
Potassium chloride (KCl).
Regenerated Tartar
Potassium acetate (KC2H3O2). In this form, the compound was made from distilled vinegar and salt of tartar.
Reguline Caustic
Potassium carbonate (K2CO3).
The pure form of a metal, e.g., regulus of antimony.
A vessel with a long neck bent down at the point where it joins the body of the vessel. Especially suited for the distillation of substances under low heat.
The restoration of a metal to the metallic state from one of its compounds. Similar to, but broader in scope, than "reduction."
See Rock Alum.
Rochelle Salt (Seignette Salt)
Potassium sodium tartrate (KNaC4H4O6 . 4H2O).
Rock Alum
Usually larger crystals or formations of potassium aluminum sulfate (KAl(SO4)2 . 12H2O). Alum of this quality often was imported from Italy.
Pure, colorless, transparent, crystalline quartz occurring naturally in large prismatic crystals. Silicon dioxide (SiO2).
Concentrated native vegetable acid. From the usual preparations, it would be primarily citric acid (C6H8O7).
Roman Vitriol
Copper sulfate (CuSO4). In Britain this terms was sometimes used for ferrous sulfate (FeSO4).
Russian Pot Ash
Potassium carbonate (K2CO3).
Rust of Copper
See Verdigris.