QUARTATION. A term ufed by refiners in a certain operation of parting. See
Lewis's Com. Tech.
QUARTZ. A name given to a variety of filiceous earths, mixed with a small portion
of lime or alumine. Mr. Kirwan confines the term to the purer kind of filex.
Rock crystal and the amethyst are species of quartz.

R,

RADICALS. A chymical term for the Elements of bodies; which fee.

compound. When the base of an acid is compofed of two or more fub stances, it is faid that the acid is formed of a compound radical. The fulphuric acid is formed with a simple radical; but the vegetable acids which have radicals compofed of hydrogen and carbon are faid to be acids with compound radicals. REAGENTS. Substances which are added to mineral waters or other liquids as tefts to difcover their nature and compofition. See Teft.

REALGAR. Red fulphuretted oxide of arfenic.

RECEIVERS. Globular glafs veffels adapted to retorts for the purpose of preserving and condenfing the volatile matter raised in diftillation.

RECTIFICATION. Is nothing more than the re-diftilling a liquid to render it more pure, or more concentrated, by abftracting only a part.

REDUCTION. The reftoration of metallic oxides to their original state of metals i which is ufually effected by means of charcoal and fluxes.

REFINING. The process of feparating the perfect metals from other metallic fube ftances, by what is called cupellation.

REFRACTORY. A term applied to earths or metals that are either infufible, or that require an extraordinary degree of heat to change or melt them.

REFRIGERATORY. A contrivance of any kind, which, by containing cold water,

anfwers the purpose of condenfing the vapour or gas that arifes in diftillation. A worm tub is a refrigeratory.

REGISTERS. Openings in chimneys, or other parts of chymical furnaces, with fliding doors, to regulate the quantity of atmospheric air admitted to the fireplace, or to open or fhut the communication with the chimney at pleasure. REGULUS. In its chymical acceptation, fignifies a pure metallic fubftance, freed

from all extraneous matters.

REPULSION. A principle whereby the particles of bodies are prevented from coming into actual contact. It is thought to be owing to caloric, which has been called the repulfive power.

RESIDUUM. What is left in a pot or retort after the more valuable part has been drawn off. Thus the fulphate of potash which remains in the pot after distillation of nitrous acid is called the refiduum. It is fometimes called the caput mortuum. RESINS. Vegetable juices concreted by evaporation either fpontaneously or by fire. Their characteristic is folubility in alcohol, and not in water. It feems that they owe their folidity chiefly to their union with oxygen.

RETORT. A veffel in the fhape of a pear, with its neck bent downwards, ufed in diftillation; the extremity of which neck fits into that of another bottle called a

receiver.

REVERBERATORY, An oven or furnace in which the flame is confined by a dome which occafions it to be beat down upon the floor of the furnace before it paffes into the chimney, Some are fo contrived that it returns or reverberates upon the matter under operation.

REVIVIFICATION. See Reduction, which is a fynonymous term: though "revivification" is generally ufed when speaking of quickfilver.

ROASTING. A preparative operation in metallurgy to diffipate the fulphur, arfenic, &c. with which a metal may be combined.

ROCK-CRYSTAL. Cryftallized filex.

S.

SACCHARUM SATURNI. The old name for the acetate of lead.

SACCOLATES. Salts formed by the faccholactic acid.

SALIFIABLE BASES. All the metals, alkalies, and earths, which are capable of combining with acids, and forming falts, are called falifiable bafes.

SALINE. Partaking of the properties of a falt.

SALTS neutral. A clafs of fubftances formed by the combination to faturation of an acid with an alkali, an earth, or other salifiable base.

triple. Salts formed by the combination of an acid with two bafes or radicals. The tartrate of foda and potah, Rochelle falt, is an inftance of this kind of combination."

SAND bath

beat} See Bath.

SANDIVER. A matter, compofed of different falts which rifes as a pellicle on the furface of the pots in which glafs is melted. It is ufed as a flux in the fufion of ores, and for other purpofes. The term is probably a corruption of "Sal de verre." SAP-COLOURS. A name given to various expreffed vegetable juices of a vifcid nature, which are infpiflated by flow evaporation for the ufe of painters, &c.; fapgreen, gamboge, &c. are of this clafs.

SAPONACEOUS. A term applied to any fubftance which is of the nature or appearance of foap,

SATURATION. The act of impregnating a fluid with another fubftance, till no more can be received or imbibed. A fluid which holds as much of any substance as it can diffolve, is faid to be faturated with that substance. A solid may in the fame way be faturated with a fluid.

SEBATES. Salts formed by the sebacic acid.

SELENITE. A falt exifting in fpring water, formed by fulphuric acid and lime. Its proper chymical name is Sulphate of Lime.

SEMI-METAL, A name formerly given to those metals which are neither mallea ble, ductile, nor fixed, if expofed to the fire. It is a term not yfed by modern chymists,

SILICEOUS EARTHS, A term used to describe a variety of natural fubftances which are compofea chiefly of silex; as quartz, Alint, fand, &c.

SIMPLE SUBSTANCES. Synonymous with elements; which fee.

SMELTING. The operation of fufing ores for the purpose of feparating the metals they contain, from the sulphur and arfenic with which they are mineralized, and alfo from other heterogeneous matter.

SOLUBILITY. A characteristic of moft falts. See Solution.

SOLUTION. The perfect union of a solid fubftance with a fluid. Salts diffolved in water are proper examples of solution.

SPARS. A name formerly given to various cryftallized ftones; fuch as the fluor fpar, the adamantine fpar, &c. Thefe natural fubftances are now diftinguished by names which denote the nature of each.

SPATULA. An inftrument like a knife, with an elaftic blade, used for mixing fmall quantities of powders or other substances.

SPECIFIC GRAVITY. See the word Gravity.

SPELTER. The commercial name of zinc.

SPIRIT. A term used by the early chymifts to denote all volatile fluids collected by

diftillation.

SPIRIT PROOF. A term made ufe of to defcribe fuch ardent fpirits as are of the fame ftrength as the brandy of commerce, or of the specific gravity of 0.930, water being 1.000.

STALACTITES.

Certain concretions of calcareous earth found fufpended like icicles in caverns. They are formed by the oozing of water, through the crevices, charged with this kind of earth.

STEATITES. A kind of ftone compofed of filex, iron, and magnefia. Alfo called French chalk, Spanish chalk, and foap-rock.

STRATIFICATION. A chymical operation by which bodies are placed in a condition to act mutually upon each other by being arranged layer by layer, ftratum fuper ftratum, as is practifed by metallurgifts.

SUB-SALTS. Salts with lefs acid than is fufficient to neutralize their radicals.
SUBERATES. Salts formed with the fuberic acid,

SUBLIMATE. A name given to feveral mercurial preparations.

SUBLIMATION. A procefs whereby certain volatile fubftances are raised by heat, and again condensed by cold into a folid form. Flowers of fulphur are made in way. The foot of our common fires is a familiar instance of this process. See

overs.

SUCCINATES. Salts formed by the fuccinic acid.

SUGAR. A well known fubftance, found in a variety of vegetables, compofed of oxy

gen, hydrogen, and carbon.

SULPHATES. Salts formed with the fulphuric acid.

SULPHITES. Salts formed with the fulphurous acid.

SULPHURES, or SULPHURETS. Combinations of alkalies, or metals, with fulphur.

SULPHURETTED. A fubftance is faid to be fulphuretted when it is combined with fulphur. Thus we fay Sulphuretted hydrogen, &c.

SUPER-SALTS. Salts with an excefs of acid, as the fuper tartrate of potash. SYNTHESIS. When a body is examined by dividing it into its component parts, it is called analyfis; but when we attempt to prove the nature of a substance by the union of its principles, the operation is called fynthesis.

SYPHON. A bent tube used by chymifts for drawing liquids from one veffel into another. It is fometimes called a Crane.

T:

TARTRATES. Salts formed with the acid of tartari

TEMPERATURE. The abfolute quantity of free caloric which

attached to any

body occafions the degree of temperature of that body. TENACITY. Is a term used when speaking of glutinous bodies. It is also expreffive of the adhesion of one fubftance to another.

TEST. That part of a cupel which is impregnated with litharge in the operation of refining lead. It is alfo the name of whatever is employed in chemical experiments to detect the feveral ingredients of any compofition. See Re-agent. TEST-PAPERS. Papers impregnated with certain chymical re-agents; fuch ae litmus, turmeric, radifh, &c. They are used to dip into fluids to afcertain by a change of colours the prefence of acids and alkalies.

THERMOMETER. An inftrument to fhow the relative heat of bodies. Fahren. heit's thermometer is thaf chiefly used in England. (See page 68). Other thermometers are used in different parts of Europe. For the difference in the fcale of thefe thermometers, fee the Table at the end of this volume.

TINCAL. The commercial name of crude borax.

TINCTURES. Solutions of fubftances in fpirituous menftrua.
TORREFACTION. An operation fimilar to foafting; which fee.

TRANSMUTATION. A favorite term among the old chymifts, fignifying the changing of one metal to another, which they fuppofed poffible.

TRITORIUM. A veffel used for the feparation of two fluids which are of different denfities. But the fame operation may be performed by a common funnel. TRITURATION. A chymical operation whereby fubftances are united by friction. Amalgams are made by this method.

TUBULATED. Retorts which have a hole at the top for inferting the materials to be operated upon, without taking them out of the fand heat, are called tubulated

retorts.

TUNGSTATES. Salts formed by the tungstic acid. TUTENAG. An Indian name for zinc. Chinese copper is alfo called by this name, which is a compound of copper, tin, and arfenic, much resembling filver in colour.

V.

VACUUM. A space unoccupied by matter. The term is generally applied to the exhauftion of atmospheric air by chymical or philofophical means.

VAPOUR. This term is ufed by chymifts to denote fuch exhalations only as can be condenfed and rendered liquid again at the ordinary atmofpheric temperature, in oppofition to those which are permanently elaftic.

VATS. Large chymical veffels, generally of wood, for making infufions, &t. VITAL AIR. Oxygen gas. The empyreal or fire-air of Scheele, and the dephlogifticated air of Priestley.

VITRIFICATION. When folid fubftances have undergone very intense heats, fo as to be fufed thereby, they frequently have an appearance refembling glafs. They are then faid to be vitrified, or to have undergone vitrification.

VITRIOLS. A clafs of fubftances, either earthy or metallic, which are combined with the vitriolic acid. Thus there is vitriol of lime, vitriol of iron, vitriol of copper, &c. Thefe falts are now called Sulphates, because the acid which forms them is called fulphuric acid.

VITRIOLATED TARTAR. The old name for fulphate of potash.

VOLATILE ALKALI. The old name for ammonia.

VOLATILE SALTS. The commercial name for carbonate of ammonia. VOLATILITY. A property of fome bodies which difpofes them to affume the gafeous state. This property feems to be owing to their affinity for caloric. VOLUME. A term made ufe of by modern chymifts to exprefs the space occupied by gafeous or other bodies.

U.

UNION chymical. When a mere mixture of two or more fubftances is made, they are faid to be mechanically united; but when each or either fubftance forms a component part of the product, the fubftances have formed a chymical union. USTULATION. The roafting of ores, to feparate the arfenic and fulphur which mineralizes the metal. When the matter is preserved which flies off, the process is called fublimation; but when this matter is neglected, the operation is called uftulation.

W.

WADD. The name given by miners to plumbago, or carburet of iron, known in commerce by the very improper name of black-lead.

WADD-black. The miners' name for the argillaceous ore of manganefe.

WATER. The moft common of all fluids, compofed of 85 parts of oxygen and 15 of hydrogen. See page 86.

mineral. Waters which are impregnated with mineral and other fubftances are known by this appellation. These minerals are generally held in folution by carbonic, fulphuric, or muriatic acid.

WAY dry. A term ufed by chymical writers when treating of analysis or decompofition. By decompofing in the dry-way, is meant, by the agency of fire.

WAY bamid. A term ufed in the fame manner as the foregoing, but expreffive of decompofition in a fluid ftate, or by means of water, and chymical re-agents, or

tefts.

WELDING HEAT: That degree of heat in which two pieces of iron or of platina may be united by hammering.

WHITING. Carbonate of lime of chalk, cleared of its groffer impurities by washing,
and made up into balls for fale. It is fold in the fhops by this name.
WOLFRAM. An ofe of tungsten containing also manganefe and iron.
WORM-TUB. A chymical veffel with a pewter worm fixed in the infide, and the

intermediate space filled with water. Its ufe is to cool liquors during diftillation. See Refrigeratory.

WOULFE's apparatus. A contrivance for diftilling the mineral acids and other gåfeous fubftances with little lofs; being a train of receivers with fafety pipes, and connected together by tubes. For a full defcription of this molt ufeful apparatus, fee Philofophical Tranfactions for 1767.

2.

ZAFFRE. An oxide of cobalt, mixed with a portion of filiceous matter. It is intported in this ftate from Saxony.

ZERO. The point from which the scale of a thermometer is graduated. Thus Ce! fius's and Reaumur's thermometers have their zero at the freezing point, while the thermometer of Fahrenheit has its zero at that point at which it stands when immerfed in a mixture of fnow and common falt. See Notes, page 68.