it may appear to us, can ever happen but in consequence of some previously established law of unerring nature. The fol lowing apostrophe of Dr. Darwin to the Fountain of all Goodness may possibly tend to impress this important truth upon the student's mind:

"Thus, at thy potent nod, effect and cause
Walk hand in hand, accordant to thy laws;
Rise at Volition's call, in groups combin'd,
Amuse, delight, instruct, and serve mankind."

A VOCABULARY

OF

CHEMICAL TERMS.

A.

ACETATES. Salts formed by the combination of any base

with the acetic acid. See page 229. ACIDS. For the nature of acids, see page 170.

oxygenized. Acids combined with an additional quantity of oxygen, for particular purposes. The oxy muriatic acid used in bleaching is an instance of this superoxygenizement. See page 182.

hyperoxygenized. Acids which are oxygenized to a maximum. See page 220.

ACIDULES.

A term applied to the natural combination of some acids with a portion of potash. The oxalic acid and the tartaric are the only acids that have hitherto been found in this state of semi-saturation. See page 215. AËRIFORM fluids. Fluid substances combined with an additional portion of caloric sufficient to give them the gaseous form. See Gas.

AFFINITY, chemical. A term used to express that peculiar propensity which different species of matter have to unite with each other, or with portions of matter of their own species. See chap. 13.

- of aggregation. A force by which two bodies of the same kind tend to combine, and by which an aggregate is formed without the chemical properties of the substances being at all changed. See page 394.

- of composition. A force by which substances of different kinds unite, and by which matter is formed whose properties are different from those of the bodies before their combination. This attraction is stronger in proportion as the nature of the bodies is different, between which it is exerted. See page 395.

AGGREGATES. Substances whose parts are united by cohesive, and not by chemical attraction. See Affinity of aggregation. See page 391.

ALBUMEN. The modern name for coagulable lymph. It is that peculiar animal substance which forms the serum of the blood, the white of eggs, and other compounds. ALCOHOL. Rectified spirit of wine. When good, its specific gravity is only 0.836. See page 287.

ALEMBIC. The term formerly given to the still used by

chemists for their distillations.

ALKALIES. Peculiar substances which have an urinous, burning, and caustic taste, and a strong tendency to combination. When united with acids they form mild alkaline salts. See page 147.

ALLOYS. A combination of any two metals, except mercury, is called an alloy. Thus gold is alloyed either with silver or copper, for the purposes of coinage. ALLUVIAL By alluvial depositions is meant the soil which has been formed by the destruction of the mountains, and the washing down of their particles by torrents of water. See page 247.

AMALGAM. A combination or mixture of mercury with any other metal, is called an amalgam.

AMMONIACAL salts. Salts formed by the union of an acid with ammonia, or volatile alkali. See page 165.

ANALYSIS. The resolution of a substance into its constituent parts, for the purpose of examination. See page 25. ANNEALING. The art of rendering substances tough which are naturally hard and brittle. Glass and iron are annealed by gradual cooling; brass and copper by heating, and then suddenly plunging them in cold water. APPARATUS, chemical. This term is descriptive of all the utensils made use of in a chemical laboratory. The principal are stills, furnaces, crucibles, retorts, receivers, matrasses, worm-tubs, pneumatic troughs, thermome ters, &c. AREOMETER.

A graduated glass instrument with a bulb, by which the specific gravity of liquids is ascertained. Baumé's areometer is that which is chiefly referred to when the French writers speak of this instrument. See table, page 465.

ARGILLACEOUS. A term descriptive of those earths which contain alumine or clay.

AROMA. A term used for the odour which arises from certain vegetables, or their infusions.

ARSENIATES. Saits formed by the combination of any base with the acid of arsenic. See page 228.

ATMOSPHERES. We use this term to express the degree of additional pressure given to fluids. Thus, if, in order to impregnate water with any of the gases, I give it a pressure of 15lbs. upon every square inch of surface, I am said to give one atmosphere; if 80lbs. two atmospheres, &c. &c. See page 51.

ATTRACTION. Chemical attraction is a term synonymous with affinity; which see.

AZOTE. A name given by the French chemists to nitrogen, to which, being the most proper, the reader is referred.

B.

BALLOON. A term given by the French to their spherical chemical receivers.

BALSAMS. Certain aromatic resinous substances, which are obtained from some trees by incisions. Of this kind are the Canada balsam, the balsam of Copaiva, the balsam of Tolu, &c.

BAROMETER. An instrument which shows the variation of the pressure of the atmosphere, by the rise or fall of a column of mercury in a glass tube attached to a graduated plate. See note ‡, page 38.

BASE. A chemical term, usually applied to denote the earth, the alkali, or the metal which is combined with an acid to form a salt.

BATHS. Vessels for distillation or digestion, contrived to transmit heat gradually and regularly.

sand. Vessels filled in part with dry sand, in which those retorts are placed which require a greater heat than can be given by boiling water. In large works, iron plates are used instead of vessels of capacity. They are often called sand-heats.

water. Vessels of boiling water, in which other vessels containing the matters to be distilled or digested are placed, in order that the same heat may be kept up throughout the whole of any particular process.

BENZOATES. Salts formed by the combination of any base with the benzoic acid.

BITTERN. The mother-liquor which remains after the crystallization of muriate of soda (sea-salt) It generally

contains sulphate of magnesia, and a small portion of sulphate of soda.

BITUMEN. A generic term, applied to a variety of fossil inflammable substances. See notes, page 271.

BLOW-PIPE. An instrument to increase and direct the flame of a lamp for the analysis of minerals, and for other chemical purposes.

BOLT-HEAD. A round chemical vessel with a long neck, usually employed for digestions. It is also called a

matrass.

BORATES. Salts formed by the combination of any base with the acid of borax. See page 227.

BUTTON. A name given to the small round piece of metal which is found at the bottom of a crucible after a metallic ore or an oxide of metal has been reduced.

C.

CALCAREOUS. A chemical term formerly applied to describe chalk, marble, and all other combinations of lime with carbonic acid. See page 133.

CALCINATION. The application of heat to saline, metallic, or other substances; so regulated as to deprive them of moisture, &c. and yet preserve them in a pulverulent form. CALORIC. The chemical term for the matter of heat.

free. Is caloric in a separate state, or, if attached to other substances, not chemically united with them. See page 74.

latent Is the term made use of to express that portion of caloric which is chemically united to any substance, so as to become a part of the said substance. See page 75.

CALORIMETER. An instrument for ascertaining the quantity of caloric disengaged from any substance that may be the object of experiment. See page 79.

CALX.

An old term made use of to describe a metallic oxide. CAMPHORATES. Salts formed by the combination of any base with the camphoric acid. See page 232. CAPILLARY. A term usually applied to the rise of the sap

in vegetables, or the rise of any fluid in very small tubes; owing to a peculiar kind of attraction, called capillary attraction.

CAPSULES. Are small saucers of clay for roasting samples

of ores, and for smelting them to ascertain their value. CAPUT MORTUUM. A term signifying dead-head, being that which remains in a retort after distillation to dryness. See Residuum, which is the modern term. CARBON The basis of charcoal. See page 264. CARBONATES. Salts formed by the combination of any base with carbonic acid. See page 223.

CARBURETS. Compound substances, of which carbon forms one of the constituent parts. Thus plumbago, which is composed of carbon and iron, is called carburet of iron. See page 278.