THE BAKERS' GUIDE

Retort. A globular vessel of glass or metal, etc., with a lon£ neck bent over on one side, and used for distillation. Some retorts have another neck or opening at their upper part, through which they may be charged, and the opening afterwards closed with a stopper ; these are called tubulated retorts.

Sac. A bag. A term, applied to a small natural cavity, as Sac of the embryo. The name given to the innermost integu- ment of the nucleus of a seed, etc.

Sal. A Salt. A definite compound of an acid with an alkaline, or salifiable base. Salts are distinguished by the six following prefixes : —

Super \ denoting excess of acid in general, as super-taxlxa.te of potash.

Sub, denoting excess of the base, as j^-borate of soda. See Sub salt

Bi, denoting two equivalents of acid, as sulphate of potash. Quadr, denoting four equivalents of acid, as quadr-oxalaite of potash.

Sesqui, denoting one equivalent and a half of acid, as sesqui- carbonate of ammonia.

Oxy, denoting the presence of a perfect oxide as oxy muriate.

Deliquescent salts are those which attract moisture from the air, and become liquid, as the nitrates of lime and magnesia.

Efflorescent salts are those which lose a portion of their water of crystallization, and fall into powder, by exposure to the air, as sulphate and phosphate of soda. By a strong heat the whole of the water is expelled, and the salt, if soluble, is dissolved, under- going what is called watery fusion.

Permanent salts are those which undergo no change on exposure to the air.

Decrepitating salts are those which burst, when heated, with a crackling noise, into smaller fragments, as the nitrates of baryta and lead.

Neutral salts are those in which the base is perfectly saturated with the acid. It does not, however, follow that neutrality and saturation accompany each other : an alkali may unite with an acid so as to saturate it, though it still manifests alkaline pro- perties.

Double salts t formerly called triple salts, are composed of one acid and two bases, of two acids and one base, or of two different acids and two different bases.

Native salts are mineral bodies, resembling precious stones or gems in their external character, and so named to distinguish them from artificial salts.

THE BAKERS1 GUIDE.

Sub-salts, or neutral salts, are those in which the excess of oxide does not stand in the relation of base to the acid.

Common salt, or Bay salt, a muriate of soda, is procured, by evaporation, from sea water, or from the produce of brine springs, or from mines.

Solution (so/vo9 to dissolve). The act of dissolving a solid or aeriform body in a liquid ; this liquid is called the solvent. Also, a liquid containing a dissolved body.

Spore. The reproductive body in Flowerless plants, which is anologous to the seed of Flowering plants, but differs from this in not germinating from any fixed point, but in producing its root and stem indifferently from any point of its surface.

Symbols, Chemical. An abbreviated mode of expressing the composition of bodies. The elementary substances, instead of being written at full length, are indicated by the first letter of their names, a second letter being employed when more than one substance begins with the same letter, — thus C stands for carbon, Al for aluminium, As for arsenic, &c. Sometimes the substances are indicated by their abbreviated Latin name : for instance, sodium chloride or common salt is written Na. CI. and not Sod. CL

Temperature (tempero, to mix various things in due propor- tions). The comparative degree of active heat accumulated in a body, as measured by an instrument, or by its effects on other bodies. Temperature, however, must not be confounded with "quantity of heat." A cup of water dipped from a gallon would be of equal temperature, but would not contain equal quantity of heat as a gallon.

Tenacity (teneo, to hold). The degree of force with which the particles of bodies cohere, or are held together; a term particularly applied to metals which may be drawn into wire, as gold and silver.

Thermometer. Literally, a measurer of heat ; an instrument for comparing the degree of active heat existing in other bodiesf by its effect in expanding a column of mercury.

i. Fahrenheit 's Thermometer. That arrangement of the scale of the instrument, in which the space between the freezing and the boiling points of water, under a medium pressure of the atmos- phere, is divided into 180 parts, or degrees, the freezing being marked 320, and the boiling 2120. This scale was adopted by Fahrenheit, because he supposed, erroneously, that 32 of those divisions below the freezing point of water (which was therefore o on bis scale) was the zero, or Greatest degree of cold.