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lence of four; capable of combining with, being replaced by, or compared with, four monad atoms; tetravalent; -- said of certain atoms and radicals; thus, carbon and silicon are quadrivalent elements.

Butane, each molecule of which has four carbon atoms.

h crotonic acid, and obtained as a colorless liquid; -- so called from having four carbon atoms in the molecule. Called also isocrotonic acid.

Pertaining to, or designating, an acid of the fatty acid series, containing fifteen atoms of carbon; called also pentadecylic acid.

racteristic, essential, and fundamental constituent of any compound; hence, sometimes, an atom. As a general rule, the metallic atoms are basic radicals, while the nonmetallic atoms are acid radicals. J. P. Cooke.

ned) in minute quantities in pitchblende, and various other uranium minerals. Symbol, Ra; atomic weight, 226.4. Radium was discovered by M. and Mme. Curie, of Paris, who in 1902 separated compounds of it by a tedious process from pitchblende. Its compounds color flames carmine and give a characteristic spectrum. It res…

The terminal part of the large intestine; -- so named because supposed by the old anatomists to be straight. See Illust. under Digestive.

The union of parts which have been severed, so that they become anatomically perfect; as, the regeneration of a nerve.

which remains of a molecule after the removal of a portion of its constituents; hence, an atom or group regarded as a portion of a molecule; -- used as nearly equivalent to radical, but in a more general sense.

, and obtained free as a white inert metal which it is very difficult to fuse. Symbol Rh. Atomic weight 104.1. Specific gravity 12.

neralization that the properties of the chemical elements are periodic functions of their atomic wieghts. "In other words, if the elements are grouped in the order of their atomic weights, it will be found that nearly the same properties recur periodically throughout the entire series." The following tabular arrangemen…

[So named from its first describer, J. C. Rosenmüller, a German anatomist.] (Anat.) The parovarium.

soft yellowish white metal, analogous to potassium in most of its properties. Symbol Rb. Atomic weight, 85.2.

res, and isolated as a hard, brittle steel-gray metal which is very infusible. Symbol Ru. Atomic weight 103.5. Specific gravity 12.26. See Platinum metals, under Platinum.

Acid salt (Chem.) (a) A salt derived from an acid which has several replaceable hydrogen atoms which are only partially exchanged for metallic atoms or basic radicals; as, acid potassium sulphate is an acid salt. (b) A salt, whatever its constitution, which merely gives an acid reaction; thus, copper sulphate, which i…

That part of anatomy which treats of the soft parts. It includes myology, angiology, neurology, and splanchnology.

Having its affinity satisfied; combined with all it can hold; - - said of certain atoms, radicals, or compounds; thus, methane is a saturated compound. Contrasted with unsaturated.

Scandinavian minerals (euxenite and gadolinite). It has not yet been isolated. Symbol Sc. Atomic weight 44

A combining form used in anatomy to indicate connection with, or relation to, the scapula or the shoulder; as, the scapulo- clavicular articulation, the articulation between the scapula and clavicle.

Discovered or described by C. V. Schneider, a German anatomist of the seventeenth century. Schneiderian membrane, the mucous membrane which lines the nasal chambers; the pituitary membrane.