Search the Dictionary

An alteration in a mineral or rock mass when involving a chemical change of the substance, as of chrysolite to serpentine; -- opposed to ordinary metamorphism, as implying simply a recrystallization. -- Met`a*so*mat"ic, a.

ormed into other matter; in plants, the act or process by which are produced all of those chemical changes in the constituents of the plant which are not accompanied by a production of organic matter; metabolism.

ydrocarbons, of which methane is the first member and type, and (because of their general chemical inertness and indifference) called also the paraffin (little affinity) series. The lightest members are gases, as methane, ethane; intermediate members are liquids, as hexane, heptane, etc. (found in benzine, kerosene, et…

A whitish soluble powder used as a developer in photography. Chemically, it is the sulphate of methyl-p-amino-m-cresol.

a structural particle of protoplasm, capable of increase or diminution without change in chemical nature.

The application of chemical tests to minute objects or portions of matter, magnified by the use of the microscopy; -- distinguished from macro-chemistry.

An inorganic species or substance occurring in nature, having a definite chemical composition and usually a distinct crystalline form. Rocks, except certain glassy igneous forms, are either simple minerals or aggregates of minerals.

A group of atoms so united and combined by chemical affinity that they form a complete, integrated whole, being the smallest portion of any particular compound that can exist in a free state; as, a molecule of water consists of two atoms of hydrogen and one of oxygen. Cf. Atom.

To destroy the active powers or essential qualities of; to change by chemical action. [Obs.] Chaucer. Quicksilver is mortified with turpentine. Bacon. He mortified pearls in vinegar. Hakewill.

, and not yet united with another, -- a hypothetical condition implying peculiarly active chemical properties; as, hydrogen in the nascent state is a strong reducer.

aws of matter and considers those effects only which are unaccompanied by any change of a chemical nature; -- contrasted with mental and moral philosophy. -- Natural scale (Mus.), a scale which is written without flats or sharps. Model would be a preferable term, as less likely to mislead, the so-called artificial sca…

time considered identical with choline, a crystalline body originally obtained from bile. Chemically, however, choline is oxyethyl-trimethyl-ammonium hydroxide, while neurine is vinyl-trimethyl-ammonium hydroxide. [Written also neurin.]

the axis cylinder of medullated nerve fibers. Like keratin it resists the action of most chemical agents, and by decomposition with sulphuric acid yields leucin and tyrosin.

To render inert or imperceptible the peculiar affinities of, as a chemical substance; to destroy the effect of; as, to neutralize an acid with a base.

lement, tasteless and odorless, comprising four fifths of the atmosphere by volume. It is chemically very inert in the free state, and as such is incapable of supporting life (hence the name azote still used by French chemists); but it forms many important compounds, as ammonia, nitric acid, the cyanides, etc, and is a…

from the surrounding protoplasm by a difference in refrangibility and in behavior towards chemical reagents. It is more or less protoplasmic, and consists of a clear fluid (achromatin) through which extends a network of fibers (chromatin) in which may be suspended a second rounded body, the nucleolus (see Nucleoplasm).…

orbs, or occludes, nearly a thousand times its own volume of hydrogen, and in this case a chemical compound seems to be formed.

nomena of mesmerism, and to be developed by various agencies, as by magnets, heat, light, chemical or vital action, etc.; -- called also odyle or the odylic force. [Archaic] That od force of German Reichenbach Which still, from female finger tips, burnt blue. Mrs. Browning.

l and vegetable kingdoms (see Palmitin). It dissolves solid fats, especially at 30-40° C. Chemically, olein is a glyceride of oleic acid; and, as three molecules of the acid are united to one molecule of glyceryl to form the fat, it is technically known as triolein. It is also called elain.

An image of external objects fixed on the retina by the photochemical action of light on the visual purple. See Optography.