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A micaceous mineral occurring in small scales. It is characteristic of certain crystalline schists.

ding the kamichi, and allied South American birds; -- called also screamers. In many anatomical characters they are allied to the Anseres, but they externally resemble the wading birds.

fat of animal tissues, with olein and butyrin in butter, with olein in olive oil, etc. Chemically, it is a glyceride of palmitic acid, three molecules of palmitic acid being united to one molecule of glyceryl, and hence it is technically called tripalmitin, or glyceryl tripalmitate.

illuminant and lubricant. It is very inert, not being acted upon by most of the strong chemical reagents. It was formerly regarded as a definite compound, but is now known to be a complex mixture of several higher hydrocarbons of the methane or marsh-gas series; hence, by extension, any substance, whether solid, liquid…

A kind of mica related to muscovite, but containing soda instead of potash. It is characteristic of the paragonite schist of the Alps.

domorph, in which there has been a change of physical characters without alteration of chemical composition, as the change of aragonite to calcite.

ies to another, so as to involve a change in physical characters without alteration of chemical composition.

The quality or condition of any substance which has no inclination to chemical activity; inactivity.

The department of science which is concerned with the mineralogical and chemical composition of rocks, and with their classification: lithology.

A chemical laboratory. [Obs.] Dunglison.

A generalization with regard to systems of chemical equilibrium, discovered by Prof. J. Willard Gibbs. It may be stated thus: The degree of variableness (number of degrees of freedom) of a system is equal to the number of components minus the number of phases, plus two. Thus, if the components be salt and water, and th…

The hypothetical principle of fire, or inflammability, regarded by Stahl as a chemical element.

A kind of mica having generally a peculiar bronze-red or copperlike color and a pearly luster. It is a silicate of aluminia, with magnesia, potash, and some fluorine. It is characteristic of crystalline limestone or dolomite and serpentine. See Mica.

nslucent waxy substance, having a characteristic disagreeable smell. It is very active chemically, must be preserved under water, and unites with oxygen even at ordinary temperatures, giving a faint glow, -- whence its name. It always occurs compined, usually in phosphates, as in the mineral apatite, in bones, etc. It…

The branch of chemistry which relates to the effect of light in producing chemical changes, as in photography.

cess of etching on copper, steel, or zinc, by means of the action of light and certain chemicals, so that from the plate impressions may be taken. Sir D. Brewster.

o*graph"ic*al*ly, adv. Photographic printing, the process of obtaining pictures, as on chemically prepared paper, from photographic negatives, by exposure to light.

aterial organization; cognizable by the senses; external; as, the physical, opposed to chemical, characters of a mineral.

r in the theory that the fundamental phenomena of life are to be explained upon purely chemical and physical principles; -- opposed to vitalist.

An ideal surface, conceived as coinciding with, or containing, some designated astronomical line, circle, or other curve; as, the plane of an orbit; the plane of the ecliptic, or of the equator.