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A reflecting telescope, part of which is made to rotate eccentrically, so as to produce a ringlike image of a star, instead of a point; -- used in studying the scintillation of the stars.

A chromosphere. [R.]

An instrument for exhibiting certain chromatic effects of light (depending upon the persistence of vision and mixture of colors) by means of rapidly rotating disks variously colored.

A colored photographic picture taken upon paper made sensitive with potassium bichromate or some other salt of chromium.

Same as Chromium. Chrome alum (Chem.), a dark violet substance, (SO4)3Cr2.K2SO4.24H2O, analogous to, and crystallizing like, common alum. It is regarded as a double sulphate of chromium and potassium. -- Chrome green (a) The green oxide of chromium, Cr2O3, used in enamel painting, and glass staining. (b) A pigment mad…

Same as Chromium steel, under Steel.

Pertaining to, or obtained from, chromium; -- said of the compounds of chromium in which it has its higher valence. Chromic acid, an acid, H2CrO4, analogous to sulphuric acid, not readily obtained in the free state, but forming well known salts, many of which are colored pigments, as chrome yellow, chrome red, etc. --…

One of the Chromidæ, a family of fresh-water fishes abundant in the tropical parts of America and Africa. Some are valuable food fishes, as the bulti of the Nile.

Secretion of abnormally colored perspiration.

Same as Chromatism.

A black submetallic mineral consisting of oxide of chromium and iron; -- called also chromic iron.

A comparatively rare element occurring most abundantly in the mineral chromite. Atomic weight 52.5. Symbol Cr. When isolated it is a hard, brittle, grayish white metal, fusible with difficulty. Its chief commercial importance is for its compounds, as potassium chromate, lead chromate, etc., which are brilliantly colore…

A chromolithograph.

An embryonic cell which develops into a pigment cell.

Vegetable coloring matter other than green; chromule.

Containing, or capable of forming, chromogen; as, chromogenic bacteria.

An apparatus by which a number of copies of written matter, maps, plans, etc., can be made; -- called also hectograph.

A chromoplastid.

A picture printed in tints and colors by repeated impressions from a series of stones prepared by the lithographic process.

One who is engaged in chromolithography.