FRU 



FUL 



FRINGT'LLID^ {fringilla, a finch). 

 The Finches ; a family of the Insessores, 

 or Perching birds, readily known by the 

 strength and shortness of their conical 

 bills. See Conirostres. 



FRINGING REEF. A Coral produc- 

 tion, diflfering from the Barrier Reef in 

 having a comparatively small depth of 

 water on the outer side, and a narrower 

 and shallower lagoon channel between it 

 and the main land, 



FRITH or FIRTH {fretum, a narrow 

 sea). A narrow and deep inlet of the 

 sea, especially in a rocky and elevated 

 coast. Such an inlet is commonly called 

 a sound. 



FRITT. The mass produced by the 

 materials of glass, on calcination. 



FROND {frons, a branch). A term 

 applied to the foliaceous part of Ferns and 

 other Cryptogamic plants, from their 

 partaking at once of the nature of a leaf 

 and a branch. 



FRONT ifrons, frontis, the forehead). 

 That part of a shell near which the head 

 of the animal protrudes. The term is 

 also applied to the under surface of spiral 

 shells, where the aperture is placed, in 

 contra-distinction to the back. 



FRO'NTLET {frons, the front). The 

 margin of the head behind the bill of 

 birds, generally covered with stiff bris- 

 tles. 



FROST. The water or vapour of the 

 atmosphere congealed by cold. Hoar- 

 frost is frozen dew, and indicates an in- 

 sensible transition from dew, in conse- 

 quence of reduced temperature. Frost- 

 smoke consists of frozen particles of 

 water floating in the atmosphere in the 

 form of crystallized spiculae ; when these 

 occur in large masses, they become ag- 

 glutinated together into flakes, and fall 

 to the earth in the form of snow. 



FRUIT. In botanical language, the 

 fruit is the ovary or pistil arrived at ma- 

 turity ; the term is also extended to what- 

 ever parts are combined with the ovary 

 when ripe. An inferior fruit is that in 

 which the pericarp adheres to the calyx ; 

 K superior fruit i^ ih?Li m vih'ich. no such 

 adhesion takes place : the apple is an in- 

 ferior, the orange a superior fruit. 



FRUSTUM. Literally, a fragment. 

 A portion cut off from any solid figure. 

 The frustum of a cone is any part cut off 

 from a cone which does not contain the 

 vertex; otherwise, the part cut off would 

 be itself a cone. The frustum differs 

 from fragment, which is a piece broken , 

 and from segment, which is a piece cut off. 

 H4 



FRUTEX. A shrub; a plant whose 

 branches are perennial, proceeding di- 

 rectly from the surface of the earth with- 

 out any supporting trunk. When very 

 small, the plant is termed fruticulus, or 

 little shrub. 



FUCI'VOROUS {fucus, sea-weed, voro, 

 to eat). A term applied to animals which 

 subsist upon sea-weed. 



FUGUE. A musical composition, in 

 which the subject, or brief air, passes suc- 

 cessively and alternately from one part 

 to another, according to certain rules of 

 harmony and modulation. 



FULCRUM. The prop, or support on 

 which a lever is sustained, and about 

 which it moves. In raising a stone, the 

 body on which the lever rests, is the ful- 

 crum. 



FULGO'RIDiE {fulgora, the lantern- 

 fly). A family of the trimerous Homo- 

 ptera, characterized by the large develop- 

 ment of their forehead, in which the 

 luminosity of the lantern-fly is said to 

 exist. 



FULGURA'TION ifulgur, lightning). 

 A term applied, in assaying, to the sud- 

 den brightening of the fused globule of 

 gold or silver when the last film of oxide 

 of lead or copper leaves its surface. 



FU'LGURITE {fulgur, lightning). A 

 term applied to a bore or tube produced 

 by the passage of lightning into a sandy 

 soil, into which it sometimes penetrates 

 to a depth of twenty feet, fusing the 

 gravel which it penetrates. 



FULI'GINOUS (Juligo, soot or smoke). 

 A term applied to vapours which possess 

 the property of smoke. 



FULIGULFN^. The Sea ducks ; a 

 sub-family of the Anatidce, named from 

 the genus fuligula : they frequent the 

 sea principally, but many of them are 

 also found in fresh-water lakes and deep 

 rivers. 



FULLER'S EARTH. A variety of 

 clay, of an unctuous quality, forming a 

 part of the Lower Oolite Formation. It 

 is named from its being employed by ful- 

 lers to remove the grease from cloth 

 before the soap is applied. 



FU'LMINATE (fulmen, a thunder- 

 bolt). A compound of the fulminic acid 

 with a base, detonating by heat or friction. 



FU'LMINATING POWDER {fulmen, 

 a thunder-bolt). A general term applied to 

 powders which fulminate on the applica- 

 tion of heat or friction. Of this kind are 

 the fulminating gold, prepared by keep- 

 ing recently precipitated peroxide of gold 

 in strong ammonia for a day ; fulmi- 



