VEX 



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VOL 



obtained its name, and in primary rocks 

 in Ireland, Scotland, and other parts of 

 Europe. Cleat-eland. Jameson. 



VE'XIL. ) (vejcillwm, a standard, or 



VEXI'LLUM. \ banner, Lat.) In botany, 

 the upper large petal of a papilionaceous 

 flower. 



VI'BRATILE ORGANS. See Cilia. 



VI'LLI. (from villits, a hair, Lat.) 



1. In anatomy, fine small fibres, resem- 

 bling a covering of down. 



2. In botany, fine downy hail's, covering 

 fruits, flowers, and plants. 



VI'LLOUS. (villosus, Lat.) Downy; pu- 

 bescent ; shaggy. 



VI'SCERA. The plural of viscus. See 

 Viscus. 



VI'SCID. > (viscidus, Lat. visqueux, Fr. 



Vi'scous. $ viscoso, It.) Glutinous; te- 

 nacious ; clammy. 



Vi'scus. (viscus, Lat.) In the plural, 

 viscera ; this term is generally applied to 

 the organs connected with digestion ; 

 sometimes to the bowels only. Any organ 

 of the body may be denominated a viscus. 



VI'TREOUS. (vitreus, Lat. vitre, Fr. vitreo, 

 It.) Glassy ; resembling glass. 



1. In mineralogy, a term used to denote a 

 particular lustre of some minerals. 



2. In anatomy, a term applied to one of 

 the humours of the eye. The vitreous 

 humour occupies more than three-fourths 

 of the globe of the eye ; it is contained 

 in an exceedingly delicate texture of cel- 

 lular substance, and is situated behind 

 the crystalline lens. 



VITRIFA'CTION. ^ (vitrification, Fr.) The 



VITRIFICA'TION. $ conversion of any mat- 

 ter into glass by the application or aid of 

 heat. 



VI'TRIFIED. (vitrifie, Fr.) Converted into 

 glass by heat. 



VI'TRIFY. (vitrifier, Fr. vitrum, glass, 

 and facio, to make, Lat. ) To convert 

 into glass by the assistance of heat. 



VI'VIANITE. The Vivianit of Werner ; the 

 Fer Phosphate of Haiiy. Phosphate of 

 iron. A mineral of a green or blue co- 

 lour. Its constituents are, protoxide of 

 iron 47*5, phosphoric acid 32'0, water 

 20-0. 



VIVI'PAROUS. (viviparus, Lat. from vivus, 

 alive, and pario, to bring forth ; vivipare, 

 Fr.) Animals are termed viviparous in 

 which no egg, properly so called, is form- 

 ed, but bring forth their young alive and 

 perfect. 



VOLCA'NIC. Relating to volcanoes; pro- 

 duced by volcanoes. 



VOLCA'NIC PRODUCTIONS. These are nu- 

 merous and diversified. Lava, scoria, 

 enamel, and glass, comprise by far the 

 most important and interesting volcanic 

 productions. The different states of lava, 

 whether vitreous, compact, or scoriaceous, 



depend on the different circumstances 

 under which it has cooled. Aqueous 

 vapour is in general very abundant. The 

 principal gases hitherto detected consist, 

 according to Dr. Daubeny, of muriatic 

 acid gas, sulphur combined with oxygen 

 or hydrogen, carbonic acid gas, and ni- 

 trogen. The sublimations of Vesuvius 

 are, according to Sir H. Davy, chloride of 

 sodium, chloride of iron, sulphate of 

 soda, muriate and sulphate of potash, and 

 a small quantity of oxide of copper. The 

 principal metallic substances in volcanic 

 rocks are iron and titanium ; but ores of 

 antimony, copper, and manganese, have 

 sometimes been found in the craters of 

 volcanoes. Tellurium, gold, and mer- 

 cury are also said to occur in some vol- 

 canic rocks. The island of Ischia, which 

 is entirely volcanic, contains a mine of 

 gold. Bakeicell. Cleaveland. Phillips. 



VO'LCANITE. Another name for augite. 



VOLCA'NO. (volcan, Fr. volcano, It. from 

 Vulcan, the god of fire.) An opening in 

 the earth's surface made by internal fire. 

 Volcanoes exist in all quarters of the 

 globe, and, .according to Jameson, about 

 one hundred and ninety-three active vol- 

 canoes have been observed; of which 13 

 belong to Europe and its islands, 66 to 

 Asia and its islands, 8 to the islands of 

 Africa, and 106 to America and its 

 islands. Volcanoes have been long con- 

 sidered in the light of safety valves, and 

 this was the opinion entertained of them 

 by Strabo, and it can scarcely be doubted 

 that the tranquillity of the incandescent 

 fluid mass, composing the earth's centre, 

 is owing to these numerous vents for the 

 passage of steam, &c. Although volcanoes 

 generally exist in the neighbpurhood of 

 the sea, yet this is not invariably the case, 

 as was once supposed. In central Asia 

 there is a volcanic region with an area of 

 2500 square geographical miles, at a dis- 

 tance of upwards of 300 leagues from the 

 ocean. Volcanoes frequently will remain 

 in a quiescent state for many centuries, 

 and again burst forth with renewed ac- 

 tivity and vigour. 



VO'LVA. (volva, Lat. that wherein a thing 

 is wrapped.) In botany, a species of 

 calyx. A term applied to a membranous 

 wrapper or covering of the fungus tribe, 

 which conceals their parts of fructifica- 

 tion : in due time it bursts, and forms a 

 ring upon the stalk. 



VOLVA'RIA. A genus of cylindrical con- 

 voluted shells known only in a fossil 

 state. The spire is not extruded ; aper- 

 ture narrow, extending the length of the 

 shell : the columella plicated at its base : 

 outer lip dentated. Volvaria approaches 

 very near to Bulla cylindrica. 



VOLU'TION. A spiral wreath or turn. The 



