See also:

• TACHYLYTES, or TACHYLITES (from Gr. Taxbs, swift, Xbew, to dissolve, meaning " easily fused," though some have erroneously interpreted it as " easily soluble in acids ")

TACHYLYTES, or TACHYLITES (from Gr. Taxbs, See also:

• SWIFT
• SWIFT, JONATHAN (1667—1745)

swift, Xbew, to dissolve, meaning " easily fused," though some have erroneously interpreted it as " easily soluble in acids ")  , in See also:

• PETROLOGY

petrology, the vitreous forms of the basic igneous rocks; in other words, they are basaltic obsidians . They are See also:

• BLACK
• BLACK, ADAM (1784-1874)
• BLACK, JEREMIAH SULLIVAN (1810–1883)
• BLACK, WILLIAM (1841-1898)

black in See also:

• COLOUR (Lat. color, connected with celare, to hide, the root meaning, therefore, being that of a covering)

colour, dark See also:

• BROWN
• BROWN, CHARLES BROCKDEN (1771-181o)
• BROWN, FORD MADOX (1821-1893)
• BROWN, FRANCIS (1849- )
• BROWN, GEORGE (1818-188o)
• BROWN, HENRY KIRKE (1814-1886)
• BROWN, JACOB (1775–1828)
• BROWN, JOHN (1715–1766)
• BROWN, JOHN (1722-1787)
• BROWN, JOHN (1735–1788)
• BROWN, JOHN (1784–1858)
• BROWN, JOHN (1800-1859)
• BROWN, JOHN (1810—1882)
• BROWN, JOHN GEORGE (1831— )
• BROWN, ROBERT (1773-1858)
• BROWN, SAMUEL MORISON (1817—1856)
• BROWN, SIR GEORGE (1790-1865)
• BROWN, SIR JOHN (1816-1896)
• BROWN, SIR WILLIAM, BART
• BROWN, THOMAS (1663-1704)
• BROWN, THOMAS (1778-1820)
• BROWN, THOMAS EDWARD (1830-1897)
• BROWN, WILLIAM LAURENCE (1755–1830)

brown in the thinnest sections, with a resinous lustre and the See also:

• APPEARANCE (from Lat. apparere, to appear)

appearance of See also:

• PITCH
• PITCH, MUSICAL

pitch, often more or less vesicular and sometimes spherulitic . They are very brittle, and break down readily under the See also:

• HAMMER, FRIEDRICH JULIUS (1810-1862)

hammer . Small crystals of See also:

• FELSPAR, or FELDSPAR

felspar or of See also:

• OLIVINE

olivine are sometimes visible in them with the unaided See also:

• EYE
• EYE (O. Eng. edge, Ger. Auge; derived from an Indo-European root also seen in Lat. oc-ulus, the organ of vision (q.v.)

eye . All See also:

• TACHYLYTES, or TACHYLITES (from Gr. Taxbs, swift, Xbew, to dissolve, meaning " easily fused," though some have erroneously interpreted it as " easily soluble in acids ")

tachylytes See also:

• WEATHER (O. Eng. weder; the word is common to Teutonic languages; cf. Du. weder, Dan. veir, Icel. ve8r, and Ger. Wetter and Gewitter, storm; the root is wa- to blow, from which is derived " wind ")

weather rather easily, and by oxidation of their See also:

• IRON [symbol Fe, atomic weight 55.85 (0=16)]

iron become dark brown or red . Three modes of occurrence characterize this See also:

• ROCK
• ROCK (O.Fr. rake, Sp. rota, Ital. rocca; possibly from a Lat. form rupica, from rupes, rock)
• ROCK, DANIEL (1799–187t)

rock . In all cases they are found under conditions which imply rapid cooling, but they are much less See also:

• COMMON

common than See also:

• ACID (from the Lat. root ac-, sharp; acere, to be sour)

acid volcanic glasses (or obsidians), the See also:

• REASON (Lat. ratio, through French raison)

reason being apparently that the basic rocks have a stronger tendency to crystallize, partly because they are more liquid and the molecules have more freedom to arrange themselves in crystalline See also:

• ORDER
• ORDER (through Fr. ordre, for earlier ordene, from Lat. ordo, ordinis, rank, service, arrangement; the ultimate source is generally taken to be the root seen in Lat. oriri, rise, arise, begin; cf. " origin ")
• ORDER, HOLY

order . The See also:

• FINE

fine See also:

• SCORIA (Lat. scoria, slag)

scoria ashes or " cinders " thrown out by basaltic volcanoes are often spongy masses of tachylyte with only a few larger crystals or phenocrysts imbedded in black See also:

• GLASS
• GLASS (O.E. glees, cf. Ger. Glas, perhaps derived from an old Teutonic root gla-, a variant of glo-, having the general sense of shining, cf. " glare," " glow ")
• GLASS, STAINED

glass . Such tachylyte bombs and scoria are frequent in See also:

• ICELAND (Dan. Island)

Iceland, See also:

• AUVERGNE

Auvergne, Stromboli, See also:

• ETNA
• ETNA (Gr. AZ-rvn, from aZOw, burn; Lat. Aetna)

Etna, and are very common also in the ash beds or tuffs of older date, such as occur in See also:

• SKYE

Skye, Midlothian and See also:

• FIFE
• FIFE (Fr. fifre; Med. Ger. Schweizerpfeiff, Feldpfeiff; Ital. ottavino)

Fife, See also:

• DERBYSHIRE

Derbyshire, and elsewhere . Basic pumices of this See also:

• KIND (O. E. ge-cynde, from the same root as is seen in " kin," supra)

kind are exceedingly wide-spread on the bottom of the See also:

• SEA (in O. Eng. sae, a common Teutonic word; cf. Ger. See, Dutch Zee, &c.; the ultimate source is uncertain)
• SEA, COMMAND OF THE

sea, either dispersed in the "red See also:

• CLAY (from O. Eng. claeg, a word common in various forms to Teutonic languages, cf. Ger. Klei)
• CLAY, CASSIUS MARCELLUS (1810-1903)
• CLAY, CHARLES (1801–1893)
• CLAY, FREDERIC (1838–1889)
• CLAY, HENRY (1777–1852)

clay" . and other deposits or forming layers coated with oxides of See also:

• MANGANESE (symbol Mn; atomic weight, 54.93 (0=16)], a metallic chemical element. Its dioxide (pyrolusite)

manganese, precipitated on them from the sea See also:

• WATER

water . These tachylyte fragments, which are usually much decomposed by the oxidation and hydration of their ferrous compounds, have taken on a dark red colour . This altered basic glass is known as "palagonite "; See also:

• CON

con-centric bands of it often surround kernels of unaltered tachylyte, and are so soft that they are easily cut with a See also:

• KNIFE (0. E. cuff, a word appearing in different forms in many Teutonic languages, cf. Du. knijf, Ger. Kneif, a shoe-maker's knife, Swed. knif; the ultimate origin is unknown; Skeat finds the origin in the root of " nip," formerly " knip "; Fr. canif is a

knife .

In the palagonite the minerals also are decomposed, and are represented only by pseudomorphs . The fresh tachylyte glass, however, often contains See also:

• LOZENGE (from the Fr. losenge, or losange; the word also appears in Span. losanje, and Ital. losanga; perhaps derived from a word meaning a stone slab laid on a grave, which appears in forms such as Provencal lousa, Span. losa, the ultimate origin of whic

lozenge-shaped crystals of See also:

• PLAGIOCLASE

plagioclase felspar and small prisms of See also:

• AUGITE

augite and olivine, but all these minerals very frequently occur mainly as microlites or as beautiful skeletal growths with sharply-pointed corners or ramifying processes . Palagonite tuffs are found also among the older volcanic rocks . In Iceland a broad stretch of these rocks, described as " the palagonite formation," is said to See also:

• CROSS

cross the See also:

• ISLAND (O.E. ieg =isle, +land')

island from See also:

• SOUTH
• SOUTH, ROBERT (1634–1716)

south-See also:

• WEST
• WEST, BENJAMIN (1738-1820)
• WEST, NICHOLAS (1461-1533)

west to See also:

• NORTH
• NORTH, BARONS
• NORTH, MARIANNE (1830—1890)
• NORTH, ROGER (1653-1734)
• NORTH, SIR THOMAS (1535?-16o1?)

north-See also:

• EAST
• EAST, ALFRED (1849- )

east . Some of these tuffs are fossiliferous; others are intercalated with glacial deposits . The lavas with which they occur are mostly olivine-basalts . Palagonite tuffs are found in See also:

• SICILY (Ital. Sicilia)

Sicily, the See also:

• EIFEL

Eifel, See also:

• HUNGARY
• HUNGARY (Hungarian Magyarorszdg)

Hungary, See also:

• CANARY
• CANARY (Serinus canarius)

Canary Islands, &c . A second mode of occurrence of tachylyte is in the See also:

• FORM (Lat. forma)

form of See also:

• LAVA

lava flows . Basaltic rocks often contain a small amount of glassy ground-See also:

• MASS (O.E. maesse; Fr. messe; Ger. Messe; Ital. messa; from eccl. Lat. missa)
• MASS, IN

mass, and in the limburgites this becomes more important and conspicuous, but vitreous types are far less common in these than in the acid lavas . In the Hawaiian Islands, however, the volcanoes have poured out vast floods of black See also:

• BASALT

basalt, containing felspar, augite, olivine, and iron ores in a black glassy See also:

• BASE

base . They are highly liquid when discharged, and the rapid cooling which ensues on their emergence to the See also:

• AIR (from an Indo-European root meaning " breathe," " blow ")
• AIR, or ASBEN

air prevents See also:

• CRYSTALLIZATION

crystallization taking See also:

• PLACE (through Fr. from Lat. platea, street; Gr. IrAar6s, wide)

place completely . Many of them are spongy or vesicular, and their upper surfaces are often exceedingly rough and jagged, while at other times they assume rounded See also:

• WAVE

wave-like forms on solidification .

See also:

• GREAT

Great caves are found where the crust has solidified and the liquid interior has subsequently flowed away, and See also:

• STALACTITES (Gr. (rraXaicros, from vraXaQVecv, to drip)

stalactites and stalagmites of black tachylyte adorn the See also:

• ROOFS

roofs and floors . On See also:

• SECTION
• SECTION (Lat. sectio, cutting, secare, to cut)

section these growths show usually a central cavity enclosed by walls of dark brown glass in which skeletons and microliths of augite, olivine and felspar See also:

• LIE, JONAS LAURITZ EDEMIL (1833—1908)
• LIE, MARIUS SOPHUS (1842–1899)

lie imbedded . From the See also:

• CRATER

crater of Kilauea thin clouds of See also:

• STEAM
• STEAM (0. Eng. steam, vapour, smoke, cf. Du. steam; the origin is unknown)

steam rise constantly, and as the bubbles of vapour are liberated from the molten rock they carry into the air with them thin See also:

• FIBRES
• FIBRES (or FIBERS, in American spelling; from Lat. fibra, apparently connected either with filum, thread, or findere, to split)

fibres of basalt which solidify at once and assume the form of tachylyte threads . Under the See also:

• MICROSCOPE (Gr. µucp6s, small, asenreiv, to %view)

microscope they prove to be nearly completely glassy with small circular air vesicles sometimes See also:

• DRAWN

drawn out to See also:

• LONG, GEORGE (1800-1879)
• LONG, JOHN DAVIS (1838– )

long tubes . Only in the Hawaiian Islands are glassy basaltic lavas of this kind at all common . A third mode of occurrence of tachylyte is as the margins and thin offshoots of dikes or sills of basalt, See also:

• DOLERITE (from Gr. SoXepos, deceptive)

dolerite and See also:

• DIABASE

diabase . They are sometimes only a fraction of an See also:

• INCH (O. Eng. ynce from Lat. uncia, a twelfthpart; cf. " ounce," and see As)

inch in thickness, resembling a thin layer of pitch or See also:

• TAR

tar on the edge of a crystalline dolerite See also:

• DIKE, or DYKE (Old Eng. dic, a word which appears in various forms in many Teutonic languages, cf. Dutch dijk, German Teich, Danish dige, and in French, derived from Teutonic, digue; it is the same word as " ditch " and is ultimately connected with the ro

dike, but See also:

• VEINS

veins several inches thick are sometimes met with . In these situations tachylyte is rarely vesicular, but it often shows very pronounced fluxion banding accentuated by the presence of rows of See also:

• SPHERULITES (Gr. cchaipa, sphere, Mhos, stone)

spherulites which are visible as dark brown rounded spots . The spherulites have a distinct radiate structure and sometimes exhibit zones of varying colour . The non-spherulitic glassy portion is sometimes perlitic and these rocks are always brittle . The commonest crystals are olivine, augite and felspar, with swarms of See also:

• MINUTE
• MINUTE (Lat. minutes, small; minuere, to make less)

minute dusty black grains of See also:

• MAGNETITE

magnetite . At the extreme edges the glass is often perfectly See also:

• FREE

free from crystalline products, but it merges rapidly into the See also:

• ORDINARY (med. Lat. ordinarius, Fr. ordinaire)

ordinary crystalline dolerite, which in a very See also:

• SHORT, FRANCIS JOB (1857– )

short distance may contain no vitreous base whatever .

The spherulites may form the greater See also:

• PARR
• PARR, CATHERINE (1512-1548)
• PARR, SAMUEL (1747-1825)
• PARR, THOMAS (c. 1483—1635)

parr of the mass, they may be a See also:

• QUARTER (through Fr. from Lat. quartarius, fourth part)

quarter of an inch in See also:

• DIAMETER (from the Cr. &a, through, µErpov, measure)

diameter and are occasionally much larger than this . These coarsely spherulitic rocks pass over into the See also:

• VARIOLITES (Lat. variola, smallpox)

variolites (q.v.) by increasing coarseness in the fibres of their spherulites, which soon become recognizable as needles of felspar or feathery growths of augite . The ultimate product of decomposition in this See also:

• CASE
• CASE, JOHN (d. 1600)

case also is a red palagonitic substance, but owing to the See also:

• ABSENCE (Lat. absentia)

absence of steam cavities the tachylyte selvages of dikes are more often found in a fresh See also:

• STATE
• STATE, GREAT OFFICERS OF

state than the basic See also:

• LAPILLI (pl. of Ital. lapillo, from Lat. lapillus, dim. of lapis, a stone)

lapilli in ash-beds . Many occurrences of basaltic pitchstones have been reported from Skye, See also:

• MULL

Mull, and the western See also:

• PART

part of See also:

• SCOT, MICHAEL (? 1175-1232)

Scot-See also:

• LAND

land; they are found also in connexion with the intrusive dolerite sills of the north of See also:

• ENGLAND
• ENGLAND, THE CHURCH OF

England and the centre of See also:

• SCOTLAND
• SCOTLAND, CHURCH OF
• SCOTLAND, EPISCOPAL CHURCH OF

Scotland . In the See also:

• SAAR

Saar See also:

• DISTRICT

district of See also:

• GERMANY
• GERMANY (Ger. Deutschland)

Germany similar rocks occur, some of which have been described as weisselbergites (from Weisselberg) . Other localities for tachylytes of this See also:

• GROUP

group are See also:

• NASSAU

Nassau, See also:

• SILESIA

Silesia and See also:

• SWEDEN
• SWEDEN [Sverige]
• SWEDEN, NORWAY AND

Sweden . The chemical See also:

• COMPOSITION
• COMPOSITION (Lat. compositio, from componere, to put together)

composition of some of the rocks of this group is indicated by the analyses given below:-passage of his See also:

• AGRICOLA (originally SCHNEIDER, then SCHNITTER), JOHANNES (1494-1566)
• AGRICOLA (the Latinized form of the name BAUER), GEORG (1490-1555)
• AGRICOLA, CHRISTOPH LUDWIG (1667-1719)
• AGRICOLA, GNAEUS JULIUS (A.D. 37-93)
• AGRICOLA, JOHANN FRIEDRICH (1720-1774)
• AGRICOLA, MARTIN (c. 1500-1556)
• AGRICOLA, RODOLPHUS (properly ROELOF HUYSMANN) (1443-1485)

Agricola, describing this as a "singularly blessed See also:

• TIME (0. Eng. Lima, cf. Icel. timi, Swed. timme, hour, Dan. time; from the root also seen in " tide," properly the time of between the flow and ebb of the sea, cf. O. Eng. getidan, to happen, " even-tide," &c.; it is not directly related to Lat. tempus)
• TIME, MEASUREMENT OF
• TIME, STANDARD

time," but the hideous reign of terror had stamped itself ineffaceably on his soul, and when he sat down to write his See also:

• HISTORY

History he could see little but the darkest See also:

• SIDE
• SIDE (mod. Eski Adalia)

side of imperialism . To his friend the younger See also:

• PLINY, THE ELDER
• PLINY, THE YOUNGER

Pliny we are indebted for the little we know about his later See also:

• LIFE

life . He was advanced to the consulship in 97, in See also:

• SUCCESSION (Lat. successio, from succedere, to follow after)

succession to a highly distinguished See also:

• MAN
• MAN, ISLE OF (anc. Mona)

man, Verginius See also:

• RUFUS, GAIUS VALGIUS
• RUFUS, LUCIUS VARIUS (c 74—14 B.c.)

Rufus, on whom he delivered in the See also:

• SENATE (Lat. senatus, from root sen-, as in senex, old; the root is the Sanskrit sana, cf. Gr. 'vos; the same element appears in senor, seigneur, seneschal)

senate a funeral eulogy . In 99 he was associated with Pliny in the See also:

• PROSECUTION

prosecution of a great See also:

• POLITICAL

political offender, See also:

• MARIUS, GAIUS (r55–86 B.c.)

Marius See also:

• PRISCUS

Priscus, under whom the provincials of See also:

• AFRICA
• AFRICA, ROMAN

Africa had suffered grievous wrongs . The prosecution was successful, and both See also:

• TACITUS, CORNELIUS (c. 55-120)
• TACITUS, MARCUS CLAUDIUS

Tacitus and Pliny received a See also:

• SPECIAL

special See also:

• VOTE

vote of thanks from the senate for their conduct of the case . It would seem that Tacitus lived to the See also:

• CLOSE
• CLOSE (from Lat. clausum, shut)
• CLOSE, MAXWELL HENRY (1822-1903)

close of See also:

• TRAJAN [MARCUS ULPIUS TRAJANUS] (A. D. 53-117)

Trajan's reign, as he seems' to hint at that See also:

• EMPEROR (Fr. empereur, from the Lat. imperator)

emperor's See also:

• EXTENSION (Lat. ex, out ; tendere, to stretch)

extension of the See also:

• EMPIRE

empire by his successful Eastern See also:

• CAMPAIGNS

campaigns from 115 to 117 .

Whether SiO2 . Al203 . FeO . Fe203 . CaO . MgO . Na2O . See also:

• K20

K20 . See also:

• H2O (combined)

H2O . I . Palagonite . Seljadalr, Iceland .

38.96 11.62 ... 14'75 9.13 6.29 o•68 0.72 17.85 II . Palagonite from deep-sea deposits, Pacific 44.73 16.28 I 4'57 1.88 2.2 3 4'5 0 402 9'S 6 Ocean (with 2.89 % MnO2) ' IV . Tachylyte . Ardtun, Mull, Scotland 53.03 20.09 ••• 9'53 6'05 2.63 4'52 1.27 2.64 V . Tachylyte . The Beal, Portree, Skye ..