CATALAjV/
MOUNT VESUVIUS.
Worfcs b professor
AUTHOR OF "MOUNT VESUVIUS."
In crown 8vo, cloth extra, price 2s. 6d.
GEOLOGY FOR ALL,
With Tables of the Principal Rock-forming Minerals,
Geological Strata, &c., &c.
In foolscap 4/0, tastefully printed and attractively bound in cloth
extra, with Map and Illustrations of Local Scenery, &c.,
price 2s. 6d.
HAMPSTEAD HILL,
With Chapters on THE FLORA OF HAMPSTEAD, by H. T.
Wharton, M.A., M.R.C.S., F.Z.S., &c., THE INSECT FAUNA OF
HAMPSTEAD, by Rev. Dr. Walker, F.L.S., F.R.G.S., &c., and THE
BIRDS OF HAMPSTEAD, by J. Edmund Harting, F.L.S., &c., &c.
LONDON :
ROPER AND DROWLEY, n, LUDGATE HILL, E.G.
Plate I.
MOUNT VESUVIUS.
A
DESCRIPTIVE, HISTORICAL, AND GEOLOGICAL
ACCOUNT OF THE VOLCANO AND ITS
SURROUNDINGS.
J. LOGAN LOBLEY, F.G.S., &c.,
PROFESSOR OF PHYSIOGRAPHY AND ASTRONOMY, CITY OF LONDON COLLEGE
AUTHOR OF "GEOLOGY FOR ALL," &c.
WITH MAPS AND ILLUSTRATIONS.
'\Here verdant vines o'erspread Vesuvius' sides,
The generous grape here poured her purple tides.'
" Now flaming embers spread dire waste around,
And gods regret that gods can thus confound."
Conbon :
ROPER AND DROWLEY,
ii, LUDGATE HILL.
TO
THE FAITHFUL GUARDIAN
OF THE
HONOUR AND LIBERTIES OF ITALY,
AND
THE FRIEND OF SCIENCE AND EDUCATION,
HIS MAJESTY
KING HUMBERT I.,
THIS ACCOUNT
OF THE
GREATEST NATURAL WONDER
OF
THE ITALIAN PENINSULA
is,
BY HIS MAJESTY'S VERY GRACIOUS PERMISSION,
MOST RESPECTFULLY DEDICATED.
627
CONTENTS.
PAGE
PREFACE I3
CHAPTER I.
THE NEAPOLITAN VOLCANIC REGION.
Three Principal Italian Volcanic Regions The Neapolitan
Volcanic Region The Phlegraean Fields The Sol-
fatara Extinct Craters Monte Nuovo Temple of
Serapis Tufa Hills Stuffe and Thermae Procida
Nisida Ischia 17
CHAPTER II.
THE SURROUNDINGS OF VESUVIUS.
Characteristics Populousness Naples Destroyed Towns
Ring of Towns Bay of Naples Appearance from
Naples View of Surroundings from the Mountain ... 47
CHAPTER III.
THE MOUNTAIN.
Name Form Both Typical and Peculiar Five Parts
The Lower Cultivated Slopes The Desert Platform
The Ridge of Monte Somma The Great Cone The
Crater 67
CHAPTER IV.
HISTORY TO 1850.
Numerous Records The Pre-Historic Volcano Vesuvius
Dormant Recognition of Igneous Indications by
8 CONTENTS.
PAGE
Ancient Writers Renewal of Activity Destruction
of Pompeii Formation of the Cone Mediaeval
Eruptions Eruption of 1631 -Eruptions of Modern
Times 94
CHAPTER V.
HISTORY: 1851-1868.
Eruptions of 1855 and 1861 Eruption of 1867-68
Aspect of the Surface of Vesuvius during the Eruption
of 1868 Ascent to the Summit Lava-Flows The
Cone The Ring Terrace The Eruptive Cone and
Crater The Eruptive Phenomena seen from the
Crater Rim 114
CHAPTER VI.
HISTORY : 1869-1888.
Repose, 1869-71 Eruption of 1872 Repose, 1873-75
Slight Activity of 1876 and 1877 Activity of 1878
and 1879 Increased Activity of 1880 Strombolean
Activity, 1881-83 Scale of Vesuvian Activity Slight
Activity of 1884-88 Continuous Observation and
Record of Phenomena 135
CHAPTER VII.
GEOLOGY OF VESUVIUS.
Vesuvius Geologically Instructive and Illustrative Three
Geological Divisions The Cone : Cause of its Regu-
larity j its Structure, Lavas, Minerals Monte Somma :
Change of Position of Axis, Formation of Great
Crater-Rings, Structure, Dykes, Minerals The Base :
Concavity of Volcanic Outlines, Structure Concealed,
Hypothetical Origin, Geological Age Theory of
Craters of Elevation ... 162
CONTENTS. 9
PAGE
CHAPTER VIII.
VOLCANIC ACTION.
Pre-scientific Opinion Hypotheses of the Eighteenth
Century Later Theories Central Heat Hypothesis
of Fused Interior of the Earth with Thin Crust-
Recent Hypotheses All Unsatisfactory Compen-
dium of the Controlling Facts of Vulcanology
Present Favourable Position of the Question for
Settlement Author's Conclusions and Hypothesis ... 187
CHAPTER IX.
VOLCANIC PRODUCTS.
Vesuvian Products largely representative Similarity and
Dissimilarity of Volcanic Products Descriptive Cata-
logue of Volcanic Products Ejected Blocks with
List of Fossils 217
CHAPTER X.
THE MINERALS OF VESUVIUS.
The Vesuvian Mountain the Richest Mineral Area
This Fact Important in Vulcanology Introduction
to Catalogue Descriptive Catalogue of Vesuvian
Minerals Index of Synonyms and Included Varieties 253
CHAPTER XL
THE FLORA OF VESUVIUS.
The Flora of Vesuvius and Capri compared Cause of
Difference Vesuvian Flora very varied List of
Families and Summary of Species List of Medicinal
Plants Genera of Graminaceae, Musci, Hepaticse,
and Lichens List of Species, with Habitats, of Ferns
and Fungi 343
IO CONTENTS.
APPENDIX.
PAGE
LETTERS OF PLINY THE YOUNGER, containing an Account
of the Eruption of A.D. 79 ... 355
THE FORMATION OF MONTE Nuovo IN 1538 : Four Con-
temporary Narratives I. By Marco Antonio delli
Falconi ; II. By Pietro Giacomo di Toledo ; III. By
Francesco del Nero; IV. By Simone Porzio 362
CATALOGUE OF RECORDED ERUPTIONS ... 378
THE STRATA UNDERLYING VESUVIUS. Artesian Well
Section (Pozzo dell' Arenaccia) ... ... ... 379
PROFESSOR PALMIERI'S SEISMOGRAPH 380
LIST OF ILLUSTRATIONS.
PLATE P p"age e
I. GENERAL VIEW OF MOUNT VESUVIUS FROM
NAPLES (Frontispiece).
II. MAP. Mount Vesuvius and its surroundings ... 17
III. MAP. The Neapolitan Volcanic Region ... 25
IV. VIEW OVER THE BAY FROM NEAR POZZUOLI
(Hamilton), showing the City of Pozzuoli, the
Bridge of Caligula, the Serapeum, Monte Nuovo,
Baiae, Misenum, Procida, and Ischia 32
V. Fig. i. MONTE Nuovo FROM POZZUOLI. Fig. 2.
PROMONTORY OF MISENUM (Scrope), showing
volcanic structure. Fig. 3. THE PHLEGR^AN
FIELDS 48
VI. RUINS OF THE TEMPLE OF SERAPIS, showing the
three remaining pillars, with the bore-holes of
Mollusca from i2ft. to 2ift. above the base ... 64
VII. Fig. i. VIEW OF VESUVIUS FROM SORRENTO
(Scrope). Fig. 2. VIEW OF VESUVIUS FROM
NAPLES. Fig. 3. VIEW OF VESUVIUS FROM
NOLA 80
VIII. Fig. i. VESUVIUS IN THE PRE-HISTORIC PERIOD.
A single great cone with an elevation of
7,000 ft. Fig. 2. VESUVIUS IN THE CLASSICAL
PERIOD. Upper part of the great conical moun-
tain blown away, leaving a vast crater ... ... 96
IX. Fig. i. THE CRATER OF VESUVIUS IN 1756
(Hamilton), showing cone in cone. Fig. 2. THE
CRATER OF VESUVIUS IN 1805. (Duca dell a
Torre in Roth) 106
X. Fig. i. THE CRATER OF VESUVIUS AFTER THE
GREAT ERUPTION OF 1822 (Scrope). Crater
greatly enlarged and the cone correspondingly
lowered. Fig. 2. THE CRATER OF VESUVIUS
IN 1828. (Monticelli in Roth) 112
12
PLATE
XI.
XII.
LIST OF ILLUSTRATIONS.
XIII.
XIV.
^ XV.
XVI.
XVII.
XVIII.
XIX.
XX.
Opposite
Page
1856
THE
Fig. i. THE CRATER OF VESUVIUS IN
(Herrn Bornemann in Roth.) Fig. 2.
CRATER OF VESUVIUS IN 1883. (Lavis) ... 114
Fig. i. VESUVIUS AFTER THE GREAT ERUPTION
OF 1631. (Carafa in Roth.) Cone lowered to
less than the height of the crest of Monte
Somma. Fig. 2. VESUVIUS AFTER ERUPTION
OF 1868. Cone almost completed by a new
summit cone. Volcano at its greatest elevation
during Historic Period ... ... ... ... 118
VIEW OF THE GREAT ERUPTION OF 1872 (5 p.m.
April 26th). From the first instantaneous
photograph ever taken of an eruption. Show-
ing the height of the column of smoke (nearly
four miles), and an " exterior eruption " ... 144
DIAGRAMMATIC GENERAL SECTION THROUGH
VESUVIUS AT THE PRESENT TIME, showing the
structure, the substructure, and the successive
accumulations ... ... ... ... ... 176
Fig. i. SECTION THROUGH VESUVIUS BEFORE THE
ERUPTION OF A.D. 79. Fig. 2. SECTION
THROUGH VESUVIUS AFTER THE ERUPTION OF
1631 186
THE LAVA OF 1858, SHOWING THE SURFACE
PRODUCED BY THE SOLIDIFICATION OF SLOWLY-
FLOWING LAVA. (From a Photograph.) (Judd's
Volcanoes) 224
SIMPLE CRYSTALLINE FORMS. Cubic and Dimetric
systems 256
SIMPLE CRYSTALLINE FORMS. Trimetric, Mono-
clinic, Triclinic, and Hexagonal systems ... 272
CRYSTALLINE FORMS OF VESUVIAN MINERALS ... 288
PROFESSOR PALMIERI'S SEISMOGRAPH 380
PREFACE.
SINCE "Mount Vesuvius" was published in 1868, much has
been written on the subject of my brief sketch. A few months
afterwards, at the beginning of 1869, Prof. John Phillips issued
" Vesuvius," a work which, while rich in classic poetry and ancient
fable, gave an extended account of the volcano and its surround-
ings, as well as a history in considerable detail of its eruptive
activity to the end of the preceding year.
Since that time Prof. Palmieri, the faithful watchman of
Vesuvius, has recorded the phenomena observable by the eye and
ear, or appreciable by the seismograph, and has occasionally
made public what appeared to him to be worthy of special atten-
tion. He has also written an account of the important eruption
of 1872, of which an English translation has been published, with
a lengthy and valuable " Introductory Sketch " by our late
distinguished seismologist, Mr. Mallet. Descriptive letters in
Nature, by Mr. Rod well, containing much scientific information,
have added considerably to our knowledge of the state of the
volcano to the year 1880.
More recently there have appeared communications from an
English resident in Naples, Dr. Johnston Lavis, who has devoted
much time and labour to the study of Vesuvius, and who, as the
secretary of the British Association Committee for the investiga-
tion of Vesuvian phenomena, has presented several reports on the
subject ; and an elaborate paper on the geology of the volcano,
by the same gentleman, has been published in the Quarterly
Journal of the Geological Society. In addition to these sources
of information and occasional letters and telegrams from Naples
in the Athenceum and other journals, a very important volume
has been published by the Italian Alpine Club, " Lo Spettatore
14 PREFACE.
del Vesuvio e del Campi Flegrei," in which is contained Prof.
Palmieri's " II Vesuvio e sua Storia," a new list of Vesuvian
minerals by the eminent Neapolitan mineralogist, Prof. Archangelo
Scacchi, and a record of changes and phenomena from 1882 to
1886, with photographs, by Dr. Johnston Lavis, together with
much interesting matter by other authors. Recent excavations
and well-borings have also added to our information respecting
Mount Vesuvius, and hence a more complete account of the
volcano can now be given than at any former period.
The present volume has therefore been prepared to give the
latest knowledge on the subject, and to bring down the history of
the mountain in a connected form through an interesting twenty
years of its existence to the present time.
All the explanations of the causes of Volcanic Activity and its
varied phenomena which have been advanced by previous
Authors are admittedly so unsatisfactory, that I recently ventured
to submit the new hypothesis given in the Chapter on Volcanic
Action. In view of the great names associated with past attempts
to solve the question, this Physio-Chemical theory is offered for
consideration with great deference, and I trust that the attention
given to the subject during more than twenty years may avert
the charge of temerity.
Included in the Appendix are the four Contemporary Accounts
of the formation of Monte Nuovo brought together for the first
time; that by Simone Porzio not having before been published
in English.
In addition to the writers on Vesuvius mentioned above, I am
under great obligations to the other authors whose works have
been consulted and whose names appear in the body of the work.
The Chapter on the Flora of Vesuvius has been revised by Dr.
Henry Wharton, M.A., F.Z.S., &c., to whom I am indebted for
giving me the benefit of his extensive botanical knowledge.
The elevation of points on the mountain are taken from the
great contour map of Vesuvius published by the Institute Topo-
grafico Militaire of Italy in 1877, a magnificent map on the scale
of i to 10,000, and for the convenience of general readers metres
have been reduced to English feet. Translations have also been
substituted for the original in classical quotations.
PREFACE. 15
To make the book sufficiently complete, the original work has
been recast and largely extended, and it is therefore hoped that
the volume may prove not altogether unacceptable to the
increasing number of Vesuvians as well as to ordinary visitors to
the marvellously interesting and attractive Neapolitan volcano.
J. L. L.
CITY OF LONDON COLLEGE,
August, 1889.
1 Oh ! land to mem'ry and to freedom dear,
Land of the melting lyre and conquering spear,
Land of the vine-clad hill, the fragrant grove,
Of arts and arms, of Genius and of Love,
Hear, fairest Italy."
" The leaves scarce rustled in the sighing breeze ;
In azure dimples curled the sparkling seas,
And, as the golden tide of light they quaff 'd,
Campania's sunny meads and vineyards laugh'd,
While gleam'd each lichen'd oak and giant pine,
On the far sides of swarthy Apennine."
" Saw ye how wild, how red, how broad a light
Burst on the darkness of that mid-day night,
As fierce Vesuvius scatter'd o'er the vale
His drifted flames and sheets of burning hail,
Shook hell's wan lightnings from his blazing cone,
And gilded heaven with meteors not its own ? "
MACAULAY'S " POMPEII.
I
^W. HH -ft
<^Xf <
S\)
MOUNT VESUVIUS
CHAPTER I.
THE NEAPOLITAN VOLCANIC REGION.
Three Principal Italian Volcanic Regions The Neapolitan Volcanic
Region The Phlegraean Fields The Solfatara Extinct Craters
Monte Nuovo Temple of Serapis Tufa Hills Stufe and
Thermae Procida Nisida Ischia.
MOUNT VESUVIUS, the world-famed volcano of
Southern Italy, has been for many centuries an
object of great interest to the inhabitants of Europe.
In -ancient times, the conspicuous position of the
mountain in one of the fairest and most frequented
portions of the Roman dominions the resort
of the most wealthy, most famous, and most
noble of the citizens of Rome and the terrible
character and dreadful results of the eruption
of the year 79, combined to render Vesuvius an
object of especial interest and wonder. In modern
times, the proximity of the volcano to one of the
greatest cities of Europe, the accessibility to
travellers, and the many attractions of the classic
and romantic coast of Italy, with, especially, the
frequency and violence of the eruptions, have
1 8 MOUNT VESUVIUS.
fixed the attention of mankind upon the Cam-
panian fiery mountain not less earnestly than in
the days of old.
But although Mount Vesuvius has absorbed so
great an amount of attention, it must not be for-
gotten that it is but one of a large number of Italian
volcanoes, active or extinct, and forms but the most
prominent feature of one of the principal volcanic
districts of Italy ; for, besides the minor areas of the
Euganian and Vicenian Hills, the Ponza Islands,
the Rocca Monfina, and Monte Vulture, there are
three principal Italian volcanic regions the Roman,
the Neapolitan, and the Sicilian, well marked and
well separated from each other.
The most northern of the three, the Roman,
occupies an extensive area between the Apennines
and the Mediterranean, and although there is not
now in Latium an active volcanic vent, there
are very perfect examples of volcanic craters.
Not twenty miles from the walls of Rome, the
Lago Albano and the Monte Albano, the Lago
Nemi, the Arco d'Aricia, and the great, though
incomplete, crater-like wall of Monte Artemesia,
at the southern side of the Roman Campagna, are
well known ; while north of Rome there are the
Lago Bracciano, an immense crater-lake of twenty
miles circumference, and the still larger Lago
Bolsenna ; while the "seven hills" of the Eternal
City itself are but accumulations of ejectamenta
from the volcanoes of the district.
THE NEAPOLITAN VOLCANIC REGION. 19
In the southern volcanic region, the Sicilian,
which is partly terrestrial and partly marine, the
giant cone of Etna is still in full activity, and with
Stromboli, the " lighthouse of the Mediterranean,'*
never dormant, Vulcano and Vulcanello not far off,
and the extinct craters of the other Lipari Islands,
there are abundant evidences of great volcanic
activity in the Sicilian Region, both at the present
day and in long-past prehistoric times.
Intermediate between the Roman and the Sicilian
regions is situated the Neapolitan volcanic region,
which, like the Sicilian, is an area partly land and
partly sea, since it comprises not only the Vesuvian
mountain and the Phlegrsean Fields, but also the
marine area in which lie the volcanic islands of
Ischia, Procida, and Nisida. It includes, therefore,
all the Bay of Naples north of a line drawn from
Ischia to Castellamare, for only on the south-eastern
side of the bay from the last-named town to Capri
are evidences of historic or prehistoric volcanic
activity absent, though even here there are small
deposits of tufa, but evidently not composed of
material ejected from any vent on the Sorrento
peninsula, a projection from the giant leg of Italy
formed by a spur of the Apennines, and chiefly
composed of the limestone called from those moun-
tains the Apennine limestone.
The Neapolitan volcanic region is, like the
Roman, and, indeed, like the Sicilian also, on the
western side of the main mountain axis of Italy,
20 MOUNT VESUVIUS.
but unlike the former, though like the latter, it has
still on one side a marine boundary. This fact has
some significance on account of the continuing vol-
canic activity in the two regions which touch the
sea, and the total extinction of the fires of that one
which has been separated, though but a little dis-
tance, from the waters of the sea by the advance of
the coast line.
But although throughout the entire district
Mount Vesuvius commands most attention from its
magnitude, its position, and the remarkable and
splendid phenomena displayed during its fre-
quently alarming and sometimes destructive activity,
yet in some respects the area of the Phlegrsean
Fields is more remarkable still. The scene of
classic fable and the theme of Roman poets, the
land of gods and giants, titans and sibyls, the Campi
Phlegraei excited the wonder and charmed the
imagination of the ancient world. A land of fire,
of smoke, of vaporous exhalations, mephitic and
deadly, of deep hollows and cavernous recesses,
of scorched rocks and stones, and subterranean
passages, it well might be taken for the ruins of an
older world, or imagined to be the vestibule of
the realms of Pluto, with the inner portal at
Avernus.
Yet, with all their terrors, the Campi Phlegnei
were not wanting in charms and allurements for
the luxurious epicures and sybarites of Rome,
Neapolis, Baise, and Pompeii, for in the Lucrine
THE NEAPOLITAN VOLCANIC REGION. 21
Lake were beds of the choicest oysters, and on
fertile volcanic soils and sunny slopes were here
produced the ancient banquet wines, and at but a
little distance the famous Falernian itself. Here,
too, were temples and baths, and looking over the
beautiful Bay of Baiae stood patrician villas, while
towns and ports made busy the water's edge.
The Phlegrsean Fields extend from Naples to
the neighbourhood of the site of ancient Cumae,
with a breadth of six or seven miles, and, to accept
the usually received etymology, were so named
because of the fiery phenomena they displayed,
from Qtiyvpos, ardent or burning. Those, however,
who love to find a Syriac origin for the names of
places in a part of Italy early colonised by the
Phoenicians, derive the word Phlegraean from the
Syriac Phele Geroh, meaning "wonderful strife," an
appropriate designation enough for a region that
seems as if it had been a battle-field for beings
having command of supernatural powers. Strabo,
however, thought the neighbourhood was made the
scene of the struggle of giants from its exceeding
fertility giving rise to battles for its possession.
Certain it is it was very early colonised. Cumae,
its chief town perhaps the most ancient of all
Italian cities flourished long before Rome was
founded, and was the greatest centre of civilisation
in Southern Italy in the days of the Tarquins, the
last of whom died and was buried here. Its glories
had even all departed in the imperial days of Rome,
22 MOUNT VESUVIUS.
for it was then spoken of as " Vacuse Cumse " and
" Quieta Cumse," and Juvenal says of it :
" Griev'd though I am an ancient friend to lose,
I like the solitary seat he chose ;
In quiet Cumse fixing his repose
Where far from noisy Rome secure he lives,
And one more citizen to Sibyl gives."
Dry den's Juvenal, iii., I.
It was afterwards fortified, and became the last
stronghold of the Gothic Kings of Italy, but now
nothing remains of this renowned city but a few ruins.
Cumae itself was situated upon a hill of volcanic
material, a trachytic tufa, which breaks the mono-
tony of the flat coast between Monte di Procida and
the mouth of the Vulturno.
Between the region of volcanic craters and tufa
hills and the Apennines lies the great plain of
Capua, the Campanus Ager, all on volcanic mate-
rial of abounding fertility, and famed also for its
beauty and the goodness of its harbours, and one of
the most valuable districts of Italy, constituting
much of the province of Campania, which extends
along the Tyrrhenian Sea from the Bay of Poli-
castro to beyond Gaeta. In the time of Augustus,
Campania was joined to Latium, and hence the
neighbourhood of Rome is called by the modern
term, Campagna di Roma.
So rich and fertile was Campania, and so easy
and luxurious was the consequent mode of life there
in the time of Hannibal, that his subsequent want
of military success, resulting in the loss of Italy and
the mastership of the world, has been attributed to
THE NEAPOLITAN VOLCANIC REGION. 23
the enervating effect of a winter's sojourn on these
volcanic soils. This affords a curious and remark-
able illustration of the far-reaching consequences of
the geological structure of a country.
It was by the Battle of Vesuvius, in 340 B.C., that
this splendid district, the Campanus Ager, fell into the
hands of the Romans. Then Puteoli and Neapolisgrew
and flourished, Baiae and Pompeii rose, and Campania
soon became the favourite place of retirement and
residence for the distinguished and the wealthy of
the dominating city on the Tiber. Great roads
were constructed, and the Via Appia, the Via
Latina, the road from Rome to Rhegium, and the
Via Domitiana along the coast from Sinuessa to
Neapolis, facilitated access to and through the
beautiful region.*
The whole area of the Phlegraean Fields appears
to be occupied by more or less completely ridge-
encircled basins, one still evolving gases, hot fumes,
and steam. Some of the wholly or partially circular
hollows are enclosed by lofty walls of scoriae and
ashes forming incomplete or truncated conical hills,
and a few are encircled by inconsiderable worn and
wasted ridges at no great height above the sea-level,
but all are evidently craters resulting from volcanic
action. Looked down upon from above, the district
would resemble most of all, to compare small things
* The chief towns of Campania were Capua, Cumse, Neapolis, Nola,
Baiae, Pompeii, Puteoli, Herculaneum, Vulturnum, Liternum, Teanum,
Salernum, Sinuessa, Misenum, Surrentum, Picentia, Venafrum.
24 MOUNT VESUVIUS.
with great, a portion of the surface of the moon,
which, like that of the Phlegraean Fields, is doubtless
also the result of past volcanic activity.
One of these craters is not yet indeed altogether
extinct. The Solfatara, the " Forum of Vulcan,"
from a fumarole * still gives forth volcanic fumes
which deposit pure sulphur on the intercepting rocks
and stones ; and from it the name Solfatara is now
generally applied to volcanic openings from whence
issue sulphurous fumes. After speaking of Puteoli,
Strabo writes : " Immediately above it is Vulcan's
assembly-room, a level space surrounded by fiery
heights, having numerous chimney-like mouths,
which throw out smoke with great noise; and the level
interior is full of drifted sulphur." Subterranean
hollows furnish evidence of themselves by giving
back resounding noises when heavy stones are
thrown down upon the old crater floor, but so wide
and level is the plain that its cavernous substructure
seems to be due rather to fissures or interspaces
between large masses than to a great abyss arched
over by the present floor of the old crater. All
around the low cliffs display degraded crater walls,
but yet the Solfatara, as an active volcano, is by no
means prehistoric, for there was an eruption here in
A.D. 1198, when a stream of lava flowed to the sea
and produced the great mass of trachytic rock forming
Monte Olibano, "Opo S B^, the barren mountain,
and covering the ancient cemetery on the Via
Puteolana. This flow of lava was a very consider-
Plate III.
LOVOOfti aOfEflJi rif>OWl.Y. II, LUDGATE. H/U.E.I
THE NEAPOLITAN VOLCANIC REGION. 25
able one, and touched the sea with a front of a
quarter of a mile in width and seventy feet in height.
The rock, essentially different from the lava rocks
of Vesuvius, which are not trachytic, has been
extensively quarried for building purposes. Dr.
Daubeny says : " The trachytic lava of Monte Olibano,
although differing from the rock of the Solfatara
itself, agrees with it in being essentially a felspar
with augite only occasionally." * The whole mass
rests on a thick deposit of scoria and ashes. Pre-
vious to the eruption of 1198, which greatly injured
Pozzuoli, the volcano appears to have been in very
much the same condition as at present.
Between the Solfatara and the sea stood the city
of Puteoli, which at one time almost extended to the.
volcano. Founded by a Greek colony from Cumae,
it was named Dicoearchia, but when in possession of
the Romans it was by them called Puteoli, and
became one of the two ports of Rome, the other
being Ostia at the mouth of the Tiber. It was then
the chief place of debarkation for travellers to Rome
by sea from the south and from the east, from Egypt,
Syria, and Greece, and was accordingly the landing-
place of St. Paul, who remained at Puteoli seven
days. So commodious was the harbour in the
time of Augustus, both in space and depth, that the
large vessels required for the shipment of the
Egyptian obelisks then brought to Rome were well
accommodated in its waters. The city has suffered
* Daubeny, "Volcanoes," p. 171 (ist ed.).
26 MOUNT VESUVIUS.
greatly by war, pestilence, earthquakes, and vol-
canoes, but under the name of Pozzuoli it is still
a town of upwards of 15,000 inhabitants.
The Solfatara may be considered to be a con-
necting link between Vesuvius and the quite extinct
craters of the Phlegrsean Fields. Of these, Astroni
is the largest, having an exterior circumference of
about four miles, and a diameter of a mile, but it has
so lost its volcanic aspect that it is now a royal
preserve for " big game," wild boars and wild deer
finding in the underwood of the arena of the amphi-
theatre, so to speak, a congenial covert and abode.
The bottom of this large crater has in its centre a boss
of trachy tic rock without traces of a crateral opening,
as if it had been pressed out of the volcanic tube in
a plastic state and had remained a mound-like mass
until entire solidification had followed. The cir-
cular hollow around is covered with oak and ilex,
and beneath their shade are three secluded pools of
water amidst rich verdure.
Monte Barbaro, anciently Mons Gaurus, is not so
large a crater, though upwards of three miles in
circuit, but it has much more lofty enclosing walls.
It is a conspicuous object, displaying a high conical
hill, with its steeply rising sides covered with vine-
yards. This is the highest of all the cratered cones
of the Phlegraean Fields, and is geologically more
than ordinarily interesting, on account of an opening
through the crater wall on the eastern side which
reveals its structure, and clearly shows that the whole
THE NEAPOLITAN VOLCANIC REGION. 27
cone has been produced by the fallen fragmentary
ejections from the central vent, probably the ejecta-
menta of one eruption only, without any flow of
lava, no lava-rock being anywhere visible. In the
immediate neighbourhood of Astroni and Monte
Barbaro are two smaller but similar craters, named
Monte Cigliano and Monte Campana.
Agnano, nearly three miles in circuit, is a crater
much degraded, but holding until 1870 a lake of
water, on the grassy banks of which frogs croaked
and lizards crawled in great numbers. So worn and
irregular are the boundaries of Agnano that it has
not the appearance of a crater, but the beds of tufa
dipping away from the interior leave no doubt that
it is one, though probably much older than its more
perfect neighbours. In consequence of unwholesome
malarious vapours arising from the lake, though due
not to volcanic fumes, but to the soaking of flax,
drainage works were commenced in 1865, and com-
pleted in 1 870, by the construction of a tunnel through
Monte Spina, which formed a conduit for the waters
of the lake to the sea. The area of the water surface
was 924,020 square metres, and the depth of the lake
40 feet.* The effect of the drainage has doubtless
had good sanitary and economic results, but it has
removed a beautiful and interesting scenic feature.
Facilis decensus Averno is a familiar phrase to
every schoolboy, but not only is the way to it
pleasant and easy, but Avernus itself is pleasant
* Murray's Handbook to Southern Italy.
28 MOUNT VESUVIUS.
also. A circular lake of about a mile in circum-
ference, surrounded by rocky shores adorned by
luxuriant shrubs, and the glassy water reflecting its
picturesque surroundings, it presents a by no means
uninviting aspect. In early times, however, mephitic
exhalations were doubtless given off from its sides,
and the large trees which then overhung the lake
that fills the old crater favouring the accumulation
of such gaseous emanations, the traditions embodied
by the classic poets in their verse would have some
foundation.
" And here th' access a gloomy grove defends ;
And here th' innavigable lake extends,
O'er whose unhappy waters, void of light,
No bird presumes to steer his airy flight ;
Such deadly stenches from the depth arise,
And steaming sulphur, that infects the skies.
From hence the Grecian bards their legends make,
And give the name Avernus to the lake."*
But now the air is pure, and the aspect of the
place cheerful, for there are no noxious gases and
no dense overhanging woods to give a gloomy
shade. Agrippa cut down the trees, and disregard-
ing poets, traditions, and fables, constructed a "ship
canal " from the sea to the lake, and thus Avernus
was converted to practical purposes and made a
secure harbour for Roman galleys. Some ruins of
baths, or " thermae," now called the Temple of
Apollo, show that, notwithstanding its forbidding
reputation, Avernus was resorted to in ancient
times for health and pleasure.
* Dryden's " JEneid t " book vi., 340.
THE NEAPOLITAN VOLCANIC REGION. 29
The way is less easy to the " Cave of the Sibyl,"
which is far underground, with a chamber having
some depth of water the " Bath of the Sibyl" so
that a visitor is fain to be content to be carried on
the shoulders of a guide. This is part of the old
subterranean road from Avernus to the shores of
Lucrinus, though containing what was reputed to
be the entrance to the realms of Pluto.
" Deep was the cave, and downward as it went
From the wide mouth, a rocky, rough descent.
*****
'Tis here, in different paths, the way divides
The right to Pluto's golden palace lies ;
The left to that unhappy region tends
Which to the depth of Tartarus descends."*
On emerging from this gloomy cavern, with the
placid water of Avernus reflecting the bright sun-
shine, and a gap in the seaward side of the old
crater wall showing the Lucrine Lake and the blue
sea beyond, even the most classically minded might
well forget that he was near the Cimmerian abodes.
Yet here were the reputed underground dwelling-
places of those sunless beings whom Ulysses visited
when on his famous travels.
11 The gates of hell are open night and day ;
Smooth the descent, and easy is the way ;
But, to return, and view the cheerful skies
In this the task and mighty labour lies."t
Exterior to the low broken walls of Avernus on
the landward side is the partly encircling larger
* Dryden's " ^Eneid," book vi., 338 and 726. t Ibid., 193.
30 MOUNT VESUVIUS.
crater of Monte Grillo, affording another instance
of an exterior and an interior crater-ring which is
so interesting a feature of the Neapolitan volcanic
region.
On a level with the sea, and just outside Avernus,
is the Lucrine Lake, and only separated from the
bay of Baise by a mere causeway, fabled to have
been first made by Hercules when driving the oxen
of Geryon. It was raised and completed in a more
prosaic manner by Agrippa. The canal from the
sea to Avernus passed through Lucrinus, making
a port with an outer and an inner harbour, and
sufficiently spacious for the Roman fleet ; but the
cutting was filled up, together, doubtless, with a
portion of the area of the lake itself, by the erup-
tion of the adjacent Monte Nuovo in the year 1538.
And this is the remarkable crater near to the
Lucrine Lake that is the newest of all in the Phle-
graean Fields, for it is the creation of historic
nay, of modern times. Monte Nuovo is also close
to the sea-shore, and, rising to a height of upwards
of 400 feet as a truncated cone, displays a perfect
though not quite circular crater, with steeply de-
scending sides, nearly as deep as the interior walls
are high. The height above sea-level of the summit
rim is stated by Professor Phillips to be 440 feet,
and the bottom of the interior crater only 19 feet
above the same level, thus giving a depth of
421 feet. The greatest diameter of the crater is
stated to be a quarter of a mile, but this must be a
THE NEAPOLITAN VOLCANIC REGION. 31
mistake, as it cannot be nearly so much. The
dimensions of Monte Nuovo are so differently
stated that I greatly regret not having myself
measured this remarkable hill. Dr. Daubeny says
of it: " Monte Nuovo, 413 feet high, and 8,000
feet in circumference ; composed entirely of frag-
ments of scoriform matter, or of a compact rock
of an ash-grey colour no tufa." And Scrope :
" Monte Nuovo, a tuff cone 430 feet high, with a
crater 370 feet deep." While Murray states that
" Internally the crater is a continuous cavity, free
from fissures or dykes, about a quarter of a mile
in circumference, 419 feet deep, and the difference
between that and the height of the rim, 2 1 feet."
Monte Nuovo was produced by the volcanic
energy of three days in September, 1538, which
opened a new vent at this place on a plain, or
" piano," not necessarily quite level, and, ejecting
ashes and scoriae, piled up the present hollow trun-
cated cone, which appears to be composed entirely
of ejected scoriae and ashes, no lava flow or lava
rock having been recorded or detected, though red-
hot pumice is mentioned. Volcanic activity has
not since recurred to alter its height or form,
and thus the accumulation of ejectamenta with its
regular crater remains very much as it was left by
the creating eruption, except that it is now well
grown over by the arbutus and other shrubs, both in-
side and out, though we are told that till the end of
the last century the scoriae was without vegetation.
32 MOUNT VESUVIUS.
From amidst the now peaceful and safe seclusion
of the abundant covert so formed, an exceedingly
fine fox was disturbed by my exploring footsteps.
Monte Nuovo is, however, more than a mere in-
teresting addition to the wonders around, since, as
will be seen subsequently, it strikingly illustrates the
method of the formation of volcanic cones generally,
and possesses, therefore, great geological illustrative
value.
The formation of Monte Nuovo was recorded
by no less than four eye-witnesses Marco Antonio
delli Falconi, Pietro Giacomo di Toledo, Francesco
di Nero, and Simone Porzio whose accounts fur-
nish an important chapter in the history of the
Phlegrsean Fields, as well as a most useful contribu-
tion to vulcanology. (See Appendix.)
Many earthquakes during the two preceding
years presaged the eruption, and no less than
twenty shocks were noted on the day of its com-
mencement the 28th of September. Condensed
volumes of steam, with showers of ashes, produced
deluges of mud that greatly injured the town of
Pozzuoli, and it was afterwards found that the
village of Tripergole, the Villa of Aggripina, and the
canal of Agrippa had all been destroyed, while a rise
of the coast was doubtless another result. Triper-
gole was a much -frequented watering-place for its
mineral springs, with a hospital, and with three inns
in the principal street.
But perhaps even more wonderful and significant
Plate IV.
Ill ?3:
THE NEAPOLITAN VOLCANIC REGION. 33
in the importance of their geological teaching are
the remains of the ancient building usually called
the Serapeum, or Temple of Serapis, but probably
built for a sumptuous bathing establishment, near the
western end of Pozzuoli, and close to the sea-shore.
These remains consist of three Cipolino marble
pillars, perfect in height, and although not connected
by a superstructure, almost so in verticality of posi-
tion, standing on a base about a foot below the level
of the adjacent sea, the water of which percolates
through an imperfectly protecting bank, and covers
the ancient floor. At about twelve feet above the
base, and occupying a zone of about nine feet in
breadth, the same on each column, are the bore-
holes of rock-boring marine mollusca (Lithodomus
lithophaga), such as live abundantly in the adjoining
sea, and now excavate their miniature tunnels in the
rocks below the water-line. The existence of this
zone of the perforations of marine animals would
seem to at once conclusively prove that two changes
of level to the extent of about twenty feet each had
taken place, and as there is evidence of the interior
of the temple having been decorated by marbles in
the third century by Septimus Severus and Marcus
Aurelius, that these changes of level had occurred
since the commencement of the Christian Era. In
other words, the site of the temple had, since the
building was used in the third century, sunk to
more than twenty feet, to which height the pillars
had been submerged, and that subsequently a
34 MOUNT VESUVIUS.
reverse movement had taken place, and the ground
had risen twenty feet, uplifting the pillars until their
bases were nearly level with the surface of the sea.
So it appeared to Breislac, but Dr. Daubeny, agree-
ing partly with Goethe and partly with the Canonico
Jorio, thought that the Hthodomi borings could best
be explained by supposing an eruption of one of the
neighbouring craters producing a mass of material
that had impounded for a sufficient length of time a
quantity of sea-water around the pillars when the sea
had risen to an unusual height from seismic action.
He considered that had two such great changes of
level occurred as has been supposed, the pillars must
have been thrown down.
Mr. Babbage, Professor James Forbes, and Sir
Charles Lyell, however, have pointed out so many
indications of change of level to the extent required,
and even to thirty feet, in the immediate neighbour-
hood of Pozzuoli, both north and south, that no
other conclusion than that there has been a sub-
sidence and subsequent upheaval can now be come
to. Dr. Daubeny's objection is replied to by the
gradual and slow alteration of level alone required,
and by the fact that buildings have actually descended
from one level to another at the time of landslips
without even injury to their walls. The three
pillars of the Temple of Serapis therefore furnish
most valuable evidence of the changes of relative
level of sea and land that may occur, even in
no very long periods of time, to entirely alter
THE NEAPOLITAN VOLCANIC REGION. 35
geographical outline and terrestrial configura-
tion.
Confirmatory of the above conclusion is the long
stretch of low land by the sea-shore of the Bay of
Baiae, with a low cliff bounding it on its landward
side, called La Starza. This is composed of hori-
zontal beds of pumiceous tufa, containing not only
recent sea-shells, but fragments of mosaic pave-
ments, &c., all indicating a marine formation of
historic times. The famous Mole of Pozzuoli, the
so-called Bridge of Caligula, too, has some of its
piers perforated by lithodomi ten feet above the
sea-level.
The exemption of the lower portion of the three
pillars of the Temple of Serapis from perforations is
accounted for by the accumulation around them of
the ejectamenta of the eruption of the Solfatara, in
1198, to the height of twelve feet, previous to the
submergence which brought the sea-water to twenty-
one feet above their bases. From this position
they probably began to emerge before the eruption
of Monte Nuovo in 1538, since in 1503 Ferdinand
and Isabella granted to the city and university of
Pozzuoli some land on the shore of the Bay of Baise
where "the sea was drying," and in 1511 where
"the sea was dried," and after 1538 newly dis-
covered ruins were said to have been found on the
shore near Pozzuoli. Previous to the formation of
Monte Nuovo, the inner cliff between the Punta di
Coraglio and the Lucrine Lake was the sea-cliff.
36 MOUNT VESUVIUS.
Since 1 780 this part of the coast appears to have
again subsided. Observations for sixteen years
from 1822 were carefully made and recorded, and
the result, as reported by Signor Nicolini, was that
the land appeared to have been sinking during that
period at the rate of about a quarter of an inch
annually. Professor Guiscardi found, from noting
the sea-line on the Mole of Pozzuoli, first in 1840,
and then twenty-five years afterwards, in 1865, that
a change of 0*349 metre had taken place, indicating
a land subsidence at the rate of i'396 metres in a
century. This giving half an inch annually shows
a doubling of the rate of subsidence.
The south-eastern boundary of the Phlegrsean
Fields is the commanding tufa-formed ridge of
Posillipo (iiavafrvTrov, end of care), which separates
this lunar-like district from the suburbs of the city
of Naples, and overlooks the great bay towards
Vesuvius, Sorento, and Capri. Through it runs the
famous Grotto of Posillipo, an artificially formed
tunnel for the high-road, of the construction of which
there is no record. It has been ascribed to those
busybodies of the olden times, the fairies, and also,
with equal probability, to the magical power of
Virgil, whose tomb is on the ridge near the eastern
end of the grotto; but possibly it was cut by
Marcus Agrippa, about the year 27 B.C.
Although the tunnel is a very considerable one,
being no less than 2,244 feet long by 21 feet wide,
with an entrance 69 feet high, diminishing to 25
THE NEAPOLITAN VOLCANIC REGION. 37
feet, yet the rock is of so soft and easily worked a
character that the labour of excavation would not be
very great. Indeed, at the other end of the ridge,
near the Punta di Coraglio, there is a still greater
work of the same kind, forming a passage to the
Villa of Lucullus. This tunnel, now called the
Grotto of Sejanus, is nearly a mile in length, and
was excavated by the engineer M. Coccineus, who
was employed by Agrippa to cut the canal to
Avernus.
The Ridge of Posillipo consists of the tufaceous
rock that forms the whole of the area comprising
the site of Naples and the hilly district on the north-
west of the city. This rock, though varying some-
what in character, is essentially the same throughout,
being a volcanic pumiceous agglomeration compacted
together by having been deposited in the sea, as
shown by its containing the shells of species of
mollusca now living in the adjacent bay. In the
neighbourhood it is quarried for cement, and has
been used for that purpose since the days of the
Romans, both Strabo and the architect Vitruvius
having praised it for its still highly prized quality of
cementing under water. It is widely known from
the name of its place of shipment as " Pozzuolana."
Near Pianura, below the hill of the Camaldoli, the
rock has a more granular structure, and is there
quarried for building purposes under the name of
Piperno. The Pianura itself, a circular plain within
the larger sweep of the Piano de Quarto, is eminently
38 MOUNT VESUVIUS.
suggestive of a crater-floor. The highest point
attained by the tufa hills of the district is at the
Convent of the Camaldoli di Napoli, where the
summit of the hill is 1,488 feet above the level of
the sea, the highest eminence next Vesuvius in the
district. As this tufa forms an area of many square
miles, and is found to have a depth below sea-level
of no less than 500 feet, while attaining so great a
maximum elevation as that just stated, there is here
the doubtless much-reduced presentation of an
enormous aggregate amount of volcanic material,
ejected long previously to the commencement of the
present geographical conditions of this region.
The fatal landslip at Santa Lucia in 1868 was
caused by the soft character of the rock at that place,
which had favoured the formation of the cracks and
fissures by which the cliff behind the houses was
shattered and a large mass of it thrown down.
From the concentric form of the two lines of
elevations at the back of Naples, that of the Castle
of St. Elmo and that of the Camaldoli, there is a
suggestion of an outer and an inner crater ring.
Breislac, indeed, was inclined to put the number of
craters, of which there were indications in the
neighbourhood of Naples, including of course those
undoubted ones of the Phlegraean Fields, as high as
twenty-seven, but the tufa, from its soft character, is
so easily acted upon by erosive agencies that some
may be hollows excavated out of a great thickness
of the deposit.
THE NEAPOLITAN VOLCANIC REGION. 39
As remnants of volcanic activity, or rather as
evidences of still continuing volcanic heat, the
stufae and thermae of the Phlegraean Fields deserve
attention.
The chief seat of gaseous emanations, the Solfatara,
has already been noticed. The fumes here evolved
appear to be the same as were noted previous to
the eruption of 1198, and consist of steam, sulphu-
retted hydrogen, and hydrochloric acid gas. Dr.
Daubeny describes a very interesting series of
chemical reactions resulting in the formation of
sulphates and the deposition of sulphur, which latter
is a conspicuous phenomenon at the Solfatara.
At the south-eastern side of Agnano, and before
the drainage of the lake was commenced not far
from the water's edge, the Stufe di Germano
gives off vapours of sulphuretted hydrogen at
182 Fahr.
Not more than a few yards distant is the well-
known and much-visited Grotto del Cane, where a
poor dog is alternately half suffocated and revived
for the gratification of tourists more curious than
humane. The gas evolved at this place is carbonic
acid, produced by the decomposition of calcareous
rocks below, and this, from its greater specific gravity
than air, accumulates near the floor of the grotto,
and so forms, as it were, an anti-vital and an anti-
combustion bath. Dr. Daubeny says: "I found
that phosphorus would continue lighted at about
two feet from the bottom, whilst a sulphur match
4<D MOUNT VESUVIUS.
went out a few inches above. It was impossible to
fire a pistol at the bottom of the cavern." *
Near to the Lucrine Lake the Stufe de Nerone
with hot vapours and a spring in the interior of a
temperature, according to Prof. James Forbes who
penetrated to the extremity of the cavern, of 182 '5
Fahr., and " sufficiently hot to boil an egg in a very
few minutes." f Dr. Daubeny attempted to follow
the example of Prof. Forbes, but was driven back by
a sense of suffocation before he had reached half-way
to the end stated to be at 1 20 paces from the entrance.
This stufe is still resorted to for curative purposes
as it was in the days of Nero, when Martial wrote :
"Quid Nerone pejus?
Quid thermis melius Neronianis ? "
The amount of volcanic vapour evolved in this
region, however, appears to be less than of old, for,
to say nothing of the reputed mephitic vapours of
Avernus, volcanic gases seem to have been emitted
from the island of Nisida in the first century of our
era, since Lucan writes :
" Thence deadly plagues invade the lazy air,
Reek to the clouds, and hang malignant there,
From Nesis such, the Stygian vapours rise,
And with contagion taint the purer skies."
Rowe's Lucan, " Phars.," vi., 141.
But so recently as 1838 fumes issued from the
Lake of Fusaro, destroying, it is said, the oysters
that took the place of those of the Lucrine Lake.
* Daubeny, "Volcanoes," p. 199. f Ibid., p. 210.
THE NEAPOLITAN VOLCANIC REGION. 41
The hot springs, or Thermae, are numerous, but
the repute and greatness of Baiae, and indeed the
words of Pliny, would seem to indicate that they
were more copious, as well as more medicinally
powerful in ancient than in modern times. Pliny
writes : " Nowhere do mineral waters abound in
greater number or offer a greater variety of medi-
cinal properties than in the Gulf of Baiae, some being
impregnated with sulphur, some with alum, some
with salt, some with nitre, and some with bitumen ;
while others are a mixture of qualities, partly acid
and partly salt. The springs at Baiae, now known
as Posidian, after the name of a freedman of the
Emperor Claudius, had waters so hot as even to
cook articles of food" (Pliny, xxxi., 2).
From the exterior of the bounding ridge of the
Solfatara, at a part called Monte Sicco, in the
hollow between it and Agnano, the aluminous
spring of Pisciarelli, called by Pliny the Fontes
Leucogaei, gushes out at a temperature of 180
Fahr.
At Bagnoli, on the sea-shore between the Capo di
Posillipo and Pozzuoli, are two mineral springs that
still furnish hot water at a temperature of 104 to
a bathing establishment in daily use. The water at
one place contains salts and carbonic acid gas, and at
another sulphur and iron.
On the west of Pozzuoli, at the Serapeum, that
monument of Art but silent witness of Nature, there
are still the warm springs that were the cause of
42 MOUNT VESUVIUS.
the erection of what some antiquaries consider were
baths ; for even if the edifice was really a temple of
Jupiter Serapis, its site was doubtless determined by
the medicinal springs, since that Egyptian deity in-
cluded amongst his attributes those of Esculapeus.
The warm springs of Avernus were, too, of suf-
ficient importance to occasion the erection of the
baths now named the Temple of Apollo, in one of
the chambers of which there is still a mineral spring,
the Acqa Capona, and a little distance beyond the
Lucrine Lake there are the Bagni di Tritoli.
The baths of Bauli are the modern representatives
of those thermae, the Myrtetae, that made Baiae, to
use a term of to-day, the greatest " watering-place "
of the ancient world. Both previous to and all
through the Imperial era there was at this, the
most flourishing pleasure resort of Italy, con-
centrated much of the wealth and luxury, the refine-
ment and the dissipation of Roman civilisation.
Horace says : " Nullus in orbe sinus Baiis praelucet
amcenis"* (Hor. Ep., b. i., 83); and Statius
writes :
" Fair Baiae's shores, for tepid springs renowned,
Where all the gay delights of life are found."
Statius, Sil., III., v. 95.
To Baiae and its neighbourhood came and abode
in elegant villas and splendid palaces Caius Marius,
Lucullus, Pompey, Julius Caesar, Nero, Caligula,
Hadrian, Severus, and Tiberias, as well as Horace,
* Nothing in the world can outshine the lovely Bay of Baiae.
THE NEAPOLITAN VOLCANIC REGION. 43
Cicero, Virgil, Pliny, and, indeed, all the greatest of
the Roman world.
11 Land of Venus, golden coast,
Nature's fairest gift and boast,
Happy Baise ! "
Martial, xi., 80.
Thus Baiae flourished till the terrible fifth century
brought the destroying power of Theodoric the
Goth.
The tufaceous ground forming the site of the
city of Naples, and connecting the Vesuvian with
the Phlegraean area, establishes the continuity of the
volcanic character of the whole district from Pompeii
to Cumae. Eastwards the whole plain is on the
same volcanic tufa, and westwards the region is
extended by the promontory of Misenum and the
islands of Procida and Ischia.
No one can doubt the volcanic origin of the bold
headland of Misenum who sails past it and sees
its almost vertical cliffs showing concave indenta-
tions that are obviously the remains of craters, and
a close inspection will show them to be composed
of volcanic materials. Behind lies the crater-like
Porto Miseno and the Mare Morto, the former of
which was the chief station of the Roman fleet,
while beyond extends the Elyssian Fields and the
Palus Acherusa, now the Lago Fusaro, lying be-
tween Avernus and the shore of the Gulf of
Gaeta.
Volcanic structure is conspicuously displayed in
the cliffs of Procida, and the alternate beds of tufa
44 MOUNT VESUVIUS.
and lava can be plainly seen from any passing
steamer. At one part of the natural section exposed
the beds are conspicuously arched, and this has been
cited in support of the " Erhebungs Cratere" or
" craters of elevation " theory of Von Buch. There
seems to have been a tradition of volcanic activity
in this island, for in Strabo's time a legend was
current of Prochyta (Procida) having been torn
away from Pithecusa (Ischia). Procida is two and
a half miles long only, but has 13,000 inhabitants,
and is richly cultivated.
The crescent-shaped isle of Nisida, the Nesis
of the Romans, is, too, conspicuously volcanic, the
little island being but the landward, less exposed,
and consequently remaining part of a crater.
Ischia (anciently named Pithecusa, Inarime, and
CEnaria), under which the Typhon was said to lie
and groan, and occasionally move under his heavy
coverings, a fable obviously founded on the volcanic
character and traditions of the island, is much
larger than Procida, being nearly twenty miles in
circumference (length, seven miles ; breadth, four
miles in the narrowest part), and though volcanic
too, is formed of different materials, the prevailing
rock being a fine-grained tufa, a re-agglutinated
comminuted pumice, while its lavas are trachytic.
Towering above the whole island is the central cone
of Epomeo, or San Nicolo, the Epompeus of the
Romans, with an elevation of 2,605 ^ eet above
the level of the sea. This mountain, although
THE NEAPOLITAN VOLCANIC REGION. 45
entirely volcanic, is, like the Puy de Dome of
Auvergne and other trachytic cones, without a
summit crater, the volcanic mouths being on its
sides. An eruption of importance, and the last to
the present time, took place here in 1302, when lava
was emitted from a mouth on the lower slopes of
Epomeo, called the Cremate, which reached the sea
and formed the Lava d'Arso. Earthquakes and
eruptions before the Christian era repeatedly drove
out the inhabitants, who had, as colonists, succes-
sively settled on the island, first the Erythrseans,
then Chalcidians, and afterwards colonists from
Syracuse. No less than twelve volcanic cones on
this small island form enduring memorials of previous
great volcanic activity ; but the fiery forces under
Ischia have not been altogether desolating in their
consequences, since the volcanic products have
formed a soil so fertile that shrubs grow beyond
their normal size, and the vines are remarkable for
their luxuriance. The most noteworthy of the cones
around Epomeo are Monte Rotaro, Montagnone
Monte Tabore, Monte Corvo, Monte Vico, and
Monte Campignano.
The whole island is evidently volcanic, and the
destructive earthquakes of 1881 and of three years
ago are indications that Ischia is still inside the
area of seismic, if not of volcanic disturbance.
Indeed, the earthquakes at Casamicciola have been
regarded as ominous warnings of a coming renewal
of the volcanic activity of Epomeo, since they have
46 MOUNT VESUVIUS.
been likened to those that injured Pompeii sixteen
years before the renewal of the long-dormant activity
of Vesuvius. But these fears may well be allayed,
if not put on one side, when it is remembered that
not far distant there is the now frequently and freely
opened vent of Vesuvius that may possibly be
sufficient to relieve all pent-up volcanic force
beneath this area. Let us hope this may be so,
and that the fires of Vulcan may serve but to heat
as now the water of the hot baths of Gurgitello
for the benefit of the Neapolitan and other visitors
to the beautiful island, who may thus be able to
continue to enjoy undisturbed the fresh Mediter-
ranean breezes, the splendid position, and the
charming scenery of this gem set in the azure sea.
47
CHAPTER II.
THE SURROUNDINGS OF VESUVIUS.
Characteristics Populousness Naples Destroyed Towns Ring
of Towns Bay of Naples Appearance from Naples View of
Surroundings from the Mountain.
THE chief characteristics of the immediate environ-
ment of Vesuvius are fertility and populousness, for
the country all around is most productive, and, apart
from Naples, the whole base of the mountain is
skirted by a series of villages and towns, some of
which have a large number of inhabitants, especially
those on the shore of the bay, where, although the
eruptions of past times have frequently covered the
ground with lava, and destroyed the habitations of
man, there is a great population living, apparently,
without any dread of the dangerous neighbour
whose threatening thunders they so often hear.
Nor is this great accumulation of humanity in the
favoured and fertile yet threatened and sometimes
devastated Campania di Napoli a merely recent
one, for Strabo speaks of the glorious Bay of
Naples, which he calls the " Crater," between
" the two promontories Misenum and Athenaeum,
which look towards the south, enriched everywhere
with the before-named cities, with villas, and with
cultivation so closely adjacent as to appear like
one continuous city."
48 MOUNT VESUVIUS.
It is estimated that there are now upwards of
80,000 inhabitants on the slopes and skirts of
Vesuvius, and that had no volcano arisen here, the
country would not have supported more than a tenth
of its present population. The destruction caused
from time to time by eruptions is therefore amply
compensated for by the abounding fertility of the
soils resulting from the decomposition of volcanic
products, which give the means of subsistence to a
vastly increased number of inhabitants.
The populousness of the immediate vicinity of
Vesuvius is emphasised in the neighbouring great
city of Naples, the most densely populated city of
Europe, containing about half a million of inhabi-
tants crowded on to an area of little more than four
square miles. The streets of Naples derive
dignity rather from the loftiness of the houses than
from the width of the roadway ; for, with few
exceptions, they are, especially in the eastern half
of the town, narrow lanes between habitations of
six and seven storeys high, without kerbs or side-
walks, but well and most enduringly paved with
hard lava-rock. Yet the few exceptions, as the old
Strada di Toledo, now the Via di Roma, and the
Riviera di Chiaja, are noble roads with good side-
walks. Neither are there large open spaces or
gardens amidst this dense mass of human habita-
tions, the chief public gardens, the Villa Nazionale
and the Giardino del Populo, being situated on the
shore of the bay.
Plate V.
Fie. I. MONTE Nuovo FROM POZZUOLI
FlG.2.PROMONTORY OF MlSENUM
FiG.3 THE PHLEGRALAN FIELDS.
THE SURROUNDINGS OF VESUVIUS. 49
The volcanic structure of the site has produced
two roughly semi-circular depressions opening to
the sea, and divided from each other by a tufa
ridge extending inland from opposite the islet of
the Castel dell' Ovo, the I sola del Salvatore (the
Megaris of Pliny), at Pizzofalcone, above Santa
Lucia, to the elevation on which stands the Castel
St. Elmo, where it joins the bounding ridge of the
two depressions.
Like Puteoli, the original city was founded by a
colony of Greeks from Cumae, and named Parthe-
nope, after the siren, whose tomb was shown in the
time of Strabo. A second party of Greek colonists,
it is said, from Chalcis and Atica, formed another
but adjoining settlement, which was accordingly the
new city, and the first settlement became the old
town, or Palaeopolis, and so they remained until
both fell into the hands of the Romans, under Publius
Philo, in B.C. 328, when they became united or
merged, and the name Palaeopolis disappeared, the
designation Neapolis, or new town, being used for
the combined city during the whole of the Roman
period, and giving the modern Italian Napoli, and
our word Naples.
Neapolis was a favourite place of residence with
some of the Roman emperors. Titus was Archon,
and Hadrian was Demarch of the city, while on
the neighbouring hill of Pausilypus (Posillipo)
Virgil composed his " Georgics," and at Neapolis
Nero made his first appearance on the stage.
E
5O MOUNT VESUVIUS.
Horace calls it " otiosa Neapolis," Martial " docta
Parthenope," and Ovid says, " in otia natum Par-
thenopem." The city suffered greatly during the
Gothic wars. It was taken in 536 by Belisarius,
and in 542 by Totila, after which it became for a
long time a dependency of the Exarchate of
Ravenna. After many vicissitudes it was, with its
territory, united with Sicily in the kingdom of the
Two Sicilies, until in 1860 Garibaldi freed it from
the Bourbons, when Naples became the chief city
of a Province of the Kingdom of Italy, since which
time much of the picturesque idleness has given
place to more prosaic industry, which has trans-
formed many of the famous lazaroni into dock-
labourers.
Though Naples has never suffered devastation
from the eruptive activity of Mount Vesuvius, its
inhabitants have at intervals been thrown into the
greatest terror by the more violent outbursts, and
Vesuvian ashes have frequently darkened the city.
The immunity enjoyed by Naples from serious
injury was ascribed to the protection of San Janu-
arius, its patron saint, in recognition of whose favour
in having saved the city from famine, war, plague,
and the fire of Vesuvius, the Cappella del Tesoro
at the Cathedral was built, between 1608 and 1637.
The Museo Nationale, containing the recovered
artistic and antiquarian treasures of Pompeii and
Herculaneum ; the University Museum, with its
great collection of Vesuvian minerals, under the
THE SURROUNDINGS OF VESUVIUS. 51
care of the venerable Professor Archangelo Scacchi,
and the Club Alpino, with a library of, it is stated,
25,000 works on Vesuvius, vulcanology, and seis-
mology, all additionally associate Naples with
Vesuvius.
The re-awakening of the long-dormant forces of
the volcano in the first century of the Christian Era
was a terrible one for the then inhabitants of the
cities and towns at the base, for four or five were
entirely destroyed, though even then it is probable
that not a large number of the population perished.
About six miles from the summit, and on the
south-eastern side of the mountain, are situated the
half-uncovered ruins of Pompeii, the chief victim of
the destructive powers of Vesuvius. At the base
of the mountain, near the shore of the bay, and
partly under the modern town of Resina, Hercu-
laneum lies buried, while the ruins of Stabiae, the
third of the cities destroyed by the eruption of
A.D. 79, are close to Castellamare, at a distance of
eight or nine miles from the crater of the devastating
volcano, and at the commencement of the peninsula
of Sorrento, which, here forming a right angle in
the shore line, extends westwards as the southern
side of the bay. In addition to these, but not
usually mentioned as victims of the devastating
eruption of 79, it seems to me probable that Retina,
at the water's edge, the harbour of which Pliny
states was blocked by fallen ashes, and the Post
Station of Oplontum, to the south-east of Hercu-
52 MOUNT VESUVIUS.
laneum, were also destroyed by the Plinian
eruption.
The mountain is completely encircled by a road
running round its wide-spreading base, and con-
necting the many villages and towns at its foot into
one long series of human habitations that has few
parallels. This road is upwards of twenty miles in
length, and commencing as it does near Naples, and
running along the shore of the bay, and then con-
tinuing round the mountain on the inland side, some
of the places through which it passes are suburban,
while some have a seaside, and others, though popu-
lous, have surroundings of a quite rural aspect and
character.
They all agree, however, in having the great
mountain towering above them on one side ; they
are all within hearing of its rumblings and bellow-
ings, and all can see its summit fires and ascending
smoke, but they are not all equally liable to injury or
devastation from its eruptive energy. The strong
and massive bulwark of Monte Somma, extending
for two miles outside of the eruptive cone, effectually
protects a large area on the north-eastern side of
Vesuvius from lava streams, but still much destruc-
tion may be caused to growing crops and fruit-trees,
and even to towns, as was the case with Pompeii, by
heavy falls of ashes even on this side, for from these
Somma is no protection.
Though the road round Vesuvius is a populous
and animated one, that between Naples and Resina
THE SURROUNDINGS OF VESUVIUS. 53
is still more so. This road of about five miles,
passing as it does through the manufacturing and
shipping, and therefore the densest part of the
Neapolitan capital, and the little less dense adjacent
suburbs, is a most busy and noisy thoroughfare,
abounding with scenes and objects calculated to
arrest the attention of the lover of the picturesque,
as well as the observation of the student of national
characteristics. Soldiers, sailors, ecclesiastics, fisher-
men, lazzaroni, and beggars attract the eye by
their varied and un-English-looking costumes, and
carrozzelle with their picturesque groups of riders,
fourteen or fifteen on one vehicle, of all ages
soldiers, sailors, priests, women, children and with
nimble, fast-trotting little horses rattling along
over the hard lava-paved road, add great animation
to an already lively scene, crowded as it is with
figures and surrounded by varied and broken
outlines, bright with colour, and lighted by bril-
liant sunshine. Sounds as well as sights are many,
and cheerful too, at this east end of Naples. The
rattle of carriages over the stony street, the
crack of whips, the jingle of harness-bells, and the
calls of drivers, mingle with the music of a
military band or the sound of church bells, while
the song of the street minstrel, and, perchance,
the squeak of Punchinello, give further local
tone.
On leaving the Piazza del Plebiscito in front of
the Palazzo Reale, the frowning towers and battle-
54 MOUNT VESUVIUS.
ments of the grim old castle of Charles of Anjou,
the Castel Nuovo, is first passed, and then the two
commercial harbours of Naples, the Porto Grande
and the Porto Nuovo, with their shipping and sailors,
extend for a long distance between the road and the
sea, into which project the moles or breakwaters
that form the harbours, with the new Giardino del
Popolo at the water's edge.
Further along the Marinella stands the Castel del
Carmine of Ferdinand I., the rendezvous and strong,
hold of the populace in Masaniello's insurrection,
and subsequently a political prison, and still further
barracks that were built for a public granary called
I Granili. The little river Sebeto, which drains the
low lands at the west of the mountain, is crossed by
the Ponte della Maddalena ; and, lined with houses of
all sorts, churches, maccaroni and other manufac-
tories, the road, now fairly out of Naples, passes
through the village of San Giovanni a Teduccio,
adjoining the little town of La Barra ; and the
town of Portici then continues the urban character
of the road the whole distance to Resina.
The name Portici is a memorial of the buried city
of Herculaneum, since it is taken from this place
being the Porticum Herculis, or approach to the
great temple of Hercules, to whom the city was
dedicated, and stated by Petronius to have been at
the west end of Herculaneum. Portici, with a
population of nearly 12,000, has a Royal Palace, built
by Charles III. in 1738, on a bed of lava rock, the
THE SURROUNDINGS OF VESUVIUS. 55
produce of the great Vesuvian eruption of 1631, and
on this lava are the beautiful gardens attached to the
palace. This great bed of lava covers the tufa in
which the ruins of Herculaneum are embedded at a
depth of 70 or 80 feet below the present surface of
the ground. At one time the palace was a place of
great interest, since in it were displayed the portable
antiquities taken from the ruins of Pompeii and
Herculaneum, but now all these objects have been
removed to the Museum at Naples. There are also
at Portici a barracks, a Francescan monastery, and
at the water-side the castle or fort of Granatello,
from which a fine view of the bay can be obtained.
A great bed of lava, 38 feet thick and 700 feet wide,
is here cut through for the railway. All this neigh-
bourhood, with Portici, St. Giorgio, and Barra, is a
favourite locality with the Neapolitans for residences.
Resina, with a larger population than Portici,
nearly 14,000, is like it a favourite place of residence
for wealthy Neapolitans. This town stands partly
over the ruins of Herculaneum, an entrance to which
is in the main street. Resina is the modern repre-
sentative of the ancient Retina, which must have
been a small place at the water's edge. It was to
Retina that Pliny the Elder, during the eruption of
79, set out from Misenum by sea to go in order to
rescue the Roman garrison from danger, but finding
the harbour so filled up with the fallen Vesuvian
ashes that he was not able to communicate with the
place, he went on to Stabise," where he died. As
56 MOUNT VESUVIUS.
Resina is the town from which the ascent of Vesuvius
is usually made, it is the chief abode of the Vesuvian
guides that so beset visitors to the mountain. It is
common to hear these very useful, though perhaps
too pertinacious, men spoken of disparagingly, but
my experiences of them were altogether satis-
factory. On one occasion, great faithfulness and
courage were displayed at a time when I might
safely have been deserted and left in considerable
danger. Of the villas of the neighbourhood, the
largest and most interesting is that of the late
Prince of Salerno, called La Favorita, which
contains a mosaic found in the Palace of Tiberias
at Capri. Like the Palace at Portici, La Favorita is
built on the lava of 1631.
About a mile further along the road, and seven
and a half miles from Naples, is the still larger lava-
built town of Torre del Greco, which has a popula-
tion of between 23,000 and 24,000, and enjoys a
very considerable amount of commercial prosperity,
notwithstanding the many and terrible injuries it has
suffered from eruptions. This port is the seat of
the Mediterranean coral fishery, which is such an
important industry that no less than 200 vessels
belonging to Torre del Greco are employed in it.
The area of the fishery is so large as to include the
waters of Corsica and Sardinia. Besides the coral
trade, there is a great production of wine and fruit
from the gardens adjacent, all on the decomposed
lavas of the lower slopes of the mountain. The fruit
THE SURROUNDINGS OF VESUVIUS. 57
grown here is exceedingly fine in quality, and
abundant in quantity, especially the grape, from
which very choice wines are made. Of these, the
most famous is the celebrated Lachrymae Christi,
which is sold cheaply at the gates of the vineyards
where it is produced. There are many good country
houses in the vicinity, and in the town a handsome
collegiate church, three convents, and a large
hospital.
Torre del Greco has suffered from the eruptions
of Vesuvius more than any other existing town,
since it has been repeatedly devastated by lava
streams, which have flowed through the place to the
sea. But these lava-flows have afterwards become
the rocky foundations for new buildings, so that the
town has stood on several levels. The eruptions of
1631, 1737, 1794, 1822, and 1 86 1 were especially
destructive, and an earthquake in 1857 also occa-
sioned great damage. A writer in the Athenaum
states that after the eruption of 1861, during the
earthquakes preceding which fissures were opened
in the streets, he descended from the surface, and
found himself in a church below that had been
covered by the products of a previous eruption.
The most destructive of all the eruptions was that
of 1631, which, by the floods of lava that poured
through Torre del Greco, completely destroyed two-
thirds of the older town, and it is on this lava that
the present town chiefly stands. The readiness of
the inhabitants of this town to rebuild after every
58 MOUNT VESUVIUS.
destructive eruption has given rise to the Neapolitan
saying, " Napoli fa i peccati, e la Torre li paga."*
Still further to the south-east the remains of the
Roman post station Oplontum can be seen. It is,
like Pompeii, buried beneath lapilli, and now not
more than the remains of a few houses, with their
intervening lanes, can be distinguished.
The shore-line here, as far as Torre del Annun-
ziata, has been greatly affected by the lava-
flows of past eruptions, especially by those of the
terrible outburst of 1631, which, advancing to the
shore of the bay, entered the sea at several points,
and formed promontories of compact lava-rock.
These masses are cut through by the railway along
the coast, running between the high-road and the
sea, and they may be well seen at several points.
One branch of the great flow is quarried at Torre
Scassata, a little way from Torre del Greco, on the
shore of the bay, where has been developed the
beginnings of that remarkable columnar structure
which is such a marked characteristic of basalt.
At a place near here a recent excavation for a
new building cut quite through a bed of this lava,
enabled me to procure some of the lapilli on
which it rested, and which was of a dull brick-red
colour, much more resembling that of some of the
tufa of Rome, the Tufa lithoide, than the lapilli of
the neighbouring Pompeii.
* Naples commits the sins, and Torre pays for them.
THE SURROUNDINGS OF VESUVIUS. 59
Standing on a considerable elevation at some
distance on the left, well up on the side of the
mountain, and not far from the " bocche," or eruption
mouths of 1861, is seen the Convent of the
Camaldoli della Torre, surrounded by a grove of
luxuriant oaks. Often threatened with destruction,
the convent has as often been protected from the
fiery lava by the eminence on which it stands, which
has repeatedly divided or diverted the flows
descending this side of the mountain.
Beyond Torre del Greco there is a stretch of
low, flat land, part of the pre-Vesuvian Campanian
plain, between the receding outline of the base of
the mountain and the sea, and over this the road
runs to the large fishing town of Torre del Annun-
ziata, on an indentation of the coast-line. This
town, with a population of about 16,000, is twelve-
and-a-half miles from Naples, and the railway from
that city, which has kept close to the shore the
whole distance, now bifurcates one branch, inclining
inland, , passes Pompeii, and the other continues
along the coast to Castellamare. Torre del Annun-
ziata is a walled town, and is further defended by a
tower which gives the place rank as a fortress. It
has several industries besides fishing, such as
milling and the manufacture of fire-arms, gun-
powder, paper, and macaroni, as well as a brisk
coasting trade. Half a mile from the town, and
close to the sea, are the mineral waters of Acqua
Termo Minerale Nunziante, containing carbonate of
6O MOUNT VESUVIUS.
iron and magnesia, with an excess of carbonic acid
gas, at a temperature of 90 Fahr.
The coast-line now trends more to the south,
leaving Pompeii a mile inland, with the river Sarno
following a winding course from the buried city
through the low, flat land to the sea. As there are
good grounds for believing that the ancient city of
Pompeii was close to the shore, and at the mouth of
the Sarno, it would seem that all this low area lying
between the ruins of Pompeii and the sea, and on
both banks of the Sarno, has been raised into dry
land, if not at the time of the destructive earth-
quakes and eruption of 63 and 79, yet since the
commencement of the Christian Era.
Leaving now the coast-line, the Vesuvian en-
circling road runs northwards, and at a little
distance inland, and at the foot of the mountain,
passes the town of Bosco tre Case, and then
continues through the neighbouring town of Bosco
Reale. These two places have together a popula-
tion of nearly 8,000 ; they contain several churches
and convents, a royal manufactory of arms, &c.
They lie between Pompeii and the summit of
Vesuvius, the route to which from that place passes
them.
Continuing northwardly, the road crosses some
spurs of the mountain, and the most northern of
the eastern lava-flows. It passes Caposecchi and
the woods of the Prince of Ottajano, and then
behind the ridge of Monte Somma runs directly
THE SURROUNDINGS OF VESUVIUS. 6 1
to the town of Ottajano, a place of 6,000 in-
habitants, chiefly engaged in agriculture, with a
castle on a neighbouring commanding elevation.
A line drawn from this town to Torre del Greco
would cut through the cone of Vesuvius, from which
they are both equally distant in a straight line.
Ottajano is, however, protected by Monte Somma,
and so it has not suffered at all from lava-flows,
while Torre del Greco has been several times almost
destroyed, yet the latter place has four times the
population. Still further round the base of the
northern slopes is the town of Somma, with a popula-
tion of upwards of 7,000. It has several churches
and monasteries, as well as the castle of the Prince.
The country extending from this side of the
base of the mountain inland is flat, and forms the
famous plain of Capua, stretching eastwards to the
Apennines that rise beyond the towns of Palma
and Nola.
Coming round to the western side again, we reach
the considerable town of San Anastasia, and further
the village of Cercola, while the less considerable
places called Trocchia and Pollena are situated
on a higher level, and on the slopes below
the Hermitage are the two closely adjacent
villages of Massa di Somma and San Sebastiano,
between which the long and unusually fluid
lava stream of the eruption of 1855 flowed.
The suburban towns of Ponticelli and Barra, with
a population together of 10,000, and the village
62 MOUNT VESUVIUS.
of San Giorgio a Cremano, are situated on the low
ground between Vesuvius and the city of Naples.
In this neighbourhood are many large residences
and villas of Neapolitans, and a very considerable
area is covered with fruit gardens. The last-named
village being close to Portici completes the ring of
towns and villages with which Vesuvius is begirt.
Without doubt the greatest and most conspicuous
feature of the surroundings or setting, so to speak,
of Mount Vesuvius is the magnificent bay, which
spreads its waters westwards from the very foot of
the mountain. The Bay or Gulf of Naples, the
Sinus Cumanus of the Romans, and the " Crater "
of Strabo, is an expanse of water of over 52 miles in
circuit, and has a shore-line, not measuring minor
indentations, of 35 miles. Two bold headlands, the
Capo di Miseno (Promontorium Misenum) and
Punta della Campanella (Promontorium Minervae),
the horns of the great crescent, distinctly define its
two extremities, and islands at a little distance
from each well separate the bay from the open sea
beyond.
Although the form of the landward outline, as
shown by maps, is both irregular and angular, yet
distance so softens all the angularities that to the
eye the whole coast-line appears to be made up of
sweeping curves, in admirable proportion to their
backgrounds, as seen from whatever point of view
may be chosen. The principal central curves are
backed by two mountain masses, that of Vesuvius
THE SURROUNDINGS OF VESUVIUS. 63
and Somma, and that of Monte St. Angelo, behind
Castellamare, both rising to upwards of 4,000 feet,
Monte St. Angelo is 4,700 feet high, while the
lower heights towards the extremities of the bay
are rendered sufficiently bold by their proximity to
the water's edge.
Below the water-line, in the central part of the
bay, the shore has a very slight slope, corresponding
with the low plain on which Vesuvius stands. The
angle of the slope is only about i, increasing to 2,
and for a long distance out from land the bottom is
covered with mud of volcanic material, for not until
the deep water region between Ischia and Capri is
reached is it found to be sandy.
From every part of the surface of the bay a
perfect panorama of its surrounding shores may be
seen, since there is no large island to obstruct
the landward view. A day's cruise in a yacht on
the bright waters of the Bay of Naples may there-
fore be spent not only most enjoyably but most
usefully, for nothing will be better calculated to
impress the memory with the various prominent
points and elevations and with their relative dis-
tances apart. But Naples itself, at the extreme
northern corner of the bay, is most admirably
placed for commanding a prospect of the coast to
the south as far as the island of Capri, and
especially for a general view of Vesuvius.
The centre of the sea-front of the city of Naples
is about nine miles due west of the eruptive cone,
64 MOUNT VESUVIUS.
and therefore at a most suitable distance from
which to obtain a good general view of the entire
mountain and its more splendid and conspicuous
phenomena. This position, Santa Lucia, near the
Castel dell' Ovo, affords an excellent view, during
a favouring eruption, of the fiery rivers on the
north-western slopes, and here groups of people
each evening congregate to witness the grand and
striking scene ; the grander and more striking from
the dark plain of smooth intervening sea which
mounts the picture, while adding to its charms by
reflecting the glowing streams and the summit
fires.
But before the traveller, journeying from Rome
by Caserta in the evening, reaches Naples, he sees
from the railway train the fires and the smoke of
Vesuvius alarmingly near, and if he has never
before seen a volcano in eruption, wonders at the
indifference of the men employed on the line, whose
safety, as well as that of the Strada Ferrata itself,
appear to him to be very doubtful. The next morn-
ing, however, the newly arrived traveller has his
anxieties and fears greatly allayed, if not altogether
removed, for by daylight the scene is by no means
so terrific. Instead of fiery streams or sheets on the
mountain slopes, and a fiery glow above, the upper
part of the volcano is partly hidden by steam, which
rises from the lava on its sides, and culminates in a
towering column above the summit of the cone,
darkening as it rises, and, canopy-like, spreading
Plate VI.
RUINS OF THE TEMPLE. OF SERAPIS.
THE SURROUNDINGS OF VESUVIUS. 65
out above and overshadowing the whole. This
steam, which is given off by the flowing lava, and
rises from out the crater in immense volumes, has
the effect of obscuring the incandescent lava, and so
greatly lessening the scenic effect of an eruption
during the day, while it has quite the contrary effect
at night, for it then, by reflecting the glow below,
greatly increases the apparent size of the flows, and
gives a flame-like appearance at the summit.
And as the day advances, and the sun gets round
to the south, lighting up the margin of the bay and
the long line of white houses and buildings sepa-
rating the bright blue sea from the bright green
slopes, gently rising and studded with villas, there is
so much that is beautiful, so much that is peaceful,
bountiful, and smiling, that all wonder at Neapolitan
gaiety and indifference to the close proximity of a
volcano, and to at least ordinary eruptions, is
speedily dissipated. Even when actually on the
slopes of Vesuvius in eruption, one cannot fail to be
free from all fear, so exhilarating is the clear air of
this Mediterranean coast. The mind refuses to
think of possible evil or harm, and the spirit rejoices
in the actual, pleasurable present, when every step
is either among rich vineyards and gardens, or
amidst surroundings of the utmost novelty and
interest, while at every pause in the ascent the
delighted eye looks round upon a scene of striking
beauty, for it ranges over an expanse of sea and
land which, for variety and the picturesque outline
F
66 MOUNT VESUVIUS.
of its general features, as well as for brightness and
richness of colouring, is perhaps unsurpassed. The
elegant curve of the shore-line, extending from the
promontory of Misenum to the base of the rugged
heights above Sorrento, separates the blue waters
of the Mediterranean from the vine-covered plain
of the Campania Felix. On the right, the noble
city of the Siren with its long white arms embraces,
as it were, its own lovely bay, while the rocky isles
of Ischia, Procida, and Capri stud the azure surface
of the sea. On the left, and at our feet, lie the ruins
of once rich and populous cities that, with the other
remains of ancient greatness with which this part of
the classic land of Italy abounds, give an additional
charm to a most interesting, most remarkable, and
singularly beautiful portion of the surface of our
globe.
6 7
CHAPTER III.
THE MOUNTAIN.
Name Form Both Typical and Peculiar Five Parts The Lower
Cultivated Slopes The Desert Platform The Ridge of Monte
Somma The Great Cone The Crater.
HOWEVER great may be the interest attaching to the
Phlegrsean Fields and their extinct craters, to the
islands in the Bay and their volcanic structure, and
to the surroundings of the mountain, it is to Mount
Vesuvius itself that the attention of all is chiefly
directed.
Though the name appears in Latin authors as
Vesbius, Vesvius, and Vesevus, it is found as we
have it at present in the Greek of Strabo, who uses
the term Spos Ovfaovi'ov, and Diodorus Siculus employs
the name of the mountain adjectively in 6 rows ofaffotios.
To the northern portion the name Monte Somma
has been given, it is thought by some from a god
of nocturnal lightning and storm called Sommanus,
to whom a temple may have been erected on the
northern slope above the plain to the west of the
town of Somma. Frequently the name Monte
Somma is used by writers somewhat loosely, some-
times to designate the whole of the northern side
from the crest to the base, and sometimes as applic-
able only to the uppermost part of this side of the
mountain. It will be in the latter more restricted
68 MOUNT VESUVIUS.
sense that the term will be here employed, since the
lower slopes on every side are really parts of the
base of the same mountain, and the Italian word
" monte " is very generally applied and restricted
to an upper part of a mountain, and even to a peak
or summit only, as it is to the elevated points along
the crest of Somma itself.
The mountain mass to which the general name
of Mount Vesuvius is given, rises grandly on a
wide-spreading circular base of nearly thirty miles
in extreme circumference, to a height of upwards of
4,000 feet above the level of the sea. On all
sides but one it rises from the low, flat Campanian
plain, and on the remaining one, the south-western,
from the shore of the Bay of Naples. It is there-
fore an isolated mountain without connection with
any other, not even with the tufa hills of the vicinity
of Naples. Its form is, however, very unlike the
simple conical figure of volcanoes generally. Vesu-
vius is a peculiar and somewhat complex volcano,
and is therefore, apart from the frequency and
character of its eruptions, of much more than
ordinary interest to the geographer and the vulcan-
ologist, combining, as it does, the most interesting
features and characters of volcanoes generally.
The great peculiarity of Mount Vesuvius is that
there are two peaks of nearly equal elevation, each
of which is of a typical volcanic character. There
are consequently, as it were, two volcanic masses of
different types combined in one mountain, and they
THE MOUNTAIN. 69
are, moreover, representative examples of the two
great classes of volcanic mountains, the extinct and
the active.
One of the peaks is the highest point of a long
semi-circular or sickle-shaped ridge, having the
usual volcanic slope on its outward or convex side
continuous with the lower slope of the mountain
below, and a precipitous face on its inward or
concave side. It is therefore precisely analogous to
those great crater walls that surround the Calderas,
or extinct craters of the Canary and other volcanic
islands, whose fires have been long since extin-
guished, and there can be no doubt whatever as to
its being a portion of such a crater wall. To this
the name of Monte Somma is properly applicable.
The other peak is a typical conical one, with a
cratered and consequently truncated summit, and
this is the present eruptive cone of the volcano, the
summit of which, being now higher than the summit
of Monte Somma, is the summit of the whole
mountain.
These two uppermost portions of the great
mountain mass have, furthermore, a particular and
special relation to each other, for the conical portion
stands partly within the curve of the semi-circular
ridge, and on the centre of the circle of which this
ridge forms a portion. The cone is thus half
encircled by the ridge of Monte Somma, and conse-
quently the great crater of which Somma formed a
part must have been produced by volcanic action
70 MOUNT VESUVIUS.
proceeding from the same central vent as that of
the eruptions of the modern Vesuvian cone. It is
therefore evident that the two uppermost parts of
the mountain are but the productions of the eruptive
energy of the same volcano during two different
epochs.
As the bay is crossed from Sorrento to Naples,
the outline and form of Vesuvius appear gradually
to change. First there is seen a conical mountain
with a projection, or end of a collar, so to speak, at
each side of the upper portion, in consequence of
the cone from this point of view being in front of
the middle of the Monte Somma ridge ; and then,
as Naples is approached, more and more of the
high, sharp ridge of Somma comes into view on the
northern side, while the end of the ridge on the
southern side disappears, until at length two sepa-
rate and distinct peaks crown, mitre-like, the great
mountain mass. It is therefore from the city of
Naples itself that the characteristic form of Mount
Vesuvius is best observed.
The outline of the mountain, as seen from
Naples, is on its southern side a singularly graceful
curve, slightly concave, rising very gently from the
low grounds, and continued with a gradually in-
creasing inclination to the summit of the cone, with,
however, a protuberance or small elevation above
the line of the general curve, at about half way
to the summit, called La Pedamentina. On the
northern side, the outline corresponds with that on
THE MOUNTAIN. 71
the south for a considerable distance from the plain,
and then increases rapidly in inclination to the
summit of the ridge of Somma that stands on the
same level, and the outside of which is at the same
distance from the centre of the cone as the
Pedamentina.
The whole mountain may be described as con-
sisting of a great circular base or lower portion,
rising very gradually from the plain, and having
two comparatively small mountains standing upon
it, one a cone with a truncated, or, rather, rounded
or dome-like summit, over the centre of the whole,
and the other a semi-circular ridge, a little less in
elevation than the cone which it half encircles, and
to which it presents an opposing, precipitous, and
almost perpendicular face. And since the surface
of the great body or lower portion of the mountain
is conspicuously divisible into two areas, one
formed of the lower cultivated slopes and the
other being a platform-like expanse which is alto-
gether desert, for purposes of general description
five parts of the entire mountain may be consecu-
tively considered. These may be conveniently
designated as follows :
1. The Lower Cultivated Slopes.
2. The Desert Platform.
3. The Ridge of Monte Somma.
4. The Great Cone.
5. The Crater.
72 MOUNT VESUVIUS.
THE LOWER CULTIVATED SLOPES. The lower
slopes of the mountain spread out so widely and merge
so gradually into the flat land of the basal plain,
that it is difficult to draw an exact line of demarca-
tion between the plain and the foot of the mountain ;
but the length of the circumference previously stated,
nearly 30 miles, may be taken as a sufficient one to
include all that properly belongs to Vesuvius. With-
in this line the angle of the inclination of the land
is at first very slight, and it increases very gradually,
i, 2, 3, and so on, until about 10 or 12 may be
taken as the maximum general inclination of the
lower cultivated slopes. Many of the surrounding
towns and villages previously noticed are built on
the foot of the mountain itself, and the ring-road of
twenty miles connecting them is consequently some-
what above the level of and inside its extreme
circumference.
Above the ring-road, for a distance of about a
mile and a half up the slope of the mountain, extends
the region of gardens and vineyards, constituting,
with the similar area below the level of the road, a
zone of cultivated and highly productive land more
than two miles in width, and having an area of
about forty square miles. Except where seamed
with undecomposed lava or grooved by an eroded
gully or fosse, the surface of this extensive area
consists of deep rich soil.
The productiveness of the soils of volcanic dis-
tricts is due to the decomposition of volcanic
THE MOUNTAIN. 73
materials, which, containing silica, alumina, magnesia,
lime, potash, and iron, give to the soil formed from
them the substances which, with the carbon and
nitrogen derived from the atmosphere, furnish
abundantly the elements required for plant growth.
When the felspar of granitic rocks is decomposed
a bed of pure clay, kaolin, is produced, but the result
of the decomposition of the felspar of ordinary
volcanic rocks is a friable and easily worked soil.
This different result is caused by the associated and
disintegrated minerals in the case of granite being
refractory and distinctly crystallised, and conse-
quently easily separable from the argillaceous matter
resulting from the decomposition of the felspar,
which is left as a mass of clay, while in volcanic
rocks the associated minerals are intimately inter-
mingled and are themselves decomposable.
Occasionally, however, the decomposition of
volcanic material produces a clay, as in the case of
some trachytes, which are very largely composed of
orthoclase felspar. Indeed, so preponderatingly
felspathic is some trachyte, that it decomposes into
a white kaolin, as in one locality of the Roman Vol-
canic Region, where a clay derived from a trachyte
gives so white a colour to the soil around one of the
villages there that the place is named Bianca.
There is a very great difference, however, in
different districts both in the time required for the
formation of soil, and in its fertility when formed.
Augitic or pyroxenic lavas are more quickly decom-
74 MOUNT VESUVIUS.
posed and produce more fertile soil than trachytic,
in consequence of a more complex composition, and
their felspar being a lime instead of a potash felspar.
Dr. Daubeny states that the trachytic lava of
Epomeo, in Ischia, which was emitted in the year
1302, was at the time of his visit to that island quite
undecomposed, while the augitic lavas of the
Vesuvian eruption of 1631 were then covered with
rich soil forming luxuriant garden ground.
Lavas, too, in a vitreous condition are less easily
decomposed, and as pumice is but a mass of fibrous,
filamentose, or vesicular vitreous lava, it resists the
action of the atmosphere in an extraordinary man-
ner. The pumiceous lapilli of Pompeii, although
not trachytic as formerly thought, but of similar
chemical composition to the dark-coloured lavas of
Vesuvius,* is to this day quite unaltered, notwith-
standing the fact that from the spongose texture of
the material itself, and the loose and open character
of the accumulation, air and rain-water have been
freely admitted to it for more than 1800 years.
Pumice, too, dredged from great oceanic depths is
found to be quite unchanged.
As has been stated, volcanic soils are remarkably
well adapted for the growth of vines, from which the
choicest wines are produced, as well as for fruit
generally, and as evidence of how great may be the
growth of timber upon them, it may be here men-
* " On the Geology of Monte Somma and Vesuvius," by Dr.
Johnston Lavis, Quarterly Journal of the Geological Society ', vol. xl.
THE MOUNTAIN. 75
tioned that in the Forest of Carpinetto, on the flanks
of Etna, the Castagno di Cento Cavalli, or chestnut
of one hundred horsemen, has five trunks of 163
feet aggregate girth at a few feet above the ground,
and a diameter of about fifty feet. Within the
compass of the five trunks one of the Queens of
Arragon took shelter with 100 horsemen. There is
another tree here of twenty-five feet diameter, one
of eighteen feet, and another of fifteen feet.* Never-
theless, Brydone states that the Canon Recupero
told him he had calculated that 2.000 years was
required to form a scanty layer of earth on a lava.
This can only be explained, in face of the abundant
facts to the contrary, by supposing the Canon to have
referred to pumiceous deposits.
Rising conspicuously above the general slope
between Torre del Greco and Torre del Annunziata,
the elevation on which stands the convent of the
Camaldoli della Torre adds a wooded knoll to the
cultivated area, which is here, however, at each side
of the hill, considerably trenched upon by recent
lavas. The ground on which the convent stands is 600
feet above the level of the sea, and sufficiently above
the contiguous surface to ensure safety to both the
buildings and the trees from lava flows, which con-
tinue their course on one or both sides of the knoll.
At a higher level, but still well within the cultivated
region, the " bocche " or mouths of the eruption of
* " Etna," by G. F. Rodwell, page 39.
76 MOUNT VESUVIUS.
1 86 1 are seen more immediately above the town of
Torre del Greco, which suffered so severely from
the lavas they poured forth. They have a linear
arrangement radially extending down the slope for
nearly 700 yards between the contours of 900 and
800 feet above the sea-level.
The bare lava-rock of the 1861 eruption will be
found extending from the bocche to Torre del Greco,
and near it that of the eruption of 1794, which flowed
from bocche at a considerably higher level, from
about 1,200 to about 1,500 feet. Near and around
the Camaldoli are the lavas of 1804, 1805, and 1806,
while in the neighbourhood of Bosco tre Case the
lavas of 1850 are met with. Further east, the great
flow of 1834 is seen occupying a large area, and
extending as far as Caposecchi, quite at the junction
of the foot of the mountain with the plain, a distance
of nearly four miles and a half from the point of
emission.
On the western side the equally long but narrower
lava-flow of 1855, after passing between Massa di
Somma and San Sebastiano, reaches almost to
Cercola, and the last great flow, that of 1872,
branching westwards from the same course as that
of the 1855 lava, spreads out and terminates at Le
Novelle de Resina.
These lava-flows and older ones now concealed
under those of more recent date, or beneath the
result of their own surface decomposition, the deep
rich soil of the cultivated area, have chiefly flowed
THE MOUNTAIN. 77
from the upper portion of the mountain through
four hollows, or ravines, called " fosse." They are
the Fosso Faraone on the west, at the end of the
Somma ridge ; the Fosso Cupaccia on the east, at the
other end of the ridge ; and, furrowing the south-
western slope, the very important intermediate
Fosso Grande, with the Fosso Bianco above Torre
del Greco. But the emission of lava in 1631 was
so copious that it formed no less than seven wide
floods, which, spreading as they descended, covered
several large areas extending to the sea, with lava-
rock. This lava, except where cut through or
exposed at the sea-shore, is masked by the soil it
has produced, and the area devastated has conse-
quently been restored to cultivation.
The cultivated ground of the lower slopes below
the protecting ridge of Monte Somma differs from
that on the unprotected side of the mountain, in
being quite free from recent undecomposed lava-
rocks intersecting the vineyard land, and also in
rising to a much higher level. It is, however,
traversed in its lowest parts by eroded furrows,
called " lagne," and in its upper part by the more
important and deeper " vallone." These latter are
numerous, upwards of thirty being named along
the whole length of five miles. At the western
end there are the Vallone della Vigna, the V. del
Piano, the V. del Sacramento, and then the V.
Cancherone and the V. Gaude are followed by the
Vallone di Castello, in which is situated on an
78 MOUNT VESUVIUS.
eminence Santa Maria di Castello. Near the
town of Ottajano are the V. Fosso dei Leone,
the V. di Palmenticello, the V. Constantinopoli, the
V. del Bosco, the V. Scuro, the V. di Sanseperino,
and the V. di Pietra Pomice. Still further, there are
the V. della Trofa, the V. Casella, the V. degli
Spiriti, the V. Cutolo, the V. di Recupo, and the V.
Mazzamei, followed by the V. Nascosto, the V.
Tagliente, the V. dei Cerri, the V. di Nicolo, the
V. della Profica, and the V. di Cola, and at the
extreme end of the ridge, at the Bosco di Cupaccia,
there is the widest one of all, called the Vallone
Grande. In this region, on the slopes in the neigh-
bourhood of the town of Somma, a lofty elevation,
called Monte Saint Angelo, rises to a height of
1,476 feet above the level of the sea.
THE DESERT PLATFORM. The desert region
forming the platform on which stands the great cone
of Vesuvius has a surface sufficiently level to be
called a plain, or " Piano," and it is doubtless in con-
sequence of the slope being here so little that it
presents the barren and desolate appearance in such
striking contrast to the aspect of the cultivated area,
since lavas from the cone have in the case of
moderately large flows spread over the surface, and
so cooled and solidified, without extending to the
lower slopes, and in the case of small streams the
movement has been so slow that rapid solidification
has confined the lava to the piano. Thus this com-
paratively level area has been so frequently covered
THE MOUNTAIN. 79
with fresh lava that there have not been sufficient
intervals of time for decomposition to affect its sur-
face, and accordingly it has been continuously an
area of hard, undecomposed lavas.
The Desert Platform has a circuit of about seven
miles, one portion having a width of a mile and a
half, and the other, that between the foot of the cone
and the base of the precipitous rocks of Somma,
of only a quarter of a mile. Nothing can well be
more distinct and conspicuously marked, except
perhaps the division between land and sea, than
the differentiation of the cultivated land and the
region of undecomposed lavas. On one side of a
wall a most productive and highly cultivated vine-
yard may be found, and on the other a desert of
hard black rocks, without a trace of vegetation.
The whole of this portion of the mountain surface
is clearly divisible into two parts, one the area lying
between the foot of the great cone on its northern
and eastern sides and the ridge of Monte Somma,
and the other that on the southern and western
sides of the cone, and unbounded by an exterior
enclosing ridge.
The last-mentioned area is a very extensive one,
being about five miles along its outer curve and a
mile and a half across, thus giving an area of nearly
seven square miles. The commencement of the piano
is about 1,500 feet above sea-level, and the base of
the great cone 2,500 feet, so that the difference
of level between the lower and the higher
80 MOUNT VESUVIUS.
boundaries is 1,000 feet, while the breadth may be
taken at 8,000 feet. This shows a mean inclination
for a very large section of the surface of the moun-
tain side of only i in 8, or 7. This large area is
called La Plaine, and a portion towards the edge is
named the Piano del Ginestre, which, terrace-like,
overlooks the south-western seaward slopes below,
with the towns of Torre del Greco and Resina, and
to the right Portici, with its palace and beautiful
gardens and park on the lower ground extending
to Granatello next the sea. To the south-east of
the Piano del Ginestre the Pedamentina rises above
the general level of the edge of the platform, and
so forms a shoulder on the Vesuvian profile, as
seen from Naples.
On the northern side of the Piano del Ginestre,
but separated from it by the Fosse Grande, rises a
conspicuous ridge-like hill of great interest, for on
this elevation stands Professor Palmieri's celebrated
Vesuvian Observatory, containing his seismographic
apparatus, and at a little distance is the Hermitage
and the ancient chapel and shrine of St. Salvatore,
while at the extreme end of the ridge fronting the
great cone is a cross, " La Crocella." The summit
of the hill where the Observatory stands is 2,080
feet above the level of the sea, and at this
level, at the Hermitage, is a well of good water.
The Hermitage is a convenient stopping-place,
a sort of half-way house to the summit, where
a mule may be stabled, and both water and the
Plate VII.
FIG. I. VIEW OF VESUVIUS FROM SORRENTO.
Fic.2 VIEW OF VESUVIUS FROM NAPLES.
=:^~iiSg
Fio.3.ViEW OF VESUVIUS FROM NOLA.
THE MOUNTAIN. 8 I
ordinary wine of the country, if not Lachrymae
Christi also, may be procured.
On one side of the hill the Fosso della Vetrana re-
ceives flowing lava from the north side of the cone, and
conveys it to the Fosso di Faraone below, and on the
other side the Fosso Grande similarly receives the
fiery floods from the western side. Sometimes, too,
a large flood of lava is divided by the Crocella end
of the ridge into two flows, one of which enters the
Fosso della Vetrana, and the other the Fosso Grande,
with the hill and its crowning Observatory standing
quite unscathed between. Thus it is rendered pos-
sible for Professor Palmieri to remain at the Obser-
vatory night and day during even a very violent
eruption, such as that of 1872, and, as an intrepid
soldier of science, with a sheet of red-hot lava on
each side, to brave their dangers, as well as those of
projectiles and possible fissures, in order to observe
and record the ever-changing aspects and phases of
a great eruption.
The Observatory is a handsome and cheerful-
looking building of white stone, affording a welcome
relief to the eye in this region of black lava, and
inviting the visitor by its appearance to enter and
inspect the ingenious and delicate instruments by
which the Professor is notified of every tremor and
palpitation of the heart of old Vesuvius. (See
Appendix.)
The shrine of S. Salvatore, where is entombed
the body of the saint, is a very ancient one, and it
G
82 MOUNT VESUVIUS.
has been suggested that possibly at this place stood
a temple to the god Sommanus, from which deity
Monte Somma is supposed to obtain its name. La
Crocella, the Italian word for a little cross, by which
the wooden cross at the end of the ridge is known,
is often used as a name for the hill itself, though it
is also frequently called the Observatory Hill, and
sometimes the hill of San Salvatore.
Extending round the northern and eastern sides
of the great cone, and hemmed in by the lofty and
frowning precipitous rocks of Monte Somma, is
situated the second of the two divisions of the
desert platform of the mountain. To this weird-
looking, deep, and perfectly desert, but almost
regularly semi-circular valley, the general name
of Atrio del Cavallo, or the court of horses, is
given,* though its eastern and somewhat more
restricted end is specially called the Valle dell'
Inferno, or sometimes the Canale del Inferno.
Throughout its entire length of upwards of two
miles the valley has an approximately level bottom,
with an elevation, above the level of the sea at
the end opposite the Crocella of 2,624 feet, and
at the Valle dell' Inferno, near the eastern end, of
2,493 feet, or only 131 feet of difference in the two
miles.
From the peculiar structure and position of the
* Since horses used in the ascent of the mountain were frequently
eft here in consequence of not being available for the ascent of the
Cone.
THE MOUNTAIN. 83
Atrio del Cavallo it forms a most conveniently placed
receptacle for all lava flows from the northern side
of the cone, and these, by their separate solidification,
have formed floor above floor, and so a modern level-
topped mass of lava-rock of considerable thickness
has been accumulated between the foot of the great
cone and the bottom of the concave side of the ridge
of Monte Somma. It has been estimated that there
is a thickness of fully 100 feet of such lava-formed
rock in the Atrio del Cavallo at the base of the
Somma cliffs, by which their height above has been
correspondingly diminished.
THE RIDGE OF MONTE SOMMA. It is not too
much to say that, although the Somma ridge has a
structure that is typically volcanic, and quite similar
to that of the walls of insular calderas and other
extinct volcanic craters, yet it is unique in its com-
bination of elevated position, limited extension, and
abrupt termination at each end.
Standing at an elevation of about 2,500 feet
above the level of the sea, and commencing and
terminating with lofty elevations, this old crater wall
does not extend further than less than half way
round the circle of which its curved outline forms a
part. The length of the inner semi-circular face of the
ridge, from the commencement at the western end,
near the Crocella, to the eastern end of the Valle
dell' Inferno, is two miles, and the general height
of the middle part of this face above the level of the
Atrio del Cavallo is about 1,000 feet. The highest
84 MOUNT VESUVIUS.
point is called the Punta del Nasione, which rises to
3,730 feet above the level of the sea, and near to it
on one side is Monte Ottajano, 3,653 feet, and on
the other, Monte Trocchia, 3,582 feet. At the
Crocella end the Primo Monte rises to 3,149 feet,
and the two prominent highest points between
Monte Ottajano and the eastern end have elevations
of 3,471 feet and 3,084 feet respectively.
It will thus be seen that the crest of Monte
Somma is a serrated ridge with an almost vertical
face on its inner concave side, and a sloping face
on its exterior convex side. The exterior slope is
roughly parallel with that of the great cone, the angle
of inclination corresponding with that of volcanic
cones generally, and in distant pre-historic ages this
was probably a part of the slope of a cone that
towered far above the present elevation of the
mountain. Though the crest of Somma has not
been affected by volcanic action for 1,800 years, yet
it has been subjected to those continually acting
weathering influences that gradually erode and wear
down the topmost heights, and furrow the sloping
sides of all mountains. Hence the exterior slopes
of the ridge are sculptured with furrows commencing
from between its highest points, and extending down-
wards to the vallone of lower levels. Weathering
action has also removed all the loose materials from
the loftiest parts, by which the uppermost slopes are
rendered bare of all vegetation, but in many places
woods and trees occupy very high ground, and even
THE MOUNTAIN. 85
vineyards may be found at elevations above the
2,500 feet contour.
THE CONE. The present eruptive cone of
Vesuvius, the seat of the visible phenomena of
our day, is the part of the mountain that is of
especially great interest. Compared with the whole
mountain mass it is a minor portion, but it is never-
theless of very considerable dimensions, having a
base of about three miles in circumference, and an
altitude which may, perhaps, be stated as being
now normally about 1,500 feet, though this may be
much reduced by a more than ordinarily violent
eruption, while every small eruption adds to the
height and tends to complete the apex of the
cone.
Much misconception exists respecting the steep-
ness or angle of inclination of the slope of the
sides of the cone. This is in a great measure
due to the ascent being made in a direct line to the
summit, there being no pathway, either winding or
zigzag, to enable the climber to avoid facing the
slope which, rising directly in front of the eye, has,
consequently, the effect of appearing to be much
steeper than it really is. The impression of great
steepness is deepened by the character and con-
dition of the materials of which the surface of the
cone is composed, for the loose, dry scoriae yield
to the tread, and so each individual stride is made
both longer and steeper, while the momentum of
the body's upward motion is diminished, and
86 MOUNT VESUVIUS.
progress consequently rendered much slower and
more laborious than if the tread were on firm
ground, while the vertical faces of the larger masses
standing above the general slope increase the
apparent steepness of the whole.
The inclination is, however, only an ordinary hill-
slope, not nearly so great as that of many hills and
mountains in England that are not unfrequently
ascended without being considered of extraordinary
steepness. The angle of the slope has been
repeatedly measured, and found to range from 30
to 40. By careful measurement with pole and
clinometer it was found by myself to be 40 at the
steepest part of a direct line from the Atrio del
Cavallo to the summit, and even this moderate
angle of inclination may have been caused by tem-
porary local conditions, since it sometimes happens
that a very small flow of lava cools on the slope and
so entirely solidifies before reaching the foot, and
thus a local and temporary increase of the normal
gradient may occur along a portion of some one
meridian, so to speak, of the cone. The majority of
measurements appear to give 34 as the mean
normal angle of the general slope, which slightly
increases towards the summit. Yet published state-
ments of the angle of inclination are frequently
incorrect. Soon after the construction of the
Funicular Railway from the base to the summit of
the cone, it was stated in a journal of great
authority that the inclination of the line was 40,
THE MOUNTAIN. 87
increasing to 63, and was at 50 at the uppermost
part !
The size and steepness of the Cone of Vesuvius
may, perhaps, be better realised by a comparison
with the well-known conical elevation of north-
western London, Primrose Hill, which stands on a
base about one- fourth as large, but is only 100 feet
in height, and has an upper slope of 10.
The summit of the Cone, and of the whole
mountain, can only be described as variable and
almost constantly varying, since it is altered or
modified by every eruption, and indeed by even
slight activity not sufficiently pronounced to be
called an eruption, while its loose materials are acted
upon by weathering agencies when volcanic action
is quite dormant. Slight activity when prolonged
sometimes fills or nearly fills the crater with lava,
when the weight of the fluid mass may break down
a portion of the encircling rirn, and so cause a de-
pression on one side, over which the lava will flow.
An opening through the side of the cone, by
giving a lower way of exit for the lava, then reduces
its height in the volcanic tube, and so empties the
crater of lava, but at the same time, together with
ashes, semi-fluid or plastic masses are ejected that,
cooling as they descend, fall as solid scoriae around
the central vent, and so very soon a small cone is
there formed, which, gradually growing from the
accumulated ejectamenta of continuous or inter-
mittent slight activity, may in time rise as high as
05 MOUNT VESUVIUS.
the level of the crater walls, with but a small open-
ing at the apex. A subsequent moderate eruption
removes this small new cone, throwing its materials
high into the air, and then commences the formation
of another but larger cone inside the great crater
that speedily increases both in height and bulk until
it overtops the surrounding crater rim, and even fills
up the intermediate circular hollow.
This last-formed cone is left with a crater of con-
siderable dimensions, the walls of which will then
furnish loose material that on the subsidence of the
lava falls into the volcanic tube and chokes it up,
and a floor of such material is subsequently formed
for the crateral hollow, on which may, perhaps, be
found one or more fumaroles giving off sulphurous
acid, carbonic acid, or other gases and fumes.
So the summit may remain until a violent eruption
removes all the infilling of the volcanic tube, all the
floor and all the walls of the last-formed crater, all
the accumulated material in the great crater, and even,
in the case of an unusually great or " paroxysmal"
eruption, part of the walls of the great crater
itself, and so reduces the total height of the
mountain.
Thus it is that the summit of the Vesuvian cone,
from the frequency and great variability of character,
duration, and intensity of the eruptions, possesses
an unusual amount of interest, and thus it is, too,
that the height of Vesuvius above the level of the
sea can only be given approximately, the elevation
THE MOUNTAIN. 89
of one year being liable to be altered the next by
even hundreds of feet, as was the case in 1821 and
1822, when the great cone was diminished in height
by 800 feet, reducing it to only the lower half of a
complete cone.
A point on the rim of the great crater, on its
northern side, has had a rather prolonged existence,
and it has therefore been regarded as an approxi-
mately fixed point. This is the Punta del Paolo,
which owes its continuance to being a point at the
side of a depression on the rim of the crater of the
greater eruptions, which can only be enlarged and
the Punta destroyed by a paroxysmal eruption of
much more than usual violence. Its elevation is
given as 3,949 feet. It may, however, be over-
topped, as before stated, by a new cone formed by
moderate eruptive activity, and in this case a small
terrace may be formed on a level with the Punta
surrounding the new cone. Thus the side of the
cone may in its profile show an angle near the sum-
mit, the uppermost portion being formed by a new
cone, which may rise to perhaps 300 feet above the
level of the Punta del Paolo, as was the case in 1868,
when the extreme height, according to Palmieri, was
4,255 feet.
An interesting list of measurements of the eleva-
tion above sea-level of the Punta del Paolo was
given by Prof. J. D. Forbes in his "Physical
Notices of the Bay of Naples,"* and, with the
* Brewster's Edinburgh Journal, 1829.
QO MOUNT VESUVIUS.
heights stated in English feet, may be here
reproduced.
Feet.
Saussure, 1773, barometric measurement . . 3894
Poli, 1794. . .. .. .. . . 3875
Breislak, 1794 . . . . . . . . 3919
Gay Lussac, Von Buch, and Humboldt, 1805 . . 3855
Brioschi, 1810, trigonometric measurement . . 479
Visconti, 1816 .. .. .. ... 3977
Lord Minto, 1822, barometric measurement . . 397 1
Scrope, 1822 . . . . . . . . 3862
Monticelli and Covelli, 1822 . . . . . . 3990
Humboldt, 1822 . . . . . . 4022
THE CRATER. The crater is the most character-
istic part of a volcano, proclaiming at once the
igneous origin of the mountain, however quiescent
it may be, even, indeed, when there are no volcanic
rocks around, as in the case of the remark-
able crater of the Meerfeld, in Germany, which
is surrounded by slatey rocks. Craters pro-
duced by single eruptions, as that of Monte
Nuovo and others in the Phlegraean Fields, as well
as those of the Eifel, in Germany, are perfectly
simple circular cup-shaped hollows with more or
less lofty walls ; but the Vesuvian crater is by no
means so simple, for it is scarcely too much to say
it is almost constantly changing. Sometimes, it is
true, it is a great cup-shaped hollow, but it does not
long remain so. The process of alteration, as pre-
viously stated, at once commences, and more and
more complexity follows, until sometimes it is not
merely double, but treble, and quadruple, and even
as many as five craters have been found within the
great crater-rim, as was the case in 1884.
THE MOUNTAIN. 9!
The eruptive crater of any eruption of Vesuvius
is only coincident with the great crater when the
eruption is an unusually violent one, which removes
all internal cones and crater-walls, and leaves but
a single deep as well as wide crater, with steeply
descending sides. After a series of moderate and
small eruptions, the floor of the crater may be a
level bed of solidified lava, with but low walls
around, and a small cratered cone rising in the
middle or near one side. Sometimes, too, when
such a floor has been formed, an opening or fissure
may be produced by the falling in of a portion,
and sometimes two craters, divided only by a wall,
may be seen side by side, and sometimes, too, a
small crater or bocca may open on the crater-rim
itself. When a passage in the side of the cone
allows of the discharge of the lava at a lower level,
the brim of the eruptive crater may be quite con-
tinuous and regular in height throughout the entire
circumference, but frequently it is lower at some
part from having given way to the pressure of the
lava within, and a lip is formed, over which is then
poured the fiery flood. Rents or fissures may also
cause indentations in the rim, so that the bounding
wall of the crater of a lava-emitting volcano is
rarely quite uniform or regular in height all along
the circumference of its rim.
The Vesuvian crater, like those of the great
majority of volcanoes, is a true summit crater,
but there are some notable instances of lateral
V 2 MOUNT VESUVIUS.
craters. The great crater of Kilauea, in the island
of Hawaii, is on the side of Mauna Loa, 10,000 feet
lower than the summit of the mountain, which,
indeed, has another crater ; and the constantly
active crater of Stromboli is also on the side of
the cone, though nearly at the summit. At Etna
the great depression on the mountain side, called
the Val del Bove, has been a lateral crater, but
the present eruptive crater of this great volcano
is at its summit.
Small temporary crater-mouths (bocche or " voc-
cole ") have been frequently opened on the side of
Vesuvius, of which those formed during the erup-
tion of 1794, at about 1,500 feet above the level of
the sea, and those of 1861, of only 800 feet eleva-
tion, are notable examples.
Much interest is given to the interior of the
eruptive crater by the fumaroles from which issue
gases and steam, and on and about which subli-
mations are abundant and beautiful. During
quiescent or normally uneruptive periods, or even
during times of slight activity, there is no difficulty
or danger in entering and inspecting the interior of
the crater. Those who ascend Mount Vesuvius at
such times, and who do not therefore witness the
grand spectacle of an eruption with its impressive
phenomena, have the, to some extent, compensating
advantage of being able to closely inspect the
interior of the crater, the mouth of the volcanic
vent, and observe thereby many interesting volcanic
THE MOUNTAIN. 93
phenomena that cannot be seen during a great
display of eruptive energy.
Thus it will be found that each of the five divi-
sions of the surface of Vesuvius presents peculiar
and special features and characteristics of great
scientific as well as general and scenic interest,
which combine to render this volcano, even when
quiescent, perhaps the most interesting mountain in
the world.
94
CHAPTER IV.
HISTORY TO 1850.
Numerous Records The Pre-Historic Volcano Vesuvius Dormant
Recognition of Igneous Indications by Ancient Writers
Renewal of Activity Destruction of Pompeii Formation of the
Cone Mediaeval Eruptions Eruption of 1631 Eruptions of
Modern Times.
THE peculiar and remarkable structure of Vesuvius
is consequent upon a remarkable history, the earlier
chapters of which can only be read by a study of the
rocks of the older portions of the mountain, but its
later, and especially its latest, epoch has had
numerous historians, some it is true of little power
of accurate observation, but many were both accurate
observers and graphic narrators. From Diodorus
Siculus to Monticelli a long list of names of obser-
vers and recorders of Vesuvian phenomena could be
given, whose accounts have furnished materials for
a most interesting and instructive record of the
eruptive energy of the world-famed Campanian
Volcano during the last eighteen hundred years.
These accounts were collected by Dr. Daubeny,
who collated them in the second edition of his
" Volcanos " (1848), and a summary of this was
given by Sir Charles Lyell in the " Principles of
Geology." This history was succinctly reproduced
HISTORY TO 1850. 95
by Prof. Phillips in his work on Vesuvius in 1869,
with an extension bringing down the record to the
year 1868.
Although the phases passed through during the
earlier periods of the volcano can only be de-
duced from a knowledge of its geology, yet the
general configuration and structure of the mountain
conspicuously indicate the existence of a pre-historic
volcano of a simple conical form and of large dimen-
sions, one with a base of nearly equal circumference
with that of the present day, and an altitude far exceed-
ing the greatest elevation of the summit during
modern times, probably seven thousand feet.
This great pre-historic volcanic mountain must have
been reduced in height by, it may be, one, or, it may
be, by more than one great and paroxysmal eruption,
that at the same time increased the size of the crater,
leaving a vast area enclosed by an amphitheatre of
rocks seven miles in circumference, with precipitous
sides rising to a height of upwards of a thousand feet.
Thus the mountain remained during many centu-
ries without any display of volcanic activity, its long
sleep continuing through the Roman period until the
first century of the Christian era. Indeed, at the time
of the Second Servile War, the crater supplied a
place of refuge for Spartacus and his followers, who
encamped within its lofty protecting walls.
During this prolonged epoch of dormancy the
form of the mountain was very different from that
which in our times attracts the eye by its picturesque
96 MOUNT VESUVIUS.
yet beautiful outline. Insteadiof a grandly swelling-
cone and a sharp serrated ridge standing on a
widely spreading base, there was a simple truncated
cone of great width and comparatively small height,
for the present eruptive cone did not then exist, and
the semicircular ridge ofSomma of our day extended
round the area on which the cone now stands,
forming an irregular circle, and being the old
crater-wall of the pre-historic volcano.
Vesuvius would consequently at that time appear
from a distance as a broad circular mountain with an
irregularly horizontal summit, a " table mountain " in
fact, and it was only by an ascent to its top that
the crateral cause of the low truncation of the wide-
based cone could be ascertained. But those who did
make the ascent to the rim of the old crater, and
then descended the steep and rugged walls, found
the arena, so to speak, of the great amphitheatre to
be a bare and sterile plain, but the enclosing sides
of lofty rocks to be covered with wild vines extend-
ing from the top to the bottom.
Little wonder, therefore, that the great mountain,
so prominent as a land-mark to the gubernatores of
Roman galleys, and that rose so gracefully, yet so
majestically above Pompeii and Herculaneum at but
a few miles from Neapolis, was not then generally
known to be volcanic. To us moderns, however,
with our extended knowledge, the structure of the
mountain and the rocks of Somma at once reveal
the volcanic origin of the whole^and clearly show
Plate VIII.
FIG I. VESUVIUS IN THE PRE-HISTORIC PERIOD
FIG. 2. VESUVIUS IN THE CLASSICAL PERIOD
LONDON ;ROfJiz<OHOn'ULr, H ttWMnNTtt.ee
HISTORY TO 1850. 97
that although the volcano had been dormant for
many centuries, yet at a pre-historic period, erup-
tions perhaps more terrific than any that have
been recorded since the renewal of its activity, had
covered its sides with red-hot lava, and had ejected
scoriae and ashes in immense quantities from a crater
many times the size of the present one.
But there were not wanting amongst the observers
of Nature of the ancient world some who saw, or
thought they saw, indications of previous volcanic
fires and eruptive action. Among the writers of
antiquity who noticed or suspected the volcanic
character of Vesuvius, the most notable were
Diodorus Siculus and Strabo. The former of these
ancient observers, a native of Agyrium at the foot
of Mount Etna, was born on volcanic ground, and
two eruptions of the great Sicilian volcano occurring
during his lifetime, he was well fitted to detect
the signs of volcanic action. These signs he
observed at Vesuvius, and was thus the first to
read in its rocks the igneous and volcanic character
of the mountain. In his fourth book he says, " The
entire district was called Phlegraean, from the culmin-
ating point, which is now called Vesuvius, bearing
many indications of having given forth fires in
ancient times." *
Subsequently Vitruvius, in writing on the tufa of
' tlvopavdai. Se KCU TO Trediov TOVTO (p\eypaiov drro rov \6<povrovro
irabmov im\frov nip eKcpvawvTos, irapa7r\r)<ria)S rr) Kara TTJV VtKcMav A.?TVTJ.
e vvv 6 TOTTOS Oueaowos, e'xuv TroXXa o^/ieia TOV K<aiicr6ai Kara
TOVS
H
98 MOUNT VESUVIUS.
Pozuolli, mentions a tradition that fire had at one
time been seen coming forth from Vesuvius. Strabo,
however, like Diodorus Siculus, inferred its volcanic
origin from the appearances presented by the rocks
around the crater.*
The year 63 of our era witnessed the earliest
indications of renewed activity, and in the early
part of that year, we are told by Seneca, that an
earthquake occurred, which destroyed a consider-
able portion of both Herculaneum and Pompeii,
and shook all the district surrounding the mountain.
In the following year, a second earthquake caused
considerable injury to the city of Naples, and it is
said that the theatre, in which the Emperor Nero
had been performing a short time before, was
thrown down. These premonitory symptoms were
followed, during the reign of the Emperor Titus,
and in the year 79, by the famous eruption which
not only destroyed two flourishing cities and com-
pleted the ruin of a third, but altogether altered the
form and appearance of Mount Vesuvius. As this
* In his fifth book of Geography (E. 4, 8) Strabo writes :
N<a\r)s de Kal NouKepiu? <al 'A^eppcoi/, 6/xooi/up.ou KaroiKias TTJS TTfpi Kpe-
PCDVU, 7riVftov eorti/ T) Ilo/iTT^/a, TTiipd TO) 2upi>a) TroTa/jLOi KOI Se^o/xeVi) ra
(popria KCU fKTT[J.7rOVTl. VTTfpKeiTO.1 $6 TtoV TOTTO)!/ TOVTCOV OpOS TO Qv(TOVlOV
dypois TTfpioiKovfjLevov nayKiiXois 7T\r)v TTJS Kopvfpfjs' avrrj S' eViVfSoy peV
TroXv /ip os '0TtX aap7Tos S' oXrj, e< 8e TTJS fyfus Tecppufys, <al KoiXudas
(baivei (TTypayycoSeis Trerpa)!/ at^aXcoScoi/ Kara rr\v ^poaj/, <uy av oc/3e/3pa>aeVcoz/
UTTO TTUpdy, a)? re*:p,atpotr' av TIS TO ^apiov TOVTO KateaQai nporepov Kal
X. fli> ^pdT^paj Trvpos, &l3f(rdr)vai S' 7rt hnrovcrijs TTJS V^TJS. rd^a de /cat
rrjs fiiKapnias rf/s KVK\<J) TOVT' a'inov, axnrfp fv rfj Kardvrj, (paai, TO Kara-
re(ppai6ev p.pos t< rrjs (nrodov rrjs dveve^deia-rjs VTTO rov AtVi/aiou nvpbs
rip yrff eVotijcrcv.
HISTORY TO 1850. 99
eruption was such an important one, not only from
the appalling results which followed, but also from
its having been the first of the long series of
eruptions which have interested and astonished
the world during the historic period, the letters con-
taining the account by Pliny the Younger, who was
an eye-witness of the awful scene, and whose uncle
was one of those who perished by the catastrophe,
are given in the Appendix to this work.
It will be remarked that in Pliny's narrative
there is no mention of lava having been seen, and
this is quite in accordance with the results of
modern observation, which has not detected any
bed of lava of the same age as the lapilli which
overwhelmed Pompeii. It appears, therefore, that
this great eruption was one of fragmentary ejecta-
menta, and that the melted rock which is given
forth in modern times^Hurmg eruptions was then
entirely wanting.
An examination of the material covering the
ruins of the ancient city will show that the bulk of
the Vesuvian ejectamenta which obscured the light
of the sun as completely as Pliny describes, and
burying the city of Pompeii destroyed it for ever,
was light, grey, pumiceous lapilli, evidently quite
dry at the time of its fall, since it is now in a
perfectly loose and uncompacted state. The present
condition of the numerous frescoes with which the
houses of the wealthy inhabitants were adorned
affords further evidence of this dryness, the
IOO MOUNT VESUVIUS.
colours of these, in many cases, beautiful decorations
being comparatively fresh and uninjured.
It is probable, however, that at a later period of
the same eruption, ashes and lapilli mingled with
water condensed from the volcanic steam, formed a
flood of mud, since the city of Herculaneum is
buried beneath a mass of consolidated tuff, and not
as Pompeii, simply covered with loose ejectamenta.
This great eruption left the mountain with only half
of the walls of the ancient crater remaining, the
sides on the south and west having been almost
completely destroyed.
It was now that the foundations of the modern
cone of Vesuvius began to be laid, and thus was
commenced the building up of the present great
central feature of the whole mountain mass, the
Great Cone. Successive ejections of fragmentary
matter accumulated material in the central cavity of
the old crater, and so formed what would be an
inverted cone, then a double cone, until at length a
large eruptive cone was built up, which, continu-
ing to increase by the aggregation of the ejecta
of successive eruptions, ultimately attained an ele-
vation exceeding that of the rim of the old great
crater, and thus has been produced the double-peaked
mountain of the present century. There was,
however, left on the southern and western sides
remnants of the wall of the old crater, and one, even
to the present time, is seen as a protuberance on the
side of the mountain, and forms the elevation at the
HISTORY TO 1850. 101
edge of the desert area named, as previously
stated, the Pedimentina, while another constitutes
the ridge on which stands Prof. Palmieri's obser-
vatory.
It may well be imagined that what has been
called the Plinian eruption, with its horrors and
devastating consequences, produced such a deep
and lasting impression that for a long period
ordinary displays of eruptive energy would appear
to be comparatively insignificant and unworthy
of special record ; and indeed Dion Cassius, writing
in the third century, gives expression to this view.
It is to be remembered also that the depth of the
crateral cavity left after the great eruption would
be so profound that much eruptive phenomena
might occur that would not be visible, or at least
conspicuous, above the summit of the surrounding
walls. Thus frequent eruptive activity may have
occurred in the early centuries of the Christian era
without being recorded, and consequently the history
of Vesuvius must be regarded as being but an
incomplete one.
The earliest renewed outbreak of which some
account is extant was that of the year 203, which
was described by Dion Cassius as a great confla-
gration. In the year 472, however, there was an
eruption which must have been of paroxysmal
violence, since it destroyed the villages that had
been built over the buried cities of Herculaneum
and Pompeii, and ejected ashes to so great a
IO2 MOUNT VESUVIUS.
distance that it is said some fell as far from the
mountain as Constantinople.
During a period of nearly six hundred years
following, only three eruptions are recorded. These
were in the years 512, 685, and 993. The first is
recorded in Procopius' " History of the Gothic
Wars," the translation of which by Sir Henry
Holcroft in 1653 gives the following quaint passage:
" At the top is a deep cave, seeming to reach to the
bottom of the mountain ; and if you peep in, you
may see fire, which ordinarily keeps in, not troubling
the people. But when the mountain bellowes like
an ox, soon after it casts out far away a large quan-
tity of cynders, which catching a man upon the way,
he hath no means to save his life."
The eruption of 1036 is important geologically,
since the first lava-flows of the Historic Period
appear to have been emitted at this time, and
to have been so considerable as to have reached
the sea.
There are reports of eruptions in 1049, 1138,
and 1139 ; but after the last-named date, for about
five hundred years, there does not seem to have
been any important outbreak. But during this
period of Vesuvian quiescence, when, according
to Sir William Hamilton, " the top of the moun-
tain began to lose all signs of fire," volcanic action
was very violent in the neighbouring districts.
Several eruptions of Etna are recorded ; the Solfa-
tara as well as the volcanic island of Ischia poured
HISTORY TO 1850. IO3
forth streams of lava of great volume ; and the
northern as well as the southern portions of Italy
were convulsed by earthquakes. It was, too,
during this season of the comparative repose of
Vesuvius that occurred the extraordinary volcanic
phenomenon of 1538, for it was in this year that
Monte Nuovo was thrown up.
For a long time previous to the great eruption of
1631, the crater of Vesuvius contained so much
vegetation that it became the resort of w r ild boars,
and cattle grazed on the plain at the bottom.
" Within the crater/' writes Bracini, " was a narrow
passage, through which by a winding path you could
descend about a mile amongst rocks and stones, till
you came to another more spacious plain covered
with ashes. In this plain were three little pools
placed in a triangular form one, towards the east,
of hot water, corrosive and bitter beyond measure ;
another, towards the west, of water salter than that
of the sea ; the third of hot water, that had no
particular taste."
At the end of the year 1631 commenced one of
the most important of the modern eruptions of the
Campanian volcano. In this year the great crater
became filled with volcanic matter level with the
brim, and on the i6th December a column of ashes
mingled with vapour was ejected from the cone,
while great quantities of stones were discharged and
volcanic lightning flashed. After this no less than
seven streams of lava descended the mountain, and
IO4 MOUNT VESUVIUS.
an earthquake caused the sea to recede for half a
mile. This terrific eruption resulted in a most awful
destruction of human life, no fewer than 18,000
persons having, it is said, perished during- its con-
tinuance. The villages of Torre del Greco, Resina,
Granatello, and Portici were either wholly or
partially destroyed ; and a large space of land was
inundated by the torrents of rain produced by the
condensation of the immense volumes of vapour
discharged from the mountain. The lava emitted
during this eruption forms a considerable portion
of the substratum under the road between Resina
and Torre del Annunziata. It may be seen at
many points along the high-road, as well as by the
side of the railway running between the road and
the sea, and it is quarried for road material close to
the sea-shore at Torre Scassata. It is this lava
which covers the tuff under which Herculaneum
lies buried, and which has rendered the excava-
tions for the exploration of the ruins of that ancient
city so costly and so difficult ; while upon it
stand the modern towns of Resina and Torre
del Greco ; and the beautiful gardens of the
royal palace of Portici cover a portion of its
surface.
An eruption, remarkable for having thrown up a
perpendicular stream of lava, occurred in the year
1676 ; and during the next twenty years various
eruptions took place, which much modified the shape
of the mountain. At this period it appears that the
HISTORY TO 1850. IO5
highest point of Somma was 1,200 feet higher than
the summit of the eruptive cone.
A stream of lava four miles in length, and
upwards of 100 yards wide, where broadest, flowed
from the mountain in 1694, an d ran in the direction
of San Giorgio a Cremano ; and one, two years
afterwards, towards Torre del Greco.
During the next hundred years the volcano was
in very frequent activity ; and several of the erup-
tions which occurred at this period are deserving of
notice, on account of the remarkable nature of the
phenomena witnessed during their continuance.
One of the early eruptions of the eighteenth
century, that of 1707, was a very violent one ; and
is noticeable for the immense quantity of ashes then
discharged by the volcano. It is stated that the
cloud of ashes over Naples was dense enough to
involve the city in such complete darkness that
nothing could be seen in the streets. The shrieks
of women, we are told, filled the air ; and the
churches were crowded with people, while the relics
of S. Januarius were carried in procession. The
wind, however, changing, and the ashes being
carried in another direction, the alarm of the people
subsided.
The eruption of 1737 poured forth a stream of
lava no less than a mile in width, and containing
upwards of 300,000,000 cubic feet. Sir Charles Lyell
speaks of the lava of this eruption in his " Principles
of Geology," in which he mentions that it may be
IO6 MOUNT VESUVIUS.
seen near Torre del Greco, where it displays an
incipient columnar structure. This section of lava-
rock is immediately outside the town of Torre del
Greco, on the road to Torre del Annunziata, and
may there be seen presenting a surface twelve or
fifteen feet in height. The great stream flowed
from the side of the mountain, but at the same time
another was emitted from the crater on the summit,
which divided into branches taking opposite direc-
tions, and causing a great destruction of property. A
large quantity of ashes was also ejected, and this
ash falling on the trees in the surrounding district,
especially in the neighbourhood of Ottajano, also
occasioned great damage. A curious mephitic
vapour was emitted by the mountain after the
eruption, which destroyed life.
In 1751, during an eruption which again pro-
duced a great flow of lava, the central cone sank,
leaving a hollow of great depth and width.
Much lava was discharged in 1754, the stream
this year taking the direction of Bosco del Mauro
and Bosco tre Case.
There was a remarkable outbreak in the year
1 760. The lava of this eruption flowed from new
cones that were formed, not on the summit of the
mountain, but on its side, not far distant from the
convent of the Camaldoli. Great columns of smoke,
and immense quantities of ashes, were also given
forth by these new cones, which may still be seen.
The great eruptions of 1 766, 1767, and 1770 are
Plate IX.
FIG. I. THE CRATER OFVESUVIUS IN 1756.
(AFTER HAMILTON)
CRATER OF VESUVIUS IN 1805.
(AFTER DUCA DELLA TORRE)
uwMnwutC
HISTORY TO 1850. 107
graphically described by Sir William Hamilton in
his letters to the Royal Society, an extract from
which, having reference to the eruption of 1 767, may
be here given.
" I observed on my way to Naples, which was in
less than two hours after I had left the mountain,
that the lava had actually covered three miles of the
very road through which we had retreated. It is
astonishing that it should have run so fast ; as I have
since seen, that the river of lava, in the Atrio di
Cavallo, was 60 and 70 feet deep, and in some places
near two miles broad. When his Sicilian Majesty
quitted Portici, the noise was greatly increased ; and
the concussion of the air from the explosions was so
violent, that in the king's palace doors and windows
were forced open, and even one door there, which
was locked, was nevertheless burst open. At Naples,
the same night, many windows and doors flew open ;
in my house, which is not on the side of the town
next Vesuvius, I tried the experiment of unbolting
my windows, when they flew open upon every
explosion of the mountain. Besides these explosions,
which were very frequent, there was a continued
subterraneous and violent rumbling noise, which
lasted this night about five hours. I have imagined
that this extraordinary noise might be owing to the
lava in the bowels of the mountain having met with
a deposition of rain-water ; and that the conflict
between the fire and the water may, in some measure,
account for so extraordinary a crackling and hissing
IO8 MOUNT VESUVIUS.
noise. Padre Torre, who has wrote so much and so
well upon the subject of Mount Vesuvius, is also of
my opinion. And indeed it is natural to imagine
that there may be rain-water lodged in many of the
caverns of the mountain ; as in the great eruption
of Mount Vesuvius in 1631, it is well attested that
several towns, among which Portici and Torre del
Greco, were destroyed by a torrent of boiling water
having burst out of the mountain with the lava, by
which thousands of lives were lost. About four years
ago, Mount Etna in Sicily threw up hot water also
during an eruption.
"The confusion at Naples this night (igth
October, 1767) cannot be described; his Sicilian
Majesty's hasty retreat from Portici added to the
alarm ; all the churches were opened and filled ; the
streets were thronged with processions of saints :
but I shall avoid entering upon a description of the
various ceremonies that were performed in this
capital to quell the fury of the turbulent mountain.
" Tuesday, the 2Oth, it was impossible to judge
of the situation of Vesuvius, on account of the smoke
and ashes, which covered it entirely, and spread over
Naples also, the sun appearing as through a thick
London fog, or a smoked glass ; small ashes fell all
this day at Naples. The lavas on both sides of the
mountain ran violently ; but there was little or no
noise till about nine o'clock at night, when the same
uncommon rumbling began again, accompanied with
explosions as before, which lasted about four hours :
HISTORY TO 1850. 109
it seemed as if the mountain would split in pieces.
* * * * * During the confusion of this night, the
prisoners in the public jail attempted to escape,
having wounded the jailer, but were prevented by
the troops. The mob also set fire to the Cardinal
Archbishop's gate, because he refused to bring out
the relics of Saint Januarius.
"Wednesday, 2ist, was more quiet than the pre-
ceding days, though the lavas ran briskly. Portici
was once in some danger, had not the lava taken a
different course when it was only a mile and a half
from it ; towards night the lava slackened.
" Thursday, 22nd, about ten of the clock in the
morning, the same thundering noise occurred again,
but with more violence than the preceding days ; the
oldest men declared they had never heard the like ;
and, indeed, it was very alarming ; we were in ex-
pectation every moment of some dire calamity. The
ashes, or rather small cinders, showered down so fast,
that the people in the streets were obliged to use
umbrellas, or flap their hats, these ashes being very
offensive to the eyes. The tops of the houses and
the balconies were covered above an inch thick with
these cinders. Ships at sea, twenty leagues from
Naples, were also covered with them, to the great
astonishment of the sailors. In the midst of these
horrors, the mob, growing tumultuous and impatient,
obliged the Cardinal to bring out the head of Saint
Januarius, and go with it in procession to the Ponte
Maddalena, at the extremity of Naples, towards
HO MOUNT VESUVIUS.
Vesuvius ; and it is well attested here, that the erup-
tion ceased the moment the Saint came in sight of
the mountain ; it is true, the noise ceased about that
time, after having lasted five hours, as it had done
the preceding days."
An eruption of no great importance occurred in
1776; but three years after, in 1779, one of very-
great violence and remarkable character took place.
Several great streams of lava were emitted on this
occasion, and the showers of ashes were sufficiently
dense to produce darkness in the vicinity of the
mountain. Vapours most destructive both to animal
and vegetable life were given off in profusion. But
perhaps the most extraordinary feature of this ter-
rible outbreak was the rising of a column of liquid
fire, as it is described, to a height which Sir William
Hamilton considered to be three times that of the
mountain. After this a black cloud, emitting flashes
of lightning, advanced from over Vesuvius towards
Naples, spreading consternation and terror among
the inhabitants of the city. The theatres were
closed, and the relics of San Januarius again carried
in procession. The destruction to property caused
by this eruption was very great, especially to the
vegetation of the district.
Terrible, however, as was the eruption of 1779,
it was exceeded by the appalling outbreak of 1 793-4,
which lasted from the February of one year until
the Midsummer of the next. This eruption pro-
duced no less than fifteen mouths, which emitted as
HISTORY TO 1850. Til
many separate streams of lava ; and these uniting
formed one vast body of liquid fire, which flowed
steadily on towards the sea, cutting in two the town
of Torre del Greco, where it was from twelve to
forty feet thick, and actually advancing into the sea
to a distance of 362 feet, and presenting a face
1,127 feet broad. It was calculated by Breislak that
the whole mass contained no less than 46,098,766
cubic feet of lava. The sea was even in a boiling
state at a distance of 100 yards from the lava. This
eruption, as has been the case with the great
eruptions generally, was preceded by a falling of
the water in the wells of the neighbourhood.
From this time until 1822 the several eruptions
that occurred were not of a very remarkable
character ; but on the 22nd of October of that year
commenced one which must by no means be passed
over. On the day following that date, the top of the
cone fell in, and this was succeeded by the emission
of a stream of lava nearly a mile in width. So
great, too, was the quantity of ashes and cinders
ejected, that the country as far as Amalfi, on the
Gulf of Salerno, was overshadowed with darkness,
and the road between Resina and Torre del Annun-
ziata was blocked up with the fallen ejectamenta.
This eruption was remarkable also for the unusually
large amount of vapour which issued from the vol-
cano. The vapour condensed into rain ; and this
was so great in quantity that some districts were
inundated. The crater was greatly altered by this
112 MOUNT VESUVIUS.
eruption, having been by it much increased in cir-
cumference and in depth, and the height of the cone
correspondingly diminished. The summit was after
this eruption estimated to be not more than 3,400
feet above the level of the sea, 600 feet of the top
of the cone having been blown away, while the
depth of the crater was stated by Mr. Babbage to
be 938 feet.
The eruption of 1828 produced a small cone in
the centre of the large crater formed by the great
outbreak of 1822 ; and in 1831 the summit of the
new cone was higher than the edge of the great
crater, which had become filled with the ejecta-
menta of the volcano. The whole of this new cone
was, however, destroyed by the eruption of 1834,
during which the volcano poured out a most copious
stream of lava, causing the almost total destruction
of the village of Caposecco, only four houses out of
five hundred remaining. The river of lava which
destroyed this village was nine miles long ; and so
great was its heat, that it is said to have been felt at
Sorrento, a distance of nearly ten miles. One stream
of the lava taking the direction of Pompeii, that
ancient city was threatened with another interment.
Since 1834 the eruptions have been very frequent,
and have been especially noticeable from the fact
that they have produced lavas containing a greater
quantity of leucite than is to be found in the lavas
of the previous eruptions of the historic period, and
therefore more like the ancient lavas of Monte
Plate X
FIG .1 THE CRATER OF VESUVIUS AFTER THE GREAT ERUPTION OF 1822
(AFTER SCROPE)
Fic.2 THE CRATER OF VESUVIUS IN 1828.
(AFTER MONTICELLI)
HISTORY TO 1850. 113
Somma, in which this mineral is very abundant.
We are told by Professor Pilla that crystals of
leucite as large as nuts were not only found im-
bedded in the lava of 1845, but were thrown out of
the crater of the volcano in that year. This fact is
of value, as showing that these crystals of leucite
were formed within the vent previous to the
eruption.
The lava of 1850 formed a flowing mass no less
than a mile and a half broad, which steadily advanced
towards Bosco Reale and the south of Ottajano,
consuming the woods of large trees that lay in its
way, and threatening with total destruction the
populous villages lying on that side of the mountain.
Thus at quite the end of the first half of this
century there was another of those emissions of lava
which had been so frequent during almost the whole
of the preceding hundred years, a century of
activity of lava-producing power and eruptive
energy, from 1751 to 1850, perhaps unsurpassed
by Vesuvius in any previous equal period of time.
n 4
CHAPTER V.
HISTORY : 1851 1 868.
Eruptions of 1855 and 1861 Eruption of 1867-68 Aspect of the
Surface of Vesuvius during the Eruption of 1868 Ascent to the
Summit Lava-Flows The Cone The Ring Terrace The
Eruptive Cone and Crater The Eruptive Phenomena seen from
the Crater Rim.
SUBSEQUENT to the eruption of 1850, normal in-
activity prevailed for upwards of four years, but the
frequent activity of Vesuvius during the first half of
the present century did not exhaust the eruptive
energy of the volcano for any more lengthened
period, since the year 1855 witnessed an eruption
of more than usual violence. This eruption pro-
duced lava which retained its fluidity for such an
unusually great length of time that it flowed in a
comparatively narrow stream almost to the suburbs
of Naples, running between the villages of Massa
di Somma and San Sebastiano, and reaching Cercola.
This stream flowed from the side of the cone above
the Atrio del Cavallo, into which it poured ; and
following the course of the Fosso della Vetrana
and the Fosso Faraone, it divided into two branches,
one of which extended, as above stated, to Cercola,
while the other took the direction of San Jorio, and
almost reached that village. The lava penetrating
so far into the cultivated region at the base of
Plate XI
FIG I. THE CRATER OF VESUVIUS IN I&56.
(AFTER BORNEMANN)
Fie. 2. THE CRATER OF VESUVIUS i N 1883
(AFTER LAVIS)
HISTORY: 1851 1868. 115
Vesuvius, caused a most deplorable destruction of
property, and greatly terrified the inhabitants of the
district, who feared it would destroy Portici, and
perhaps reach even to the city of Naples.
Three years afterwards, another eruption occurred ;
and it was the lava of 1858 that formed a very con-
spicuous feature on the side of the mountain for
many years, covering as it did a large area crossed
by the usual route to the summit from Resina.
This lava was emitted in copious 1 streams from new
craters, which opened in the Piano and flowed into
the Fosso Grande at the base of the Crocella ridge.
Another great flow of lava occurred in 1861, but
so low down on the mountain-side did the mouth
open from which the stream poured, that it was not
more than a mile distant from the town of Torre
del Greco. Besides the opening from which the
lava was emitted, ten other craters were formed,
that ejected great quantities of ashes. The
neighbourhood, as well as the town of Torre del
Greco itself, again suffered greatly from this erup-
tion, which caused the ground to be rent with
fissures, and a large area to be covered with a fiery
flood that threatened to at length completely destroy
that much-enduring city.
Professor Palmieri reported that after the year
1 86 1, there was a large and deep crater with a few
fumaroles of moderate temperature, and often
evolving only pure carbonic acid gas. Occasional
slight ejections, however, gradually built up a small
Il6 MOUNT VESUVIUS.
cone inside the great crater. But general, if not
complete quiescence reigned from the termination
of the eruption of the year 1861 until towards the
end of 1867, when the eruption of that and the
following year commenced.
The eruption of 1867-8 was a long-continued one
of great irregularity and variation of volcanic force
and energy, sometimes becoming so violent as
almost to rise to the dignity of what is commonly
called a" great eruption ; " at others, and for a consider-
able time together, falling away in intensity, and
sometimes even displaying so little violence that the
volcano almost reached a normal state of repose,
and on several occasions it was confidently but
prematurely predicted that the eruption was
terminating.
For a fortnight previous to the night of Novem-
ber 1 2th, 1867, the Vesuvian seismograph by its
agitation, increasing until the outbreak, clearly
indicated that volcanic force was acting in the
interior of the mountain. On the morning of the
1 3th, at half-past twelve, lava appeared from the
new cone which was shortly afterwards ruptured,
and from four or five openings the molten matter
issued, and flowed into the hollow of the great
crater. It is stated that the rupture of the cone
was produced by an elevatory force that uplifted
masses of compact lava into vertical prisms. This
cone just overtopping the great crater rim, continued
to discharge lava until there was a sufficient weight
HISTORY: 1851 1868. 117
of it to break down a portion of the wall of the great
crater, when it poured over on one side towards
Ottajano and on another towards Massa cli Somma,
in this case forming a stream upwards of 10 yards
wide and soon reaching 1,000 yards from the
summit. The ejections consisted chiefly of small
partly cooled masses locally called {t schiuma," which
were thrown about 300 feet high above the top of
the eruptive cone, but solid masses of great weight,
some half a ton, it is said, were also ejected.
By the 2ist of November the eastern flow had
increased so much as to form a stream of 40 or 50
feet in width. The new cone now rapidly increased
in height and bulk, with a corresponding increase
of its crateral opening, until it attained a height of
nearly 400 feet, and then filling up completely the old
great crater, it produced a ring-like plain around
itself, a circular terrace at the level of the rim of
the old great crater, which was now no longer in
existence. The loose materials of which the new
cone was formed soon gave way on its west side to
allow of the escape of lava from the small new
crater, and this lava then flowed down the new
cone over the terrace and down the side of the
great cone. It soon covered a large area at the
base of the great cone, spreading out on the region
of La Plaine, between the Crocella and the Piano
del Ginestre.
Prof. Palmieri has put it on record that he ob-
served two maxima and two minima daily in the
Il8 MOUNT VESUVIUS.
flow of the lava, and that the maxima were half an
hour later each day, and, moreover, that the eruption
strengthened at full and new moon and weakened
at the quarters.
In the early part of December, there was much
violence with a great ejection of ashes, scoriae, and
lava, accompanied by loud thunderings and bellow-
ings, called " beoti," heard at Capri twenty miles
away, and violent earth movements that caused so
much alarm to the inhabitants of the neighbouring
towns that hundreds of chests of coral were sent off
from Torre del Greco to Naples for safety. During
this period, no less than thirteen streams of lava on
the cone were counted, and some falling over pro-
jecting masses gave the splendid effect of cascades
of fire.
The new cone had now meanwhile grown to
maturity, and so gave an approximately complete
apex to the summit of Vesuvius, and, at the same
time, a greater height than ever before during his-
torical times, to the mountain, and, too, a more
regular conical outline. In the latter part of Decem-
ber, the lava-flow on the western side of the great
cone slackened, leaving but a small stream, the
principal issue being then on the eastern side.
On the 3rd of January, 1868, there was a recom-
mencement of the great flow on the western side,
and this was so copious as to threaten the Observa-
tory and even Resina and Torre del Greco. The
lava flowed in two streams that formed an ellipse.
PlateXII
FlCl. VESUVIUS AFTER THE GREAT ERUPTION OF 1631.
(AFTER CARAFA)
Fic.2 . VESUVIUS AFTER THE ERUPTION OF 1868 .
HISTORY: 1851 1868. 119
One advanced in two days from the foot of the
great cone to a point near the Observatory, but then
stopped, while quite a river of molten rock sixty
yards wide reached, on the I2th of January, the
Piano del Ginestre, threatening the towns below.
On the 1 5th of January, however, there was a lull,
and the lava ceased to flow further. So little, how-
ever, were the people of Resina alarmed during
this flow, that they met it with bands of music and
celebrated the advance of the lava with polkas and
marches, for a lava-flow brings many visitors with
money to Resina ; nor was their confidence in its
harmlessness unjustified, as proved by the event.
From the middle of January until the 26th of
that month, the pause continued, but on that day
the lava again flowed over the summit of the cone,
but quite tranquilly, and covered all the upper part
of the mountain with liquid fire, affording a grand
spectacle from the bay or from Naples, where, on
the Strada Santa Brigida, crowds assembled, near to
where on this night occurred the fatal fall of the
tufa cliff at Santa Lucia.
During the early part of February, the action
was much diminished and intermittent, thereby
affording an opportunity for the deposition of subli-
mates, the chemical productions of the volcano.
Thus it was that salts of lead and copper, chiefly
chlorides, as well as chloride of sodium, were in
great abundance on the surface, especially about
the fumaroles. Palmieri says, on February 6th, the
I2O MOUNT VESUVIUS.
fumarole are again decorated with copious white,
yellow, and green sublimates, amongst which,
besides common salt, are found copper and lead.
A curious phenomenon was produced by the dimin-
ished flow of lava which, as it descended the great
cone, had its surface cooled and solidified, while re-
maining fluid in the mass. The result was the formation
of a tunnel or great tube of solid black rock on the
side of the cone, with the hot fluid lava flowing out
at the bottom, and giving the appearance of issuing
from the base of the cone. There was still a con-
siderable flow, and on the i7th of February,
five streams fell over ridges producing as many
cascades of fire.
There was another diminution with a brief
revival on the 3rd of March, when the eruption was
unusually splendid, and again a lull until the 8th of
March, when violent activity recommenced, and
ejectamenta were fired up to 1,600 feet.
On the nth, a great fissure opened on the
Pompeiian side from which issued " rough slaggy "
lava, while on the Naples side the flow was filling
the valley at the base of the Crocella. Volcanic ash
fell very abundantly round the mountain, so that
Resina, Naples, and even Posillipo ten miles
distant, suffered much from this black powder. It
is estimated that on the night of the I2th of March,
the ashes covered an area of six square kilometres
to the extent of 14 kilogrammes to the square metre,
which would give a fall of ash of 84 millions of
HISTORY: 1851 1868. 121
kilogrammes in one night in the immediate neigh-
bourhood of the mountain, and on the I3th and
1 4th the ash was carried as far as Sicily and Gaeta.
On the 2ist, 22nd, 26th, and 2/th March, great
activity prevailed, and much lava flowed, producing
splendid effects as seen from Naples.
During the summer there was a great diminution
of activity, but the volcano was far from quiet,
smoke and ashes being constantly ejected, and on
the 22nd of June the shocks were so violent that
people passed the night in the open air, while on
the ist of July the ejections were so great that
several who ascended the mountain were severely
injured. A renewal of lava-flow occurred on the 8th
of October, and the amount increasing on the loth of
November, the cultivated area was again threatened,
but the 26th of that month witnessed the last lava
of this eruption, one which had been continuous
from the i2th of November of the previous year,
and therefore having had a duration of more than
twelve months.
The appearances and phenomena presented by
the volcano during an eruption, may perhaps be
best gathered from an account of an ascent to the
summit I was able to make during a somewhat
violent phase of this one in March, 1868.
The observable phenomena are many and varied,
and if at times terrific, yet are so interesting and
indeed fascinating, that fear or thought of danger
is driven away. On the question of danger it may
122 MOUNT VESUVIUS.
be admitted, as shown by the preceding record, and
still more by the sad fatality of 1872, that a con-
siderable amount of danger to observers undoubtedly
exists. But it is worthy of remark that although
the spirit of inquiry naturally induces scientific
observers to make repeated explorations and to
make them as complete as possible, yet the fatalities
that occur are almost always those which befall
tourists or others most probably on a volcano while
active for the first time in their lives, leading to
the conclusion that a little knowledge of volcanic
action is a great safeguard.
Though the ascent from Pompeii has some re-
commendations, that from Resina is by far the most
interesting, and gives the best and clearest under-
standing of the topography, as well as of the
structure of the mountain. It is not unusual for
visitors to ascend as far as the Hermitage on
saddle, as there is a practicable bridle path, and
much fatigue is doubtless thereby prevented, but
an ascent on foot ought always to be made by those
who wish to observe the phenomena presented by
the volcano with the greatest advantage. An
ascent on foot indeed must be made if any explora-
tion or anything more than a mere visit to the
mountain by the usual route, be desired, and it is
a waste of opportunity for any one to go to Vesuvius
with its many remarkable features, without attempt-
ing more than an ordinary ascent.
A stout pole or alpenstock, thick-soled boots, a
HISTORY: 1851 1868. 123
pocket compass, a clinometer, a map, and a
geological hammer, with paper and bag for
specimens, will be found very useful, and yet not
forming an encumbering burden. Guides, although
not necessary to show the route, which is clear
enough, are very useful both to parties and to indi-
viduals, for many purposes, and especially as guards
against the importunate solicitations of other guides
who will be met with on the mountain-side.
The ascent commences at once from the main
road by a narrow lane between the houses, and
very soon a position is gained from which a less
confined view is obtained. The inclination of the
path is not at all steep, but the pavement is
somewhat rough, and it is only the heat, which is
often great at Resina, that causes any difficulty.
Once clear of the houses, the foliage of the vine-
yards and gardens through which the path now
passes is refreshing to the eye, and the cooler air,
the more and more extensive prospect, with the
sparkling waters of the bay dotted with the lateen-
sails of fishing-boats, refresh the spirit. From time
to time a table is seen at the gate of a garden
where wine and fruit may be bought, and this is
the wine and fruit for which the slopes of Vesuvius
are so famous, and both may be purchased where
produced, at a very cheap rate. The belt or zone of
cultivated land is, as has been previously stated, on
a slope of about 10 or 12 and about two miles
broad, giving a walk sufficiently long for a protracted
124 MOUNT VESUVIUS.
enjoyment of the luxuriance and beauty seen on all
sides.
And then there is a change from a garden to
a desert, for as soon as the cultivated zone is crossed,
a vast expanse of undecomposed black rock is
reached. In place of beautiful gardens in which
the orange, the lemon, the almond, the fig, and the
vine flourish in perfection, and in which roses and
camellias bloom in profusion, there extends around,
a black sterile waste without a trace of verdure of
any kind, and displaying only huge folds, waves,
and unshapely masses of rough dark-coloured
lava-rock.
So totally unlike anything else is it, that there
is some difficulty in conveying to those who have
not seen a volcano, a clear idea of the extraordinary
aspect of the part of the mountain covered by
recent lava-flows ; but its appearance may perhaps
be to some extent understood, if it can be imagined
that a stormy sea of boiling pitch has been suddenly
cooled so as to retain in a solid form all the rough-
ness, angularity, and irregularity which the surface
possessed while liquid. In some places, indeed, the
lava has assumed the appearance of great coils of thick
black ropes, but in others, sharp and rugged ridges,
like the crests of breakers, rise, and in others, again,
huge blisters stud the surface, while large areas
are covered as it were with smoother rolling waves.
This is the region of desolation, the Desert Plat-
form, of about a mile in breadth, diminishing to a
HISTORY: 1851 1868. 125
quarter of a mile in the Atrio del Cavallo, which
extends around the mountain at the base of the
Great Cone and inside the ridge of Somma, both of
which rise from it. Here were to be found those
smaller lava streams which allow of a close inspection
without danger. They are marked, as seen from a
distance, by a line of steam which arises continuously
from them, but on being approached, they are found
to be glowing molten rock, not white-hot, yet more
than red-hot, being, in fact, yellow-hot, if such a
term may be used.
They flow rather on elevations than in depres-
sions, but elevations made by themselves, for they
are indeed embankments formed by their own
cooled surface portions, which, falling over the end
of the slowly-flowing lava, form a bed in advance of
the stream, which, with the diminishing rapidity of
the increasingly viscid mass, receives more rapid
additions to its bulk, and this being on a slope, the
bed thus produced increases in height as the ridge
advances, and so becomes more nearly level, and
this gradual diminution of inclination again lessens
the rapidity of the flow, and facilitates cooling
and solidification. Thus it is that small and even
rather large streams are prevented reaching the
cultivated zone, and so inspire no terror to the
owners of the gardens and vineyards near. Indeed,
work was going on in the most assured way possible,
in a garden immediately in front of, and at no
great distance from the end of such a stream, the
126 MOUNT VESUVIUS.
proprietor evidently feeling quite sure that the flow
would never reach his boundary wall.
These small streams were moving over this part
of the mountain, which has little slope, at about
300 yards per hour ; but it will be readily under-
stood that this is no measure of the rate of
progression of larger, and therefore more fluid,
because hotter, flows, and no indication whatever of
the rapidity with which lava fresh from the volcanic
tube descends the steep slope of the cone.
Some lavas, too, are more fluid than others, on
account of a somewhat different composition, as
was the lava of the eruption of 1855, which was
especially mobile, its great liquidity being attributed
to its containing the mineral Cotunnite, a chloride of
lead. Statements of the rate at which lava has been
found to flow are therefore of little value if the
position, circumstances, and conditions of the flow
are not at the same time stated.
Solidification goes on very rapidly on the surface
of lava when the mass is not great, and hence it
is that on small streams there is a very abundant
production of scoria or flattish masses with a
vesicular structure. The vesicular structure of
scoriae is due to the absence of pressure, which
allows of the formation of vesicles by the gaseous
emanations from the lava. Thus it is that small
lava-flows produce abundance of scoriae, and great
lava-flows produce masses of compact rock. An
ordinary lava-flow will consequently ultimately form
HISTORY: 1851 1868. 127
a bed of compact rock reposing on one of scoriae,
and covered by another layer of scoriae, the under-
lying scoriae being that which has been pushed over
the end of the stream while flowing, and so has
formed its bed, and the overlying scoriae being that
which has formed on the surface immediately before,
and at the time the lava ceased to flow. Such
masses of compact lava-rock with scoriaceous
bottom and top beds, the result of volcanic action
in far-distant periods, are often met with in various
geological formations.
The lava of these streams seems to be of greater
consistence than honey, small stones thrown upon
it not sinking into the mass, but remaining on its
surface, and it readily lends itself to being moulded
by iron moulds into medallions.
The heat given off is considerable, but so much
less on the windward side, that no inconvenience is
experienced in standing by the side of the flow and
lighting the end of a wooden stick by the hot lava.
Steam seems to be almost all that is given off from
the fluid mass, as the immediately adjacent air is
not at all offensive.
The general surface of the Piano was very
difficult to traverse, the ridges being high, hard, and
sharp. In some places, the crests of the masses of
lava were breast high, in others less so, but in all
great care and no inconsiderable labour was required
to traverse a large part of this sea of solidified
lava.
128 MOUNT VESUVIUS.
In some places, too, the rough hard surface was
very hot, so much so that boots were scorched, and
cracks at places showed red-hot lava at but a little
distance below. A large area, overlooked by the
Crocella, was recently solidified lava, with hot lava
immediately underneath, so that the atmosphere
above was visibly affected. A little earlier all this
area was covered with fluid lava that spread out at
the bottom of the cone like a sea of fire. The flow
from the base of the great cone issued with remark-
able tranquillity and quietness, like molten iron
from a furnace, from the lower mouth of the tunnel
the lava itself had formed upon the slope.
It is remarkable what a small amount of solid
lava-rock is to be seen on the sides of the great
cone, notwithstanding the large number of flows
that have solidified on its slopes. The amount of
scoriae that is found on the surface of solidifying lava-
flows and the great quantity of scoriae, bombs, and
ashes, that falls on the side of the cone and covers
and conceals any solid lava-rock that may have
there been formed, renders the surface of the Great
Cone a slope of loose incoherent material. A partial
exception to this rule was the remarkable tube
of lava-rock from top to bottom of the slope,
standing out, though not conspicuously, from the
normal surface of scoriae.
Volcanic ash, which, when mingled with the
ascending steam from the crater, constitutes the
" smoke " of the volcano, falls chiefly on the lee side,
HISTORY: 1851 1868. 129
or that in the direction of the wind, but when there
is little wind, it is more equally distributed with a
heavier fall near to the ejecting orifice.
On the hill of the Crocella to the left, the light-
coloured, modern, and handsome Observatory, with
its straight architectural lines, stands clearly against
the blue sky, conspicuous in its great contrast to the
dark weird waste around, which is completely over-
looked from the terrace. The top of the stone
balustrade in front was covered with the black ash,
and whenever this was swept off, the surface of the
stone was quickly re-covered.
Those having mules or horses must leave them at
the Hermitage of San Salvatore, and prepare to
ascend the Great Cone on foot if no eruption
forbids it, or now by the rope tramway or " Funicular
Railway," as it is called, which was opened in 1880.
This latter method certainly saves labour and time,
but it so far detracts from that complete exploration
of the mountain which can only be made by a
considerable expenditure of both labour and time.
An old mode of ascent was by means of a chair
on poles, carried by porters up the slope of the cone
in such a way that the occupant of the chair was
always in a vertical position.
The Atrio del Cavallo at the base of the great
cone has a most gloomy and desolate aspect. It is
truly a " valley of rocks " without the slightest relief
from verdure or vegetation of any kind. On
the right hand the steep and rugged side of the
K
130 MOUNT VESUVIUS.
great cone rises, and on the left the still more
steep and still more rugged escarpment of
Monte Somma, while the bottom is paved with
irregular masses of bare, dark lava from one side to
the other. Rain storms appear to wash out all
loose material from the bottom of the Atrio, leaving
a solid floor composed of the lavas of the most
recent flows on this side the cone, which spread
over and across the approximately horizontal
bottom. Somma's precipitous wall-like cliffs show
a rugged surface from the frequent alternation of
beds of scoria and sheets of lava, and the frequent
projection of the vertical or highly inclined basaltic
dykes which are so numerous in this ancient crater
remnant, while the uppermost edge of the enormous
ridge shows a jagged and serrated ridge with sharp
points against the sky.
The laborious ascent of the Great Cone occupies
a long time, but the frequent necessary pauses
enable the opposite cliffs of Somma and their
wonderful and instructive structure to be well seen
and well impressed on the memory, so that the
time is by no means wasted, while, during the
progress of an eruption, the fall of bombs and scoria
sometimes too near to be altogether agreeable,
and the explosions becoming louder and louder,
render the ascent by no means devoid of excite-
ment. The elevation attained was now upwards of
3,000 feet above the level of the sea, and as we were
on the north-western side of the cone a more bracing
HISTORY: 1851 1868. 131
air and a cool shade counteracted the fatiguing
effects of the laborious climb.
At length a rounded surface indicated the sum-
mit of the long slope, and in a few yards more an
almost flat plateau, or rather terrace, was reached.
This was the circular terrace around the new cone,
and at the summit of the Great Cone, the infilling in
fact of the great crater by the ejectamenta of the
eruption in progress. But how beautiful was the
surface ! Orange, red, bright blue, and white, on
all sides. Light fumes were rising, but only suffi-
cient to slightly veil, not to obscure, the " Persian
pattern " of this carpet of the throne of Vulcan.
This chromatic variegation of the surface was due to
the formation of salts of lead, and copper, and iron, as
well as of chloride of sodium or common salt, which
was rapidly going on over the surface of the ash-
covered scoriae, and hydrochloric acid gas was being
evolved at the same time, with perhaps hydrogen and
sulphurous acid gas intermingled. Some specimens
of the surface accumulations here were collected,
and these even now, after the lapse of twenty years,
give off very perceptibly free chlorine, though it is
right to state they have been preserved in stoppered
bottles that have, however, been many times
opened.
The terrace was perhaps 20 yards across, with
a slope very slightly inclined towards the exterior
edge, and from it arose the new cone with the
actual eruptive crater. Explosions, each with a
132 MOUNT VESUVIUS.
tremendous roar and discharge, followed each other,
and the cinders and scoriae were being ejected to a
great height. The windward side of the new cone
was the only one approachable, as the fumes were
blown over to the other side, but from this position
the firing out of the ejectamenta was seen perfectly,
the distance to the edge of the crater not being more
than a hundred yards.
Prof. Phillips states (but not from his own obser-
vation) that the height of the new cone in November,
1867, was 392 feet, but as the crateral hollow around
it was not then filled up he may have intended this
as the height from the then base considerably below
the level of the rim of the old crater ; or the ring
terrace, the new and more elevated base of the new
cone may have been considerably raised above the
level of the old crateral rim by the accumulation of
ejectamenta, some falling on to it vertically and
some rolling down the slope of the new cone, and
resting on the almost level surface at its base.
However this may be, the new cone was not at
the time of my ascent more than 300 feet above
the level of the terrace ; and this estimate agrees
with Prof. Palmieri's statement that 1296*9 metres >
or 4,255 feet, was the extreme height of the summit
in 1868, this being 306 feet above the level of the
Punta del Palo, which was then covered, but still
not much below the surface of the ring terrace.
Higher than the terrace no guide would go,
but the phenomena had now become so deeply
HISTORY: 1851 1868. 133
interesting and the eruptive crater was so near, that
the impulse to gain the summit of the new cone
was to me irresistible. Much denser fumes arose from
the sides of this cone, but they were kept low and
carried closely over the uppermost edge by a strong
wind, so that they added no difficulty, and soon I
had the long-desired satisfaction of standing, while
the volcano was in eruption, on the rim of the
eruptive crater, the summit of Mount Vesuvius.
The fumes were dense as high as the waist, but
my head was in clear air, and so there was no dan-
ger from them except by stumbling and falling
down. A complete view of the crater-rim could
not be obtained in consequence of these dense fumes
obscuring the opposite side, but the depressed lip
over which the lava had flowed at an earlier period
of the eruption could be clearly seen. The lava had
now, however, made a way for itself through the side
of the new cone considerably lower down, and this
had necessarily reduced the height of the fluid mass
in the volcanic tube, and so it was not now visible in
the crater, which was filled with the white fumes,
chiefly steam, and as it was a bright day the hot
lava below indicated its presence only by a faint
glow amidst the steam in the crater. Firing out of
scoriae, cinders, and bombs continued, and was in-
tensely fascinating, while the tremors and shakings
of the ground which the explosions occasioned still
further added to the interest, but, as is elsewhere
stated, there was no actual flame (see Flame, chap. ix.).
134 MOUNT VESUVIUS.
The explosions, and consequent violent ejections
of bombs and fragmentary lava, were not con-
tinuous, but followed each other with intervals of
a few seconds between. Neither were they of
uniform violence, sometimes the projectiles being
much more numerous and reaching a much greater
elevation than at others.
Yet, fascinating as was the scene, only a very
brief stay on the edge of the crater-rim was per-
missible from the momentary danger of the falling
masses, and so the narrow ridge was soon left,
though reluctantly, for great was the attractive
power of the novelty and sublimity of the wondrous
scene.
J35
CHAPTER VI.
HISTORY: 1869 1888.
Repose, 1869-71 Eruption of 1872 Repose, 1873-75 Slight Activity
of 1876 and 1877 Activity of 1878 and 1879 Increased Activity
of 1880 Strombolean Activity, 1881-83 Scale of Vesuvian
Activity Slight Activity of 1884-88 Continuous Observation and
Record of Phenomena.
THE year 1868 was succeeded by a period quiet
and uneventful, for following the cessation of
the flow of lava in November of that year
Vesuvius relapsed into dormancy during both the
years 1869 and 1870, except that a slight activity
was manifested by the fumaroles at the head of the
old fissure, which resulted in the further production
of the sulphide of potash and the chlorides and
sulphides of copper.
1871. After being in a quiescent state from
November, 1868, to the beginning of this year,
during which no lava appears to have issued from
the cone and no solid ejecta to have been dis-
charged from the crater, Vesuvius commenced to
give indications of renewed activity early in January,
1871, by such tremors as caused greater disturbance
of the seismograph, and, at the same time, slight
explosions were accompanied by the discharge of a
few " incandescent projectiles."
On the 1 3th of January lava appeared from an
opening on the summit of the cone, at first in small
136 MOUNT VESUVIUS.
quantity, but with a continuous increase until the
beginning of March, but yet the flow was a moderate
one, and did not, although the lava was freely
mobile, extend far from the base of the cone. A
small cone, which had been early produced, sub-
sided in March, but left four masses standing, one
of which was compact lava-rock, apparently ejected
from an inclined position by the volcanic forces. In
the bottom of the small crater a miniature cone, of
little more than six feet high, was found emitting
smoke and small incandescent scoriae, but gradually
increasing in size, it filled the crater and rose above
the brim. Then followed copious streams of lava,
which flowed down into the Atrio del Cavallo,
then into the Fosso della Vetrana, and extended
along the Observatory Hill for upwards of 300
yards, near which solidification stopped further
flow.
Prof. Palmieri collected what he called " filiform
lapilli," consisting of threads of lava, each containing
very small crystals of leucite. This product of
highly leucitic lava was in great quantities. Another
peculiarity of ''this lava is the formation of a skin,
instead : of a covering of fragmentary scoriae, on the
surface of the flows, which, gradually thickening,
allowed the fluid lava to flow below it. Thus the
flow of lava continued for months to descend
covered over, until it reached a part of the moun-
tain below the Canteroni, but soon afterwards its
flow was terminated. While exposed, however,
HISTORY: 1869 1888. 137
large bubbles formed on its surface, that burst and
gave forth "smoke."
A small crater was formed on the edge of the
central crater in October, and from it and from
openings in the cone small streams of lava flowed
until the end of that month, when there were the
usual signs of an increase of activity, and on
the 3rd and 4th of November large streams of
lava flowed down the west side of the cone, and
then there was a cessation until the end of
the year, but still smoke was given off, and,
rendered luminous by the incandescent matter
below, continued the alarmed interest of the Nea-
politans.
1872. Activity was resumed quite at the be-
ginning of January in this year, and the crater of
the cone of the preceding year poured forth lava,
Prof. Palmieri says, " in the most singular and
enchanting manner." In February, however, there
was a decadence, but at the time of full moon in
March a line of fumaroles indicated a fissure on the
north-west side, from which lava noiselessly poured
into the Atrio del Cavallo, extending quite across
its floor to the base of the ridge of Somma. Lava
o
flowed from this fissure for a week, and then ceased,
but a new crater with intermittent activity opened
between the excentric cone, now 100 feet high, and
the central crater. So matters remained until the
commencement of the terrific outburst of the latter
part of April.
138 MOUNT VESUVIUS.
This disastrous eruption, or rather close of a
long-continued eruption, also commenced at the
time of full moon, on the 23rd of April, when
the seismograph was agitated, and the volcanic
activity increased. On the next evening grand
streams of lava flowed down the cone on various
sides, but with the exception of one these ceased
on the morning of the 25th, but this one flowed
from the base of the great cone, near to the
place of issue of the month before. What fol-
lowed on the succeeding evening is of so tragic
a character that it will be best described by
Prof. Palmieri himself, who was out on the
mountain during the night. The Professor says :
"After midnight the Observatory was closed, and
my assistant retired to rest. Late and unlucky
visitors passed unobserved with an escort of
inexperienced guides ; at half-past three o'clock
in the morning of the 26th they were in
the Atrio del Cavallo, whence a copious tor-
rent of lava issued. Two large craters formed
at the summit of the mountain, discharging
numerous incandescent projectiles with white ashes,
and glittering with particles of mica, which fre-
quently recurred. A cloud of smoke enveloped
these unfortunates, who were under a hail of
burning projectiles, and close to the lava torrent.
Some were buried beneath it, and disappeared for
ever ; two dead bodies were picked up, and eleven
grievously injured, one of whom died close to the
HISTORY: 1869 1888. 139
Observatory."* Mr. Mallet states that " Eight
young medical students perished beneath the lava,
with others unknown by name."
The fatal outgush of lava was not from the
fissure on the side of the cone, but quite at the
bottom, in the Atrio del Cavallo. In the fissure on
the cone itself an elongated mound was formed, but
this accumulation had no similarity to a cone.
At the same time a fissure opened in the upper
part of the southern face of the cone, from which
lava flowed towards the Camaldoli. Other minor
streams of lava flowed, and, indeed, so abundant
and diffused was the emission from the cone, that
Prof. Palmieri writes : "It (the cone) seemed
completely perforated, and the lava oozed, as it
were, through its whole surface. I cannot better
express this phenomenon than by saying that
Vesuvius sweated fire"
During this profuse outpouring of lava there
were terrific discharges from the summit, accom-
panied by loud bellowings and thunderings. The
smoke and ashes are estimated to have reached a
height of between four and five thousand feet above
the summit of the mountain. From a remarkable
photograph of the eruption at its maximum, taken
from near Naples,f the regularity of the usual pine-
* " The Eruption of Vesuvius in 1872," by Prof. Palmieri. Trans-
lated by Robert Mallet.
f Photography was first used for d icting eruptive phenomena on
this occasion.
I4O MOUNT VESUVIUS.
tree form of the smoke appears to have been con-
siderably interfered with by the wind, which inclined
the whole towards the south-east.
A rain of white ashes, lapilli, small fragments of
scoriae, and dark sand descended, and darkened the
air, especially on the 28th, when the inhabitants of
the neighbouring towns were terror-stricken, the
thundering noises all the time continuing, for the
explosion appeared to gain strength after the
cessation of the great lava-flow of the 27th. The
whole history of the volcano shows that darkness,
caused by the ejection of ashes, and loud thunder-
ings inspire more terror in the minds of the
inhabitants of the surrounding towns than do lava-
flows, although, with the exception of that of 79,
the eruptions have caused little devastation in towns
and villages, except by lavas. Considerable injury
to crops has, however, been sustained, both from dry
ashes and from ash-mud. The people of Naples
went about the city with umbrellas and covers for
their faces, to protect themselves from the falling
ashes, which were abundant even there, and the
lighter portions were carried by the wind to great
distances.
A remarkable feature of this eruption, and the
first of the kind Prof. Palmieri thinks authenticated,
was the " external eruptions " that occurred on the
great stream of lava that flowed by the Observatory.
So decided and conspicuous were these explosions
and ejections of projectiles that one is distinctly
HISTORY: 1869 1888. 141
recognisable in the photograph before mentioned.
These the Professor considers to be essentially
different from the apparently somewhat similar
miniature eruptions of 1850, 1855, and 1858, which
he believes to have emanated from fissures below
the lava. The three eruptive points of 1872 were
each in action from fifteen to twenty minutes, and
then entirely disappeared, being carried away by the
fiery torrent. Mr. Mallet seems to justly say that
they were " most probably merely the bursting
upwards of large bubbles ; that is, of cavities formed
in the mass of the more or less liquid lava by
intestine movements, as its mass winds and rolls
along, and by the aggregation of smaller cavities
all being filled with steam and gases." Neverthe-
less, it seems to me that Palmieri thinks rightly
that they " cause the recognition of a power in the
lava itself to form eruptive fumaroles," and if so,
they must have an important bearing on the
causes of, if I may so term them in contradistinction,
the internal eruptions, or the principal eruptive
phenomena.
The lava that was poured out so abundantly on the
26th and 27th, besides being so sadly fatal to life as
in the occurrence before stated, was most destructive
to property. On the south side of the mountain the
lava did not travel further than the borders of the
cultivated region, and so the beautiful slope towards
the sea and the towns at its foot were uninjured, and
similarly the eastern slope with Bosco-tre-Case and
142 MOUNT VESUVIUS.
Bosco-Reale escaped. On the western side, however,
an immense flow, proceeding from the great fissure,
descended the Fosso della Vetrana and so through
the Fosso di Faraone to the Plain of the Novelle,
and these devastating fields, gardens, and houses,
caused great havoc. One still more destructive
stream flowing over that of the eruption of 1855,
which partly destroyed Massa di Somma and San
Sebastiano, again swept over parts of these villages,
obliterating in the case of Massa one-third, and in
that of San Sebastiano nearly a fourth of the
houses. So rapidly did the flood of lava come
upon the villagers that they were barely able to
save some of their portable property, and many
lost everything. Prof. Palmieri thinks that if
the emission had not greatly diminished, as it did
after a brief outflow, the lava in twenty-four hours
would have passed through Ponticelli and reached
Naples itself. It was estimated that the amount of
lava emitted during this eruption was about 600
millions of cubic feet, and that the value of the
property destroyed was over three million of francs.
On the 29th of April the explosions were less
violent, and at night became less continuous with
decreased noise, while on the following day all the
eruptive symptoms were quite subdued, and on the
ist of May the eruption was at an end. Its
decadence was, however, accompanied by a storm
with thunder and some rain. " The grass, the
seeds, the vine tendrils, the leaves and tops of the
HISTORY: 18691888. 143
trees dried up immediately, and the country was
changed from spring to winter." The cause of this
notable injury to vegetation was doubtless the
conveyance by the rain of destructive gases and
sea-salt, obtained from the canopy of smoke and
ashes above, to the more tender parts of the
plants. A few years ago a south-west gale, by
carrying sea-spray inland, produced a somewhat
similarly injurious effect on the early foliage of the
oaks of Sussex which had just put forth their
leaves.
The chief characteristics of this eruption were its
long-continued simmering and its most violent but
brief ebullition at the close, the " exterior eruptions,"
and the great amount of volcanic lightning with
thunder proceeding from the canopy of smoke above
the mountain.
The curious phenomenon of a great accumulation
of insects (Coleoptera) on the cone was observed
after this as after previous eruptions. Mr. Mallet
states that he has observed a similar abundance of
insect life, great and small, on Etna, and suggests
that it may arise merely from the local dryness and
warmth, and the nidzis afforded by the vesicular
lava for the eggs and earlier stages of insect life.
As was to be expected, the violent eruption of
18/2 had the usual effect produced by paroxysmal
eruptions of reducing the height of the mountain a
little, and forming a large crater. The crater now
produced was divided by a " Cyclopean wall," and
144 MOUNT VESUVIUS.
Prof. Palmier! found its depth to be more than
800 feet, with a tunnel near the bottom of the
eastern half perforating the side.
That abundant product of Vesuvius, common
salt, or " sea-salt," as Palmieri prefers to call it,
from its containing, besides chloride of sodium, the
other compounds characteristic of the salt of the
sea, so extensively and conspicuously covered the
ground that " not only the Vesuvian cone, but the
whole adjacent country appeared white for many
days, as if covered with snow, when exposed to
sunlight."
1873. The very violent and destructive eruption
of 1872 was, as was to be expected, followed by a
period of tranquil inactivity, and nothing noteworthy
has been recorded of Mount Vesuvius during the
year 1873. Visitors to the now quiet volcano were
numerous, and the rugged and still hot lava was
traversed by travellers from all countries, while the
ruins at San Sebastiano and Massa di Somma
attracted great attention, affording, as they did,
most cogent evidence of the destructive power of
the now slumbering giant of the Neapolitan
Campania.
1874. The repose of 1874 was not quite so
complete as that of the preceding year. On the 3rd
and 4th of January a rumbling noise was to be
heard at the crater, while dense smoke gave evi-
dence of incandescent matter being not far distant.
Subsequently the restlessness of the volcano some-
HISTORY: 1869 1888. 145
what increased, and showed itself particularly
towards the north-east of the crater, and globes of
smoke were evolved, with a hissing sound and
odour of hydrochloric and sulphurous acids. Near
the end of the great fissure of the eruption of the
previous year, sublimations of alkaline compounds
were deposited on the surface. On the 2ist of
January a slight shock of earthquake was felt at
Casamicciola, on the island of Ischia. The volcano,
however, was not further active, with the excep-
tion of a slight eruption on July i8th, giving off
clouds of smoke only, during the year, and at its
termination was quite quiescent.
1875. Neither explosive ejections of fragmentary
matter nor emissions of lava appear to have been
observed during the year 1875, but there was a
considerable evolution of gases, and it is stated by
Mr. Rodwell that carbonic acid diminished and
hydrochloric acid commenced, thus indicating the
highest stage of fumarole activity. During January
much sulphurous acid was given off, rendering a
descent into the crater impossible. In December,
however, there were indications of renewed activity.
Earthquake shocks were felt at Naples, and a
large portion of the interior of the great crater of
1872, towards the north-east, fell in, and dense
clouds of black smoke arose, and on the iQth, lava
was seen below, which became more conspicuous on
the 2Oth, but no eruption took place during the
remainder of the year.
L
146 MOUNT VESUVIUS.
1876. In March, 1876, great volumes of smoke
arose from the crater with, at night, the reflection of
glowing lava below, and the instruments at the
Observatory were in a condition of disturbance.
The lava gradually increased in height, and ulti-
mately rose to the top of the chasm produced by the
giving way of the floor of the crater in the previous
December, while slight ejections formed a small
new cone.
1877. At the beginning of January in this year,
Palmieri reported that the Observatory instruments
were agitated, and that smoke was issuing with
greater force from the crater, and with increased
volume. The lava of the volcanic axis gradually
increased in height, and ultimately rose to the top
of the chasm in the crater floor, and slight ejections
of fragmentary materials gave a small new cone to
the interior of the great crater.
In the year 1878, Vesuvius had a very con-
siderable access of activity, attaining a stage which
might be termed completely " Strombolean." The
coming eruption was presaged in April by a column
of what is called " flame " arising at short intervals
from the summit of the mountain. This would
doubtless be the reflection of the lava in the crater
rendered intermittent by the occasional intensity
of the blackness of the smoke consequent upon
temporary increase of the volcanic ash ; but it was
not until the following September that decided
eruptive symptoms were manifested. In this
HISTORY: 1869 l888. 147
month it is stated that volumes of lava were pro-
jected 100 yards above the new crater, accompanied
by loud explosions, and that no "flames" were
visible. This statement is difficult to understand,
for if an accurate one, it was a most unusual phe-
nomenon, and of great importance in vulcanology.
After this there was a slight diminution of activity,
which Palmieri notes was increased at the time of
new moon.
At the beginning of October, the crater appears to
have been, by the continuous uprise of the lava,
almost full of the fiery fluid, and on the ist of
November it flowed over the lowest part of the
rim, or rather it carried away the loose fragmentary
crest of a depression in the rim, and so formed a
lip over which it continuously flowed. This was on
the north-west side, giving to the lava a direction
that took it into the Atrio del Cavallo, and thence
through the same ravine and over a similar course
for some distance, as the lava of 1872. The main
flow divided into three streams, neither of which
reached the cultivated region, and so no devastation
was caused by this eruption. The flow of lava was
not of long continuance, but on the 29th of Decem-
ber, Mr. Rod well says that the new cone was pouring
out vast volumes of steam and smoke, accompanied
by detonations and loud noises as if lava was
surging in the crater, the walls of which were 100
feet high. The sublimates then observed were
chiefly sesquichloride of iron and sea-salt, but
148 MOUNT VESUVIUS.
Palmier! detected some sulphates, boracic-acid and
lithium. This new lava was very leucitic, though not
resembling that of the eruption of 1872, and when
viscous could easily be drawn out into fine threads,
but when cold it was quite black and had a good
lustre.
1879. As in the preceding year, there was no
marked activity of the volcano until November,
when Vesuvius, it was said, had on the 3rd of that
month again " hoisted its red flag," that is the crateral
lava manifested itself by illuminating the ascending
volumes of steam, thus producing the flame-like
light that is so ominous when seen from Naples.
At this time the cone that had been gradually
growing in the centre of the great crater of 1872
was a few yards above the enclosing rim, like, as
was said, a small cup in the middle of an immense
saucer, which latter was almost full of lava that had
been flowing over a depression since October the
30th.
Continuous, though slight, activity prevailed for
several weeks, when, on the 1 7th of December, the
maximum activity was recorded, and the snow-
capped mountain was seamed with fire on the side
above Portici, when it presented a striking and
beautiful spectacle. On the next day the reduced
disturbance was accompanied by local shocks and
heavy breathing, but there was no pronounced
explosion. At the end of the year there was much
smoke, but no lava flowing, while the new cone was
HISTORY: 1869 1888. 149
50 feet above the great crater-rim. Prof. Palmieri
observed that the volcanic energy was greatest at
times of new and full moon.
In this year, Prof. Scacchi, the eminent Professor
of Mineralogy in the University of Naples, reported
the discovery of a new chemical element in some
yellow and green incrustations on the lava of 1631,
which he called Vesbium, from an old name of
Vesuvius mentioned by Galen. These substances
were accordingly named the " Vesbiate of
Aluminium " (the yellow) and the " Vesbiate of
Copper " (the green). (See Vesbine, Chapter X.)
1880. In January of 1880 there was increased
energy, and the eruptive cone gave off volumes of
dense white steam, while large masses of scoriae
were at the same time ejected to a considerable
height at frequent intervals, while lava rose in the
volcanic tube, very frequently flowing from the vent
through a hole in the side of the small cone near
its base, of about five feet diameter. One stream
descending on the north-west side of the cone
reached the Atrio del Cavallo.
In the lateral " bocca" the lava was much agitated,
and Mr. Rod well says it was thrown up three or
four feet above the opening, in every respect re-
sembling small geysers he had seen in Iceland.
Another but smaller stream of lava also flowed
from the summit into the Atrio, but on the next day
the activity diminished. The lava of this eruption
was very leucitic and similar to that of 1871, and
I5O MOUNT VESUVIUS.
the fumaroles yielded copious sublimates of chlorides
and sulphates, while the spectroscope revealed the
presence of the metals lithium and thallium. Hy-
drochloric and sulphurous acid gases were given off.
At the time of full moon in the latter part of
March, greatly increased volcanic activity was mani-
fested. Two new mouths opened at the foot of the
new cone, from which jets and red-hot stones were
ejected to a great height, while lava was emitted
from the central crater. After a time of suspension
of activity, volcanic energy again manifested itself
in the autumn, and at the beginning of November
lava was flowing freely. The eruption continued to
increase, and the lava streams multiplied, present-
ing, towards the end of the month, a magnificent
spectacle. An outwork built to protect the upper
station of the Funicular Railway, which had been
opened in the previous June, was destroyed by the
lava-flow, but the railway itself remained uninjured.
1 88 1. At the beginning of March, 1881, lava
again flowed copiously, and seamed the snow-
covered mountain with fire. This flow was on the
north side, and the lava, being both very mobile
and abundant, the course threatened to extend
further than the Atrio del Cavallo, into which the
lava first flowed. Another stream descended the
side of the cone a little further to the west before
the end of the month.
The large crater left by the eruption of 1872 had
been filled for a long time with lava to the level of
HISTORY: 1869 l888. 151
the lowest depression in its rim, and the plain of
lava so produced formed a platform, on which arose
a small, steep-sided, eruptive cone. This was partly
destroyed in July of this year by an access of erup-
tive energy, which left an increased opening with
lower enclosing walls.
In a tunnel of lava-exit through the walls of the
eruptive crater, Dr. Johnston Lavis obtained thirty
stalactites, which were chiefly composed of common
salt or halite, and were highly diliquescent. Together
with chloride of sodium, there were present chlorides
of potassium, iron, and manganese, with sulphates of
soda, potash, iron, and copper. There were also
crystals of halite, sylvine, and a few of molysite.
These stalactites had been formed by rain-water
percolating through decomposing lavas, and re-
depositing in the interior of the tunnel the extracted
soluble compounds. The month of December of
this year again witnessed an emission of lava, this
time on the eastern or Pompeiian side of the great
cone. Towards the end of the month the eruption
increased, and on Christmas Day a fissure opened
on the north side and extended a third of the
way down the great cone, with a breadth at the
top of 1 20 feet. The copious flow of lava descended
into the Atrio del Cavallo too far to the north to
do any damage. On this occasion also a covering
was formed over the descending flow of lava by
surface solidification, and a tunnel or tube was so pro-
duced. The lava is described as having had almost
152 MOUNT VESUVIUS.
the liquidity of water, and some experiments by
Dr. Lavis led him to conclude that, contrary to
Prof. Palmieri's previously obtained results, cold
solid lava has a higher specific gravity than the
incandescent fluid.
On the lowering of the level of the lava in the
volcanic tube, a remarkable alteration took place in
the character of the ejectamenta. Instead of soft
masses of pasty lava, there were discharged rounded
fragments of solid and evidently old lava, together
with volcanic ashes. As suggested by Dr. Lavis,
this may be explained by regarding the fragments of
solid lava as derived from the walls of the volcanic
tube, which were no longer supported by a column
of lava, and which therefore bit by bit fell into
the line of fire of the volcano and were consequently
discharged, the ashes being formed by the attrition
and trituration of these fragments.*
1882. This year opened quietly, and it was not
till the middle of January that any light on the
summit was seen at Naples, and this ceased before
the end of the month, but revived in February. In
March and April there was no activity visible at a
distance. Towards the end of April there was a
crater less than 400 feet diameter, occupying about
one-third of the area of the great crater of 1872,
but not concentric with it. There was still a small
Bow of lava, reaching to the Val del Inferno.
* For a detailed account of Vesuvian activity in 1881, see Dr.
Johnston Lavis in Nature, vol. xxv., p. 295.
HISTORY: 1869 1888. 153
A slight increase of activity coincided with an
eclipse of the sun in the middle of May. This was
followed by greater tranquillity till the first week in
June, when, at the time of earthquake shocks in
Isermia and Vinchieta, in the Apennines, there
were increased explosions, but these soon ceased,
and till the end of the month there was no reflection
seen. At the beginning of July, however, the
activity increased, and lava flowed again freely.
From this time till the end of the year there was
little activity, although smoke was constant, and a
slight flow of lava continued in the direction of
Pompeii, but stopping at the edge of the Atrio.
Dr. Lavis, on visiting the summit in July, found
a fourth crater forming. The old floor of the 1872
crater was much decomposed, and covered with
fumaroles towards the south-west.
1883. Throughout the whole of the year 1883,
Vesuvius was in a condition, to use a somewhat
paradoxical phrase, of much-disturbed tranquillity,
during which, in every month, the volcano mani-
fested sometimes considerable activity, and often-
times almost complete quiescence, though absolute
dormancy was never attained. A gentle and quiet
emission of a small volume of lava continued for
lengthened periods, and occasionally increased to a
considerable flow, while the ejectamenta only seldom
reached any great altitude.
In the latter part of February there was a stream
of lava descending towards Torre del Annunziata,
154 MOUNT VESUVIUS.
but it did not continue to flow more than a day ;
and in the first half of March there was a somewhat
copious emission of lava, but, with the exception of
an increase on the last day of the month and during
the third week in April, there was not much action
till the 1 8th of May, when the projectiles were both
high and brilliant, and on the 25th of the same
month there was a considerable explosion.
In this state of feebleness, with occasional dis-
plays of increased power, Vesuvius continued
through the months of June and July, and at the
end of the latter month, when the disastrous earth-
quake at Cassamicciola, in the neighbouring island
of Ischia, occurred, the volcano was almost in its
quietest phase. It was not until after the middle
of August that there was again an abundant flow
of lava, and this diminished two days afterwards.
Again there was little action till the 7th of October,
when, and once or twice in this month afterwards,
there was vigour displayed. In the middle of
November the volcanic energy, for about four days,
was high, and then there was a subsidence that,
broken only by a spurt on the 27th of December,
continued till the end of the year.
On visiting the crater on the 22nd of April,
Dr. Lavis found much fine fillamentose lava spread-
ing over, as a light cover, the crater floor, and,
from the rapid decomposition of old lava by acid
vapours, crystals of pyroxene and of leucite were
very abundant. It may be worthy of note that on
HISTORY: 1869 1888. 155
the 1 6th of February of this year an earthquake
shook the city of Bologna and the whole of
southern Romagna, and at the same time there
was an increase in the activity of Vesuvius.
1884. A somewhat greater activity appears to
have prevailed during the year 1884, though only
once or twice did it rise to the dignity of an
"eruption." Strombolean activity may, perhaps,
best describe the almost constant ejections of frag-
mentary material going on throughout the year.
On the night of the gth of January there was a
conspicuous display of lava and projectiles, that was
called in the English newspapers " a violent erup-
tion," with a flow of lava into the Atrio del Cavallo
at the Pompeiian end, but it quickly terminated, and
on the 1 2th there was a great diminution of activity.
Much filamentous lava was again produced.
The following useful scale of Vesuvian activity is
given by Dr. Lavis, ( in his Report to the British
Association in 1885, and also in " Lo Spettatore
del Vesuvio dei Campei Flegrei," by means of
which the eruptive phenomena may be briefly and
comprehensively recorded by an observer at Naples
after nightfall whenever the mountain is free from
cloud :
SCALE OF VESUVIAN ACTIVITY.
1st degree. A faint glimmer, above the main vent, interrupted by
complete darkness.
2nd degree. The glimmer is continuous, but the ejection reaches
hardly above the central crater-rim at most.
3rd degree. Glimmer continuous and well marked ; the ejections are
156
MOUNT VESUVIUS.
distinctly discernible as they rise and then fall on the slopes of
the cone of eruption and roll down its slopes.
4th degree. The ejections reach a considerable height, are brilliant,
and light up the top of the great cone.
5th degree. Verging on an actual paroxysmal eruption, the ejections
are shot up very high, being only very slightly or not at all
influenced in their course by a strong wind. Each explosion
follows with much rapidity, and corresponds with the " boati "
heard all around the west, south, and south-east slopes of the
mountain.
From the record given in " Lo Spettatore " of
the results of the application of this scale in the
year 1884, it appears that in 239 observations the
activity was at 4^ three times, 4 five times, 3
twenty-six times, 2^ seven times, 2 fifty-four times,
i J thirty-two times, and at the lowest stage, or i,
one hundred and twelve times.
The fluctuating character of the volcanic energy
of Vesuvius during a period of Strombolean activity
is well shown by the register for a single month,
which may be thus tabulated :
FEBRUARY, 1884.
ist, cloud
8th, ;
}
i 5th, i
22nd,
4
2nd, cloud
9th, :
1 2
i6th, i
23rd,
3rd, 4^
loth,
i7th, i
24th,
4th, 3
nth,
i 8th, i
25th,
5 th, 4
1 2th,
1 9th, 2^
26th,
6th, 4
1 3th,
2Oth, 2
27th,
7th, 3
i 4 th,
2ISt, 2
28th,
The small flow of lava which had been going
on continuously, with an occasional increase, since
December, 1881, was considerably lessened in
March of this year ; and during April, May, and
HISTORY: 1869 1888. 157
June the activity was very languid. A slight but
short increase in July was followed by a diminution
that continued till the October following, when 3 of
activity were registered on several occasions. Until
the end of the year the volcano continued in the
same state of varied but low activity.
Changes of more or less importance modified the
interior of the old great crater of 1872, new cones,
new mouths, new fissures, being formed and obli-
terated by the alternation of the eruptive phases.
A modification of the outline or profile of the great
cone was also produced by the long-continued
ejection and emission of materials, and its greater
accumulation on one side, which gave a double
hump on the profile of the slope, as seen from
Torre del Greco and the Camaldoli della Torre.
1885. Strombolean activity still characterised
the state of Vesuvius throughout the year 1885,
with the usual alternating increase and decrease.
In the middle of January the eruptive energy
rose to 4 for two days, but speedily fell again
to i. A new mouth was formed on the i8th of
January, on the eastern side of the eruptive cone,
where was the cleft of 1882, and the lava descended
through the conduit then formed. In the latter part
of the month, Dr. Lavis found near the eruptive
mouth mammilary, submetallic-looking, dull-brown
masses, which, when struck with a hammer, proved
to be as soft as starch.
There was a somewhat abundant flow of lava
158 MOUNT VESUVIUS.
early in May from a rent not far distant from the
upper station of the Funicular Railway, which
flowed in the direction of Pompeii and Torre del
Greco, but did not extend very far. The rent on the
cone was the termination of an interior fissure which
had been gradually forming, proceeding radially
outwards, and the partial in-filling of which with
lava formed a new dyke. A slip of part of the cone
gave a section of this, showing it to be hollow. The
lava flowed in two parallel streams about 150 feet
apart, and moved at the rate of about three feet per
second, thus giving about 10,000 cubic yards of lava
rock in twenty-four hours to the mountain slopes.
Lava appears to have flowed continuously, though
in diminished quantity, until the end of the year.
!886. A cessation of the lava-flow from the rent
of the previous May, with the exception of a slight
emission for three days early in January, continued
until February 4th of this year, when an abundant
stream issued to the north of the principal vent of
the volcano, and flowed down the northern side of
the cone. The lava, moving at the rate of about
three feet in five seconds, gave a mass of material
of nearly 30,000 cubic yards. After the nth of
February the outflow diminished, and ceased in the
third week in March ; but there were slight flows in
April, and unimportant variations in May, during
which month there was an eruption of Mount
Etna, but with which Vesuvius did not show any
sympathy.
HISTORY: 1869 l888. 159
In June the eruptive cone was found to be
greatly increased in height and in the diameter of
its base, since it covered nearly all the crater rings
on the floor of the great crater of 1872. On the
28th of this month this cone partly gave way, and
the upper part crumbled in, and at the same time
there was an increased flow of lava. Then followed
a cessation until the 8th of July, when the fused
rock flowed into the Val del Inferno, and, then
descending, reached the cultivated region, destroy-
ing some of the trees of the woods belonging to the
Prince of Ottajano and injuring some vineyards.
Again, on the 2ist of the same month, the lava
caused a similar extent of injury, and a considerable
flow took place in the first week in August, when it
was found that the eruptive cone had been reduced
by about 100 feet. So much chloride of copper was
sublimed that Dr. Lavis speaks of the nails in
his boots being plated with the metal. In the
next month (September) the lava once more
reached the cultivated lands at the south end
of the ridge of Somma, but little damage was
done.
Variations of lava-flow continued until the end of
the year with ejections of ashes that again increased
the eruptive cone. The eruptive crater became
oval with the larger end towards the east, and early
in November a new rent appeared on the eastern
slope of the great cone, and near to the opening of
1 88 1 -2, while there was found a new fissure in the
160 MOUNT VESUVIUS.
floor of the great crater of 1872 and having a north-
east direction.
1887. Few changes and little activity charac-
terised the state of the volcano throughout this year,
the eruptive energy not exceeding the third degree.
A small flow continued to descend the great cone on
its eastern side, under the cover of a lava-formed
tunnel, and to emerge in small streams at its
base in the Val del Inferno, not far from the
Pedamentina.
1888. During the greater part of last year the
activity of the volcano was similar to that of 1 887, but
the summit of the new eruptive cone had attained in
June the level of the crater's rim, and a small emission
of lava continued. The close of the year was marked,
however, by an increase of activity, as the following
paragraph from Nature of the 28th December,
giving the latest information of Vesuvius in 1888,
records: "Vesuvius has lately been very active. It
has been rapidly throwing up a new cone of
eruption about thirty to forty yards to the south-
west of the original one, and the fissure across the
crater plane towards the west-south-west is increasing
in size, and is richer in acid and incrustations. It
is possible, therefore, that an eruption may take
place soon on that side of the cone, since the vent
tends to shift along the fissure pointing in that
direction."
Thus it will be seen that Vesuvius has been in a
state of slight activity for six years. Such a long-
HISTORY: 1869 1888. 161
continued, slightly eruptive condition of the volcano
may have occurred during previous centuries, as its
minor and less striking phases were not recorded.
Indeed, the present assiduous and unremitting
observation of the condition of Vesuvius is alto-
gether without parallel, and the warmest thanks of
all vulcanologists and students of science, as well as
of all lovers of Nature, are due to Prof. Palmieri
and Dr. Johnston Lavis, as well as to the British
Association for its annual grant in aid of this
important and most interesting work.
162
CHAPTER VII.
GEOLOGY OF VESUVIUS.
Vesuvius Geologically Instructive and Illustrative Three Geological
Divisions The Cone : Cause of its Regularity; its Structure, Lavas,
Minerals Monte Somma : Change of Position of Axis, Formation
of Great Crater-Rings, Structure, Dykes, Minerals The Base :
Concavity of Volcanic Outlines, Structure Concealed, Hypo-
thetical Origin, Geological Age Theory of Craters of Elevation.
THE geology of Vesuvius is as interesting as its
history ; indeed, the one is a sequel to the other,
for the geology of the volcano is the result of its
remarkable history, and a knowledge of the latter is
a necessary preparation for the consideration of the
former, since an acquaintance with the character
and effects of the various eruptions which have
modified the form of the mountain and gradually
brought it to its present state forms a basis for a
correct understanding of its structure and geological
formation.
Mount Vesuvius is an especially instructive
volcano to geological students, who find in this
easily accessible mountain of moderate elevation
illustrations of almost every form of volcanic
phenomena, and in its frequent eruptions almost
every phase of volcanic activity.
But although the mountain is a complex one, and
largely illustrative of varied volcanic phenomena,
it is not difficult to obtain a clear perception of its
GEOLOGY OF VESUVIUS. 163
structure and the formation of each portion that
contributes to its peculiar configuration. The whole
is readily divisible into three parts, that, although
united and forming one mountain mass, are in many
respects distinct, as well as the production of the
volcanic activity of three different epochs. These
three chief geological divisions of the volcano
are :
1. THE CONE;
2. MONTE SOMMA ; and
3. THE BASE, or body of the mountain, under-
lying both Somma and the Cone.
THE CONE. The newest of these three portions
of the mountain, the cone, which we have seen
gradually growing up from the accumulation of
the ejectamenta of successive eruptions, demands
attention first, since it will explain not only the
structure of the other two portions, but the structure
of volcanic cones generally, of which this is a typical
example. In addition to the light thrown upon its
formation by the accounts of past eruptions, there
have been special and remarkable opportunities
for actually observing its internal structure and
anatomy, so that no doubt remains either as to
its structure or the manner in which it has been
built up.
The Cone is simply the resulting accumulation of
successive falls of ashes, lapilli, cinders, and scoriae
ejected, and of solidified lava-flows emitted, during
many eruptions, and is, therefore, composed of a
164 MOUNT VESUVIUS.
series of beds or sheets formed of these materials,
and lying more or less parallel with the exterior
slope. They consequently have a quaquaversal dip,
or an inclination outwards on all sides from a
central axis, which is the tube, funnel, or chimney
of the volcano, and through which the lava rises
from the deep-seated source of the volcanic energy
in the interior of the earth.
Did a volcano eject only loose solid material,
there would be no difficulty presented by the
conical form of these mountains, for, notwith-
standing the influence of the wind in determining
the side on which the greater amount of the ejected
fragmentary material would fall, yet the various
directions of the wind during different eruptions
would account for the ultimate regularity of the
conical outline. Some crateral cones consist
only of loose material notably those in the
Phlegraean Fields but the great majority of
volcanoes emit lava which forms beds of solid
rock of various widths, and the result of the whole
action is still a cone. The flows of lava must
therefore be as diverse in their direction as are
the falls of ejectamenta in the direction of their
maxima. The many different points from which
the wind blows at once account for the latter, but
what can ensure such a continuance of diversity of
the points of emission as will account for the
former ? To reply to this, it may be assumed that
a solidified lava-flow will strengthen the adjacent
GEOLOGY OF VESUVIUS. 165
parts of the side of the cone, and that consequently
another part of the circumference of the crater-wall
will yield more easily to the pressure of the fluid
mass the next time the crater fills, or partly fills,
with lava, and so the succeeding flow will be over a
depression in the rim or from an aperture through
the wall at another part of the circumference of the
cone. Thus the flows will in succession commence
their descent of the exterior of the cone from
different points of the circumference of the summit
ridge, or from openings or tunnels at different
azimuths or meridianal positions on the slope of the
cone.
The ultimate and general result of a large
number of eruptions must consequently be that in
the aggregate there will be an approximately equal
amount of compact rock, as well as of loose material,
on every side of the central axis or volcanic tube,
and that although each bed of compact solidified lava
may be but narrow, yet a section of the interior will
display on any side a roughly regular alternation of
beds of compact rock and beds of loose material.
The great enlargement of the crater of Vesuvius
in 1822, consequent upon the violent paroxysmal
eruption of that year, showed very distinctly the
structure of the cone, clearly establishing the fact
that it was built up as just stated. This was most
important evidence, since the crater was so large
and deep, that the very heart of the cone was
exposed, and so the structure of the whole was
1 66 MOUNT VESUVIUS.
revealed. And this regularity of alternation is
moreover continued into the newest portions, for
Prof. Palmieri, after the eruption of 1872, found in
the interior of the crater of that year exactly
the same structure compact beds of lava rock
alternating with beds of loose material, scoriae
and ashes.
A crateral section necessarily shows horizontal
* v .dges of the lava beds, but their dip, or angle of
inclination downwards, was ascertained in 1822, and
it was then found that the beds declined outwards
at angles varying from 26 to 30. This is not
quite so great an inclination as that at the upper
part of the exterior surface, but this greater inclina-
tion of the outside slope may be accounted for by
the greater amount of scoriae and ashes which
falls near the summit, and which lies and
accumulates at a high angle of slope that, together
with the more frequent dyke-forming injection
of lava into fissures in the part of the cone
nearest the central lava conduit, increases the angle
of slope of the next formed solidified lava-flow, and
consequently the upper beds of lava in an ordinary
volcanic cone have a greater inclination than the
lower ones.
That compact lava-rock can be produced on steep
slopes by the solidification on them of lava-flows
has been shown by Sir Charles Lyell in his paper
to the Royal Society, " On the Structure of Lavas
which have Consolidated on Steep Slopes," in which
GEOLOGY OF VESUVIUS, 167
he gave the results of personal observations on the
subject at Etna. Both Dufresnoy and Elie de
Beaumont had previously asserted that only thin
scoriaceous beds could be produced on steep slopes,
and that compact and crystalline lavas must have
consolidated on slopes not exceeding 3. At Aci
Reale on the coast, at the foot of Etna, Lyell found
compact lava-rock 20 feet thick that had consolidated
in 1669 at an angle of 29 over ground previously
highly cultivated. In the Cava Grande on the
eastern flank of the volcano there was found still
more cogent evidence, since here is a very compact
bed of rock five feet thick lying at so high an angle
as 35, the solidified lava of a branch of the great
flow of 1689, and reposing on a slope of the side of
a ravine in which there has been no change of level
or slope since that time. And still more remarkable
than this, Sir Charles Lyell found stony lava of the
eruption of 1852 covering a precipice, the Salto
della Giumenta, at angles of 35, 40, and even as
high as 45, and indeed at one spot he says at 49 if
not 50. At the Cava Secca, at Giuamicola, and at
the Casa del Vescovo, highly inclined beds of compact
stony lava also testify abundantly to the formation
of such beds by the solidification of fluid lava on
steep slopes.
But in addition to the parallel beds of scoriae and
lava, there was found to be walls of compact rock
cutting through them at high angles up to the
vertical, and that this rock was solidified lava too.
1 68 MOUNT VESUVIUS.
These " dykes," as they are termed, are the result
of the infilling of radial fissures by molten lava from
the volcanic tube, and they therefore proceed from
the central axis towards the exterior of the cone.
Sometimes the fissure has been a way of exit for the
lava, which on the cessation of the interior dynamic
propelling force has solidified, and so filled up,
or partly filled up, the conduit with compact rock.
The general effect of these dykes of tough basaltic
rock is to greatly strengthen the cone, and bind
together the whole structure of beds of incoherent
scoriae and ashes, and narrow beds of lava-rock, and
so to enable it to more effectually withstand subse-
quent rending and tearing eruptive forces.
A diagrammatic section of the cone would give an
appearance of regularity and continuity that is
deceptive and yet is justified. For although the
beds of lava do not extend round the cone, and are
indeed for the most part of little width, they thin
out towards their sides, and others, likewise thinning
out, and being partly on the same level, a section across
would show on each side of the axis corresponding
or similar beds, and so give an appearance that
would primd facice lead to the conclusion that the
lava extended in sheets or complete coats one over
the other, with intermediate coatings of loose
materials, quite round the cone.
The mouth of the central volcanic tube and axis
of the cone, the Crater, varies in size and shape with
almost every eruption as already explained. (See
GEOLOGY OF VESUVIUS. 169
Chapter III.) Sometimes it is a vast more or less
circular hollow with an irregular rim of half a mile
or more in diameter, and sometimes it is a very
small opening of not more than a hundred yards
wide. Sometimes, too, as after the eruption of 1822
it is a profound abyss of a thousand feet in depth,
and at other times it is a shallow saucer-like
amphitheatre, with an almost level lava-formed
floor, having in one or more places a small mouth
or fumarole whence issue fumes and steam.
As shown by the previously narrated history of the
volcano, the whole of the present eruptive cone
of Vesuvius has been produced since A.D. 79, for
the eruption of that year not only destroyed the
south-western side of the great crater of the pre-
historic volcano, but left, there is every reason to
believe, a cavity so deep as to reach below the level
of the sea. Such a cavity would be funnel-shaped,
or a hollow inverted cone, and the infilling of its
apex would necessarily be the commencement of
the formation of the present eruptive cone, which
has by successive eruptions attained its present
proportions, with, however, occasional checks to its
growth by the destructive action of such terrific
outbursts as those of 1631, 1794, and 1822, when
for a time the summit was considerably lowered,
and the cone was proportionally more truncated.
The lavas of the cone, those emitted in modern
times, appear for the most part to be markedly
different from those of earlier epochs, for they
170 MOUNT VESUVIUS.
contain usually little free leucite, which so con-
spicuously distinguishes the ancient lavas of Monte
Somma. There has, however, been a noticeable
increase in recent eruptions of the amount of free
leucite, and the lava of 1871 was especially leucitic.
Pyroxene and olivine take the place of the leucite and
constitute many of the modern lavas true basalts or
dolerites, the composition being pyroxine or augite, a
triclinic felspar, with olivine and ferruginous matter,
blended together in acompact and homogeneous mass,
and forming a hard dark-coloured rock when cooled in
mass, but when solidified from small streams that
have cooled rapidly and without pressure, the lava is
very scoriaceous and vesicular or spongiform in
texture, and has a harsh and trachytic feel.
Prof. Palmieri, describing the manner of solidifi-
cation of lava-flows, writes as follows :
" The part which begins to harden breaks readily
in some lavas into fragments which float on the
viscous fluid beneath ; these, increasing in number,
with distance from the source, conceal the molten
matter beneath and retard its progress, and at last
nothing is seen but the more or less red-hot scoriae
moving along. These lavas I shall call ' Lavas with
fragmentary scoriae.' On other occasions a skin
forms on the surface of the lava, which, gradually
thickening, keeps flexible for some time, and then
wrinkles or swells or extends and breaks to give
egress to the hot fluid within, which, in its turn,
skins over and repeats the same phenomena. This
GEOLOGY OF VESUVIUS. 171
I shall call 'Lavas with a united surface.'" Palmieri
states that the former of these two classes comprises
the lavas with little leucite and abounding in
pyroxene and olivine, while the latter includes
those rich in leucite and containing little or no
pyroxene.*
It is, too, a remarkable fact that, although more
species of minerals have been obtained from this
mountain than from any other equal area in the
world, yet the modern ejectamenta forming the
present cone of Vesuvius have yielded but a small
number. Yet again the more recent eruptions
have produced an increased number. Augite or
pyroxene, titaniferous iron, hornblende, sodalite,
mica, breislakite, leucite and tenorite are sometimes
found in the modern lavas in distinct crystals.
Cotunnite, a chloride of lead, was found after the
eruption of 1822 inside the crater, and was a
marked constituent of the lava of 1855, which was
unusually fluid, rendered so, it has been thought,
by the presence of this mineral. Prof. Palmieri
says : " I found the crystallised chloride of lead, or
' cotunnite,' as it is called, for the first time in the
lavas of 1855, and thought it a singular circum-
stance ; but from that time I recognised it in all the
lavas, though not always so beautiful and abundant ;
and even when not found as a distinct substance,
*" Eruption of Vesuvius in 1872," by Prof. Palmieri, translated by
Robert Mallet, page 103.
172 MOUNT VESUVIUS.
I observed it in combination with chloride of
copper." * (See Chapter X.)
MONTE SOMMA. This (sometimes named Monte
di Somma, from the town of Somma, in the plain
below) is the second of the three great divisions of
the mountain, and is the remaining portion of the
enclosing wall of the vast ancient crater which
existed before the Christian Era, and which was
not active during the whole of the preceding
historic period. The western and southern sides
of the crater wall having been destroyed, the re-
maining half, Monte Somma, forms a semi-circle,
with its concave or inner side facing the Cone on
the north and east.
It has been calculated that the centre of the base
of the modern cone is coincident with the centre of
the circle, of which the escarpment of Somma forms
a part. Thus it is seen that the vent, or eruptive
axis, of the modern Vesuvius was also that of the
last stage of the pre-historic volcano, and that con-
sequently there has been no change in the position
of the axis as a consequence of its long dormancy,
that, in fact, the axis of the modern Vesuvius
coincides with the position of the axis of the great
crater of which the Atrio del Cavallo formed a
part.
It has been found, however, from careful calcula-
tions, that the curve of the Atrio is not concentric
* Palmieri, "Eruption of Vesuvius in 1872," page no.
GEOLOGY OF VESUVIUS. 173
with what remains of the circumference of the
original simple but lofty conical mountain, the
outer or convex side of Monte Somma, and that
consequently the centre of the inner curve is not
the centre of the outer one. But as the centre
of the outer curve must have been the primary
eruptive axis, and the centre of the inner one is
the present eruptive axis, it follows that the position
of the axis must have at some period been changed.
This alteration of the position of the eruptive axis
has been calculated to be no less than about a
thousand yards towards the south or a little to the
west of south. A change in the position of the axis
of a volcano is nowhere perhaps more conspicuously
seen or more beautifully shown than in the Puys
Noir, Solas, and La Vache, in Central France, and
in the island of Vulcano, one of the Lipari Islands,
where, in both localities, there are three contiguous
excentric craters, clearly indicating that the eruptive
axis has twice changed its position. At Mount
Etna, too, the Val del Bove, on its side, is doubtless
the old crateral opening of the early axis of the
volcano, while the present eruptive vent at the
summit of the mountain, Mongibello, is four miles
distant.
It is doubtless in consequence of a change in the
position of the axis during the middle period of the
existence of the Vesuvian volcano, and the con-
sequent oblique or irregular truncation of the cone
at that time, that is due to some extent the absence
174 MOUNT VESUVIUS.
of an opposing ridge on the southern side of the
present cone, since, doubtless, before the eruption
of A.D. 79, the old great crater-rim was much lower
on this than on the northern side. The remnant of
the wall of the pre-historic crater on the southern
side is the eminence called La Pedamentina, and
this evidently formed a portion of the outside slope
of the old crater wall, corresponding to the outside
slope of Somma at the same elevation above the
level of the sea. The hill of La Crocella, on which
stands the Observatory and the Hermitage, is also
a small remnant of the base of the bounding walls
of the pre-historic crater separated from the main
portion of what is left of it, the ridge of Somma, by
the Fosso della Vetrana.
The escarpment or wall of Somma, extending for
a distance of upwards of two miles, is more than a
thousand feet high, and presents a face almost per-
pendicular. The upper edge is irregular in outline,
and is, indeed, a serrated ridge or line of small
peaks of more or less angularity.
Crater-rings of great diameter, like that of which
Monte Somma is the remnant, are by no means
rare, either amongst active or extinct volcanoes,
and some are of dimensions far exceeding that of
the old crater of Vesuvius. The great circular
platform on which stands the present eruptive cone
of Etna is doubtless but the surface of the infilling
of such a great crater, and the summit of the Peak
of Teneriffe is partly surrounded by what remains
GEOLOGY OF VESUVIUS. 175
of a crater that was no less than eight miles in its
longest diameter. So, too, in the Isle of Bourbon
the volcano there has a similar crater wall enclosing
its present eruptive cone ; while Madeira, St.
Helena, and the Mauritius afford illustrations on an
equally grand scale. The vast craters of Java and the
Calderas of the Canary Islands are also conspicuous
examples of these great craters that are, indeed,
analogous to the enormous crater-rings which so
conspicuously variegate the surface of the moon.
The formation of these vast craters is doubtless
due to paroxysmal eruptions which have destroyed
the upper portions of volcanic cones. Accounts of
such destructive eruptions are numerous, for, in
addition to the Plinian eruption of Vesuvius, there
was an outburst in the Mollucas in 1638 that carried
away an entire volcanic mountain of great size, and
so completely that, instead of an elevation, a hollow
was left, which, holding water, became a lake.
Another eruption in the same region that destroyed
one of the Molluca islands occurred in 1693. ^ n
the Leeward Islands, in 1718, a mountain was
similarly entirely removed, and the extraordinary
and well-known Javanese eruptions that of Papan-
dayang in 1772, and that of Sumbawa in 1865, as
well as the recent one of Krakatoa are instances
of paroxysmal eruptions of similar destructive
violence.
So enormous is the amount of material removed
and distributed by these eruptions, that but for the
176 MOUNT VESUVIUS.
facts being indisputable they would be incredible.
It must not, however, be supposed that these astound-
ing results are produced by single explosions, but
rather that they are the consequences of continuous
and continued explosive force. As shown by
Scrope, such an eruption cannot be compared, as
thought by Humboldt, to the shock of an explosion
of a mine or a steam boiler, but that the explosive
energy " having once forced a communication with
the open air, at the weakest point of some fissure
broken by its expansive efforts through the over-
lying rocks, blows itself out through this opening by
degrees, although with terrific violence; just as would
the boiler of a high-pressure steam-engine of
enormous dimensions and infinite lateral strength,
when the valve of the steam-pipe, or an accidental
aperture was opened and not after the manner of a
boiler bursting, and discharging' all its steam at
once, or of an exploding mine of gunpowder"*
Unlike the craters of the Campi Phlegraei which
are enclosed by cliffs of pumiceous tuff and by loose
fragmentary materials, scoriae and ashes, but like
the modern crater of Vesuvius, the ancient crater
was encircled by w^lls formed of successive layers of
lava, alternating with beds of scoriaceous deposits,
and traversed by dykes of basaltic rock. The
various layers appear to be horizontal, but they are
in reality not so, the appearance of horizontality
*Scrope's "Volcanos/' edition 1872, pp. 206-7.
Plate XIV.
LONDON: HOPE** onon'te.r, n, LUOGA je.mu.,c..C.
GEOLOGY OF VESUVIUS. I 77
being derived from the edges of the beds only being
seen. These beds, or at least the lower ones, dip
away from the exposed section at an angle of 26,
and so form the basis of the exterior slope of this
side of the mountain, which has an inclination of
about 30, the increase of the angle of the exterior
slope being attributable to the causes previously
explained,
The dykes crossing and cutting through both the
sheets of lava and the beds of scoriae are generally
nearly perpendicular, but they rise at all angles from
90 to 45. A great similarity exists between the
basalt of the dykes and the rock of the sheets of
lava, the former, however, appears to be more
homogeneous in texture.
The dykes of Somma have long been objects of
interest to geologists, and must always remain so,
since they are conveniently and prominently dis-
played on a grand scale, thus clearly revealing the in-
ternal structure of volcanoes, and while they illustrate
the manner in which the fissures of volcanic cones
become filled with solid ro^k, strikingly show the
very large number of such dykes which exist in
these cones. At Etna there is also evidence of the
important part that dykes play in the formation o!
volcanic cones, for in the Val del Bove, the great valley
on the side of the Sicilian volcano, so many dykes
are exposed that it is seen that there, as at Somma,
the aggregate amount of matter in the dykes forms a
considerable proportion of the whole mass of the cone.
N
178 MOUNT VESUVIUS.
The obvious ultimate effect of the injection of
fluid lava into fissures and its subsequent solidifica-
tion into dykes is, besides that of strengthening the
cone as previously said, an increase of the bulk of
the solid materials of the cone. Thus a volcanic
cone increases in size both by external and internal
accretion, and hence its growth may be said to be,
to apply botanical language to an unbiological
subject, both exogenous and endogenous. Still it
does not appear that the increase due to the forma-
tion of dykes is more than a tenth of the whole
mass. The more frequent and the more violent the
eruptions, the more numerous and the wider will
be the fissures produced by the shakings of the
mountain, and consequently the more numerous and
more massive will be the dykes that will be subse-
quently added to the structure and bulk of the cone.
The lava-rocks of Somma are hard and compact
leucitic dolerites of a bluish-grey colour. Many
contain the mineral leucite in abundance, and not
merely as a constituent mineral of the rock, but free
and separate in the form of white embedded crystals,
and these in great numbers. This is the distin-
guishing characteristic of these Somma rocks, for no-
where else do volcanic rocks display this mineral so
conspicuously, although leucitic lavas were produced
by the once active volcanoes of the Roman and
some other volcanic regions, and the mineral is,
perhaps, as abundant in some modern Vesuvian lavas.
Leucite is a silicate of alumina and potash, is an
GEOLOGY OF VESUVIUS. I 79
opaque white mineral with a specific gravity of
2-48, and is not quite so hard as felspar. It
crystallises in the cubical or monometric system,
and is often found here in detached and perfect
trapezohedrons half an inch and sometimes more
in diameter. (See Leucite, Chapter X.)
It is a remarkable and suggestive fact, that
although so few minerals have been found in the
modern lavas, or have been produced by the modern
activity of Vesuvius, no less than 300 species of
minerals have been enumerated as having been dis-
covered in the ancient lavas of Monte Somma.
The critical examination of these by Prof. Scacchi
has, however, resulted in greatly reducing the
number of distinct species. The variety and abun-
dance of the minerals found associated with the
rocks of Somma and their scarcity in the more
recent products of the volcano very distinctly dif-
ferentiate the pre-historic ejectamenta from that of
modern times. Besides leucite, augite, hornblende,
sodalite, and the other minerals found in the modern
lavas, those of Somma yield vesuvianite or idocrase
in beautiful crystals, olivine, humite, nepheline or
sommite, garnets, apatite, aragonite, glassy felspar,
&c. (See Chapter X.)
THE BASE. This wide-spreading and almost
circular mass underlying the Cone and the Ridge of
Monte Somma, does not so conspicuously reveal its
geological structure as the two upper portions of
the mountain. Encrusted with sterile undecomposed
l8o MOUNT VESUVIUS.
lavas on its upper, and covered with cultivated land
on its lower surface, its interior is not exposed,
hence recourse must be had to a large extent to
inference.
Looking at the escarpment of Somma as a part
of the wall of the crater of the volcano of which the
present base was also then the lower portion, it is
fair to assume that the upper part, at least, of this
lower portion would be similar in character and
structure to the immediately overlying portion of
the same great cone. Thus we may conclude that
the alternation of sheets of lava-rock and beds of
scoriae of which the face of Somma in the Atrio del
Cavallo is composed continues downwards for some
distance, and that such is the structure of the upper
part of the wide-spreading base.
But whether the whole of this base is so composed,
or whether the earliest portion is formed, like the
hills of the Phlegraean Fields and the neighbourhood
of Naples, of fragmentary materials or tufaceous
deposits only, there do not appear to be any means
of determining with certainty.
Vesuvius may have originated in a small cratered
hill of scoriae and ashes thrown up in a short time
like Monte Nuovo ; this may have received suc-
, cessive accretions from repeated eruptions of frag-
mental materials until it had attained fair proportions
like Monte Barbaro or Astroni, though both of
these cratered mounts were doubtless produced by
single eruptions, and then subsequently emissions
GEOLOGY OF VESUVIUS. iSl
of lava may have accompanied ejections of scoriae.
On this hypothesis, the core or nucleus of the
base would be entirely composed of fragmentary
materials, but would be covered over by a succes-
sion of beds of lava-rock alternating with beds of
scoriae and forming all the mountain above.
This hypothesis, however, rests on the assump-
tion of the relative level of land and sea at this part
of the Italian coast being the same at the origin of
Vesuvius as now, and that the first ejection of
volcanic material from the Vesuvian vent was on
the land. But this is open to grave doubt, and it
seems more probable that the vent was first active
beneath the sea. Some of the upper lava sheets of
Somma that is, some of the later lavas of the pre-
historic volcano are found at Cisterna at about the
sea-level, leading to the conclusion that the older
flows or lower lava sheets of Somma are much below
sea-level, and pointing to the early Vesuvius being
a marine volcano, a short distance from the coast-
line. If such were the fact, the lowest beds of
fragmental materials, whether interbedded or quite
unassociated with lava, would be consolidated by the
action of the sea water into tufaceous rock similar
to the tufa of Naples, though not necessarily of the
same age. The oldest part of the mountain would
then be submarine, but it would early rise above
the waves, and continue to grow with successive
eruptions, while an uprise of the sea bottom would
uplift the entire base of the mountain, placing it on
1 82 MOUNT VESUVIUS.
the land, and forming a new coast-line outside the
volcano.
But whether we regard the earliest Vesuvius
as a submarine or as a terrestrial volcano, the fact
must be recognised that it rests on older sitbmarine
volcanic beds.
At the artesian-well boring at the Royal Palace
of Naples the fundamental sedimentary rock of the
country, the Apennine limestone, was found at
1,560 feet below the surface. Above this was
153 feet of Eocene beds of sandstone and marls,
called Macigno, and overlying these deposits about
700 feet of beds containing marine shells of recent
species, which would indicate post- Pliocene or
Quaternary age. Over these lie beds of volcanic
tufaceous materials with marine shells, which reach
the surface, and range under the city from 600 to
900 feet and upwards in thickness. This is, in
fact, the tufa of which the hills about Naples and
Pozzuoli are formed, and which spreads over the
country in the interior, and this is the bed on which
Mount Vesuvius stands. Volcanic action, therefore,
ejected fragmentary matter, which was spread out
by the sea, and consolidated into tufa long before
the opening of the Vesuvian vent.
Thus it will be seen that Vesuvius is a compara-
tively recent volcano, and posterior to the post-
Pliocene volcanoes that ejected the enormous masses
of material that have been since sculptured into the
hilly district at the back of Naples, attaining at the
GEOLOGY OF VESUVIUS.
18
hill of the Convent of the Camaldoli di Napoli the
elevation of 1,483 feet above the level of the sea.
The extensive ridge of Posillipo is also formed of
this pre-Vesuvian volcanic material.
But though the commencement of the formation
o
of Mount Vesuvius was in a very late geological
period, the mountain has probably passed through
many and varied phases, of which its present one,
dating from A.D. 79, is but the latest.
From a lengthy and careful study of the geology
of the whole mountain mass and its materials,
Dr. Johnston Lavis has suggested the following
SCHEME OF THE ERUPTIVE ACTIVITY OF THE
VOLCANO.*
f Introductory parox-
Era A< ysmal stage Pro-
! blematical.
Era B
("Ancient chronic ac-
\ tivity.
/'Apparent extinction,
Era cJ interrupted by }
J paroxysmal and"]
\_ other eruptions. Phase V.
\ Phase I.
C Chronic activity, outflow
of lava with scoria,
(_ ash, &c.
'Phase II.
f Inactivity.
[ Denudation.
Phase III.
( Violent paroxysm dwin-
\ dling into
Phase IV.
( Apparent return of
{ chronic activity.
Phase VI.
f Inactivity.
\ Denudation.
f Violent paroxysmal
\ eruptions.
Era
Modern chronic ac-
tivity.
Phase VII. { Le t S Q S violent dwindling
5 Chronic activity, out-
flow of lava, scoria,
&c.
The elaborate paper by Dr. Johnston Lavis on " The Geology
184 MOUNT VESUVIUS.
The concave outline observable in the profile of
volcanoes, beautifully shown in that of the very
symmetrical Fusi Jama in Japan, a mountain that
may be regarded as a typical example of volcanic
form, has been ascribed to a slight subsidence of
the mass of the mountains, caused by the removal
by the eruptive action of underlying material. It
may be contended, however, that it is scarcely
necessary to call in such a cause, since the more
abundant formation of internal dykes and the more
abundant fall of ejectamenta in the neighbourhood
of the crater, together with the expansion of the
foot of the base by the spreading out of the loose
surface covering brought down by the gradual yet
continuous descent of fragmentary material effected
by gravitation and by the removing action of wash-
ing rains, sweeping storms, and eroding and trans-
porting floods, would seem to sufficiently explain the
phenomenon.
In the early part of the present century there was
much discussion as to the manner of the commence-
ment of volcanic cones. From his observations in
the Canary Islands, and especially in Palma, in the
year 1815, Von Buch was led to the conclusion
that the walls of first-formed craters are the result
of the uplifting of the rocks around a central point,
the volcanic axis, and the subsequent bursting
of Monte Somma and Vesuvius," published in the Quarterly Journal
of the Geological Society, vol. xl., p. 35, should be consulted by those
desiring a more detailed knowledge of the geology of the volcano.
GEOLOGY OF VESUVIUS. 185
through of the middle of the dome or blister so
formed, by the volcanic eruptive energy. This
view, with details of his observations in Palma and
other islands, he published in a treatise entitled
" Erhebung Cratere," or Craters of Elevation. The
great Humboldt, from the formation of the remark-
able volcano Jorullo in Mexico, in eruption in 1759,
on a flat dome of lava, the " Malpais," favoured
Von Buch's theory, and it had a wide popularity.
The many wide-cratered volcanic islands, the
ridge of Monte Somma, and even Monte Nuovo,
were regarded as illustrations in support of this
hypothesis, and the formation of Jorullo was con-
sidered conclusive evidence. Poulett Scrope, how-
ever, closely examined the illustrations cited, and
the arguments used, and then boldly attacked the
crater-elevation theory. He showed that the Mal-
pais was formed by a great emission of viscid lava
on to a flat plain, which did not give a thicker mass
at its highest point than some lava-flows in Iceland
had produced, and that its maintenance of that
thickness until solidification, in the middle part of
the area, and its gradual declination around, was
the result of the viscid character of the lava. Sir
Charles Lyell supported Scrope by other observa-
tions, notably by those he made at Etna as to the
greatest angle of inclination at which lava will
solidify on a volcanic cone (see page 167). The
result has been that the " Erhebung Cratere"
theory is now obsolete, and volcanic cones are
I 86 MOUNT VESUVIUS.
regarded by geologists, both in their inception
and their completion, as the simple result of the
accumulation of ejectamenta solid or fluid, or
both, around a central axis, the volcanic tube.
The base of Vesuvius and the ridge of Monte
Somma must therefore both be regarded as having
been altogether so formed, a conclusion strikingly
confirmed by the structure and history of the build-
ing up of the present eruptive cone.
PlaieXV
FIG! SECTION THROUGH VESUVIUS
BEFORE THE ERUPTION orA.D.79.
Z. SECTION THROUGH VESUVIUS
AFTER THE ERUPTION OF 1631 .
LONDON ; nor-ot * onovrixr, n. i occur* HIU..S.C.
187
CHAPTER VIII.
VOLCANIC ACTION.
Pre-scientific Opinion Hypotheses of the Eighteenth Century
Later Theories Central Heat Hypothesis of Fused Interior of
the Earth with Thin Crust Recent Hypotheses All Unsatisfac-
tory Compendium of the Controlling Facts of Vulcanology
Present Favourable Position of the Question for Settlement
Author's Conclusions and Hypothesis.
CLASSIC fable and mediaeval superstition, inspired
by the uncontrollable and terrific fiery character of
volcanic eruptions, and their subterranean origin,
so invested volcanoes with the supernatural, the
mysterious, and the awful, that until the beginning
of the last century scarcely any attempt was made
to investigate and account for the phenomena
they presented. The volcanoes known to man-
kind, also, previous to modern, or rather, recent
times, were few in number, and in inverse propor-
tion to the number known was that exaltation that
lifted them out of ordinary everyday phenomena
and gave them a supernatural character.
In ancient times they were accordingly placed on
the stage where gods and goddesses, both celestial
and infernal, displayed their attributes. They were
regarded as beyond the ken of mortals, and so
especially the domain of the gods that the most
inquiring minds were content to rest satisfied with
1 88 MOUNT VESUVIUS.
a mythological interpretation of all volcanic action.
Classic fable abounds with allusions to volcanoes,
associating them with Pluto, Proserpine, Vulcan,
and Typhceus. Pluto seized Proserpine in Sicily,
near to Etna, and carried her down with him to
reign as his queen in his own dominions far below.
Vulcan, the God of Fire and Fusion, the same as
the Greek Hephaestus, forged the thunderbolts of
Jove by volcanic fires, and the smoke, and flames,
and bellowings, and shakings of an eruption were
but the evidences of his industry. The Greek
Typhon was the personification of the principle of
evil, called by the Egyptians, Set, and described by
the Latins under the name Typhceus, as having a
hundred dragon heads, fiery eyes, a black tongue,
and a terrible voice, and lying groaning and uneasy,
buried under the volcanic regions of Sicily and
Ischia, all obviously suggested by the volcanic
character of those islands.
In mediaeval times, superstitious dread of the
crater of a volcano as an opening to the place for
lost souls supplanted the mythological fables of the
ancients, and even at the present day this super-
natural association lingers amongst the inhabitants
of volcanic regions. The denizens of the immediate
neighbourhood of Etna so regard the crater, ten
thousand feet above them, and think of it with mind-
oppressing awe.
The renaissance in art preceded the renaissance
in science, but just as Raphael and Michael Angelo
VOLCANIC ACTION. 189
stepped into the footsteps of Phidias and Praxitiles,
so did Bacon and Newton follow in those of Plato
and Aristotle. The inductive philosophy of Bacon
and its application by Newton paved the way for
that widespread desire for the investigation of the
operations of Nature that have produced in this
century a Humboldt, a Faraday, and a Darwin.
But however great may be the achievements of the
nineteenth century, the preparatory work of the
eighteenth it would be most unjust to lightly
esteem. At the very beginning of that century,
in 1700, Lemery ascribed volcanic phenomena to
comprehensible causes, and seeing that rapid chemi-
cal combination, with evolution of heat, results from
the contact of certain metallic with certain non-
metallic substances, and building on the fact of the
usual association of sulphur with volcanoes, sug-
gested that below the surface stores of metals might
be in juxtaposition with accumulations of sulphur,
and from that contiguity such rapid and violent
chemical action would ensue as would account for
volcanic phenomena. It is easy to smile at Lemery's
sulphur and iron filings illustration of his hypothesis,
but that it was the best outcome of the science of
the time is shown by the fact that it was not until
the latter part of the century that another theory
was advanced by any man of scientific repute.
Breislak propounded the somewhat similar hypo-
thesis that bituminous masses, as petroleum and
asphaltum, might exist in such association with
MOUNT VESUVIUS.
other substances that combustion would be the
result, and subterranean combustion would produce
volcanic effects, These were both obviously mere
hypotheses, incapable of proof from actual observa-
tion of the phenomena displayed.
So, too, was the theory that, following those from
France and Italy, emanated from England. The
great chemist of the early part of this century will
be chiefly known to fame as the discoverer of the
bases of the alkaline earths, for to Sir Humphrey
Davy we owe the knowledge that potash and soda
are compounds of oxygen with the metals potassium
and sodium, and that such is the eagerness of these
metals for oxygen, that intense heat is the result of
the process of combination. When Davy could
rivet the attention and the interest of an audience at
the Royal Institution by dropping a small piece of
potassium on to the surface of a basin of water and
so producing fire, it is not to be wondered at that
he conceived the idea of the metallic bases of the
alkaline earths being the cause of volcanic action.
It was only necessary to suppose these existing in
large quantities, deeply seated below the borders of
seas from which water might pass, to postulate all
the conditions necessary to produce the most violent
volcanic effects. And such was the glamour of the
great name of Davy, and so simple and probable
did his hypothesis then appear, that it at once
commanded great attention and almost monopolised
assent ; and not only so, but it long held the field
VOLCANIC ACTION. 19 I
at a period when activity of scientific investigation,
followed by abundant results, was a conspicuous
characteristic of the time. So late as 1826, Dr.
Daubeny, in his comprehensive work on volcanoes,
stoutly advocated Davy's chemical hypothesis, and
showed that all the usual gaseous products and
emanations of a volcano can result from the contact
of the "alkaline metalloids," to use Daubeny's phrase,
with sulphur and the water of the sea.
It is curious to note that all three, Lemery,
Breislak, and Daubeny, presuppose the existence of
large amounts of native sulphur at the seat of vol-
canic action, whereas sulphur we now know to be a
result instead of a cause of subterranean igneous
conditions. Yet Davy and Daubeny gave promin-
ence to the action of water, and thus approached the
position taken up by later vulcanologists.
The remarkable persistence of contiguity or
proximity to the sea of our present active volcanoes,
and the contemporaneous extinction of volcanic
activity in many areas with the emergence of ad-
jacent lands from the sea, all directly point to the
conclusion that water is an agent, and a great agent,
in the production of volcanic excitement. The
immense volumes of steam given off by fluid lava
and evolved from crateral openings, with the great
amount of common salt and other chlorides, support
this conclusion. And indeed the phenomena of an
eruption are so consonant with the action of super-
heated steam when intermingled with molten matter,
MOUNT VESUVIUS.
that vulcanologists, however they may differ as to the
cause of rock-fusion, appear to be now agreed that
water has much to do with volcanic activity. Grave
and, to my mind, insuperable difficulties exist in
explaining the method by which water can pass
from the sea to a deep source of volcanic action,
since open fissures would either not allow of water
descending in the face of the steam that would force
it back, or they would themselves be the channels
of emission for the lava, and this would confine
volcanoes to the sea bottom or marine areas ; and
the suggestion of capillary transmission, which has
been called in to meet the difficulty, is equally un-
satisfactory. For although the experiments of
Daubree showed that under certain limited condi-
tions water can pass by capillary action through
sections of rock in the face of steam, these condi-
tions are not analogous to those that would obtain
in intensely heated and deep-seated regions con-
tiguous to volcanic foci. The Rev. Osmond
Fisher has shown that such capillary passage of
water cannot take place, and even if it could, it is
impossible to believe that by this means such a
rapid and abundant supply of water can be given as
would provide the ejecting and explosive power of
great eruptions.
But although no method for the supply of water
to lava free from difficulty and entirely adequate to
the circumstances and requirements of volcanic
action in detail and in aggregate, has yet been
VOLCANIC ACTION. 193
described by any of the advocates of the hypotheses
which require water for the force that produces
ejection of lava from its source, still the position and
the phenomena as well as the products of volcanoes
leave no room for doubt that to water is due violent
volcanic eruptive effects.
The questions of the source of the lava, of its
fusion^ and of the cause of the reqiiisite heat are not,
however, so generally agreed upon.
For a long time the widespread opinion that the
earth consists of a thin shell or crust enclosing an
o
interior mass in a state of fusion, sufficed to account
to most for the emission of the lava of volcanoes, which
indeed was regarded as a proof of a fused interior.
This belief, however, did not by any means entirely
rest on the outpouring by volcanoes of fluid rock
material from the interior of the earth, but also on
the fact deduced from many mines, sinkings, and
borings, that the temperature of the earth increases
with depth below the surface. The rate of increase
varies in different localities, but it is usually stated
as being i for each 60 feet of descent (though the
Rev. Osmond Fisher gives it at i for each 51 feet
of descent) below about 100 feet from the surface.
At this rate of increase the temperature at a mile
below the surface will be 150, always supposing
continued uniformity of augmentation, at two miles
about 240, at five miles 500, at ten miles 940, and
at thirty miles a temperature of 2,700, a greater
heat than is required for rock fusion, so that were
o
MOUNT VESUVIUS.
the conditions the same as those on the exterior of
the globe, there would be fused rock at a depth of
thirty miles from the surface.
M. Cordier, the most prominent advocate of the
thin-crust and fused interior hypothesis, carried out
very elaborate calculations, and estimated that a
contraction of the radius of the earth to the extent
even of the TTTSTF of an inch would suffice to press
out through any opening in the crust the amount of
lava produced by a volcanic eruption, and that a
similar contraction of a millimetre, or '03937 of an
inch, would cause the exudation of lava sufficient
for 500 of the greatest known volcanoes.
Careful consideration, however, of the physical
requirements of a vast revolving globe of fused
matter, and the consequences of its being enclosed
and retained by only a thin exterior shell, has led to
the general, though not universal, abandonment of
the hypothesis, and consequently to the disassociation
of volcanic lava from a great central fluid mass.
The elaborate calculations and arguments of Mr.
Hopkins and Sir William Thomson led those
physicists to the conclusion that a thickness of at
least 800 miles must be given to a crust adequate
for the satisfaction of cosmical conditions, and
although Sir William Thomson subsequently (1876)
abandoned his method of calculation and its extreme
results, it has been sufficiently established that a
thin crust, such as Cordier supposed, around a vast
interior fused mass nearly 8,000 miles in diameter
VOLCANIC ACTION. 195
would be too flexible to be as rigid as it is while
subjected to the attractive influence of the moon and
the sun, and that as one result, among others, there
could be no marine tides. A much thicker crust is,
therefore, required, but any such sufficiently thick
solid rocky mass would render impossible the egress
of lava, which often issues in very small quantities.
Indeed, when we consider what a single mile of
solid rock means, thicker than the height of any
mountain in the British Islands, it scarcely needed
the authority of Mr. Mallet to assure us that with
400 miles even he believed " it may be proved, on
various grounds, hydraulic amongst others, that
neither water could reach the nucleus nor the
liquid matter of the nucleus reach the surface."
The similarity of volcanic products all over the
world was long a favourite argument on the side of
the common central source hypothesis, but when it
is remembered that the great rock masses all over
the globe are composed of the same few chemical
elements, it is not difficult to understand why the
results of the fusion of these similarly composed
rocks should be themselves similar.
Central heat of high intensity is admitted, how-
ever, by all, for not only is it consonant with, and
indeed required by, the nebular hypothesis of the
formation of the solar system, with the present con-
dition of the sun, and with the secular cooling of the
earth, but it is pointed to by the already mentioned
general and continuous increase of heat with descent
196 MOUNT VESUVIUS.
below the surface. That increase of heat does not
produce fusion at a depth where fusion-heat
may be expected, is accounted for by the increase
of pressure consequent upon greater depth from the
surface. Water passes into steam at different tem-
peratures according to the pressure of the atmos-
phere, at 212 at ordinary sea-level pressure, at
193 at the diminished atmospheric pressure of
10,000 feet elevation, and, conversely, water under
great artificial pressure can be raised to a very high
temperature while still retaining its liquid form. So
also the change from solidity to liquidity obeys the
same law, and therefore solid bodies under great
pressure retain their conditions of solidity at temper-
atures much higher than would suffice for their
fusion under less pressure. Thus the increase of
heat with depth may be consistent, it is contended,
not only with a very thick solid crust, but even with
a continuously solid interior nucleus. Should, how-
ever, at any part of a sufficiently highly-heated
interior region, pressure be removed, or sufficiently
lessened, the hindrance to fusion would cease to
exist and solid rock would become at once fluid lava.
Thus have modern vulcanologists accounted for
the production of the sources of volcanic outpourings,
giving as the cause of the removal or diminution of
pressure the local elevation of the uppermost crust,
or the fracturing or giving way of rocks below vol-
canic areas. The names of distinguished vulcan-
ologists are associated with this hypothesis, which
VOLCANIC ACTION. 1 97
has reigned as the most favoured one during the
last thirty or forty years.
As an outcome of this view, more or less perma-
nent reservoirs or underground lakes of fluid lava
are assumed to exist, where pressure has been
removed or diminished, and into which sea-water
finds its way, causing, by the resulting super-heated
steam, violent ebullition, which elevates a portion of
the fluid mass above the surface of the earth, when
with the explosive escape of the steam violent
volcanic phenomena are produced.
To the existence of such permanent extensive
lakes of fused rock there are, it seems to me, the
strongest objections, for the temperature of the
molten mass must be the temperature appropriate
to its depth, and therefore the same as the tempera-
ture of all the materials at its level, or distance
from the surface of the earth, and consequently of
the bounding walls of the fiery lake. But there will
be as little pressure on those walls as on the fluid
mass, and so they must also pass into the fluid state,
and as more and more of the surrounding solid mass
became liquefied there would be fresh rock surfaces
brought into conditions favouring fusion, and so the
subterranean reservoir would continually be enlarged
by the liquefaction of surrounding solid rock, until
so great and widespread a cavity would be pro-
duced, and such an enormous mass of melted rock
would be accumulated, as would speedily bring about
a catastrophe greater than the world has ever seen.
198 MOUNT VESUVIUS.
If there were any vacuity from the discharge of a
portion of the mass with a vent for evolved gases
there would be a falling in of the overlying roof
with all the area above, and if there were no vacuity
the expansion consequent upon the change from the
solid to the liquid condition of such a vast quantity,
together with the production of gaseous compounds
and super-heated steam, could neither be satisfied
by a mere comparatively minute volcanic vent, nor
by an insensible rise of land, but only by the burst-
ing upwards of the roof of the great reservoir, and
the consequent destruction of a large portion of the
earth's surface.
The hypothesis of removal of pressure and the
consequent liquefaction of rock with the formation
of reservoirs of lava, did not find favour with the
late great English seismologist and vulcanologist,
Mr. Mallet, who, in 1872, brought before the Royal
Society a paper " On Volcanic Energy : an Attempt to
Develop its True Nature and Cosmical Relations,"
and in the next year published his views in " An
Introductory Sketch " to his translation of Prof.
Palmieri's "Eruption of Vesuvius in 1872."
Mr. Mallet shows that internal movements are
not the result of forces primarily vertical proceeding
radially, but are, as stated by Constant Prevost, " tan-
gential pressures acting horizontally, and resolved by
mutual pressures at certain points into vertical result-
ants." To these pressures, consequent upon the
shrinkage from cooling of the solid crust of the globe,
VOLCANIC ACTION. 199
are to be therefore attributed the elevation of moun-
tain chains which went on with much greater rapidity
while the crust was thinner than at the present
time when the solid portion of the globe is very
thick. Nevertheless, contraction is still going on,
and produces tangential pressures, which, not being
now so readily resolved into vertical movements,
are transformed into heat, computed by Mr. Mallet
to be far more than all the volcanic heat we know,
and " that making large allowances for presumably
defective data, less than one-fourth of the total
telluric heat annually dissipated (represented by 777
cubic miles of ice melted) is sufficient to account
for the annual volcanic energy at present expended
by our globe." Thus, to use the words of the author
of the hypothesis : " We see here linked together as
parts of one grand play offerees, those of contraction
by cooling, producing by direct mechanical action the
elevation of mountain chains, and by their indirect
action, by transformation of mechanical work into
heat, the production of volcanoes ; and both by
direct and by indirect action, of earthquakes, never
previously shown to have thus the physical connec-
tion of one common cause, but merely supposed, more
or less, to be connected by their distribution upon
our earth's surface."
Such is a very brief statement of an hypo-
thesis which from Mr. Mallet's life-long investi-
gation of seismic and volcanic phenomena is
entitled to great respect. One objection is that
2OO MOUNT VESUVIUS.
it does not seem to employ the great heat it assumes
to exist at great depths apart from that produced
by lateral pressure, and which on that diminution
of pressure that must locally result from foldings,
however slight, of overlying strata must act in the
direction of fusion. And it is difficult for me to
understand, though I have not seen this objection
stated, how tangential pressure can be transformed
into heat at particular points or along particular
lines for many centuries with the result of the fusion
and emission of vast aggregate amounts of material
without, while the pressure is still going on, surface
derangements being produced on an extensive
scale. The Rev. Osmond Fisher has shown, too,
that the heat produced by crushing pressure can-
not be sufficiently localised to produce fusion, but
must be by conduction disseminated through a large
surrounding region, and so be inoperative for the
effect claimed. And I would venture to say that
the elevation of land as shown by the geology of
the great mountain ranges was by no means small in
late geological times, when the crust of the globe
must have been similar in thickness to what it is
at present from the palaeontological evidence of
similar climatal conditions.
Indeed, it may here be added that palaeontologicai
evidence, showing, as it does, similar life-forms in
Cambrian and Silurian rocks to those now living,
clearly proves that not widely dissimilar climatal
and general cosmical conditions from those at
VOLCANIC ACTION. 2OI
present obtaining, prevailed also in the Palaeozoic
Period. Thus the conclusion is irresistible that
throughout the three great geological periods the
Palaeozoic, the Mesozoic, and the Cainozoic there
has been no very great change in the amount of
heat given to the surface from the interior of the
globe, and consequently it may be safely assumed
that during this vast lapse of time the thickness of
any " crust " overlying an internal fused mass
cannot have materially altered.
To overcome the difficulties of the hypothesis of
a thin crust with the whole of the interior of the
globe a fused mass, Dr. S terry Hunt suggested a
solid, very large nucleus, surrounded by a sea of
re-fused material, impregnated with water from the
exterior, surrounding and enclosing which is the
solid crust of the globe of moderate thickness, and
through cracks and fissures in this the fused matter
would rise to the surface, as was supposed by Cordier.
There was still the difficulty of the passage of
water to the lava below, and this was insuperable
to the Rev. Osmond Fisher, who, believing that the
increase of temperature with depth may be depended
on to give a rock-melting temperature at 30 miles,
accepted Dr. Sterry Hunt's central solid nucleus
(solidified by pressure) and an inter-layer of fused
matter, under the exterior crust (solidified by cooling),
but advanced in his " Physics of the Earth's Crust"
the bold hypothesis that the steam given forth by
volcanic lavas is the result of an extravasation of a
2O2 MOUNT VESUVIUS.
primogenial " water substance " in the molten matter
of the earth's interior, and not derived from the sea
or from surface water at all.
This view resembles the more circumscribed one
of Prof. Tschermak, who held that gaseous ejections
at volcanic vents are portions of the original consti-
tution of the magma of the globe, and that to their
escape the activity of volcanic vents is due.
A still later hypothesis is that of Prof. Prestwich,
who, in his recently published work, " Geology,''
states his adherence to the opinion that the source
of the lava of volcanoes is below the crust of the
globe, which gently presses upon the fluid mass in
consequence of continued slow cooling, and so forces
the lava through whatever vents may exist, but that
the water of volcanic eruptions is derived in the
first place from land surface water and subsequently
from the sea after the lava has risen in the volcanic
vent. In the concluding portion of this hypothe-
sis, Prof. Prestwich approaches an opinion I have
myself for some time held namely, that the
water of volcanic action is met with by the
lava not far below the surface ; but I cannot
agree with the learned Professor either as to the
source of the lava, the cause of its rise in the
volcanic tube, the importance of land surface water,
or the secondary and subordinate place assigned
to sea water.
Neither can I agree with Prof. Dana that deep-
seated water may be a constant force and surface
VOLCANIC ACTION. 2O3
water a secondary force, since I do not believe
there is any deep-seated water at all that is
sufficiently deep to approach the neighbourhood of
any established volcanic focus.
To summarise my objections to these various
hypotheses, I may say that I am opposed to
1. A common infra-crust source of lava.
2. The passage of what are comparatively insig-
nificant quantities of lava through 30 miles of rocks,
and consequently through all greater thicknesses.
3. The ejection of lava from its source by vertical
pressure.
4. The ejection of lava from its source by steam,
or "potential steam," force.
5. The passage of water through deeply-seated
hot rocks, whether by open fissures or by capillary
transmission.
6. The accumulation or the presence of water at
volcanic foci.
7. The primogenial " water-substance " source of
volcanic water.
8. The importance of land surface water.
To justly estimate or adequately appreciate the
value of any theory or hypothesis, it is necessary,
before all things, that the facts to be accounted for
should be fully recognised and constantly borne in
mind. I have accordingly prepared a statement of
the leading and controlling facts connected with
volcanoes and volcanic phenomena. While en-
deavouring to make this compendium sufficiently
2O4 MOUNT VESUVIUS.
comprehensive, I have stated each of the facts
briefly, but, it is hoped, clearly as well as concisely,
and the whole have been numbered for facility of
subsequent reference.
COMPENDIUM
OF THE CHIEF FACTS CONNECTED WITH VOLCANOES
AND VOLCANIC PHENOMENA.
1. The outputs of volcanic eruptions relatively to
the bulk of the globe are individually infinitesimal,
and in their aggregate form only a small part of
even the visible surface of the earth.
2. Astronomical calculations, ocean tides, and the
general stability of land and sea during long periods,
demonstrate great rigidity of the solid exterior of
the globe, and consequently a great thickness of
solid rocky substructure.
3. There is no general constant flexibility or
mobility of the earth's exterior, each subsidence or
upheaval being confined to a certain area, and
limited to a certain period, while some subsidences
and upheavals are confined to very small areas, as
those of the Bay of Baiae.
4. The general inorganic and climatal conditions
of the earth's surface were generally similar in
Palaeozoic to those of Neozoic times, as shown by
similar organisms, ripple-marks, worm-burrowings,
rain-pittings, &c.
5. Palaeozoic volcanic action does not appear to
have been greater than Neozoic, and the highest
VOLCANIC ACTION. 205
mountain ranges of the globe have received a large
amount of their present elevation since the close of
the Secondary Period.
6. The specific gravity of the whole globe is only
5*5, while that of cognisable rocks is over 2*5,
although Waltershausen calculates the pressure at the
centre to be equal to 2,498,600 atmospheres, and
Laplace, 3,000,660.
7. Heat has been found to increase with dis-
tance from the surface at a rate that if continued
would give rock-fusion under atmospheric pressure
only, at from 25 to 30 miles (in some areas the rate
of increase is greater), and at half the distance to
the centre a temperature equal to that of the sun,
an impossible heat. There is, therefore, not a
continued uniform increase of heat.
8. Rock-fusion, resulting from simple relief of
vertical pressure in subterranean regions where the
heat is sufficient to fuse rocks under surface con-
ditions, would not be limited in lateral extension if
there is an open vent, and surface depression and
derangements with consequent lava outputs on a
scale far transcending any terrestrial catastrophes
that have occurred would result.
9. Volcanic action has gone on for long periods
of time in many areas without causing any surface
derangements, except the building up of cones, or
the rupture of very small areas.
10. Areas of great volcanic activity in Palaeozoic
and even in Tertiary times, although still contiguous
2O6 MOUNT VESUVIUS.
to the sea, are, and have been, through immense
periods of time perfectly unvolcanic, as the Southern
Hebrides ; and insular volcanoes in more recent
times have become quite extinct without change of
geographical conditions, as in Madeira and the
Canary Islands.
11. Lavas from different volcanic regions, though
having a general resemblance, are not the same in
composition, and some present considerable differ-
ences.
12. Lava solidifies with a small loss of heat, small
quantities solidifying rapidly, and many lava-flows
are very inconsiderable in volume.
13. The products of the same volcanic centre at
different periods may be respectively trachytic and
augitic, as those of the Alban Hills ; or may be
characterised by different mineralogical features, as
those of the Somma-Vesuvian centre ; while trachytic
and augitic lavas may respectively characterise two
vents in the same volcanic region, as in the
Neapolitan.
14. A sequence of volcanic rocks has been
detected, and may be stated as follows, according to
Richthofen : I. Propylite (Earliest). II. Ande-
site. III. Trachyte. IV. Rhyolite. V. Basalt
(Latest), or, in other words, the earlier lavas of the
same volcanic centre are usually trachytic or acidic,
and the latest lavas augitic or basic.
15. Sudden eruptive energy may occur where no
volcanic vent previously existed, in some cases
VOLCANIC ACTION. 2OJ
followed by a continuance of activity, as at Jorullo,
and sometimes after a brief outburst, followed by
perfect quiescence, as at Monte Nuovo.
1 6. Two volcanic craters on the same dome may
not be sympathetic in activity, as Kilauea and
Mauna Loa.
17. The eruptive axes of volcanoes sometimes
vary their position, as in Vulcano and Vulcanello.
1 8. The volcanic foci of Etna and Vesuvius were
calculated by Mallet to be only a few miles deep.
19. There are permanent hot springs in non-
volcanic districts, indicating long-continuing, uniform,
and considerable heat at no great depth, as at Bath,
Clifton, and many other places.
20. The chief Northern European Tertiary vol-
canic outpouring, that of the lavas of Antrim, lona,
Staff a, and Mull, was in the same geological epoch
as the great Central European subsidence, that of
the Alpine region ; and the great Central European
Tertiary outpouring, that of the lavas of Auvergne,
central Germany, Bohemia, and Hungary, was con-
temporaneous with the principal Central European
Tertiary elevation, that of the Alps.
21. Volcanic action generally is in rising rather
than in subsiding areas.
22. Volcanoes, though sometimes in groups and
sometimes isolated, have by far their greater number
arranged in linear extension, and this is round the
chief water area of the globe, the Pacific Ocean,
marking the commencement on their eastern and
2O8 MOUNT VESUVIUS.
western sides of the great land masses, and coin-
ciding with a line of elevation on the crest of which
the volcanic vents are situated.
23. Active volcanoes, with few exceptions, are
either in the sea (insular or sub-marine), or are on
coasts either contiguous to or at but little distance
from the sea.
24. Inland extinct volcanoes were near the sea, or
sea-like lakes, at the period of their activity, as in
Auvergne and Hungary.
25. The extinction of volcanic activity has fol-
lowed the removal of the coast-line to a very
moderate distance, as in the Roman Campagna.
26. Steam is a most abundant and sea-salt a pro-
minent product of explosive eruptions, and all the
elements of sea-water are contained in the ejecta-
menta of explosive volcanoes, while some volcanic
tuffs consist largely of marine Diatomaceae, as in
Patagonia.
27. Nitrogen and various chlorides occur as
volcanic products.
28. Volcanic phenomena seem to be absent from
oceanic or deep-sea bottoms.
29. Some eruptions are altogether explosive, as
those of Vesuvius in A.D. 79, Monte Nuovo, and the
recent one of Krakatoa ; while some are altogether
non-explosive and merely quiet emissions of lava,
as those of Mauna Loa.
30. Neither Daubree's or any other experiments
have shown that water, either by capillary trans-
VOLCANIC ACTION. 2OQ
mission or by fissures, will pass through massive
rocks bordering on a fusion-temperature.
31. Enormous flows of lava have occurred with-
out explosive effects, and there are vast beds of
lava-rock that have not been, when fluid, associated
with any volcanic cones, as in Antrim, Abyssinia,
and Idaho.
32. Plutonic igneous rock-beds and dykes have
been formed without explosive effects.
33. The volcanic tubes of the non-explosive
craters of Mauna Loa and Kilauea are surrounded
by solid, always hot, lava-rock, and in the products
of these craters chlorides are rare.
34. Volcanoes quite dormant for many centuries
have, some, commenced a new epoch of activity, as
Vesuvius ; and, sometimes after one eruption, have
relapsed into complete quiescence, as Epomeo.
35. " Eruptive action is characterised by spasmodic
fitfulness " (Geikie), and frequently the most violent
eruptive phenomena are exhibited at the close of a
lengthened period of Strombolean activity.
36. " When explosive force is spent lava rises in
vent" (Judd).
37. Feeble volcanic action may continue for cen-
turies without change, as at Stromboli and the
Solfatara.
38. Pressure caused by shrinkage of the earth's
crust is tangential, not vertical.
39. The heat produced by crushing pressure of
rocks is not localised at the points of contact, but
2IO MOUNT VESUVIUS.
disseminated through the rock masses synchronously
with production.
40. Observations of the activity of Stromboli and
Vesuvius seem to indicate an approximation to
periodicity of eruptive energy coincident with
(i) Autumn and Winter, (2) the Lunar Syzygies,
and (3) with hygrometric atmospheric conditions.
41. 2,000,000 tons pressure are removed from
every square mile of the earth's surface when the
barometer falls two inches.
42. Vegetable remains have been present in vol-
canic mud and water, and fishes, such as live in the
local caverns, ejected ; while remains of fresh-water
diatoms were found by Ehrenberg in volcanic rocks
of the Rhine, and in the Island of Ascension.
43. Immediately before or at the commencement
of eruptions the water in neighbouring wells falls,
and the sea recedes, followed by a returning wave.
44. Antecedent to eruptions, earthquakes, earth-
quake shocks, or earth tremors occur, especially and
more violently previous to the opening of new vents,
asjorullo and Monte Nuovo,and after long dormancy,
as before the first historic eruption of Vesuvius.
45. Though great volcanic activity may be noted
at particular periods, yet sympathy between the
eruptive energy at any two well-separated vents
has not been found with certainty to exist.
The difficulty of finding a theory to which some
one or other of the foregoing facts is not
VOLCANIC ACTION. 2 I I
at variance, must be obvious ; and there is little
wonder, therefore, that opinions widely differ, or
that the discussion of the cause of volcanic action
seems to promise to be well-nigh interminable. Still
it should be borne in mind that some of the most
eminent observers, thinkers, and logicians amongst
geologists have made vulcanology a special study,
with the result that a very great amount of data
has been accumulated, forming, we may hope, an
approximately complete and firm foundation on
which to build the long-desired conclusive super-
structure of this branch of geological science.
The sister branch, Seismology, has, during the
last fifty years, made great advances through the
continued and assiduous observations and researches
of Mr. Mallet, and more recently of Prof. Milne, in
Japan, and both of these authorities have brought
their special knowledge and experience of earth-
quakes to the elucidation of volcanic phenomena.
Prof. Palmieri and Dr. Lavis are patiently watching
every phase of Vesuvian action ; a seismic observa-
tory, like that on Vesuvius, has been established on
Etna ; and not to mention foreign savants, Prof.
Judd has specially visited various volcanic regions
to obtain facts and make observations that might
throw light on the question. We are, therefore, now
in a much better position than ever before to obtain
a satisfactory solution, and it may be confidently
hoped that as far as is possible from the nature of
the subject, the matter may soon be set at rest.
212 MOUNT VESUVIUS.
As a contribution to a settlement of the question,
I brought before the British Association, at the
recent meeting at Bath, conclusions, arrived at after
many years' attention to the subject, which appear to
me to be more consonant with observed phenomena
and known facts than the hypotheses previously
advanced. While here giving these conclusions as
then stated, I can in this work do no more in sup-
port of them than appeal to the facts stated in my
" Compendium," but this appeal is made with some
degree of confidence that the facts and the
hypothesis will not be found to be altogether
antagonistic.*
A. The primary cause of the formation of fluid
lava, it seems to me, is the internal heat of the globe
inducing chemical, and possibly electrical, action in
subterranean regions where the chemical composition
of the rocks and their contained and associated
minerals are favourable, and when, moreover, the
conditions become more favourable by the removal
of the restraining vertical pressure of the superin-
cumbent rock masses by the counteracting lateral
* The paper " On the Causes of Volcanic Action," containing my
views, and their advocacy in brief, was read in the Geological Section
of the British Association at the Bath meeting on September loth,
1888. An abstract giving the conclusions appeared in the Times
of Sept. nth, and one more lengthy in Scientific News of Sept. I4th,
as well as in the " Report of the British Association for the Advance-
ment of Science for 1888," page 670. The paper was also read at the
meeting of the Geologists' Association of London on December 4th
following, and has since been printed in extenso in the " Proceedings
of the Geologists' Association," vol. xi., page i.
VOLCANIC ACTION. 213
or tangential pressure produced by secular cooling
causing shrinkage.
In this view there is room for the operation of
chemical combination and electrical and magnetic
influence, induced by a degree of heat not nearly
sufficient for ordinary rock-fusion, that consequently
may exist at such a moderate depth as not to render
impossible the passage of small ejections of the
resulting lava through vents in the overlying rocks.
In other words, a moderate heat may induce,
where there are suitable materials and conditions,
such chemical and other action as will produce suffi-
cient additional heat to cause rock-fusion, which
will necessarily be confined to the region and the
period where and when the suitable materials and
conditions exist.
This hypothesis is founded on the doctrine that
chemical re-actions favoured by fusion may be
restrained or prevented by a pressure that raises
the fusion-point of temperature, and that when the
liquefaction of substances fusible at low tempera-
tures is effected, changes are initiated that will
produce sufficient heat to fuse the more refractory
substances with which they may be in contact.
That, in fact, fluxes exist and operate in Nature's
laboratory as well as in the furnaces of man.
It appears to me that this hypothesis fulfils the
requirement of Sir Charles Lyell when he says in
his " Principles of Geology," "It is only necessary,
in order to explain the action of volcanoes, to discover
214 MOUNT VESUVIUS.
some cause which is capable of bringing about such
a concentration of heat as may melt one after the
other certain portions of the solid crust, so as to
form seas, lakes, or oceans of subterranean lava."
I am not prepared to deny, however, that water
may be present, and, too, as an agent of reaction,
where and when that chemical action commences
which produces the greater heat that brings about
rock-fusion, but after rock-fusion has commenced,
and a lava source has been established, I cannot
believe it to be possible for water to approach
such a source.
Nor can I understand how water, after acting as an
oxidiser, can remain in any form to take part in the
ejection of lava. If the water has given up its
oxygen to combine with bases, it can no longer
be water, and only hydrogen will remain. The
enormous volumes of steam given forth from ex-
plosive eruptions would remain to be explained.
True it is that M. Fouque reports considerable
quantities of hydrogen as given forth from eruptions,
but the amount is altogether insignificant when com-
pared with that of the watery vapour, the whole of
which being undecomposed has had nothing to do
with any chemical re-combinations that may have
taken place.
B. The ejection of lava from its source, and its
rise in a volcanic tube or conduit, is due to the
expansion caused by the change from the solid to
the liquid state (comparable with the rise of mercury
VOLCANIC ACTION. 215
in the tube of a thermometer from increased
liquidity), together with the production of poten-
tially gaseous compounds from chemical reactions
amongst the many compounds forming, and acces-
sory to, the mass of the magma, favoured by the
fused condition.
This rise of the lava in the volcanic tube may be
influenced by meteorological conditions, as the posi-
tion of the top of the column of mercury in the tube
of a barometer is affected by the weight of the
atmosphere, and the meteorological effect may be
supplemented by lunar attractive influence. Thus
it appears to me the lower or plutonic part of a
volcanic tube is a thermometer and subsidiarily a
barometer, and to use a new word, an helkmometer*
(or measure of attractive influence) combined.
C. The explosive features of volcanic eruptions
I hold to be altogether secondary, and that these as
well as the determination of the position, and to
some extent the distribution, of volcanic vents to be
due to the sea, the water from which, conveyed by in-
terstitial percolation through cool or not highly heated
rocks, pours into the comparatively cool upper por-
tion of fissures or old volcanic conduits, together with
that derived from ordinary land surface sources.
This water, converted into steam by its descent
to heated lower depths and by the approach of
ascending lava, causes by its expansive and ex-
plosive power the opening of rents admitting large
* From ehxvffts-eas = attraction.
2l6 MOUNT VESUVIUS.
and sudden flows or gushes of sea-water to the
lava conduit, which may have receptive expansions
at but moderate depths where water may have
accumulated, and thus the conditions are produced
that occasion the greater explosive effects of violent
eruptions.
Simple emissions of lava without ashes or ex-
plosive phenomena are due to the absence of water
except in small quantities, such as may be derived
from the surface or from the rain or snow on crateral
openings. The non-explosive simply lava-emitting
character of the Hawaiian volcanoes is explained
by their conduits being surrounded by water,
excluding always highly heated though solid lava.
Purely explosive and ash eruptions are explained
by the introduction of water into a fissure partly
filled with lava which does not reach the top of the
tube, and which, by cooling and solidification, if the
fissure be a branch one, may effectually and per-
manently seal it, and so prevent any further eruption
at that point, as in the case of the single-eruption
cratered ash-cones of the Phlegrsean Fields.
The actual volcano I consider to be due to the
sea, which, by giving its water in sufficient volume
when lava is ascending, produces that explosive and
rending force that opens a vent at the surface and
adds a volcano to the globe, and thus is explained
that wonderful association of volcanoes with the sea
that so markedly characterises their distribution.
CHAPTER IX.
VOLCANIC PRODUCTS.
Vesuvian Products largely representative Similarity and Dis-
similarity of Volcanic Products Descriptive Catalogue of Volcanic
Products Ejected Blocks, with List of Fossils.
THERE are not many volcanic products unrepre-
sented in the Vesuvian area, as the result of either
the pre-historic or the later eruptive activity of its
volcanic focus and vent, and therefore in the
following pages these few have been included. The
list given is, consequently, one of volcanic products
generally.
It is perhaps otherwise desirable to give here such
a comprehensive enumeration, since however much
the materials produced by volcanic action may differ
among themselves, in the aggregate they possess a
striking similarity, in whatever part of the world
they may be studied, and hence forms of volcanic
ejectamenta unrepresented in a particular area may
nevertheless be most usefully illustrative of those
forms that are there produced, and may, moreover,
afford indirect evidence of considerable value in the
study of vulcanology.
The general similarity of volcanic products from
remotely separated regions cannot be, according to
the hypothesis stated in the last chapter, a matter
for wonder when it is remembered that the known
2l8 MOUNT VESUVIUS.
rocks of the globe are almost entirely made up of
about a dozen mineral substances only, and that
these are composed of about the same number of
chemical elements. For it is fair to assume, and
to a geologist the conclusion is inevitable, that the
materials of the surface regions of the earth are in
their chemical composition, in the aggregate, similar
to those of the underlying masses, and that, there-
fore, the rocks far below the surface will be gene-
rally similar in all parts of the globe, and that if
similar substances, under similar conditions, are
subjected to the same agency, heat, the resulting
products will be generally similar.
On the other hand, the dissimilarity existing
amongst volcanic products may also be easily
explained, for though but few chemical elements or
mineral substances make up the great mass of the
rocks, yet there are not a few other elements
existing in these rocks, in certainly but a small pro-
portion, but in by no means inconsiderable quan-
tity, and these are very irregularly distributed.
Although, therefore, the general conditions on
which volcanic products are based are similar, still
sufficient local diversity exists to account for the
varied chemical and physical characters of volcanic
ejectamenta.
DESCRIPTIVE CATALOGUE OF VOLCANIC PRODUCTS.
ALLOGOVITE. A form of basalt, occurring in the
Allgau, of a grey, or reddish colour, with labra-
VOLCANIC PRODUCTS.
dorite intimately blended, and named as a distinct
rock by Winkler.
AMPHIGENITE, Cordier, called also Leucito-
phyre. A name given by Cordier to augitic lavas
in which leucite, either wholly or in part, takes the
place of labradorite. Such is the ancient lava of
Monte Somma, and such are the modern lavas
of Vesuvius. In the Roman Campagna this rock
is seen at the Capo di Bove, on the Appian
Way, about two miles from Rome and near the
tomb of Cecilia Metella, where it is quarried. It
is also to be found in the German volcanic district
of the Eifel. At Somma the leucite has separated
itself very distinctly, forming fine complete trapezo-
hedrons as large as nuts, and these in great abund-
ance. The rock is here not so dark in colour nor so
heavy as that of the Capo di Bove, where it is
very compact, hard, and dark-coloured, with small
grains only of leucite embedded in the augitic mass.
Of the modern leucitic lavas of Vesuvius some con-
tain much more of the mineral than others.
Etymology : From amphigene, from ^<pj, on both
sides, and y evo s , origin, a name for leucite.
AMYGDALOIDAL DOLERITE. Amygdaloid is the
name applied to rocks having almond-shaped cavities
either empty or partly or wholly filled with crystalline
minerals, and may be used adjectively to describe
such a rock, or given as a name for the rock itself
when plutonic. Amygdaloid volcanic rocks, how-
ever, frequently occur, as was shown by Von Buch,
22O MOUNT VESUVIUS.
in the Canary Islands. The almond-shaped cavities
have been produced by evolved gases when the
mass was in a fused state, and the elongated form
of the cavity is the result of the motion of the
fluid mass, the larger diameter being in the direc-
tion of the movement. The sparry or crystalline
contents of the cavities have been subsequently
deposited from infiltrated solutions.
Etymology : From ^wy8A, an almond.
ANALCYMITE (Cyclophyre). A basic rock of the
Cyclades, two-thirds of the mass of which is made
up of Analcime filling up fissures and cavities. It
may be, in the opinion of Von Cotta, an altered
Nepheline Dolerite.
ANAMESITE, Von Leonhard. An augitic or
pyroxenic massive lava closely allied to basalt and
dolerite. It is similar in composition, but not so
fine-grained as basalt, and not so conspicuously
granular as dolerite.
ANDESITE, Von Buch. Andesite, from its rough
texture, was thought to be a form of Trachyte from
the volcanoes of the Andes, consisting largely of a
sanidine felspar ; but it is now known that the
prevailing felspar is plagioclastic, allied to oligoclase
but containing more lime, and named Andesine.
Some Andesites contain free quartz, to which the
name Dacite is given, and those without quartz are
divided by Mr. Harris Teall into Augite-Andesite,
Eustatite-Andesite, Hornblende-Andesite, and
Mica- Andesite.
VOLCANIC PRODUCTS. 221
Besides the Andes, Abich says the Caucasus and
Mount Ararat are localities where Andesite occurs.
Etymology : The name is from the Andes, the
mountains in which it chiefly occurs.
ASH, VOLCANIC. Volcanic Ash is the fine black
dust or sand that falls on the surface after an
eruption. 1 1 is first carried upwards with the volumes
of ascending steam which it darkens, and so pro-
duces the " smoke " of a volcano. It is sometimes
carried to a very great height, and forms with the
steam an overhanging canopy, from which the larger
and heavier particles first fall and cover the surface
of the mountain-top, and the smaller are carried in
the direction of the wind and gradually fall, the finest
dust being borne along to the greatest distance.
This dust is sometimes carried by the upper cur-
rents of the atmosphere to very long distances, and
crews of ships far from land are apprised of an erup-
tion by finding on the decks a deposit of volcanic ash.
After the Krakatoa eruption in 1883 there were
for a long time remarkably coloured sunset glows
both in Europe and America, and it has been con-
tended, especially by so eminent an authority as
Norman Lockyer, that these were produced by the
extremely fine volcanic ash from Krakatoa, retained
as suspended particles in the upper regions of the
atmosphere. Some of the Krakatoa ash was
actually found in Europe.
This black dust is evidently the result of the
trituration of fragmentary ejectamenta produced by
222 MOUNT VESUVIUS.
the repeated explosions in the volcanic vent, and has
been found by microscopical examination to corre-
spond in composition with the lava of the same erup-
tion. The eminently leucitic lava of 1 87 1, when artifi-
cially reduced to powder, was found by Prof. Palmieri
to perfectly resemble the volcanic ash then ejected.
When washed with water the ash loses by solution
some constituents, of which the principal is sea-salt,
but there are other chlorides and free acids. This
offers an explanation of the destructive effect of
volcanic ash, and of the rains which pass through
it, on vegetation. When the tender tops of plants
are watered by a solution of Vesuvian salt they soon
afterwards wither. Some years ago the young
leaves of the oaks of Sussex were found, after a
violent south-west gale, to be withered, and this
blight, which was very conspicuous in the early
summer, was attributed to the salt of the sea borne
inland by the spray-charged wind.
In 1872 ''white sand" fell on a part of Vesuvius,
presenting a striking contrast to the black surface
around. Some of this, collected by Palmieri, was
found in a few days to be coated with red, and
mingled with green particles. On examination the
white grains, which had their angles rounded, proved
to be leucite, and the green particles augite or
pyroxene, while the red coating on the white grains
was "a deposit of organic matter."^
BASALT. Basalt is a name equally applicable to
* Palmieri's "Eruption of Vesuvius in 1872," p. 120.
VOLCANIC PRODUCTS. 223
massive lavas of recent and of long-past geological
times. It is a fine-grained, heavy, dark, sub-crys-
talline rock, composed of augite, labradorite, plagio-
clase (or nepheline), and magnetic peroxide
of iron, often with olivine. The term has been
rather loosely used to designate massive lavas
generally, but it is now restricted to the finest-
grained or most compact solidified lavas, lava-rock
of a coarser texture being called Anamesite, and
when still coarser, Dolerite.
Basalt is amorphous, tabular, and globular, but its
most characteristic condition is columnar, which is
very decided and conspicuous. The columns may
have three, four, five, six, or eight sides, but they
are usually hexagonal, and fitting so closely together
that it is sometimes difficult to insert a knife between
them. They range from 5 to 150 feet in height,
with a diameter from 3 to 18 inches, and are often
divided horizontally by semi-spherical joints
that is, the bottom of one section of a column
has a convex surface fitting in a concave top of
the section below.
The Giant's Causeway of the North of Ireland,
and Fingal's Cave in the Isle of Staffa, offer per-
haps the best-known examples of columnar basalt
in the British Islands, and furnish excellent illus-
trations of the hard and durable character of the
rock, as the edges of the columns, exposed though
they have been to the action of the waves for ages,
are still quite perfect.
224 MOUNT VESUVIUS.
Etymology : The name is from basal earth,
used by Pliny, meaning " iron earth," since basalt
often contains much iron.
BOMBS, VOLCANIC. Volcanic bombs are the
rounded, usually ovoid, and partly vesicular masses
of solidified lava that are after ejection from the
crater precipitated on the slopes of a volcano. The
rounded symmetrical form is doubtless due to the mass
of lava of which they are formed being in a soft, semi-
solid state at the time of ejection, which would allow
of an irregular form being reduced to a compact
rounded one by the rotation of the masses during
their passage through the air previous to cooling and
entire solidification. Volcanic bombs are usually
from six to twelve inches in diameter, though some
have been found of a much greater size.
CINDERS, VOLCANIC. Volcanic cinders are
scoriaceous fragmentary lava of irregular form and
size, but not flattened like the scoriaceous cakes
formed on the surface of lava-flows, and are inter-
mediate in size between volcanic bombs and lapilli.
They are usually vesicular, and frequently have sur-
faces coloured with deposits of sublimed compounds.
Volcanic cinders are, in fact, the medium-sized
fragments ejected from the volcanic vent, and
largely make up the loose material partly composing
the surrounding cone. Their production is due to
the volcanic explosions ejecting to a moderate
elevation small portions of fused lava which in their
flight through the air evolve gases giving the
PLATE XVI.
THE LAVA OF 1858, SHOWING SURFACE PRODUCED BY THE
SOLIDIFICATION OF SLOWLY-MOVING LAVA.
(From a Photograph.) (Judd's Volcanoes.)
VOLCANIC PRODUCTS. 225
vesicular structure while gradually cooling and
solidifying.
DACITE. This name is given to Andesite in
which is disseminated free quartz.
DOLERITE, Harris. Dolerite may be briefly
described as a coarse-grained basalt, since it is a
solidified lava of augite or pyroxene, labradorite,
and magnetic peroxide of iron. It is sometimes
amygdaloidal, and sometimes porphyritic, the dis-
tinct crystals in the latter case being either felspar
or augite.
Ordinary recent lavas on the flanks of a volcano
may usually be described as Dolerites, while the
massive lavas of unusually great flows are best
described as Basalts or Anamesites. Thus the
ropey and wavy solidified lavas in the Atrio del
Cavallo and on the Piano of Vesuvius are doleritic,
and the thick-rock masses of the lava of 1631 at
Torre del Greco and Resina are basaltic. Mr.
Harris Teall gives the following as varieties :
Olivine-Dolerite, Eustatite-Dolerite, Mica-Dolerite,
and Hornblende-Dolerite.
Dolerite is from Boxe^, deceptive, from the difficulty
of seeing its constituent minerals.
DOMITE. Domite is a trachyte with an earthy
rather than a harsh or rough feel. It is greyish-
white in colour, and resembles an impure chalk.
Domite, as its name indicates, is the peculiar rock of
the Puy de Dome and the other extinct volcanoes
of Central France, which, issuing as a very viscid
Q
226 MOUNT VESUVIUS.
lava, has produced in some cases cones without
craters. The felspar, of which Domite chiefly con-
sists, appears to be oligoclastic, instead of ortho-
clastic sanidine, from which this rock has been
named Oligoclase Trachyte (see Trachyte).
Etymology: The name is from the "domes" of
the extinct volcanic region of Auvergne, in Central
France, of which the Puy de Dome is one, where
Domite is characteristic.
FLAME. Although volcanoes are popularly called
" burning mountains," and flaming fire is commonly
supposed to characterise all eruptions, it is only to a
very limited extent true that actual flame, or incan-
descent gas, is produced by volcanic activity. The
fiery glow and illumination of the clouds of steam
and ashes, and of the sky, which form the grand and
perhaps the most impressive feature of a volcanic
eruption, are simply due to the reflection of the
incandescence of the lava below, and not as a rule to
flame at all.
Still it cannot be doubted that true flame is some-
times produced, and, too, in some cases perhaps
conspicuously. Even if old accounts be disregarded,
the very positive statements of modern observers
cannot be set aside. In his description of the erup-
tion of Etna in 1838, Mr. Gladstone says he saw a
" sheet of flame which leapt up with a sudden
momentary blast, and soon disappeared in
smoke." * So great a scientific authority as Sir
* " Etna," by G. F. Rodwell, p. 58.
VOLCANIC PRODUCTS. 22 7
Humphrey Davy has reported flame, and Giuscardi,
Abich, and Pilla have confirmed the report. Pro-
fessor Pilla states that he saw from the edge of
the crater of Vesuvius during the eruption of 1833
a column of flames. "It rose," he goes on to say,
" to the height of four or five yards, and then
disappeared among the volumes of smoke, so that
a person whose eye was on a level with the edge
of the gulf could not have seen it. Hence it is
that the existence of flame has been so confidently
denied. The flame which I observed was of a
decided violet-red colour."
That this is not constantly the case inside the
crater at the time of an explosive eruption, I can
affirm from my own observation of the interior of
the Vesuvian crater during the eruption of 1868
while standing on its rim, the same position as that
occupied by Prof. Pilla at the time of the eruption
of 1833. I then certainly saw, although it was a
very bright day, a considerable illumination of the
dense white fumes that filled the interior, but
there was no flame, not even at the moment of
an explosive discharge of ashes and bombs.
The flames, however, which it must be admitted
are sometimes observed, are doubtless due in the
main to discharges of hydrogen gas, which burns in
air, as is well known, with but a faint flame.
FULGORI. See Lightning, Volcanic.
GASES. The fumes of a volcano, although con-
sisting chiefly of watery vapour, contain several
228 MOUNT VESUVIUS.
gases which, except when absorbed by water,
retain the gaseous condition. Of these, perhaps the
most abundant is hydrochloric acid and then sul-
phurous acid gas. After these, chlorine, hydrogen,
and carbonic acid gas in a later stage of eruptive
action, and less abundantly nitrogen, hydrofluoric
acid, and sulphuric acid. The last-named in its
anhydrous or gaseous state is very rare.
HAUYNOPHYRY. This is a basic rock of the
Monte Vulture Volcanic Region, consisting mainly
of augite and haliyne, but containing also olivine,
mica, and leucite. The haliyne appears to be the
mineral that takes the place of the labradorite of
ordinary dolerite. The well-known volcanic rock of
Niedermendig, on the Rhine, which has been used for
millstones for ages, contains haliyne conspicuously.
LAPILLI. Lapilli is a frequently used word to
designate small volcanic ejectamenta, smaller than
" volcanic cinders," and not so fine as " volcanic
ash." It is most usually pumiceous, and it is then
generally considered to be trachytic in composition.
Perhaps the best example of lapilli is that of the
material now being cleared away from the streets
and houses of Pompeii. This is a light grey
pumiceous lapilli made up of fragmentary ejecta-
menta ranging from the size of a pea to that of a
small orange, though specimens 8 inches across, it
is said, have occasionally been found.
Etymology : Latin lapillus, contraction of lapi-
dnlus, diminutive of lapis, a stone.
VOLCANIC PRODUCTS. 2 29
LAVA. Lava is the most common word used in
connection with volcanoes and volcanic eruptions,
and is the name used for both the fluid fused rock
emitted by a volcano, and the solidified stony masses
that result from its cooling. In this place, however,
only the fluid will be referred to, solidified lava
being described under the various names that
have been given to its varieties, as dolerite, ana-
mesite, basalt, trachyte, domite, &c.
Though lavas from all parts of the world have a
general resemblance in being fused rock, and have
a generally corresponding mineralogical composition,
in consisting mainly of silicates, yet they vary so
considerably that their chemical composition is
widely different, and their specific gravity as well as
their colour and other physical characters when
cooled not less so. They usually agree, however,
in having a felspar as a principal constituent, but the
two groups into which lavas generally are divided
are characterised by two different felspars. These
two groups are the augitic and the trachytic, called
so in the one case from its characteristic mineral,
and in the other from the character of the rock it
forms when cooled ; or the basic and the acidic, from
the relative proportions of their basic and acidic
constituents.
The lava now usually seen and spoken about is
augitic or basic, and is composed of augite, called
also pyroxene, a lime felspar such as labradorite,
olivine, and iron oxide, though in the Vesuvian
230 MOUNT VESUVIUS.
lavas leucite to a great extent replaces the felspar.
Augitic lava, consisting as it does of two and some-
times three silicates, has a large proportion of
basic material, alumina, magnesia, lime, potash, &c.,
and has a specific gravity of 2*85 to 3*10, which is
much more than that of the ordinary surface rocks
of the globe. It is also, when cooled, dark-coloured
or black.
The following, from Roth's " Petrographie der
plutonischen Gestein " (1869), gives the composition
of Vesuvian lavas of the great eruption of 1631 and
of the eruption of 1867-8 :
1631.
1867-8.
Silica
46-41
46-94
Alumina ...
19-67
21-35
Peroxide of Iron
6-88
7-27
Protoxide of Iron
4-17
4-96
Magnesia...
5-23
378
Carbonate of Lime
10-53
9-69
Soda
2'O2
O-62
Potash
4^9
5'57
00-00
lOO'lS
The other type of lava, the Trachytic, mainly con-
sists of a potash felspar or orthoclase, and is much
lighter in weight, and when solidified usually much
lighter in colour than the augitic lava. I ts composition
gives it so much silica or silicic acid as to justify the
name acidic applied to trachyte and its varieties.
The temperature at which lava fuses is greatly
affected by its composition, that containing the
greater proportion of basic constituents being more
readily fusible, but ordinary augitic lava fuses at
VOLCANIC PRODUCTS. 231
about 2,000 Fahr., the temperature, too, at which
ordinary plutonic rocks melt.
There is also a great difference in the liquidity
and viscidity of lavas, those of the Hawaiian craters
being perhaps the most mobile of all, flowing and
spreading rapidly over the surface, and solidifying
at a very low angle. These lavas have also the
property of being very ductile, so much so, indeed,
that they are drawn out by the wind into very fine
threads, forming filamentose lava called " Pele's
Hair" (which see). One of the Vesuvian lavas,
that which flowed during the eruption of 1855, was
especially fluid, flowing in a narrow stream a long
way into the cultivated region ; and it was found to
contain an unusual compound called " Cotunnite,"
a chloride of lead, to the presence of which the
abnormal liquidity was attributed. The more
leucite, too, there is in a lava the more mobile it
appears to be, and the more easily the filamentose
condition is produced. Such lava is remarkable for
forming on its surface when cooling in a lava-flow a
continuous skin instead of a covering of loose
fragmentary scoriae, and consequently the rapidity
of movement over the same decline, and the
character of the cooled solidified surface product,
indicate to some extent the mineralogical and
chemical composition of the fluid mass. The
Vesuvian lava of the eruption of 1867-8 was one of
the least fluid of the augitic lavas, moving very
owly, and forming scoriae abundantly.
232 MOUNT VESUVIUS.
Trachytic lava is less fluid and mobile in character
than the augitic. So viscid, indeed, is trachytic lava
sometimes that it refuses to flow after exudation
and maintains a mound-like form, as in the case of
the "Mammelons" of the Isle of Bourbon, The
great dome-like volcanoes of Central France, on the
summit of which there are no crateral hollows, are
formed of solidified trachytic lava, to which the
name " Domite " is given.
The colour of fluid lava changes like that of
melted iron. When issuing from a " bocca " it is
a bright light yellow, then it gradually becomes a
richer yellow, then orange, and finally when solidify-
ing a dull red, like red-hot iron. With these
changes of hue there is also a gradual increase
of viscidity, and so great does the consistency
become before the end of a flow is reached, that
stones thrown upon the surface scarcely make an
impression.
The low heat-conducting power of lava is remark-
able, and sometimes produces curious effects. It is
often possible to stand on a solid black surface and
through the chinks see underneath the red-hot lava,
while deep and wide flows may have a solid crust that
may be walked over for months, while at some dis-
tance below the lava is still quite hot. Tunnels formed
by the solidification of the surface of lava-flows
have been several times mentioned, and strikingly
attest the slow conduction of heat by lava.
The name " Lava de fuoco" is locally given to
VOLCANIC PRODUCTS. 233
lava to distinguish it from volcanic mud, which is
termed " Lava d'Acqua."
The material used for cameos, &c., in the Vesuvian
district is locally called " lava," though it is not lava
at all, never having been in a fused state, and being
simply limestone altered by the volcanic heat.
Etymology : The Neapolitan word lava primarily
means a torrent of water overflowing and washing
the streets, from the Italian lavare, to wash (same
as the Latin), from which it was applied to the
streams of fluid matter descending the slopes of
Vesuvius.
LAVA D'ACQUA, see Mud, Volcanic.
LAVA DE Fuoco, see Lava.
LIGHTNING, VOLCANIC (Fulgori\ Frequent ob-
servations of lightning, or electrical manifestation,
in the cloud of smoke produced by volcanic erup-
tions leave no doubt whatever that this is not the
ordinary lightning of meteorology, but is entirely
due to electricity consequent upon volcanic action.
An ingenious apparatus by which the electricity
of eruptions can easily be studied was devised by
Prof. Palmieri and installed at the Observatory. It
is named by the Professor "Apparachio aconduttore
mobile," or apparatus with movable conductor, and
possesses a bifilar electrometer of great delicacy.
Palmieri says : " The Observatory is distant in a direct
line from the central crater of Vesuvius 2,380
metres, so that, when the smoke is copious, it is
properly situated for the study of electricity, parti-
234 MOUNT VESUVIUS.
cularly when the wind inclines the pine-tree cloud
in the direction of the Observatory, as frequently
happened on the last occasion (1872). With smoke
alone, without ashes, we obtained strong tensions of
positive electricity ; with ashes only, which some-
times fell while the smoke turned in the other
direction, we had strong negative electricity ; when
the smoke inclined towards the Observatory, accom-
panied with ashes and lapilli, we had sometimes one
kind of electricity, and sometimes the other, just as
the smoke or the ashes predominated ; and often
with a fixed conductor we obtained negative elec-
tricity, and with a 'movable conductor' positive
electricity."
" The conditions under which ('fulgori') lightning
flashes are seen from the cloud of smoke are that it
is conveying great abundance of ashes. In 1861
there were small flashes even from the line of
eccentric mouths above Torre del Greco, although
the smoke was not very great ; and when these
ceased to discharge, and the central crater became
somewhat active, with a moderate amount of smoke
but a great deal of ashes, small and frequent Irght-
ning flashes were observed in the twilight darting
through the smoke, which was dark in colour." *
LIPARITE. See Trachyte Porphyry.
MASENGA. This is a name given to the Trachyte
of the Euganian Hills, in Lombardy.
* "The Eruption of Vesuvius in 1872," by Prof. Palmieri. Trans-
lated by Robert Mallet, pp. 130-31.
VOLCANIC PRODUCTS. 235
MUD, VOLCANIC. In South America and other
parts of the world there are ejections of a sulphurous
mud of a foetid and offensive character, to which the
name " volcanic mud" is given. But volcanic mud
may also be produced by ordinary volcanoes dis-
charging great volumes of steam that condensing,
cause floods of water which converts the smaller
ejectamenta of the same eruption into a thin mud.
This descends the mountain slopes and deluges the
lower grounds and habitations, sometimes causing
more devastation than the lava-flows. Such was
the manner in which Herculaneum was over-
whelmed and destroyed, and its ruins are now im-
bedded in the consolidated and indurated volcanic
mud of the eruption of A.D. 79. To the mobile
mass the name " Lava d'Acqua " is locally given.
NEKROLITE. The name given by Brocchi to the
Trachyte of the neighbourhood of Viterbo and Tolfa
in the Roman Volcanic Region.
NENFRO is another of Brocchi's names for a local
Trachyte, that of the Cimini Mountains.
NEPHELINE DOLERITE. A variety of Dolerite in
which nepheline, or sommite, takes the place of
labradorite. It has, like all the Dolerites, a
crystalline granular texture, and consists essentially
of augite and nepheline, with as accessories titanite
sanidine, olivine, and acicular crystals of apatite,
First distinguished by Von Leonhard.
OBSIDIAN. Obsidian is a vitreous form of acidic
lava, and closely resembling dark-coloured bottle
236 MOUNT VESUVIUS.
glass, it is often called " volcanic glass." So like
glass is it in the hardness and sharpness of its
edges, that in Mexico and Peru cutting weapons
were made of it by the natives. Only when thin is
it semi-transparent. As it is the result of a rapid
cooling which does not allow of the formation of a
crystalline structure, it can be artificially imitated by
melting and casting, as was done with the Rowley
Rag, an igneous rock of Staffordshire, for economic
purposes, but as this was a basic rock the vitreous
product of the fusion was rather Tachylite than
Obsidian.
Etymology : The name Obsidian is from
" Obsidianus lapis," stone of Obsidius, a name
used by Pliny in honour of Obsidius, the reputed
discoverer of the rock in Ethiopia.
PELE'S HAIR. This is a filamentose form of the
very fluid lava of Mauna Loa and Kilauea, in
Hawaii, produced by the wind catching the jets of
the hot lava as they rise from the surface of the
fiery lakes in the craters, and blowing it in fine
silk-like threads on to the rocks around. On several
occasions similar filamentose lava has been found in
the crater of Vesuvius, especially after flows of
highly leucitic lava.
Etymology : From Pele, the name of a goddess
of the Sandwich Islands.
PEPERINO. Peperino is a variety of tufa formed
by the aggregation of small fragments of a some-
what varied character, which give to it the peculiar
VOLCANIC PRODUCTS. 237
partly rounded granular structure suggesting its
name, which is from the Latin pifer-; Italian pepe,
pevere = pepper, in allusion to the peppercorn
appearance of the materials of which it is composed.
PERLITE (Pearlstone). This richly siliceous rock
consists of a compact matrix with a somewhat pearly
lustre, containing imbedded spherical grains having
sometimes a concentric structure, and often showing
crystals of several minerals, as sanidine, mica,
garnets, and occasionally quartz. Perlite in all its
varieties is most conspicuously developed in the
volcanic districts near Schemnitz, in Hungary. Beau-
dant names the following varieties : Granular Shelly
Perlite, Sphaerutitic Perlite, Perlite-Porphyry, Vi-
treous Perlite, Argillaceous Perlite, Pumiceous
Perlite.
PHONOLITE, or Clinkstone. Phonolite, called
also clinkstone, is trachytic in composition, but not
so in structure. It is compact, smooth, and fissile or
slaty, while chiefly consisting of a potash felspar,
and contains usually a disseminated zeolitic mineral.
It varies in colour, but its most general tint is a
bluish-grey, in some cases much darker than in
others. The character by which it is best known is
its sonorous quality of giving a somewhat metallic
sound, or clinking, when struck, and arrangements
of different toned stones of this rock have been
made to form a musical instrument called the rock-
harmonicon.
Etymology : QMS, sound, and x/0o?, stone.
238 MOUNT VESUVIUS.
PITCHSTONE. Pitchstone is a vitreous acidic
lava, not so glassy as Obsidian, but, as its name
implies, with a considerable likeness to solid pitch,
having a conchoidal fracture and a dark colour ad-
mitting of chromatic variations. Under the micro-
scope, minute crystals of felspar may be detected.
Though Pitchstone is usually classed amongst the
plutonic rocks, it is conspicuously displayed as a
volcanic rock in the Isle of Ponza, where it has a
prismatic and globiform structure.
POZZUOLANA. Pozzuolana is a name that was
used in old times to designate the volcanic tufa of
the neighbourhood of Pozzuoli, which was exten-
sively used as a material for cement and shipped
in large quantities from the port whence it takes its
name. Its cementing properties are due to its
chemical composition, and render it valuable for
hydraulic cement or that which sets under water,
and it is said that the original " Roman cement "
was made from this material. The so-called " Roman
cement" of England is manufactured from the sep-
taria of the London Clay.
PUMICE. Pumice is a highly porous and conse-
quently very light volcanic material of a pale grey
or a light straw colour. It has so little specific
gravity that it floats on water, and after the eruption
of Krakatoa, in Java, in 1883, ^ covered the
surface of the sea to such an extent that ships
sailed through it for long distances. The pores
or vesicles being longitudinal, the substance has
VOLCANIC PRODUCTS. 239
a somewhat fibrous appearance, and having a
softly rough texture it is very useful for smoothing
purposes and much used for removing old surfaces
of paint.
From its lightness both in weight and colour,
pumice has been considered to be essentially trach-
ytic and almost altogether composed of orthoclase
s^nidine felspar. It is now found, however, that in
some instances it may be augitic, and that its pumi-
ceous characters are due to its structure. The
peculiar structure and texture of pumice is doubt-
less produced by the evolution of gases in the
mass of fluid lava, together with an ebullition
causing a surface froth of the upper portion of
the lighter and more viscid lava, which is broken
up and ejected in solidified fragments, Lyell's
definition is : "A light spongy lava chiefly fel-
spathic, of a white colour, produced by gases or
watery vapour getting access to the particular
kind of glassy lava called Obsidian when in a
state of fusion. It may be called the froth of
melted volcanic glass."
Etymology : Latin pumexicis, the name given by
the Romans to the substance, originally spumex,
foam, from spuo, to spit.
RHYOLITE. The name Rhyolite is used to
designate the ultra acidic volcanic rocks or those
containing a larger percentage of silica than ordinary
trachytes, and is thus made to include Trachyte
Porphyry, Perlite, Obsidian, and Trachytic Pumice.
240 MOUNT VESUVIUS.
In the Rhyolites free quartz is found much oftener
than in Trachyte, while Amphibole and Pyroxene
are much more rare. Von Cotta's definition of
Rhyolite is: "A compact, enamel-like, or vitreous
matrix, enclosing grains or crystals of sanidine,
oligoclase, mica, or even quartz. Specific gravity
2 '3 2 '6, silica 67 82 per cent."
SCHIUMA. Schiuma is a local Campanian name
for the smaller cindery ejectamenta analogous to
lapilli, the word meaning froth, foam, scum, dregs,
impurities, dross.
SCORIA. Scoria is a comprehensive name for
the rough, irregular, cindery, and vesicular frag-
mentary ejectamenta of a volcano, and more especi-
ally for the cooled fragmentary material from the
surface of small lava-flows. The surface of these
streams, chilled by contact with the air, becomes,
near their termination, covered with cakes more or
less vesicular and rough, which fall over the end of
the flow or from its sides, and are therefore flattish
masses of moderate size, eighteen inches and under
across.
Etymology: Latin scoria, from Greek axopia, from
axop = ordure.
SMOKE, VOLCANIC. The so-called smoke of a
volcanic eruption is chiefly composed of steam and
the fine black dust called volcanic ash (which see),
and accordingly the various proportions of this
'black dust, intermingled with the ascending steam,
determines the various shades of blackness or
VOLCANIC PRODUCTS. 241
darkness of the smoke. Thus it is that when the
explosive features of an eruption are not very pro-
nounced the smoke is whiter, and when explosive
phenomena prevail the smoke is darker in colour.
When the weather is calm, or when there are but
light winds, the column of smoke after ascending to
a great height with little or no expansion, then
spreads out horizontally, and so the whole assumes
a form usually likened to a pine-tree. During some
eruptions the smoke ascends to an enormous
height, several times that of the volcano. In the
case of Vesuvius, three times its height is mentioned
by Sir William Hamilton as the elevation attained
during the eruption of 1779, and in the great
eruption of 1822 the extreme elevation is stated to
have been four or five times the height of the
mountain. In the photographic representation of
the comparatively recent eruption of 1872, the
smoke or column of ash-charged vapour is clearly
shown to have been three times the height of the
crater above the level of the sea, or upwards of
10,000 feet.
STEAM. It may perhaps be said that steam is the
greatest of volcanic products, for no eruption that
is, no explosive eruption occurs without producing
immense volumes of watery vapour, which, given off
in gigantic puffs, form an ascending column of great
height, and a canopy-like expansion above of great
magnitude. And even lava emitted tranquilly from
a volcanic cone gives off clouds of steam that quite
R
242 MOUNT VESUVIUS.
cover and hide the flowing and glowing mass of red-
hot lava.
SUBLIMATIONS. Sublimations are found on the
walls of the crater, on the summit of the cone, on
the sides of fissures and " bocche," in the cracks and
chinks of lava, but especially around the fumaroles
of volcanoes. They are deposited from fumes
which arise from the lava, and which have been
produced in it by the vaporisation by heat of
various chemical compounds. The sublimations of
Vesuvius are numerous, abundant, and sometimes
very conspicuous by their bright and varied colours.
Red, blue, green, yellow, and white variegate what
would otherwise be a dark and sombre surface. So
dappled over and adorned with bright colours,
the surface of the summit of the cone is sometimes
very beautiful. Some of the sublimations collected
by myself twenty years ago are now as bright in
colour as when first deposited. The emanations of
the fumaroles of the tranquil lavas of long and
moderate Vesuvian eruptions appear to have a
certain sequence, which is stated to be as follows :
ist, watery vapour; 2nd, sea salt; 3rd, oxide of
copper ; 4th, hydrochloric acid ; 5th, sulphuric acid,
and afterwards chlorides or sulpho-chlorides, and
sometimes sulphides, which give soda, magnesia,
copper, lead, and traces of other substances. On
lavas of great eruptions, chloride of iron is sublimed
with the above-named compounds, and this changes
their appearance.
VOLCANIC PRODUCTS. 243
On small lavas the action of sulphuretted hydro-
gen with sulphurous acid deposits crystals of
sulphur, and distinct crystals of sal-ammoniac, ten-
orite, and cotunnite are also found. Micaceous
peroxide of iron (ferroligiste), though common near
eruptive cones, is only found on lava when trans-
ported from the crater. Palmieri is of opinion
that the chlorides are sometimes derived from the
oxides.
TACHYLITE, Breithaupt. As obsidian is the
vitreous form of the acidic volcanic rocks, so Tachy-
lite is the vitreous form of the basic or doleritic
class. It accordingly, while resembling obsidian
in its general glassy appearance, is augitic in
chemical composition. The Rowley Rag, a basic
igneous rock of Staffordshire, when artificially fused,
produced a Tachylite.
Etymology : ru^s, quick, and A/&K, a stone, from
reference to the quickness with which it fuses under
the blowpipe.
THOLEITE. A rock consisting of, according to
Bergemann, 70 per cent, of labradorite, 5 of pyroxene,
3 of magnetite, 9 of carbonate of lime and protoxide
of iron, and 1 1 of an undetermined silicate, and which
may therefore be classed with the dolerites. Von
Cotta, however, appears to doubt whether this rock
may not be a plutonic rock, and allied to the mela-
phyres. The rock is at the Schaumberg, near Tholei,
whence the name was given to it by Steininger.
TRACHY-DOLERITE, Abich. An intermediate rock
244 MOUNT VESUVIUS.
between the acidic and the basic, containing, in
some varieties, only 52 per cent of silica, though
the usual range is from 57 to 62. Von Cotta says
of it that it is " a compound of oligoclase (or labra-
dorite) with hornblende or augite, some magnetic
iron ore, and frequently also mica. These minerals
lie imbedded in a grey or brown matrix." The
hornblendic trachy-dolerites are to be found at the
Peak of Teneriffe, among the older lavas of Etna,
and on the island of Liscanera, near Stromboli, while
the augitic or pyroxenic rock occurs on the central
cone of the Rocca Monfina.
TRACHYTE, Hatiy. Trachyte is at the head of one
of the two divisions of volcanic rocks, since it is the
typical acidic rock in which silica forms so large a
proportion of the whole. It is usually mainly com-
posed of orthoclase-felspar in the form of sanidine,
and its chemical composition as given by Abich is
as follows : Silica, 67.09; alumina, 15.64; potash,
3.47; soda, 5.08; lime, 2.25 ; oxides of iron, 4.59;
magnesia, 0.98; oxide of manganese, o. 1 5 ; titanic
acid, 0.38 ; water, &c., 0.45. It forms sometimes
very large masses of rock, and so viscid has its lava
been in some cases that it has exuded and retained
its mound-like form, and so produced a dome-like
elevation without a crateral opening.
The colour of trachyte is usually grey, and the
texture rough to the feel, which justifies its name.
This roughness of surface is due to a minute por-
phyritic structure, small crystals of felspar being
VOLCANIC PRODUCTS. 245
disseminated through the mass, and sometimes there
are to be found crystals of pyroxene, amphibole, or
mica. The following have been included by Von
Cotta under the name Trachyte : Sanidine trachyte,
sanidine-oligoclase trachyte, oligoclase trachyte or
domite, andesite, trachy-dolerite.
Etymology : rpaxvs, rough, in allusion to its rough-
ness of feel.
TRACHYTE-PORPHYRY, or Liparite. This rock
and its varieties are richer in silica and consequently
more acidic than the trachytes proper, and the group
has been defined by Von Cotta as follows :
" Trachyte-Porphyry is the name given to those
rocks (prevalently felsitic and porphyritic with a
compact matrix) which are geologically allied to the
trachytes." Sometimes crystals or grains of quartz
or mica, or both are imbedded. The varieties
defined are six, with silica forming from 67 to 81
per cent., and having a specific gravity of 2.4 to 2.6.
The varieties as given by Von Cotta are : Common
trachyte-porphyry, perlite-like trachyte-porphyry,
argilo-trachyte-porphyry, vesicular or millstone
porphyry, pumiceous trachyte-porphyry, and slaty
trachyte-porphyry.
TRASS. This name is given to very extensive
deposits of Tufa in Germany, in the neighbourhood
of the Rhine, and especially well seen near Ander-
nach and in the valley of Brohl. Its striking
similarity to the Neapolitan tufa was pointed out by
Dr. Daubeny, who showed that it was antecedent in
246 MOUNT VESUVIUS.
age to the great deposit of fresh-water marl in the
Rhine valley and of marine deposition, while being
the product of the now extinct neighbouring volcanic
craters. It contains fragments of pumice and also
of non-volcanic rocks, such as clay-slate, and has
imbedded in it carbonised trunks of trees. In one
place land-shells have been found, but their occur-
rence may be due to an after valley-wash.
TUFA, OR TUFF. Tufa, or Tuff, is an agglomerate
of small fragmentary materials of volcanic origin
compacted together by the agency of water. It is
various in its cohesion, and also in its composition
and colour, but it is never so hard that it cannot be
called a soft rock, while it is usually hard enough
to constitute a useful building material, when over-
coated with some kind of stucco, and thus it is
largely used in and about Naples. At Naples and
its vicinity may perhaps be found the most typical
tufa, which there forms not only the hills to the
north and east, but the site of the city itself. The
Neapolitan tufa has been well described by Dr.
Daubeny as follows : " Its basis is generally of a
straw-yellow colour, dull and harsh to the feel, with
an earthy fracture, and commonly a loose degree of
consistence. It contains imbedded fragments of
pumice, obsidian, trachyte, and many other varieties
of compact as well as cellular lava, the softer kinds
often rounded, the harder mostly angular." This
tufa is chiefly trachytic, and its materials have been
deposited in the sea, as shown by the presence in it
VOLCANIC PRODUCTS. 247
of the shells of the Mediterranean mollusca. It is
in its structure and constitution, therefore, a marine
1 ' mechanically-formed " rock of volcanic materials,
and such appears to be a correct description of
tufas in many other localities.
Amongst tufas of an analogous character to that
of Naples, perhaps the one most resembling it is the
rock in the neighbourhood of the Rhine in the
district of the Eifel, to which the name Trass is
there given (which see), and which is especially
thick near Andernach.
The tufa of the Roman Campagna and of the
" Seven Hills " of Rome is somewhat similar, though
this appears to have been compacted by the action
of fresh-water, in which the volcanic materials were
deposited. The Roman tufa is of two kinds, called
by Brocchi the lithoide and the 'granular. The
former is more compact and of a dull red colour,
and forms the Capitoline and Esquiline Hills, while
the latter, the granular, a fresh fracture of which
gives a granular surface, is yellow, brown, or dark
violet, and is seen in the Pincian and Quirinal Hills.
Another tufa is formed by the condensation of the
watery vapour given off at an eruption causing a
flood on the slopes of a volcano, by which the
ejected ashes are converted into a mud that may
be deposited, and afterwards consolidated on the
lower ground around. Such is the character of the
tufa in which the ruins of Herculaneum are im-
bedded. (See Mud, Volcanic.)
248 MOUNT VESUVIUS.
Since lapilli and ashes, which constitute the
material of tufa, may be either doleritic or trachy tic,
it is obvious that the mineralogical and chemical
composition of tufas must be various, but as lapilli
is usually pumiceous, and pumice is usually trachytic,
the majority of tufas are in the main trachytic,
though frequently containing particles and crystals
of augite, and in Italy and the Eifel leucite, with
small fragments of mica, olivine, hliyine, &c.
Etymology : Tufa, Italian name for a porous
stone, from Lat. tophus, the name for the rock tufa.
EJECTED BLOCKS.
A notable addition to ordinary volcanic products
is furnished by Vesuvian ejectamenta, and it is
therefore perhaps better to place this class 'of the
products of volcanic energy, Ejected Blocks, sepa-
rately. These masses, shot forth in a solid form
from the Vesuvian vent at various periods, and now
found imbedded in the fragmentary materials of the
mountain, are of great importance and value, both
as showing the character of the underlying rocks of
the volcano, and as being the repository of many of
the Vesuvian minerals. They consist of both non-
volcanic and volcanic material, for very many are
blocks or fragments of limestone, an essentially
aqueous or water-formed rock, and all have been
torn from the platform or foundations of the
mountain by the eruptive forces, and thrown out
of the central vent of the period by great or
VOLCANIC PRODUCTS. 249
paroxysmal eruptions, the explosive energy of which
has been too great to be restricted within the
circumference of the normal volcanic tube. These
ejected masses are very various in size, many being
small fragments, smaller than an orange, some the
size of cocoa-nuts, and many much larger, ranging
to large and heavy blocks, such as one seen in a
section the face of which, when measured by Lavis,
was found to be about 6 feet 6 inches by 9 feet.
As will be seen from what has been said of the
underlying rocks of Vesuvius, the limestone that is
so conspicuous in the Apennines, and is seen as a
surface rock as near as Castellamare and Capri, is the
bed-rock of the whole of the volcanic beds and
elevations of the Neapolitan Volcanic Region. It is
from this rock that a large proportion of the
Ejected Blocks are derived, but the effect of the
volcanic heat has been sufficient to, in many cases,
convert the rock from a coarse limestone, which the
Apennine Limestone is, to a marble-like limestone
as fine in texture as are the ordinary marbles of
Italy. It is this altered limestone that is used for
cameos and sold as "lava." It is, too, in the
cavities of these changed, or, as geologists say,
metamorphosed masses, that occur many of those
rare minerals that distinguish the Vesuvian area.
Some, however, of the ejected calcareous blocks are
almost, if not entirely, unaltered from their original
condition of coarse limestone.
Some of the Ejected Blocks are fragments of the
250
MOUNT VESUVIUS.
Tertiary Macigno which overlies the limestone, and
some are portions of the super-imposed rocks of
Post Pliocene age on which the mountain stands.
From these non-calcareous fragmentary masses,
some sandstone, some marl, and many tufa, have
been derived the fossil shells which so clearly
prove the geologically late commencement of the
volcano, and which, with the exception of one, the
Buccinum semistriatum, Broc., are all now living in
the adjacent sea. In the year 1773, Sir William
Hamilton found fossil shells in the Fosso Grande,
and, in 1841, Monticelli enumerated 30 species.
The following List, re-arranged from that given
by Roth in " Der Vesuv," is founded partly on the
authority of Roth, and partly on that of Scacchi and
Prof. G. O. Costa :
PTEROPODA.
Hyalcea trispinosa, Lesueur.
GASTEROPODA.
Buccinum ascanias, Brug.
,, mutabile, Lin.
,, semistriatum, Broc.
Bulla.hydatis, Lin.
,, lignaria, Lin.
truncatula, Brug.
utriculus, Broc.
Calyptrsea vulgaris, Pil.
Cassidaria tyrrhena, Lam.
Cerithium mammilatum, Risso.
,, vulgatum, Brug.
Chemnitzia pallida, Phil.
Chenopus pes-pelicani, Phil.
Delphinula exilissima, Phil.
Dentalium dentalis, Lin.
,, entalis, Lin.
strangulatum, Desh.
spec.
Fusus rostratus, Olivi.
Limnaeus ovatus, Drap.
Marginella secalina, Phil.
Natica intricata, Donov.
,, Guilleminii, Pasc.
macilenta, Phil.
Paludina tentaculata, Lin.
Pleurotoma costulatum, Risso.
,, nanum, Scacchi.
Ringicula auriculata, Men.
Rissoa monodonta, Bivon.
,, oblonga, Desm.
Scalaria communis, Lam.
Siliquaria anguina, Lam.
Turritella communis, Risso.
LAMELLIBRANCHIATA.
Anomia spec.
Astarte incrassata, Jouk.
Cardium aculeatum, Lin.
., ciliare, Lin.
VOLCANIC PRODUCTS.
251
Cardium Deshayesii, Payr.
,, echinatum, Lin.
edule, Lin.
,, rusticum, Chemn.
,, sulcatum, Lam.
,, tuberculatum, Lin.
Corbula nucleus, Lam.
Cytherea chione, Lin.
cyrilli, Scacchi (Venus min-
ima, Mont.).
,, exoleta, Lin.
,, lupinus,Poli (C. lincta, Lam.)
,, rudis, Poli.
Donax semistriata, Poli.
,, trunculus, Lin.
Erycina angulosa, Bronn. (Tellina
striata, Broc.)
,, Renierii, Bronn.
Isocardia cor, Lam.
Lima subauricula, Montagu.
Lucina commutale, Phil.
fragilis, Phil.
,, lactea, Lam.
Lutraria elliptica, Lam.
Mactra stultorum, Lin.
triangula, Ren.
Mesodesma donacilla, Desh. (Mactra
cornea, Poli.).
Mytilus spec.
?
Nucula margaritacea, Lam.
sulcata, Bronn.
Ostrea cristata, Born.
spec.
Pecten aspersus, Lam.
,, hyalinus, Phil.
,, jacobaeus, Lin.
,, opercularis, Lam.
Pecten pygmceus, Miinst.
,, sanguineus, Lin.
,, varius, Lam.
Pectunculus glycimeris, Lam.
pilosus, Lam.
Psammobia vespertina, Lam.
Saxicava arctica, Phil.
,, rugosa ? Lam.
Solen coarctatus, Lin.
,, ensis, Lin.
,, legumen, Lin.
,, siliqua, Lin.
Tellina donacina, Gru.
fabula, Gru.
,, nitida, Poli.
planata, Lin.
pulchella, Lam.
,, serrata, Broc.
,, tenuis, Met. and Rack.
Thracia phaseolina, Kien.
,, pubescens, Kien.
Venus fasciata, Dunov.
,, gallina, Lin.
,, ovata, Lin.
ANNELIDA.
Serpula cereolus, Gru.
FORAMINIFERA.
Polystomella crispa, d'Orb.
Quinquiloculina Akneriana, d'Orb.
,, longirostra, d'Orb.
Rosalina amalise, Costa.
,, radiata, Costa.
,, sub-radiata, Costa.
Triloculina cultrata, Costa.
,, flexa, Costa.
,, inflexa, Costa.
Those blocks containing well-preserved fossil
shells have obviously been little acted upon by the
volcanic fires, but many of the fragments, apart from
the altered limestones, are by no means so unscathed,
and consequently there is amongst them much
252 MOUNT VESUVIUS.
variety of lithological character, some being com-
pact, some vesicular, and some conglomeratic or
brecciated in structure or appearance.
The Ejected Blocks of Vesuvius have been ob-
tained chiefly from the Rivo di Quaglia, Molara di
Massa, Fosso Grande, and the Fosso di Cancheroni,
and they occur abundantly as stated by Lavis in the
beds exposed in the sections exposed in the
Vallone Sanseverino, the Vallone di Pollena, and
other places on the north-western slopes of Monte
Somma.
253
CHAPTER X.
THE MINERALS OF VESUVIUS.
The Vesuvian Mountain the Richest Mineral Area This Fact Im-
portant in Vulcanology Introduction to Catalogue Descriptive
Catalogue of Vesuvian Minerals Index of Synonyms and in-
cluded Varieties.
THE extraordinary number of minerals which have
been obtained from the Vesuvian area will, apart
from its eruptive phenomena, ever render this
district one of the greatest interest to the naturalist.
Its richness as a field for the mineralogist is
perhaps generally known, but to merely say that
this area surpasses all others of equal size in the
variety of its minerals, very inadequately states the
fact. In the article " Mineralogy" in the new edition
of the " Encyclopaedia Britannica," 731 mineral
species are enumerated, while occurring in the
Vesuvian area alone, which is but a spot on the
surface of the globe, upwards of a hundred distinct
mineral substances are recognised by Prof. Scacchi.
Nor is this fact of interest to the mineralogist only,
since it is very suggestive, and bears significantly on
the causes of volcanic action, for any hypothesis to
account for such action should be capable of ex-
plaining how it is that so many more mineral species
may be found in one volcanic area than in another.
The physio chemical hypothesis if the one I have
254 MOUNT VESUVIUS.
ventured to advance in this work may be so termed
appears to me to be the only one which offers a
sufficient explanation of the remarkable and quite
exceptional mineralogical richness of the Vesuvian
volcano. Other theories require either a common
source of lava, or extensive subterranean lava lakes
or seas, and consequently such a conspicuous mine-
ralogical pre-eminence of one small area as is found
at Vesuvius would be in the highest degree improb-
able, if not altogether impossible.
It is most fortunate for science that at Naples, in
the immediate neighbourhood of the volcano, there
is so eminent a mineralogist as Prof. Archangelo
Scacchi, who has been ever ready to examine
the mineral productions of Vesuvius, and ever
willing to describe them, and bring them before
the notice of mineralogists and geologists all over
the world.
Doubtless some of these minerals will be event-
ually determined to be rather varieties of others than
worthy of distinct specific appellations ; but, on the
other hand, it is not too much to expect that future
eruptions, and still further investigation, may give
some additional species to the Vesuvian catalogue.
The results of the critical examination of the
products of the eruptions of recent years certainly
point in this direction.
It has not been deemed requisite to burden the
following descriptive notices of the minerals with
crystallographic details that can only be stated in
THE MINERALS OF VESUVIUS. 255
an abstruse technical manner, and which possess an
interest, or, indeed, a meaning, for only an ex-
tremely limited number of naturalists, and these
few mineralogists have access to special mineralo-
gical works, wherein such purely technical minutiae
may be found.
Prof. Scacchi's determination of species, as given
in the recently published " Lo Spettatore del Vesuvio
e dei Campi Flegrei," has been followed with but
slight deviation, and the nomenclature has been
based on that of the great American work, "A
System of Mineralogy," by Prof. J. D. Dana, which
favours the uniform termination ite to the scientific
names of minerals.
The names here adopted, however, differ con-
siderably from those of Prof. Scacchi, and also in
several instances from those of Prof. Dana. The
division of what has hitherto been regarded as a
species into several having distinct names, and on
the other hand, the grouping of named varieties
having a similar chemical composition under one
specific designation, occasion sometimes considerable
difficulty in deciding upon the name possessing the
greatest claim for adoption. But it is hoped that
from the consideration which has been given to
each, the names that have been decided upon may
meet with general approval.
In the chemical formulae the old system of
symbolism has been employed from its being
more generally familiar, as well as from its sim-
256 MOUNT VESUVIUS.
plicity and the distinctness wherewith it indicates
the amount of oxygen in the oxygenated com-
pounds, which form nearly the whole of the
Vesuvian minerals.
For the convenience of visitors to the museums
of Italy, and especially of those who may desire to
examine the collections of Vesuvian minerals at
Naples, the name used for each species by Prof.
Scacchi is given in brackets following the name here
adopted, and a list of synonyms and included
varieties with references is appended.
Mineralogists are not yet in agreement on the
best method of classifying minerals, and as any
classification based on chemical composition is in-
convenient to general readers, a simple alphabetical
arrangement has been thought best adapted for this
work. It will, with the Index of Synonyms, enable
reference to the description of any species to be
made without difficulty.
DESCRIPTIVE CATALOGUE OF VESUVIAN
MINERALS.
ALUM (Alume), Kalinite, Potash Alum, Native
Alum, Common Alum.
Hydrous sulphate of alumina and potash,
KO SO 3 + A1 2 O 3 3SO 3 + 24H 2 O, or sulphate of
alumina 36.2, sulphate of potash 18.4, and water
45.5 = 100.
Alum crystallises in the Cubic System, in octahe-
drons, but it usually occurs fibrous or as a mealy
PlateXYII.
FIRST OR CUBIC SYSTEM
Rhombic*
Dodecahedron Oduhudrcru
Six faced/ Four faced/ PtnJtayonal;
SECOND OR SQUARE PRISMATIC SYSTEM
Tetragonal; Pyramid*
Truncated
Pyramids
LONDON ;ftOPeHtOROWLY.II.U>DGATe. HILL. C
SIMPLE CRYSTALLINE FORMS
THE MINERALS OF VESUVIUS. 257
efflorescence. Hardness 2 2.5,* Specific Gravity
1.75. Its colour is white, with a vitreous lustre, and
its crystals are transparent or translucent. It is very
soluble in boiling water, little more than its own
weight being sufficient for its solution, but it requires
1 6 to 20 times its weight of cold water. Before the
blowpipe it quickly melts in its water of crystallisa-
tion, and then intumesces violently till it becomes a
white spongy mass. Alum is well known by its
sweetish astringent taste.
In Yorkshire, at Whitby, it is obtained from the
"Alum Shales" of that place by lixiviation and
evaporation, and in Dorsetshire it is manufactured
from clay by the use of sulphuric acid. At Vesuvius
it is not rare in the crater.
AMPHIBOLE, Haliy (Anfibolo), Hornblende,
Tremolite.
The group of minerals to which the names Am-
phibole and Hornblende have been given contains
varieties with a very considerable diversity of com-
position, but all agreeing in being silicates of
magnesia and lime. Some, however, contain
alumina, some have iron and some manganese, upon
which differences a large number of names have
been based. The composition of the Vesuvian
* SCALE OF HARDNESS.
1. Talc. 6. Felspar.
2. Rock Salt. 7. Quartz.
3. Calcite. 8. Topaz.
4. Fluor. 9. Corundum.
5. Apatite. 10. Diamond.
258 MOUNT VESUVIUS.
mineral, as given by Prof. Scacchi, is simply silicate
of magnesia and lime (MgO, CaO) SiO 2 .
Crystallisation, Monoclinic ; sometimes in isolated,
sometimes in aggregated, and sometimes in macled
crystals. It occurs also granular and fibrous as well
as granular massive. Hardness 5 6, Specific Gravity
2.9 3.4. Colour usually a very dark green or
black, but also lighter shades of green, and some-
times white. Opaque and translucent, usually sub-
translucent, but occasionally transparent. Lustre,
vitreous to pearly, and when fibrous, silky. When
massive it is very^ tough, and has a subconchoidal
fracture. The best-known varieties of Amphibole
are Actinolite, Amianthus, Asbestos, Edenite,
Grammatite, Hornblende, Rock Cork, Mountain
Leather, Nephrite or Jade, Tremolite.
Amphibole, when the name is used comprehen-
sively, is a very widely distributed mineral, occurring
in a large number of igneous and crystalline rocks and
in very many localities. At Vesuvius black amphi-
bole is abundant in the crystalline masses of Monte
Somma, usually associated with glassy felspar, and
as white, yellow, or brown acicular and filamentose
varieties, it occurs as a product of sublimation in the
metamorphic conglomerate of the eruption of 1872.
Etymology : From ^<p//3oxo ff , ambiguous, from this
mineral having been confounded with tourmaline.
ANALCIME (Analcime), Cubic Zeolite.
This is one of the class of minerals called
Zeolites, from $, to boil, all of them containing
THE MINERALS OF VESUVIUS. 259
water and intumescing before the blowpipe. Anal-
cime is a silicate of alumina and soda with water,
and is expressed by 3A1 2 O 3 Si 2 O 3 +6H 2 O=silica
54.6, alumina 23.2, soda 14.0, water 8,1 = 100.
It crystallises in the Cubic System in 24-sided
trapezohedrons. Hardness 5 5.5, Specific Gravity
2.22 2.29. Colourless and white, but occasionally
tinted variously. Lustre vitreous. Transparent to
nearly opaque. Fracture subconchoidal. It is feebly
electric by friction, and is readily decomposed by
hydrochloric acid, when it yields viscid silica and so
gelatinises.
Analcime occurs in the cavities of igneous rocks,
and is found in those in the Orkneys and the
Hebrides, at Dumbarton, at Arthur's Seat, and at
the Giant's Causeway, as well as at many other
localities in Scotland and Ireland. At Vesuvius it
is found in the cavities of the ejected blocks of
Monte Somma, but it is not common.
ANGLESITE (Anglesite), Anglesine.
Sulphate of lead, or PbOSO 3 =oxide of lead
73.6, sulphuric acid 26.4=100.0.
Crystallises in the Rhombic System in rhombic
prisms. Hardness 2.75 3, Specific Gravity 6.12
6.39. It is white, grey, or. yellowish in colour, but
frequently tinged blue or green by oxide of copper.
Lustre adamantine inclining to resinous. Fracture
conchoidal and very brittle.
Anglesite was so named from being first found
in Anglesea. It occurs, however, in Derbyshire,
26O MOUNT VESUVIUS.
Cumberland, and in Scotland, both at Leadhills and
Wanloch Head. At Vesuvius it was found on the
lava of 1872 at Le Novelle.
ANHYDRITE (Anidrite).
Anhydrous sulphate of lime, Ca O, So 3 = lime
41.18 and sulphuric acid 58.82 100.
Crystallisation Rhombic, usually in rectangular
prisms, but it most commonly occurs in massive
granular beds. The usual colour is white, but it
is sometimes tinged bluish or reddish, with a lustre
somewhat pearly. The hardness of Anhydrite is
greater than that of the hydrous sulphate of lime,
Gypsum, being 3 3.5, with a specific gravity of
2.899 2-985. It is sometimes transparent, but
commonly translucent, and is doubly refractive.
Does not effervesce with acids, but is slightly
soluble in water.
In the British Islands Anhydrite occurs in
Nottinghamshire and Derbyshire, and in Ireland at
Cave Hill, near Belfast. At Vesuvius it occurs in
the ejected lavas of Monte Somma and in the
metamorphic conglomerates, but not common.
Etymology : a, without, and "vlap, water.
ANORTHITE (Anortite), Christianite.
Silicate of alumina and lime, 3A1 2 O 3 Si O 2 + Ca O
Si O 2 =: silica 43.1, alumina 36.8, lime 20.1. An
analysis by Abich of a specimen from Somma gave
the following result: Silica 44.12, alumina 35.12,
lime 19.02, peroxide of iron 0.70, magnesia 0.56,
soda 0.27, potash 0.25 := 100.04.
THE MINERALS OF VESUVIUS. 26 1
Crystallisation Triclinic, Doubly Oblique, or, so
called from this mineral, Anorthic. Hardness 6 7,
Specific Gravity 2.66 2.78. Found in transparent
to translucent white crystals having a vitreous
lustre inclining to pearly, but in Glen Cairn and
Labrador it is rose-red. It is brittle, and has a
conchoidal fracture, and is entirely decomposed in
hydrochloric acid.
Anorthite occurs in the Faroe Islands, in Iceland,
the Ural Mountains, and other places. In Ireland it
has been found in the Carlingford Mountain. At
Vesuvius it is chiefly found in the cavities of com-
pact calcite, associated with meionite, and occurs
generally in the crystalline masses of Monte Somma.
Etymology : ^o?, oblique, in allusion to its
crystallisation.
APATITE (Apatite), Asparagus Stone, Moroxite,
Phosphorite.
Phosphate of lime, sCa O PO 5 + Ca (Cl. F.)
lime 50., phosphoric acid 42.26, calcium 3.97,
fluorine 3.77. Part of the fluorine is sometimes
replaced by chlorine.
Crystallisation, Hexagonal ; usually in six-sided
prisms. Hardness 5, Specific Gravity 2.92 3.25.
Colour usually white, but often variously coloured
with pale tints as yellowish-white, sea-green, pale
red, &c. Transparent to opaque with a vitreous
lustre. Fracture conchoidal and uneven. Brittle.
Some specimens are phosphorescent on incandescent
charcoal. Apatite is associated with rocks con-
262 MOUNT VESUVIUS.
taining tin veins, but also occurs in limestone and
serpentinous rocks.
In England this mineral is obtained from various
localities in Cornwall, Devonshire, and Cumberland,
and also in Scotland and Ireland. At Vesuvius
it occurs, but not commonly, in the crystalline
masses and metamorphic conglomerates of Monte
Somma.
Etymology : Aviiratu, to deceive, from its resem-
blance to other minerals.
APHTHITALITE (Aftalosa), Glaserite, Arcanite,
Vesuvian Salt.
A sulphate of potash, KOSO 3 : potash 54.1,
sulphuric acid 45.9=100, but it has always
associated with it sulphate of soda and other salts.
A specimen from Vesuvius contained sulphate of
potash 71.4, sulphate of soda 18.6, chloride of sodium
4.6, chloride of ammonium, copper, -,nd iron
5.4=100.0.
Crystallises in the Rhombic System. Hardness
3 3.5, Specific Gravity 1.731. Colourless or white,
sometimes tinged with blue or green. Lustre
vitreous. Transparent to opaque. Taste saline
and bitter.
This salt occurs in thin tables, in crystalline
blades, massive, and in crusts. At Vesuvius it is
sublimed in delicate white crystallisations on the
lava about the fumaroles and in the crater. It was
found both on the lava of 1868 and on that of 1872.
Aphthitalite occurs at other volcanoes also.
THE MINERALS OF VESUVIUS. 263
Etymology : *<pfaros, unalterable, and ***$, salt, this
mineral being unalterable in the atmosphere.
ARAGONITE (Aragonite), Aragon Spath, Flos Ferri,
Satin Spar.
Carbonate of lime, CaO, CO 2 =lime 56.0, car-
bonic acid 44.00=100.
Crystallisation Rhombic, in radiating groups of
acicular crystals, also columnar, fibrous, and silky.
The calcareous incrustations in boilers are usually
Aragonite. It is usually white, but sometimes tinted
with yellow, blue, and green. Hardness 3.5 4,
Specific Gravity 2.93. Fracture sub-conchoidal, with
a vitreous lustre. Though the same in composition,
Aragonite is harder than Calcite, which it scratches
easily, and from which it may be otherwise dis-
tinguished by being heated, when it immediately
becomes a powder, while calcite remains un-
changed.
This form of carbonate of lime occurs both in
North and South Devon, at Torbayand Ilfracombe,
and in Cumberland, and fine crystals are found at
Leadhills, in Scotland. At Vesuvius Aragonite is
in the ejected lavas of Somma, and appears in
radiated and minute crystals in cavities in the
ejected calcareous blocks.
Etymology : From Aragon, in Spain, where it
was first discovered.
ATACAMITE (Atacamite), Muriate of Copper.
Hydrochloride of Copper =Cu Cl + 3^u O +
2HCO=zoxide of copper 55.8, chloride of copper
264 MOUNT VESUVIUS.
31.5, water 12.7=100, or copper 59.45, chlorine
16.64, oxygen 11.25, water 12.66.
Crystallisation Rhombic, usually in small rectangu-
lar octahedrons of various shades of bright green.
Translucent to sub-transparent. Hardness 3 3.5,
Specific Gravity 3.9 to 4.3. Before the blowpipe
Atacamite tinges the flame bright green or blue, and
gives off fumes of hydrochloric acid. It is soluble
without effervescence in nitric acid.
In England this mineral has been obtained at St.
Just, in Cornwall, and in Australia at Burra Burra,
but it occurs chiefly in South America, and from the
Desert of Atacama, on the west of the Andes, it
derives its name. At Vesuvius it is common in the
chinks and crevices of the lava of the eruption of
1631, but Scacchi says the green substance in the
crater is not Atacamite as is usually thought. (See
Euchlorinite).
ATELITE, A. Scacchi (Atelina).
Another hydrochloride of copper, which may per-
haps be considered to be a variety only of Atacamite,
having the composition, according to Prof. Scacchi,
Cu Cl+2Cu O+3H 2 O, and stated to be produced
by the action of hydrochloric acid on the mineral
Tenorite (which see).
BELONESITE, A. Scacchi. (Belonesia.)
Molybdate of magnesia ?
This new Vesuvian species of Prof. Scacchi is
rather rare, in minute acicular crystals in a
fragment of ancient volcanic rock enclosed in
THE MINERALS OF VESUVIUS. 265
lava of the eruption of 1872. (" Lo Spettatore,"
p. 68.)
BIOTITE (Biotite), Mica in part, Magnesia Mica,
Uniaxial Mica, Meroxene.
Silicate of alumina, magnesia, and potash, with
iron (A1 2 3 , Fe 2 O 3 ) SiO 2 + (MgO, KO, Fe
O) 3 SiO 2 . An analysis of Biotite from Vesuvius
by Chodnef gave: Silica 40.91, alumina 17.79,
magnesia 19.04, potash 9.96, protoxide of iron 7.03,
peroxide of iron 3.00, lime 0.30=198.03.
Crystallisation, Hexagonal ; in six-sided tabular
prisms, with a perfect cleavage parallel to the base,
but often in disseminated scales. Hardness 2.5 3,
Specific Gravity 2.7 3.1. Colour usually dark
brown or green, or black, but sometimes white or
colourless. Biotite, like Muscovite, is highly sectile,
and thin plates are both flexible and elastic. It is
transparent to opaque, and optically uniaxial, thereby
differing from common mica, or Muscovite, which
is biaxial. Its lustre is pearly, inclining to metallic,
and its streak uncoloured. Biotite may be readily
distinguished from biaxial mica by its being entirely
decomposed by strong sulphuric acid. It is but
slightly acted upon by hydrochloric acid. Before
the blowpipe it is only with difficulty fusible, when
it produces a grey or black glass.
In Scotland Biotite occurs in Inverness-shire and
Skye. At Vesuvius it is most abundant, while
being variable in colour, in the crystalline masses of
Somma. It is also to be found in the lavas of the
266 MOUNT VESUVIUS.
ejected conglomerates as well as, resulting from
sublimation, in the chinks of the lava of 1631.
Etymology : Named after M. Biot, who first
showed the optical peculiarities of the micas.
BLENDE (Blende), Sphalerite, Black Jack, Sul-
phide of Zinc, Zn S = zinc 67, sulphur 33 = 100.
Crystallisation Cubic in tetrahedrons ; occurs also
massive, fibrous, and botryoidal. Hardness 3.5
4.0, Specific Gravity 3.9 4.2. Colour brown,
yellow, red, green, and black, whence the miner's
name black-jack. Translucent, or opaque. Brittle
with a conchoidal fracture, and Lustre resinous to
adamantine. When strongly heated before the
blowpipe it gives off vapours of zinc, and dissolves
in nitric acid, giving off sulphuretted hydrogen.
Blende is common in metalliferous districts,
and is associated with the ores of lead, silver, and
copper. At Vesuvius it is rather rare in the crystal-
line calcareous masses of Monte Somma, where it
is associated with galena.
Etymology : From the German blendena, bril-
liant (blenden, to dazzle).
BREISLAKITE (Breislakite), Augite and Pyroxene
in part.
This mineral, though having the same composi-
tion as Augite (which see), of which indeed it is but
a variety, yet has a sufficiently distinct form to
make it worthy, in Prof. Scacchi's opinion, of a
separate place and designation. It occurs in fine
brown flexible fibres or filaments, described as
THE MINERALS OF VESUVIUS. 267
''wool-like/' not only at Vesuvius, but in the lava-
rock of Capo di Bove, near Rome. At Vesuvius it
is in the chinks of the older lava of the eruption
of 1631.
CALCITE (Calce), Calcareous Spar, Iceland Spar,
Double Refracting Spar.
Carbonate of lime, CaO, CO 2 : lime 56, carbonic
acid 44.
Crystallisation, Hexagonal ; in an extraordinarily
large number of forms, no less than 700 having
been figured by Count Bournon, including 50 rhom-
bohedrons and 155 scalenohedrons. The primary
or fundamental form is an obtuse rhombohedron,
which may be obtained by cleavage, and is well
seen in Iceland spar, the purest form of calcite.
Calcite also occurs massive (limestone), granular
(marble), pisolitic (oolite), earthy (chalk), lamellar,
fibrous, and stalactitic. Hardness 2.5 3.5, Speci-
fic gravity 2.508 2.778. When not colourless
it is usually white, but it is often tinged with
colour by various impurities such as iron, man-
ganese, &c. Transparent, translucent, and opaque,
with a vitreous or earthy lustre and white streak.
A non-cleavage fracture is conchoidal. All forms
of calcite may be readily known by their strong
effervescence with acids. Before the blowpipe it is
infusible, but when incandescent it gives an intense
white light, while the carbonic acid is driven off
leaving a residue of pure or quick lime. The
transparent rhombohedral crystals of Iceland spar
268 MOUNT VESUVIUS.
possess very strong double refractive powers,
giving to this form the name Double Refracting
Spar. The following are other forms of Calcite :
Dog-tooth spar, Nail-headed spar, Prunnerite,
Natrocalcite, Reichite, Ferrocalcite, Neotype,
Spartaite, Fontainebleau limestone, Hislopite,
Satin spar, Aphrite, Lithographic stone, Stalac-
tites, Oriental alabaster, Rock milk, Rock meal,
Argentine.
Fine crystals of Calcite are obtained in Cumber-
land at Alston Moor and the Greenside mine, Derby-
shire, Devonshire (Plymouth), Cornwall, and other
localities, Andreasberg, in the Hartz Mountains,
has long been famous for its six-sided prisms of
Calcite, and in Iceland a crystal (rhombohedron) six
yards long was found. At Vesuvius it is abundant
in the crystalline masses of Monte Somma, and
occurs enveloped in the lava of 1631. Sometimes it
is found in the chinks of this lava crystallised in a
form resembling balls of cotton-wool.
Etymology : From calx, Latin for lime.
CARBONIC ACID GAS (Anidride Carbonica).
Anhydrous carbonic acid, CO 2 .
This gas, Professor Scacchi says, is occasionally
evolved at various points on the slope of the moun-
tain, when it does great injury to the roots of trees
that are planted in the neighbourhood.
CHESSYLITE (Azzurrite), Azurite, Blue Copper,
Blue Carbonate of Copper, Kupferlasur.
Hydrous carbonate of copper, or 2CuO, CO 2 +
THE MINERALS OF VESUVIUS. 269
CuO + H 2 O = oxide of copper 69.2, carbonic acid
25,6, water 5.2 = TOO.
Crystallisation, Monoclinic. Hardness 3.5 4,
Specific Gravity 3.5 3.831. Colour, various shades
of azure, passing into Berlin blue. Transparent to
opaque. Brittle, with a conchoidal fracture. Be-
fore the blowpipe Chessylite decrepitates, and after
turning black yields a globule of copper. It is
soluble both in ammonia and nitric acid, and with
the latter it effervesces.
At Chessy, near Lyons, from which place it de-
rives its name, it is abundant and beautiful. It is a
valuable ore of copper, but is not found in England
in sufficient quantity to be so used. It occurs in
Cornwall, Devonshire, Derbyshire, and Cumberland,
as well as in Scotland and Ireland. At Vesuvius it
is found on the sides of the chinks of the lava of
1631.
CHLORALLUMINITE, Scacchi (Cloralluminio).
Chloride of aluminium, A1 2 C1 3 , Scacchi ; A1 2 C1 6
+ *H 2 O, Dana. (Att. Accad. Napole, VI.)
Produced along with Molysite and Chloromag-
nesite at the eruption of 1872.
CHLOROCALCITE, A. Scacchi (Clorocalcite).
Chloride of Calcium = Ca C1 2 , Dana ; Ca Cl,
Scacchi.
Crystallisation, Cubic; in small crystals with cubic,
octahedral, and dodecahedral planes. Very soluble
and deliquescing readily. It is mingled with chlo-
ride of soda, potash, and manganese, the per-
270 MOUNT VESUVIUS.
centage of CaCl 2 being 58.76. Produced by the
eruption of 1872. Transparent, sometimes stained
a light violet.
Chlorocalcite, crystallised, is abundant about the
fumaroles of the craters.
CHLOROMAGNESITE, A. Scacchi (Cloromagnesite),
Bischofite.
Chloride of magnesium, MgCl, or, according to
Dana, Mg C1 2 + 6H 2 O =: magnesium n.86, chlo-
rine 35.04, water 53.10 = 100.
Hardness i 2, Specific Gravity 1.65. Colourless
to white, with a lustre vitreous to dull. It occurs
mingled with the other chlorides of the crater of
Vesuvius, and was obtained by crystallisation from
a solution.
CHLOROTIONITE, A. Scacchi (Clorotionite).
Chloride of potash and copper with sulphuric acid,
K,Cu,ClSO 4 , or K 2 SO 4 + Cu C1 2 = potassium
26.29, copper 19.56, chlorine 20.04, sulphuric
acid 32.29.
Occurs in thin mammillary crusts of a bright
blue colour, or, as stated by Scacchi, in the form of
crystalline blue globules subsequent to the eruption
of 1872. Dana considers this to be rather a mixture
of two salts than a single species.
Etymology : Chlorine and Qtlo, sulphur.
CHONDROTITE, Bournon (Umite).
Silicate of magnesia, with part of the oxygen re-
placed by fluorine, same as Humite, but Monoclinic,
and thus crystallographically as well as optically
THE MINERALS OF VESUVIUS. 271
distinct. This is Type II. of Humite as de-
scribed by Prof. Scacchi, but determined by Des
Cloiseaux to be crystallographically specifically
separable.
Etymology : From xfalpo;, a grain, from its granular
structure.
(See Humite and Clinohumite.)
CHRYSOLITE (Peridoto), Smaragdus, Olivine, Peri-
dote.
Anhydrous silicate of magnesia with protoxide
of iron, 2(MgO, Fe O) Si O 2 . An analysis by
Walmstedt of a Vesuvian specimen from Somma
gave silica 40.08, magnesia 44.22, protoxide of
iron 15.26, manganese 0.48, alumina 0.18=100.24.
Crystallisation Rhombic, usually in imbedded
grains, and also compact or granular.
Hardness 6 7, Specific Gravity 3.33 3.50.
Colour usually olive-green (Olivine), but sometimes
greenish-yellow (Precious Chrysolite), and sometimes
white (Forsterite). Transparent to translucent, with
a vitreous lustre and conchoidal fracture. When
powdered it is readily decomposed by hydrochloric
and sulphuric acids, when with the separation of
silica, it gelatinises. Before the blowpipe it is in-
fusible when alone, but with borax fuses to a glass
coloured by iron.
The darker-coloured mineral, Olivine, is largely
disseminated in basalts and lavas, and occurs some-
times in grains and sometimes in masses, and it even
constitutes rocks. Olivine is in the basalt of the
272 MOUNT VESUVIUS.
Giant's Causeway in Ireland, and in that of Arthur's
Seat, Edinburgh, as well as in the modern lavas of
Italy and the Sandwich Islands. At Vesuvius it is
common in the crystalline masses of Somma, asso-
ciated with biotite and augite, as well as in the lavas
of both the ancient lavas of Monte Somma and the
modern lavas of Vesuvius. On the sea-shore
wave-worn rounded crystals of Olivine are often
found.
The pale yellowish-green transparent variety, or
Precious Chrysolite, has been used from ancient
times as a gem, and was probably that which Pliny
called "Topazion," while his " Chrysolite " was
probably our Topaz. The white variety, Forsterite
of Levy, which Dana describes as distinct from
Chrysolite, occurs at Vesuvius in the calcareous
masses with crystals of Pleonaste.
Etymology: Chrysolite, from wv s , gold, and
xWoff, stone, or golden stone, from its colour.
Olivine, named from its olive-green colour.
CLINOHUMITE, Des Cloiseaux (Umite).
Silicate of magnesia, with part of the oxygen
replaced by fluorine, same as Humite, but crystallo-
graphically and optically distinct.
This is Type III. of Humite, as described by
Prof. Scacchi, but which Des Cloiseaux ("Phil.
Mag.," III., ii., p. 286. 1876) found to be Monoclinic,
while Type I. is Rhombic, and thus to be sufficiently
crystallographically distinctive to justify its being
constituted a distinct species, and separable also by
Plate XVIII.
THIRD OR RHOMBIC
SYSTEM
CcmJb inalitrt is
of ObUfiie Forrns
FOURTH OR MONOCLINIC
SYSTEM
Tetragonal Sphenoids
FIFTH OR TRICLINIC SYSTEM
Ccrmbinaticns of Triclzriic Farms
SIXTH OR HEXAGONAL SYSTEM
Hejcagvnal Prism
Hwojgcnal Prisnv
with Pyramid
SIMPLE CRYSTALLINE FORMS
THE MINERALS OF VESUVIUS. 273
its optical differences from Type II., which is also
Monoclinic. (See Humite and Chondrotite.)
COQUIMBITE (Coquimbite), White Copperas.
Hydrous tersulphate of iron zr Fe 2 O 3 , 3SO 3 +
9H 2 O = peroxide of iron 28.5, sulphuric acid 42.7,
water 28.8.
Crystallises in the Hexagonal System, but occurs
also in fine granular masses. Hardness 2 2.5,
Specific Gravity 2 2.1. Colour white, yellowish,
brownish, and sometimes with a pale violet tint.
Fracture conchoidal, taste astringent. An analysis
by Rose gave: Peroxide of iron 24.11, sulphuric
acid 43.55, water 30.10, alumina 0.92, lime 0.73,
magnesia 0.32, silica 0.31.
Occurs as a bed in a felspathic rock in Coquimbo,
in Chili, and in Bolivia it forms part of a hill near
Calama. It was obtained by Professor Scacchi at
Vesuvius, from a solution of a brownish friable crust,
about the fumaroles of the crater after the eruption
of 1850.
Etymology : Called Coquimbite from Coquimbo,
in Chili.
COTUNNITE (Cotunnia).
Chloride of lead, Pb Cl =z lead 74.5, chlorine
25.5 = 100.
Crystallisation, Rhombic ; in small white acicular
crystals. Hardness 2, Specific Gravity 5.238. Lustre
adamantine, inclining to silky or pearly. Before the
blowpipe this mineral fuses readily, emitting a white
smoke and giving a blue colour to the flame. It
T
274 MOUNT VESUVIUS.
is also soluble in about twenty-seven times its
weight of water.
Cotunnite was discovered by Monticelli and
Covelli in the crater of Vesuvius after the eruption
of 1822, along with chloride of sodium and chloride
and sulphate of copper. It was also found after
the eruption of 1839, and by Profs. Scacchi and
Guiscardi on the lava of 1855, the unusual liquidity
of which has been ascribed to this mineral.
Scacchi says it is not rare in the craters and upon
the lava (of 1872 ?).
Etymology : Named after Dr. Cotugno, of
Naples.
COVELLITE, Beudant (Covellina), Covelline, Covel-
linite, Indigo Copper.
Sulphuret of copper, Cu S, Scacchi ; Cu 2 S 2 , Dana
=z copper 66.5, sulphur 3.35.
Crystallisation Hexagonal, but commonly
massive or spheroidal. Hardness 1.5 2, Specific
Gravity (of crystals) 4.590 4.636. Colour
indigo blue, streak lead-grey to black. Lustre
sub-metallic, inclining to resinous. Opaque ;
thin leaves flexible. It is soluble in nitric
acid, and before the blowpipe burns with a blue
flame, and with soda melts to a globule of metallic
copper.
In England, Covellite occurs in Cornwall, at
Huel Maudlin mine, and at several localities
in Continental Europe. At Vesuvius it is in
black or greenish-blue incrustations about the
THE MINERALS OF VESUVIUS. 275
fumaroles, sometimes in a net-work like a spider's
web.
Etymology : Named after Covelli, the discoverer
of the Vesuvian mineral.
CRYPTOHALITE, A. Scacchi (Criptoalite).
Fluo-silicate of ammonium = NH 4 F + Si F 2 .
Found by Prof. Scacchi along with sal-ammoniac
in the lava of 1872, and obtained from an artificial
solution.
CUPRITE (Ziguelina), Zigueline, Red Copper Ore,
Ruberite, Tile Ore.
Dioxide of copper, Cu 2 O = copper 88.8, oxygen
1 1. 2 = 100.
Crystallisation, Cubic ; in octahedrons, dodeca-
hedrons, and in cubes lengthened into capillary
forms. It also forms granular, compact, and earthy
masses. Hardness 3.5 4, Specific Gravity 5.6
6.15. Colour red of various shades, with an ada-
mantine or sub-metallic to earthy lustre, and a
brownish-red shining streak. The crystals are
subtransparent to subtranslucent. It is brittle, with
a conchoidal or uneven fracture. Cuprite is soluble
with effervescence in nitric acid, and without effer-
vescence in hydrochloric acid and ammonia. On
charcoal before the blowpipe it is reduced and
yields metallic copper.
This ore of copper is obtained in Cornwall,
Devonshire, and Staffordshire, and at several locali-
ties on the Continent. At Vesuvius it is found in
the chinks of the lava of 1631.
276 MOUNT VESUVIUS.
CUPROMAGNESITE (Cupromagnesite).
A hydrosulphate of magnesia and copper,
expressed by the formula, Cu O Mg O, SO 3 +
7H 2 0.
This is one of the newly discovered species of
Prof. Scacchi, obtained from the solution of some
sublimations produced by the eruption of Vesuvius
in 1872. These were in the form of bluish-green
crusts of copper vitriol and sulphate of magnesia,
and the crystals obtained from the solution were
isomorphous with the sulphate of iron.
CUSPIDINE, A. Scacchi (Cuspidina).
Silicate of lime with fluorine = CaO Si O 2 + F
and CO 2 .
Orthorhombic, in spear-shaped crystals formed of
two pyramids. Colour, pale rose-red.
Rare in the ejected blocks of Monte Somma.
CYANOCHROITE (Cianocroma), A. Scacchi's species
but Dana's name.
Hydrous sulphate of potash and copper, KO,
SO 3 +CuOSO 3 + 6H 2 O, or, as Dana gives it,
KOSO 3 + 1 Cu SO 3 + sH 2 O.
Crystallisation Monoclinic, obtained from a solu-
tion of the saline crust of the crater of the eruption
of 1855.
The colour is a clear blue, hence the name
Cyanochroite, from xvAw, blue, and %?**, colour,
given by Dana in preference to Scacchi's original
word Cianocroma, a name suggesting the presence
of chrome, which it does not contain.
THE MINERALS OF VESUVIUS. 277
CYANOSITE (Cianosa), Cyanose, Calcantite, Chal-
canthite, Blue Vitriol, Copper Vitriol.
Hydrous sulphate of copper, CuOSO 3 +
5H 2 O = oxide of copper 31.8, sulphuric acid 32.1,
water 36.1.
Crystallisation Triclinic, but usually occurring
stalactitic, reniform, and amorphous, or pulverulent.
Hardness 2.5, Specific Gravity 2.213 2.27. Colour
Berlin blue to sky blue. Transparent to translucent,
with a conchoidal fracture, and vitreous lustre.
Brittle. Taste metallic and nauseous. Soluble in
three parts of cold water, but in boiling water
a half-part is sufficient to effect a solution. This
has a fine blue colour, and will deposit pure
copper on iron with a bright surface. Cyanosite
also yields metallic copper before the blowpipe on
charcoal with soda.
This mineral occurs in many localities, especially
in the waters of cupriferous mines. Scacchi says it is
not rare near the fumaroles of the craters of Vesu-
vius, and produced by the emanation of CuO SO 3
being changed to Cyanosite by exposure to the
ambient air.
DOLEROPHANITE, A. Scacchi (Dolerofano).
Sulphate of copper = Cu 2 SO 3 = copper 62.27,
sulphuric acid 36.07, insoluble matter 1.22, loss
0.44=100. Another analysis : copper 65.20, sul-
phuric acid 33.49, insoluble and loss 1.31 = 100.
Crystallisation Monoclinic. The crystals are so
minute that they seldom have a diameter of more
278 MOUNT VESUVIUS
than two millimetres. Colour brown ; opaque, but
well polished. Powder brownish-yellow. Before
the blowpipe fuses, leaving a black scoriaceous
residue; but it is unaltered at a temperature of 260.
This mineral was found by Prof. Scacchi beauti-
fully crystallised, and not rare amongst the sublima-
tions of the crater after the eruption of 1868. The
crystals undergo decomposition, when the rocks on
which they are deposited are disintegrated by the
action of the atmosphere.
Etymology : From SoT^o'f, fallacious, and Qetbu, to
appear.
DOLOMITE (Dolomite), Dolomie, Bitterspar,
Pearlspar, Rautenspath.
Carbonate of lime and carbonate of magnesia =
CaO CO 2 + MgO CO 2 carbonate of lime 54.35
and carbonate of magnesia 45.65 zz 100. Carbonate
of iron or carbonate of manganese are often present.
Crystallisation Rhombohedral. Often in granular
masses as magnesian limestone. Hardness 3.5 4,
Specific Gravity 2.8 3.1. Colour various, with a
vitreous lustre, inclining to pearly. Subtransparent
to translucent and brittle. It is soluble in acids,
but not so readily as carbonate of lime. On the
coast of Durham, where it constitutes the sea-
cliff rocks near Sunderland, it assumes various
curious forms, including globular and radiated con-
cretions, and it also yields a fissile stone, thin
slabs of which are quite flexible while not quite dry.
At Vesuvius it is not rare in the conglomerates of
THE MINERALS OF VESUVIUS. 279
Monte Somma, crystallised in small rhombohedrons
with the faces parallel to the planes of exfoliation.
Etymology : Named after the eminent geologist
Dolomieu.
EUCHLORINITE, A. Scacchi (Euclorina).
Sulphate of potash, soda, and copper = (KO +
NaO)SO 3 +3CuO, 2SO 3 .
This mineral, in the form of a thin green crust,
has been found at various times in the crater, and
was mistaken for the chloride of copper or Atacamite.
It was obtained abundantly amongst the sublima-
tions of the crater, after the eruption of 1868.
EPSOMITE (Epsomite), Epsom Salts.
Hydrous sulphate of magnesia = MgO, SO 3 -f-
7H 2 O = magnesia 16.26, sulphuric acid 32.52, water
51.22 = 100.
Crystallises in the Rhombic System, and also
occurs in botryoidal masses and delicately fibrous
crusts. Hardness 2.25, Specific Gravity 1.751.
Colour white, transparent to translucent, with a
vitreous lustre, and bitter saline taste. Epsomite
is soluble in less than double its weight of water,
and before the blowpipe dissolves easily by its
water of crystallisation, though it fuses with difficulty.
This salt occurs commonly in mineral waters,
notably at Epsom, in Surrey, whence it takes its
name, and is seen as an efflorescence on the surface
of rocks. At the Mammoth Cave of Kentucky it
forms loose snowball-like masses adhering to the
roof. At Vesuvius it was obtained by crystallisa-
280 MOUNT VESUVIUS.
tion from solutions of the sublimations of the
crater.
ERIOCHALCITE, A. Scacchi (Eriocalco), Muriate
of Copper.
Hydrochloride of copper.
This mineral was found by Professor Scacchi
among the sublimations in the crater, after the
eruption of 1868 (in 1869), like balls of cotton-wool,
but of a bright blue colour. (" Bull. Soc. Min.,"
i., 132.)
ERYTHROSIDERITE, Scacchi (Eritrosidero).
Hydrous chloride of potash and iron.
Crystallisation Rhombic. Colour red, very
soluble.
Found at Vesuvius after the great eruption of
1872 amongst the sublimations of the crater in very
beautiful crystals. Erythrosiderite is related to
Kremersite, which occurs in ruby red octahedrons.
Etymology: epvfyts, red, and ffftypos, iron.
EXANTHALOSE, Beudant (Exantalosa).
Sulphate of soda with water = Na O SO 3 +
2H 2 O, thus differing from Glauber salt or Mirabilite
(which see) only in containing less water, that mineral
having ioH 2 O instead of 2H 2 O. The analysis of
the Vesuvian mineral gave soda 35.0, sulphuric acid
44.8, and water 20.2.
This salt occurs as a white efflorescence, and may
result from the exposure of Glauber salt to the air.
Considerable deposits of Exanthalose are found
in Spain, and it is also found in veins in the salt
THE MINERALS OF VESUVIUS. 28 1
deposits of Villafranca, in the South of France. At
Vesuvius it was obtained from the lava of 1813.
Etymology: ii*^, to effloresce, and *AO, salt.
HAEMATITE (Ematite), Red Iron Ore, Iron
Glance, Red Oxide of Iron.
Peroxide (sesquioxide) of iron = Fe 2 O 3 = iron
70, oxygen 30= 100.
Crystallisation Hexagonal, but occurs columnar,
granular, botryoidal,reniform,stalactitic,and lamellar.
Hardness 5.5 6.5, Specific Gravity 4.5 5.3.
In a tabular crystalline specimen from Vesuvius,
Rammelsberg found protoxide of iron 3.11 and
magnesia 0.74. This had a specific gravity of
5.303 and was magnetic. It also sometimes con-
tains titanium. Colour dark steel-grey or iron-black
when crystallised, but when earthy red, and in other
forms reddish-brown. The streak is cherry-red or
reddish-brown, distinguishing haematite from mag-
netite. Opaque except in very thin laminae.
Fracture sub-conchoidal and uneven, with a metallic
lustre which is sometimes splendent.
Haematite is a most abundant and valuable ore of
iron in England, on the Continent of Europe, and in
the island of Elba. At Vesuvius it occurs abun-
dantly amongst the sublimations of the fumaroles
and the lavas.
Etymology : From afc*, blood. " ' And the
haematites, or blood-stone, which is of a dense, solid
texture, dry, or, according to its name, seeming as if
formed of concreted blood.' Theophrastus, chap.
282 MOUNT VESUVIUS.
Ixvi. Five varieties of haematite were known to the
ancients, of which the most esteemed, and probably
that referred to above, was obtained from Ethiopia."
Bristow.
FERRIC NITRATE (Azoturo di Ferro).
Prof. Scacchi says that the very thin films of
various colours with a metallic lustre which are on
the surface of the scoria of the lava of 1884-5 have,
according to Prof. Silvestri, the composition of
nitrate of iron.
FLUORITE (Fluorite), Fluor, Fluor Spar, Derby-
shire Spar, Blue John.
Fluoride of calcium = Ca Fl = calcium 51.3,
fluorine 48.7 100.
Crystallises in the Cubic or Monometric System,
usually in large cubes and also in octahedrons and
rhombic-dodecahedrons, and occurs, too, nodular
compact, and earthy. Hardness 4, Specific Gravity
3.01 3.2. A mean of sixty specimens gave 3.183.
Colour various, with a vitreous lustre and a white
streak. Transparent to translucent. Fracture flat
conchoidal. Fluorite exhibits a phosphorescent
light when powdered and heated. Some crystals
which appear blue by reflected light are green by
transmitted light, a property termed " fluorescence"
by Prof. Stokes.
This beautiful mineral is abundant in Derbyshire,
where it is made into various ornamental articles.
It also occurs in Cornwall, Devonshire, Cumberland,
and Durham. At Vesuvius Fluorite in minute octa-
THE MINERALS OF VESUVIUS. 283
hedral crystals is found in the crystalline masses of
Monte Somma, and has been obtained from the
cavity of a lava probably of the eruption of 1631.
GALENITE (Galena).
Protosulphide or sulphuret of lead = PbS = lead
86.6, sulphur 13.4 = 100.
Crystallises in the Cubic System, usually in cubes,
but often in octahedrons and other forms, with a
perfect cleavage parallel with the planes of the
cubes, and it also occurs in lamellar and granular
masses. Hardness 2.5 2.75, Specific Gravity 7.25
7.70. Colour lead-grey, with a fine metallic
lustre, which sometimes has an iridescent tarnish.
Opaque. Sectile and easily pulverised. Galena
contains silver in the proportion usually of i to 3 or
5 in 10,000, and rarely i per cent., and sometimes
antimony, cadmium, copper, selenium, or zinc.
Pure metallic lead may easily be obtained from
the mineral before the blowpipe, when the sulphur
is driven off.
In the British Islands the finest crystals have
been obtained from the lead mines of the Isle of
Man. It is the usual ore of lead, and extensively
obtained both in that island and in Durham, Cum-
berland, and other counties of England, as well as
in Scotland and Wales. At Vesuvius it is associated
with blende in the calcite of the crystalline masses of
Somma.
Etymology : From y*xw, tranquillity, from its sup-
posed power to mitigate disease.
284 MOUNT VESUVIUS.
GARNET (Granato), Carbuncle of the ancients.
Silicate of alumina with a silicate of either lime,
magnesia, or iron oxide, and sometimes with man-
ganese or chromium oxide.
The composition of the Vesuvian mineral is given
by Prof. Scacchi as s(Ca Mg Fe)O, (Al Fe) 2
O 3 , 3Si O 2 , which will place it as a lime-magnesia-
iron garnet. An analysis, however, of a specimen
from Vesuvius, by Wacht, gave the following
result: Silica 39.93, alumina 13.45, n * me 3 J -66, per-
oxide of iron 10.95, protoxide of iron 3. 35, manganese
1.40 = 100.94, showing an absence of magnesia.
To such a garnet Dana gives the name " Andradite."
A simple lime garnet is grossularite, while the
" common" and the precious garnet (Pyrope) are
iron garnets, having the composition A1 2 O 3 Si O 2 +
3FeO = silica 36.3, alumina 20.5, protoxide of iron
43.2 = 100. Several other names have been given
to the different varieties.
Crystallises in the Cubic System, usually in dode-
cahedrons, also granular and lamellar. Hardness 6.5
7.5, Specific Gravity 3.1 4.3, specific gravity of
iron garnet 3.7 4.21. Colour various, the most
prized being a rich crimson. Transparent to opaque.
Brittle with a sub-conchoidal, uneven fracture, but
very tough when compact or cryptocrystalline.
Most varieties are easily fusible before the blow-
pipe, the iron garnets giving an iron reaction.
The finest garnets are obtained from Pegu,
and are called Syrian from the name of its
THE MINERALS OF VESUVIUS. 285
capital. Bohemia, Ceylon, and Brazil are other
localities for precious garnets. In England garnets
occur in Cornwall, Devonshire, and Cumberland.
At Vesuvius Garnet is abundant and of various
colours in the crystalline masses of Monte Somma,
often associated with idocrase, and is likewise found,
Scacchi says, as a rare product of the effect of sub-
limation in the conglomerate and in the bocche.
Etymology : From garanatns, from the mineral's
red colour, resembling that of the seed of the pome-
granate.
GRAPHITE (Grafite), Tremenhurite (impure Indian
variety), Plumbago, Blacklead.
Pure carbon, or C with a little iron oxide and
earthy matter = carbon 98.8, ash 1.2.
Crystallises in the Hexagonal System in flat six-
sided tables, but it is usually in concretionary or im-
bedded masses. Hardness i to 2, Specific Gravity
2.0891 2.229. Colour iron-black to a dark steel-
grey, with a metallic lustre. It is opaque, sectile,
has a greasy feel, and readily soils paper, whence
its use for pencils. Graphite is infusible before the
blowpipe, and is unaltered by acids, but at a high
temperature burns without flame or smoke. It is
used for crucibles intended to withstand great
heat.
Masses of fine graphite of great value for the best
artists' pencils are found at Borrowdale, in Cumber-
land, but the principal supply comes from abroad.
It also occurs in Cornwall and the Isle of Man.
286 MOUNT VESUVIUS.
At Vesuvius it is in the crystalline calcareous
masses of Monte Somna.
Etymology : From ypa<pa, to write, from being
used for writing purposes.
GUARINITA, G. Guiscardi (Guarinite).
Silicate of lime and titania = (CaO + TiO 2 )
SiO 2 = silica 33.64, lime 28.01, titanic acid 33.92,
with trace of peroxide of iron and peroxide of
manganese.
Though similar to titanite or sphene in composi-
tion, Guarinite crystallises in the Square Prismatic
System, while sphene is Monoclinic. Its colour is
honey-yellow, with a sub-adamantine lustre. Trans-
lucent to transparent. Hardness 6 6.5, Specific
Gravity 3.487.
Found at Vesuvius in minute crystals in small
cavities in projected crystalline blocks of Monte
Somma, consisting chiefly of glassy felspar, with
hornblende and melanite. It was also found in the
ordinary Somma lava-rock along with sphene.
Named after Prof. Guarini, of Naples.
GYPSUM (Gesso), Selenite, Alabaster, Satin Spar.
Hydrated sulphate of lime = CaO SO 3 + 2H 2 O
= lime 32.6, sulphuric acid 46.5, water 20.9 = 100.
Crystallises in the Monoclinic System, when it is
called Selenite, but usually occurs in beds which are
largely worked for the production of plaster of Paris,
which is calcined Gypsum. Hardness 1.5 2 (may
be easily scratched by the nail), Specific Gravity 2.2
2.4, colourless and white, sometimes coloured by
THE MINERALS OF VESUVIUS. 287
impurities. Crystals transparent or translucent.
The value of gypsum for the making of a quick set-
ting stucco or cement was known to the ancients,
and Theophrastus mentions it under the name of
yvj/o St and describes the manner of preparing the
cement, as well as the uses to which it was put in
his time in Cyprus, Phoenicia, and Italy.
Gypsum is abundantly obtained in Staffordshire,
Nottinghamshire, Derbyshire, and other counties,
chiefly from Triassic rocks, and a very fine bed has
been discovered in Purbeck strata, near Battle, in
Sussex. At Vesuvius it is not uncommon amongst
the sublimations of the crater.
Etymology: Ancient name yityo?, from y% earth,
and i^<y, to cook. Selenite, from a^fa, the moon,
from its fancied association with the moon.
HALITE (Alite), Common Salt, Rock Salt.
Chloride of sodium, NaCl = sodium 39.3, chlorine
60.7.
Crystallises in the Cubic System usually in cubes.
Hardness 2, Specific Gravity 2.03 2.257. Colour-
less, but usually coloured with impurities. Trans-
parent and translucent, with a vitreous lustre, and
a conchoidal fracture. Its taste is typically saline.
It occurs in massive beds in England
(Cheshire, Worcestershire, and Yorkshire), in the
Trias, and also in Spain, Poland, the Tyrol, and
other places in Europe. It is also found as a
surface deposit covering large areas in Asia, America,
and Africa, and as an efflorescence. At Vesuvius
288 MOUNT VESUVIUS.
it is abundant as a sublimation in the fumaroles of
the crater and on the lava, but always containing a
notable quantity of chloride of potassium.
HAUSMANNITE (Ausmannite), Raucierite.
Protoxide and peroxide of manganese, or 2Mn O
+ Mn O 2 = protoxide of manganese 31.03, peroxide
of manganese 69.07, or manganese 72.1, and oxy-
gen, 27.9= TOO.
Crystallises in the Pyramidal or Dimetric System,
in acute square-based pyramids, and it also occurs
massive. Hardness 5.5, Specific Gravity 4.7 to 4.8.
Colour iron-black, with a brown streak, and a metallic
lustre. Very hard, with an uneven fracture.
Dissolves in heated hydrochloric acid, giving off
chlorine.
Hausmannite occurs in Thuringia, in the Hartz
Mountains, and in Alsace. At Vesuvius it forms
very thin crusts with rainbow reflections on the
crystals of sodalite in the chinks of the lava of 1631.
Named after Professor Hausmann, of Gottingen.
HAUYNITE (Auina), Hauyne, Haliyna, Latialite,
Lazialite.
Silicate of alumina and soda with lime and sulphuric
acid, or 3A1 2 O 3 SiO 2 +NaO 3 SiO 2 + 2CaO + SO 3 =
silica 34.13, alumina 29.18, soda 14.69, lime 10.62,
sulphuric acid 11.38=100.
Crystallises in the Cubic System in rhombic dode-
cahedrons and in octahedrons, and is also in grains
and massive. Hardness 5.5, Specific Gravity 2.5.
Colour indigo-blue, bright blue, asparagus-green.
Plate XIX.
Arrtpkcbiyle Atacarrate.
Garrwl
Ifumile L&uudtftf.
Meicnite Orlhcdase.
Somnute Vesuwianzta WollastonXte
; _ U>HSON,metHt HIIOtVLLY.il, WK
CRYSTALS OF VESUVIAN MINERALS
THE MINERALS OF VESUVIUS. 289
Translucent and opaque, with a vitreous lustre.
Very brittle, with a flat conchoidal fracture. Before
the blowpipe haiiynite decrepitates, and with borax
effervesces, forming on cooling a yellow glass.
Gelatinises in heated hydrochloric acid.
The occurrence of this mineral in the igneous
rocks near Andernach, on the Rhine, is interesting
as forming one of several points of resemblance
between the volcanic products of the Eifel and those
of the Italian volcanoes. Not only at Vesuvius, but
at Monte Vulture and at Monte Albano also is
Haiiynite found. At Vesuvius it is tolerably common
in the crystalline masses of Monte Somma.
HUMITE, Bournon (Umite), Chondrotite in part.
Silicate of magnesia, 8MgO 38! O 2 , with part of
the oxygen replaced by fluorine. An analysis by
Rammelsberg of Vesuvian Humite gave : Silica
34.80, magnesia 60.08, fluorine 3,47, protoxide of
iron 2.40= 100.75.
Crystallisation, Rhombic; often hemihedral in octa-
hedral planes producing forms monoclinic in
character (Dana), Monoclinic (Brooke and Miller)
(see Chondrotite and Clinohumite) in small im-
planted but distinct transparent to translucent
crystals. Hardness 6 6.5, Specific Gravity 3.177
3.234. Colourless to yellow and brownish, usually
yellow, with a polished glassy surface, giving a
shining vitreous lustre. Dissolves in hydrochloric
acid with the separation of gelatinous silica. It is
also soluble in sulphuric acid, when the fluorine is
u
2QO MOUNT VESUVIUS.
disengaged. Before the blowpipe the mineral is
insoluble, but with borax fuses to a clear glass.
Humite occurs at Vesuvius in the ejected granu-
lar or crystalline masses of Somma, usually accom-
panied by spinelle.
The Vesuvian mineral was named Humite as a
distinct species by Bournon, and although Rammels-
berg showed it to be the same in composition as
chondrodite of d'Ohsson, yet Des Cloiseaux found
a sufficient crystallographic difference to constitute
it a distinct species. Prof. Scacchi, in a very
elaborate paper (PoggendorfFs Annalen, 1851, Er-
ganzung, iii., 161), shows that there are three types
of Humite, based on its crystalline forms and optical
characters. These types are very fully and carefully
described with complete mathematical details. Des
Cloiseaux considers the three " types" of Scacchi to
be optically distinct. Type L, Rhombic, he calls
Humite; to Type II., Monoclinic, he allows the
original name Chrondrodite, and to Type III., which
appears to be Monoclinic also, he gives the name
Clinohumite ; and to this tripartite differentiation
Prof. Scacchi, in " Lo Spettatore," gives his adhesion.
Etymology : The name was given in compliment
to Sir Abraham Hume.
HYDROCHLORIC ACID GAS (Acido Cloridrico).
Anhydrous hydrochloric acid, HC1.
This gas is an abundant emanation from the
fumaroles of the crater.
HYDROCYANITE, A. Scacchi (Idrociano).
THE MINERALS OF VESUVIUS. 29 1
Sulphate of copper, or CuO SO 3 = oxide of
copper 49.47, sulphuric acid 50.30, loss 0.40= 100.
Crystallisation Rhombic. Colour pale green,
brownish or yellowish, and sky-blue, and the crystals
are translucent. This mineral effloresces very readily
by exposure to the atmosphere, from which it
quickly absorbs water, forming cyanon or chalcan-
thite (which see).
Hydrocyanite was found by Prof. Scacchi at
Vesuvius after the eruption of 1868, produced by
sublimation, and it occurred in great quantities
finely crystallised in 1870.
Etymology : \lup, water, and xv*vos, azure blue.
Dana says of the name, "an unfortunate name,
suggesting a hydrous mineral, and one relating
to cy anile?
HYDRODOLOMITE, Rammelsberg (Idrodolomite).
Hydrous carbonate of lime and magnesia (3CaO
+ 3 Mg O) sCO 2 + H 2 O or Ca O CO 2 + Mg O CO 2
+ \ H 2 O. Results of two analyses of Vesuvian
specimens :
Lime. Magnesia. Carbonic Acid. Water.
25.22 24.28 33.10 17.40 (Kobell).
26.90 23.23 4340 6.47 (Rammelsberg).
Occurs massive and in stalactitic, stalagmitic, and
globular concretions, as well as in crusts. Specific
Gravity 2.495. Colour yellowish-white, greyish and
greenish. Before the blowpipe yields water in a
closed tube.
This mineral is abundant among the crystalline
masses of Monte Somma. Prof. Scacchi says that
2Q2 MOUNT VESUVIUS.
it is " probably derived from the fragments of
magnesian limestone erupted from the ancient
volcano, which have retaken from the ambient air
the carbonic anhydrite lost through the high tem-
perature to which they had been exposed."
HYDROFLUORITE, A. Scacchi (Idrofluore).
Hydrofluoric acid = HF1.
This compound in the gaseous form was first
found emanating from the lava of 1850, but it has
been observed at the fumaroles and on the lavas
of 1870 and 1872.
HYDROMAGNESITE, V. Kobell (Idrogiobertite).
Hydrous carbonate of magnesia, or 3(MgOCO 2
+ H 2 O) + MgOH 2 O = magnesia 43.9, carbonic
acid 36.3, water 19.8= 100.
Crystallisation Monoclinic. Occurs also amor-
phous and as chalky or mealy crusts. Hardness (of
crystals) 3.5, Specific Gravity 2.145 2.18. Colour
white, with a vitreous lustre passing to silky or
sub-pearly, and earthy. Brittle.
Occurs in the Hebrides and in the Shetlands
associated with Brucite. At Vesuvius it is rare,
and found enclosed in a large fragment of ancient
lava. Eugenio Scacchi gives it the name Idrogio-
bertite, and states the composition of the Vesuvian
mineral as Mg O, CO 2 , 3H 2 O.
Etymology : Map, water, and magnesite.
LABRADORITE (Plagioclasia), Labrador Felspar,
Lime Felspar.
Silicate of alumina, lime, and soda, 4A1 2 O 3
THE MINERALS OF VESUVIUS. 293
SiO 2 + 3 CaO SiO 2 + NaO, Si O 2 , or ( 4 A1 2 O 3 +
3CaO + NaO) 8SiO 2 = silica 52.9, alumina 30.3,
lime 12.3, soda 4.5 = 100.
Crystallisation, Triclinic, often in twinned crystals;
and also massive, granular, and sometimes crypto-
crystalline. Hardness 6, Specific Gravity 2.67
2.76. It has various colours, as grey, brown, and
green, and gives when polished very beautiful
chatoyant reflections of various and brilliant tints,
blues, greens, richbrowns, and lemon- gold- and
orange-yellows. Brittle, with an imperfect con-
choidal, uneven, or splintery fracture, and it has a
vitreous lustre and a white streak. Unlike the potash
felspar (orthoclase), this, the lime felspar, is entirely
dissolved by heated hydrochloric acid when pow-
dered, but before the blowpipe it is like orthoclase,
difficultly fusible. From its beautiful play of
colours Labradorite is manufactured into articles of
jewellery.
This species of felspar was originally brought
from the Isle of Paul, on the coast of Labrador,
about 1770, and it occurs in many parts of North
America. As a rock-forming mineral it is a con-
stituent of the basic volcanic rocks, as basalt,
dolerite, as well as of the plutonic rocks, diabase,
hypersthenite, &c. At Vesuvius it occurs in glassy
crystals in the crystalline ejected masses of Monte
Somma.
In " Lo Spettatore," Professor Scacchi has adopted
Breithaupt's name "Plagioclase/'butas that designa-
294
MOUNT VESUVIUS.
tion embraces the whole group of triclinic felspars,
viz., Labradorite, anorthite, andesine, oligoclase, and
albite, and as the Vesuvian triclinic felspar appears
to be Labradorite, that name is here used. It is,
however, quite possible that further observation
may reveal the presence at Vesuvius of the other
triclinic felspars also.
LAPIS LAZULI (Lapislazuli), Native Ultramarine,
Sapphairos of the Ancients.
Silicate of alumina, soda, and lime, with a sulphide
probably of iron and sodium = (A1 2 O 3 NaO CaO)
SiO 2 . An analysis by Varrentrapp gave : Silica 45.50,
alumina 31.76, soda 9.09, lime 3.52, sulphuric acid
5.89, sulphur 0.95, iron 0.86, chlorine 0.42, water
O.I 2.
Crystallisation, Cubic in dodecahedrons ; but it
occurs usually massive and compact. Hardness 5.5,
Specific Gravity 2.38 2.45. Colour rich Berlin or
azure blue, with a faintly glimmering lustre. Opaque,
but usually translucent at the edges. Fuses, only with
intense heat, to a white enamel, but effervesces and
forms a colourless glass with borax. Lapis Lazuli
is the substance from which by pulverisation
the highly valued pigment ultramarine is made,
and the mineral in its native state is prized, on
account of its beautiful colour, for mosaics and orna-
mental articles. The colour is probably due to the
sulphide of sodium and iron,
Several parts of Asia, Persia, China, Bucharia, and
near Lake Baikal, in Siberia, furnish the supplies of
THE MINERALS OF VESUVIUS. 295
the mineral. At Vesuvius it occurs in the compact
limestone of the crystalline masses of Somma.
LEUCITE, Werner (Leucite), Amphigene, White
Garnet.
Silicate of alumina and potash = A1 2 O 3 38! O +
KOSiO 2 , or as given by Scacchi, KO,Al 2 O 3 4Si
O 2 = silica 55.0, alumina 23.5, potash 21.5 = 100.
An analysis of a Vesuvian specimen by Rammels-
berg gave: Silica 56.05, alumina 23.16, potash 20.04,
soda 0.30, loss by ignition 0.52 = 100.07. Small
quantities of lime and iron are also sometimes
present.
Crystallisation, Cubic, usually in trapezohedrons ;
but frequently disseminated in lava-rocks in grains.
Hardness 5.5 6, Specific Gravity 2.44 to 2.56.
Colour cream-white, passing into ash-grey, rarely
reddish-white, with a vitreous lustre. Translu-
cent. Brittle, with an imperfect conchoidal fracture.
Leucite is anhydrous analcime, from which it may
be readily distinguished by its infusibility and by
never having a cubical face.
Leucite is confined to volcanic rocks, and ap-
parently to those of Italy and the Eifel in Germany.
In the neighbourhood of Rome, at Borghetto
Albano and Frascati, it is very abundant in pre-
historic lava-rocks, giving to those rocks a value for
millstones, which have been obtained from them for
2,000 years, since some have been found in Pompeii.
At Vesuvius, however, Leucite occurs in the finest
crystals, and forms a most important mineral con-
296 MOUNT VESUVIUS.
stituent of the lavas of the volcano, both ancient
and modern. According to Deville, the Leucite of
the modern lavas of Vesuvius contains more soda
than that of the ancient lavas of Somma, as shown
by the following statement :
Ratio of soda to potash in lava of 1855, i to 2.09
1847, i 1.67
Somma, i ,, 8.21
Richter has found, by spectrum analysis, lithia in
Vesuvian leucite. It is worthy of remark that
potash, previously thought to be confined to the
vegetable kingdom, was first found in minerals in
Leucite by Klaprotte.
In the dykes of Somma the crystals of leucite
are of the size of a pea, while the larger crystals
of four centimetres diameter are in a particular
kind of ejected lava, along with crystals of glassy
felspar, and it is worthy of note that with the entire
crystals are associated fragments of crystals indicat-
ing a second fusion, causing the fracture of many of
the previously formed crystals. Amongst the con-
glomerates of Somma, crystals of augite carry on
their surfaces minute crystals of leucite formed by
sublimation. In the lavas of the eruption of 1631
there are considerable masses of crystals confusedly
aggregated, and not so found on Somma. In the
years 1844 and 1846 there were produced by
Vesuvius crystals of leucite of the size of a pistol-
shot.
THE MINERALS OF VESUVIUS. 297
Etymology : tevx6 s , white, from its prevailing
colour.
LIMONITE, Beudant (Limonite).
Hydrated peroxide (sesquioxide) of iron, or 2Fe 2
O 3 + 3H 2 O = sesquioxide of iron 85.6, water 14.4.
Occurs commonly in mammillated, botryoidal,
and stalactitic forms with a fibrous structure usually
radiating. It is also compact, earthy, and dissemin-
ated. Hardness 5 5.5, Specific Gravity 3.6 4.
Colour, various shades of brown with a silky lustre,
but sometimes dull and earthy. It is soluble in
warm nitro-hydrochloric acid ; before the blowpipe
blackens and becomes magnetic, but in thin
fragments it fuses to a black magnetic glass.
Limonite is a very valuable ore of iron, and in-
cludes brown haematite, bog-iron-ore, wood haematite.
It is likewise the oxide of iron that is disseminated
in brown, yellow, and red clays and rocks, which
from it derive their colour. At Vesuvius it is found
in the crystalline masses of Monte Somma.
Etymology : From Ag/^*, a meadow, from its
being produced in bogs or meadows as bog-iron-ore
and meadow-iron-ore.
LINARITE (Linarite).
Cupreous sulphate of lead, PbO, SO 3 + CuO, H 2 O
(Dana, Scacchi, and Bristow) ; (PbO SO 3 +PbO,
2 H 2 0) + (CuO S0 3 + CuO, 2 H 2 0) (Heddle)= sul-
phate of lead 74.8, oxide of copper 19.7, water 5.5
= 100.
Crystallisation, Monoclinic, often in twinned
298 MOUNT VESUVIUS.
crystals. Hardness 2.5 3, Specific Gravity 5.3
5.5. Colour deep azure blue with a vitreous or
adamantine lustre and conchoidal fracture. Trans-
lucent, and brittle with a pale blue streak. In the
inner flame of the blowpipe Linarite gives a metallic
globule which produces a coating of oxide of lead.
In England this mineral occurs in Cumberland,
Red Gill and Roughton Gill, and in Scotland at
Leadhills. At Vesuvius it was found among the
sublimations of the crater of 1881, and described as
one of them by Prof. Freada.
Etymology : The name is from Linares, a locality
for this mineral in Spain.
LITHIDIONITE, Eugenio Scacchi (Litidionite).
Silicate of potash and soda with copper and iron,
or possibly (KO, NaO) SiO 2 + CuO + FeO = silica
71.57, potash 10.92, soda 6.78, oxide of copper 6.49,
protoxide of iron 4.02 = 99.78, but Dana regards it
as a mixture of quartz with the other compounds it
contains and not a definite species, and Prof.
Archangelo Scacchi states that the composition does
not correspond to any one simple formula.
Hardness 5 6, Specific Gravity 2.535. Colour
blue.
Lithidionite was found at Vesuvius in the crater
in June, 1873, coating lapilli of from 7 to 25 mille-
metres diameter, and consisting of a white earthy
substance, with a glassy crust.
MAGNESIOFERRITE, Rammelsberg (Magnesio-
ferrite), Magnoferrite.
THE MINERALS OF VESUVIUS. 2Q9
Magnesian oxide of iron, MgO Fe 2 O 3 = oxide of
iron 80, magnesia 20 100.
Crystallisation, Cubic in octahedrons, some with
truncated edges, but the crystals are usually inter*
sected by very many extremely thin laminae of
haematite lying parallel to the faces of the octahe-
dron. Hardness 6 6.5, Specific Gravity 4.568
4.838. Colour iron-black with a metallic or sub-
metallic lustre and black streak, agreeing in all three
with magnetite, and like it also strongly magnetic.
Magnesioferrite occurs at Vesuvius amongst the
sublimations of the Fosso di Cancherone, and was
also found produced from the lava of the eruption
of 1855 at the foot of the great cone. Two of
Rammelsberg's analyses of Vesuvian specimens
one of the mineral produced by the eruption of
1855, and one of that of an older eruption gave
results differing considerably. They are as follows :
Peroxide of Iron. Magnesia.
Eruption of 1855 86.96 12.58= 99-54-
Older . . 84.20 1.600=100.20.
Etymology : Rammelsberg originally named the
species Magnoferrite, but Dana proposed Magnesio-
ferrite, from magnesium and ferrum, iron, which
is here adopted.
MAGNETITE, Haidinger (Magnetite), Magnetic
Iron Ore, Lodestone.
Peroxide with protoxide of iron, or FeO, Fe 2 O 3
= peroxide of iron 96.03, protoxide of iron 30.97 =
100, or iron 71.68, oxygen 28.32 = 100.
300 MOUNT VESUVIUS.
Crystallises in the Cubic System in regular octa-
hedrons with an imperfectly lamellar structure, the
laminae being parallel to the planes of the octa-
hedron. It also occurs earthy, compact, granular,
and lamellar. Hardness 5.5 6.5, Specific
Gravity 4.9 5.2. Magnetite has an iron-black
colour, with a black streak and metallic or sub-
metallic lustre. It is opaque and brittle, with an
uneven or conchoidal fracture, and possesses the
remarkable property of being strongly magnetic,
which makes this mineral so famous as lodestone,
and it moreover sometimes exhibits polarity. It is
soluble in heated hydrochloric acid, but insoluble in
nitric acid, and before the blowpipe becomes non-
magnetic and turns brown, but is not easily fused.
Magnetite is a widely dispersed and abundant ore
of iron, especially in the north of Europe, where in
Sweden it constitutes the ore from which the fine
Swedish iron is obtained, and several hills in the
Scandinavian Peninsula, as well as in Lapland, are
largely composed of it. In the British Islands it
occurs in Cornwall and Devonshire, in Scotland,
Shetland, and the Hebrides, and in several localities
in Ireland. At Vesuvius it is to be found, but not
abundantly, in the crystalline masses of Monte
Somma.
MEIONITE, Haiiy (Meionite).
Silicate of alumina and lime, 6CaO, 4A1 2 O 3 9SiO 2
(Scacchi), 3 CaO SiO 2 + 2A1 2 O 3 SiO 2 (Bristow) =
silica 42. i, alumina 31.9, lime 26 = 100. An analysis
THE MINERALS OF VESUVIUS. 30 1
by Stromeyer of a specimen of Meionite from Monte
Somma gave the following result : Silica 40.53
alumina 32.73, lime 24.24, soda and potash 1.81,
protoxide of iron 0.18 99.50.
Crystallises in the Second or Square Prismatic
System, usually in small four or eight sided prisms,
terminated by four-sided pyramids, the angles of
which are sometimes replaced. Hardness 5.5 6,
Specific Gravity 2.5 2.74. (Crystal from Monte
Somma, 2.734 2 -737> Von Rath.) Colourless to
white or greyish-white, with a vitreous lustre, and
transparent to translucent, and often exhibiting many
internal cracks. Meionite gelatinises in hydrochloric
acid, in which it is quite decomposed, and before the
blowpipe strongly intumesces and then fuses to a
blistered colourless glass.
This mineral occurs at Vesuvius in the geodes or
internal cavities of the granular compact limestone
of the crystalline masses of Monte Somma. Scacchi
says : " The inside walls of the cavities are covered
with a green layer formed of biotite and pyroxene
and with the meionite are often associated leucite
and anorthite."
Etymology : From pewy, less, from the termina-
ting pyramids of the crystals of meionite being less
acute than those of Vesuvianite (Idocrase).
MELANOTHALLITE, A. Scacchi (Melanotallo).
Hydrochloride of copper.
Found in the form of black laminae among the
sublimations of the crater of Vesuvius in 1869,
302 MOUNT VESUVIUS.
associated with " Idrociano." On exposure to the
air the black laminae become green. Att. Accad.
Napoli (Bull. Soc, Min., i,, 38),
MELILITE, Delamette (Melilite), Mellilite, Zurlite,
Humboldtilite, Somervillite, Gelenite.
Silicate of lime and magnesia with a silicate of
alumina and peroxide of iron, or 2(CaO, MgO)
2 Si0 2 + (A1 2 3 , Fe 2 3 ) Si0 2 (Heddle), or
i2(CaO 2 MgO NaO) + 2(Al a O 3 Fe 2 O 3 ) 9$i O 2 . An
analysis by Damour of a specimen from Capo di
Bove gave : Silica 38.34, lime 32.05, magnesia 6.71,
soda 2.12, potash 1.51, alumina 8.61, peroxide of
iron 10.02 = 99.36. One by Von Kobell of a spe-
cimen from Somma gave : Silica 43.96, lime 31.96,
magnesia 6. 10, soda 4. 2 8, potash 0.38, alumina 11.20,
protoxide of iron 2.32 = 100.20.
Crystallises in the Square Prismatic System in
small square prisms, with the lateral edges usually
replaced. Hardness 5 5.5, Specific Gravity 2.910
3.104. Colour shades of yellow from yellowish-
white to yellowish-brown. Translucent to opaque,
with a vitreous or resinous lustre, but transparent
when in thin laminae, and possesses weak double
refraction. Fracture uneven to conchoidal. This
mineral is soluble in nitric acid, and before the blow-
pipe is reduced to ashes without flame and almost
without emitting an odour.
Occurs in the pre-historic lava of Capo di Bove
in association with nephiline and pleonaste.
The Vesuvian varieties of Melilite, the Humboldt-
THE MINERALS OF VESUVIUS. 303
ilite of Monticelli and Covelli, the Somervillite of
Brooke, and the Zurlite of Ramondini, occur in the
crystalline blocks of Monte Somma. Melilite has
also been found in a Somma lava, and Zurlite is
often associated with green crystalline pyroxene.
Humboldtilite is found in cavities associated with
greenish mica and covered with a calcareous coating.
The gelenite stated by Monticelli to be a Vesuvian
mineral is also, on the authority of Prof. Scacchi, a
variety of Melilite.
Etymology: pfae, honey, from its colour.
MICROSOMMITE, A. Scacchi (Microsommite).
Silicate of alumina, lime, potash, and soda, with
chlorine and sulphuric acid, or (A1 2 O 3 , CaO, KO,
NaO) SiO 2 + Cl + SO 3 = silica 33.0, alumina 29.0,
lime ii. 2, potash 11.5, soda 8.7, chlorine 9.1, sul-
phuric acid 1.7=104.2. This species differs in
composition from sommite or nepheline in contain-
ing chlorine and sulphuric acid.
Crystallises in the Hexagonal System in very small
hexagonal crystals, frequently in groups, with
vertical striations and sometimes truncated edges.
Hardness 6, Specific Gravity 2.60. Colourless to
yellow, and transparent with a silky lustre.
This Vesuvian species occurs as a result of
sublimation in the cavities of the ejecta of the
eruption of 1872.
Etymology: PI*W, small, and sommite.
MILLERITE, Haidinger (Millerite), Capillary
Pyrites.
304 MOUNT VESUVIUS.
Sulphuret or sulphide of nickel, or NiS = nickel
64.9, sulphur 35.1 = 100.
Crystallises in the Hexagonal System in capillary
six-sided prisms ; and, rarely, in columnar tufted
coatings partly semi-globular and radiated. Hard-
ness 3 3.5, Specific Gravity 4.6 5.65. Colour
brass-yellow, inclining to bronze-yellow, with an
iridescent tarnish. Opaque with a metallic lustre
and bright streak. Brittle. Dissolves easily in nitro-
hydrochloric acid, forming a green solution, but in
nitric acid alone it is only with difficulty soluble.
Before the blowpipe it discharges its sulphur in
sulphurous acid, and after fusion leaves a magnetic
bead of nickel.
Millerite is found in South Wales in cavities in
nodules of clay ironstone, and it occurs in the mines
of Devon and Cornwall. The largest crystals, but
only a fifth of a line in diameter, have been obtained
from Sterling Mine, New York. At Vesuvius
Millerite was found by Prof. Freda among the
sublimations of the crater.
Named after Prof. Miller, of Cambridge.
MIRABILITE, Haidinger (Exantalosa), Glauber
Salts.
Hydrous sulphate of soda, NaO SO 3 + ioH 2 O =
soda 19.3, sulphuric acid 24.8, water 55.9= 100.
Crystallisation, Monoclinic ; usually occurring
as an efflorescence or earthy. Hardness 1.5 2,
Specific Gravity 1.48. Colour greyish or yellowish
white with a dull surface lustre, but fresh fractures
THE MINERALS OF VESUVIUS. 305
vitreous. Transparent to opaque, very efflorescent,
and falls to powder readily. The taste is cooling,
then feebly saline and bitter. It is very soluble in
water, and in the closed tube before the blowpipe
yields much water in which it dissolves.
Mirabilite is in the hot springs of Bohemia, and is
found in large quantities in Spain. At Vesuvius it
was obtained from a solution of the salts collected
in the crater.
Etymology : The name Glauber Salts is from the
name of the discoverer of the artificial salt, Glauber,
a German chemist, who exclaimed, "Sal mirabile!"
hence " Mirabilite." Though Prof. Scacchi calls
this salt in "Lo Spettatore " " Exantalosa," he
shows its difference from Beudant's species, which
has ten parts of water.
MIZZONITE, A. Scacchi (Mizzonite).
Silicate of alumina, lime, and soda, 6(Ca O, Na O)
4Al 2 O 3 i5SiO 2 (Heddle), similar in composition
to that of Meionite. The similarity and difference
will be seen from the following two analyses of
Vesuvian specimens :
Silica. Alumina. Lime. Soda and Potash.
Mizzonite 54.70 23.80 8.77 9.83 2.14 ign. 0.13 = 99.59
V. Rath.
Meionite 40.53 32.73 24.25 1.81 P.O. of Iron 0.18 = 99.50
Stromeyer.
Crystallises in the Square Prismatic System in
larger prisms than Meionite. The general cha-
racters are like those of Meionite, but is not so
readily acted upon by acids, and does not intumesce
so much before the blowpipe. It is a Vesuvian
x
306 MOUNT VESUVIUS.
mineral exclusively so far as is yet known, and
occurs in the crystalline ejected blocks of Monte
Somma like Meionite, but differs from it in being
associated with glassy felspar instead of with calcite.
Etymology : P*\&, greater, from the axis of the
prism being larger than in Meionite.
MOLYBDENITE (Molibdenite), Molybdena, Molyb-
dic Acid.
Bisulphide of molybdenum, Mo S 2 =. molybdenum
59.0, sulphur 41,0.
The System in which this mineral crystallises is
somewhat doubtful, but the balance of authority
appears to be that it is the Hexagonal. Dana,
however, gives " Monoclinic ?" also. It is found in
short or flat hexagonal tables, but it usually occurs
massive, with a foliated structure, or in scales.
Hardness i 1.5, easily indented with the finger
nail. Specific Gravity 4.44 4.80. It has a lead-
grey colour, both colour and lustre resembling those
of freshly-cut lead. The laminae are very flexible,
but like lead not elastic. It is opaque, and leaves
a metallic grey mark on paper, and a greenish one
on porcelain, and has a greasy or unctuous feel.
In boiling sulphuric acid Molybdenite dissolves,
forming a blue solution after giving off sulphurous
acid, which it also does before the blowpipe, and
on platinum wire colours the outer flame green.
It is distinguished from Plumbago by its lustre
and streak.
This mineral in the British Islands occurs in
THE MINERALS OF VESUVIUS. 307
granular limestone, and in granite in several parts
of Scotland Ross, Aberdeen, Argyll, Perthshire,
and Kirkcudbrightshire and in England in Corn-
wall, Cumberland, and Westmoreland. It is often
associated with Apatite and Tungstate of Lime. In
the last-named county, at Shap, it is used in the
preparation of blue carmine for colouring porcelain.
At Vesuvius it is rather rare in the crystalline
ejected blocks of Monte Somma.
MOLYSITE (Molisite).
Chloride of iron, Fe 2 C1 3 = iron 34.5, chlorine
65.5-100.
Molysite occurs as an incrustation on the lavas of
recent eruptions of Vesuvius, and was noticed by
Hausmann in 1819, and by Prof. Scacchi as a result
of the eruptive activity of the volcano between the
years 1850 and 1855. Its general colour is a yel-
lowish darkening into a brownish red, and to this
mineral is to be attributed the yellow colour of the
lavas about the fumaroles and craters. Prof. Scacchi
has not found the protochloride of iron, Fe Cl, on
Vesuvius as announced by Monticelli and Covelli,
who probably mistook Molysite for that compound.
Etymology : pfa.v*ib stain, from the stain it gives to
lavas.
MONTICELLITE, Brooke (Monticellite).
Silicate of lime and magnesia (2Ca O + 2 MgO) Si
O 2 Scacchi, or (Ca O + ^ MgO) 2 Si O 2 = silica 38.5,
lime 35.9, magnesia 25.6=100.
Crystallisation Right Prismatic and isomorphous
308 MOUNT VESUVIUS.
with Chrysolite. Occurs in small imbedded crystals
and also massive. Hardness 5 5.5, Specific
Gravity 3.03 -3.25. Colourless to yellowish-grey.
Nearly transparent to translucent, having the general
aspect of quartz, and like that mineral having a
vitreous lustre and a conchoidal fracture. It is
soluble in dilute Hydrochloric Acid, and forms a
clear solution, which, on heating, gelatinises.
Monticellite is found at Vesuvius imbedded in the
crystalline calcareous ejected blocks of Monte
Somma, with black Mica and small crystals of
Augite.
Named after Monticelli, the eminent Neapolitan
mineralogist.
NEOCHRYSOLITE (Neocrisolito).
Anhydrous silicate of lime and protoxide of iron,
2(CaO, FeO) Si O 2 . The composition of this
mineral differs from that of Chrysolite (Olivine or
Peridote) in containing lime instead of magnesia.
Crystallises in the Rhombic System in small black
crystalline plates.
Neochrysolite occurs at Vesuvius in the Cupa di
Sabataniello, not uncommonly in the cavities of the
lava of the eruption of 1631, as an effect of sublima-
tion.
NEOCYANITE, A. Scacchi (Neociano).
Anhydrous silicate of copper (probably).
Crystals, Monoclinic, extremely small and tabular,
of a beautiful blue colour.
This mineral has not yet been fully examined.
THE MINERALS OF VESUVIUS. 309
It was found about the fumaroles and amongst the
sublimations of the Vesuvian crater of October,
1880, associated with three other substances. One,
probably Silica, was a white granular mass, having
a Specific Gravity of 2.287. The second was a
white substance like Asbestos, but containing lime,
only decomposible in boiling acid, and fusible with
difficulty. The third, insoluble in acid, was in
yellowish-brown crystals in six-sided rhombic plates.
ORPIMENT (Orpimento), Auripigmentum of Pliny.
Sulphuret of Arsenic, As 2 S 3 =z arsenic 61,
sulphur 39.
Crystallisation, Rhombic in small crystals, but
much more commonly massive, foliated, or columnar,
as well as reniform and disseminated. Colour, shades
of a yellow commonly called lemon-yellow, but
darkening into a golden yellow. Hardness 1.5 2,
Specific Gravity 3.4 3.48. Subtransparent or
translucant only at the edges, with a resinous lustre
and a streak paler than the colour. It is sectile, and
thin laminae are flexible, but not elastic. It dis-
solves in nitro-hydrochloric acid, and in caustic
alkalies, and before the blowpipe burns with a
bluish flame, emitting sulphurous and arsenical
fumes.
Orpiment occurs in Persia in splendid yellow
masses, called golden orpiment, and the mineral is
obtained also from several parts of Central Europe.
At Vesuvius it is rare among the sublimations of the
crater. It was first found by Bergman, and after-
310 MOUNT VESUVIUS.
wards by Monticelli subsequent to the eruption of
1822. It occurs also at the Solfatara.
Etymology : The name is from Auripigmentum,
or gold paint, from its use as a pigment, and the
belief that it contained gold.
ORTHOCLASE (Ortoclasia), Orthoclase Felspar,
Potash Felspar, Common Felspar.
Silicate of Alumina and Potash, A1 2 O 3 38! O 2 +
KO Si O 2 i=silica 64.8, alumina 18.4, potash 16.8 =
100. An analysis by Abich of Orthoclase from
Baveno gave: Silica 65.72, alumina 18.57,
potash 14.02, soda 1.25, lime 0.34, magnesia
0.10=100.
Crystallisation, Monoclinic, in oblique rhombic
prisms often twinned. Orthoclase, which is one of
the three constituents of ordinary granite, occurs
also massive, granular, compact, sometimes lamel-
lar, and sometimes flint- or jasper-like. Colour,
white, grey, flesh-coloured, rose-red, and sometimes
green, with a vitreous lustre and a greyish-white
streak. Transparent, translucent, and opaque.
Fracture conchoidal to uneven. Hardness 6,
Specific Gravity 2.44 2.62. Orthoclase is not
affected by acids, and before the blowpipe only
fuses with difficulty to a turbid glass, but is very
liable to decomposition by the carbonic acid of the
atmosphere which, combining with some of the
potash, and the remainder combining with part of
the silica forming two soluble compounds, leaves an
insoluble silicate of alumina as a clay (kaolin),
THE MINERALS OF VESUVIUS. 3 I I
and thus granitic rocks become disintegrated and
destroyed.
Orthoclase is a most abundant mineral, being a
constituent of granitic and syenitic rocks and
ordinary porphyries, as well as of the acidic or
trachytic volcanic rocks. Fine crystals are dis-
played in the granites of Shap, Westmoreland, and
in some of those of Cornwall. The Cornish
crystals are well shown in the stonework of London
Bridge. At Vesuvius, glassy Orthoclase is abundant
in the crystalline masses of Monte Somma, and
occurs in the ejected lavas of Somma too, derived,
Prof. Scacchi thinks, from a metamorphism of
crystals of leucite. It is also found in small lamellar
crystals in the chinks of the lava of 1631.
Etymology : From opM s , straight, and *A<y, to
cleave. Varieties of Orthoclase : Adularia, Moon-
stone, Necronite, Amazonstone, Sanidin, Microlin,
Loxoclase, Perthite, Murchisonite, Halleflinta.
PERICLASITE, Scacchi (Periclasia).
Magnesia with Protoxide of Iron, Mg O + FeOzz
magnesia 89.04, protoxide of iron 8.56 (Scacchi) ;
magnesia 93.38, protoxide of iron 6.01 (Damour).
Crystallisation, Cubic, in octahedrons with a per-
fect cubic cleavage in small clustered crystals, and in
grains. Hardness 6, Specific Gravity 3.674 3.75.
Colour greyish to dark green, with a vitreous lustre.
Transparent to translucent. It is only with difficulty
soluble in nitric acid, and is infusible before the
blowpipe.
312 MOUNT VESUVIUS.
Periclasite occurs at Vesuvius, disseminated
through the " lamellose calcite" of the crystalline
ejected masses of Monte Somma, and is sometimes
associated with Forsterite and earthy magnesite.
Etymology : From *epl, around, and xAa<7/, cleavage,
from its cleavage at the angles.
PHILLIPSITE, Levy (Fillipsite), a Zeolite.
Hydrous Silicate of Alumina, Potash, and Lime
=Al a 3 3 Si 2 + (KO + Ca O) Si O 2 + sH 2 O=:
silica 47.9, alumina 20.5, lime 7.4, potash 6.3, water
17.9=1100.
Crystallisation, Rhombic, occurring in twin or
complex cruciform crystals. Hardness 4 4.5,
Specific Gravity 2.21. Colour white, but sometimes
pink, with a vitreous lustre, and uneven conchoidal
fracture. Translucent to opaque. Easily and
entirely decomposed in hydrochloric acid with
gelatinisation, and as a zeolite gives off water before
the blowpipe. In the British Islands it is found
chiefly in the igneous rocks of the North of Ireland,
where it occurs in white or flesh-coloured trans-
lucent crystals. In Italy it occurs in the old lava
rock of Capo di Bove, near Rome, and at Vesuvius
it is abundant in the ejected lavas of Monte Somma,
where it has been mistaken for Gismondine of
Beaudant, or Abrazite of Breislak.
Etymology: It is named after the English miner-
alogist, William Phillips.
PICROMERITE, A. Scacchi (Picromeride).
Hydrous Sulphate of Potash and Magnesia, KO
THE MINERALS OF VESUVIUS. 313
SO 3 -h Mg O SO 3 + 6HO zz potash 23.5, magnesia
9.9, water 26.8=100.
Crystallisation, Monoclinic, in crystals and
crystalline crusts. Hardness 2.5. Colour white.
This mineral was obtained from the sublimations
of the crater of 1857 by solution, and it has also
been found at the salt mine of Stassfurt.
Etymology : From irmpos, bitter, in allusion to the
magnesia present.
PROIDONITE, A. Scacchi (Proidonina).
Fluoride of Silicon, Si F1 2 .
An emanation of the lavas of Vesuvius during
the eruption of the year 1872, and Prof. Scacchi
thinks probably produced by other eruptions among
the exhalations of the crater and lavas (Att. Accad.
Napoli, vi., 1873).
PSEUDOCOTUNNITE, A. Scacchi (Pseudocotunnia).
Chloride of Lead with Chloride of Potassium,
PbCl+KCl or PbCl 2 +KCl.
This mineral, which has the composition of a
combination of Cotunnite and Sylvine, was obtained
from the sublimations of the crater of Vesuvius
following the great eruption of 1872, and occurred
in the form of acicular yellow crystals that were
both opaque and without lustre. Cotunnite itself was
associated with the Pseudocotunnite.
PYRITE (Pirite), Pyrites, Marcasite, Iron Pyrites,
Mundic, Pierre d'Arquebuse.
Bisulphide of Iron, FeS 2 zz iron 46.7, sulphur
53.3zzioo.
314 MOUNT VESUVIUS.
Crystallisation, Cubic, in cubes and pentagonal
dodecahedrons, sometimes single and isolated,
sometimes in groups, but the mineral commonly
occurs in nodules in chalk, clays, and other rocks,
spheroidal, reniform, botryoidal, and in other forms
with a radiated subfibrous structure and crystalline
surface. It also occurs as an impregnation and in-
crustation of organic remains, and sometimes it is
massive and amorphous in immense quantities as at
Rio Tinto, Spain. The paler variety, called Mar-
casite, crystallises in the Rhombic System, usually in
brilliant crystals, some very pale, almost tin-white,
called Pierre des Incas, from being used by the
Incas of Peru for amulets. The colour is a pale
brass yellow, with a splendent to glistening metallic
lustre, and a greenish or brownish black streak.
Hardness 6 6.5, Specific Gravity 4.83 5.03,
Polished crystals 5.2. Sufficiently hard to strike
fire with steel. Brittle with a conchoidal, uneven
fracture, and when fractured a smell of sulphur is
perceived. Though scarcely acted on by hydro-
chloric, it dissolves in concentrated nitric acid, but
leaves a residuum of sulphur. Before the blow-
pipe it burns with a blue flame, and in the outer or
reducing flame it easily passes to a black globule,
which is magnetic. This mineral, not used as an
ore of iron, is largely employed for the manufacture
of copperas and sulphuric acid.
Pyrite is very largely and widely distributed,
being found in many rocks and in many countries.
THE MINERALS OF VESUVIUS. 315
In England it occurs abundantly in nodules in the
Chalk of the south-eastern counties and in the
London Clay, especially of the Isle of Sheppey, as
well as in other clays, especially the Gault and
the Kimmeridge Clay, the fossils of which are often
encrusted with the mineral. It also occurs in iso-
lated crystals in the slates and other rocks of
Wales, Scotland, and Ireland. The great deposit
at the Rio Tinto mines, near Huelva, in Spain, con-
sists of a cupiferous Pyrite, the mineral containing
from i to 10 per cent, of copper, for which metal
the mines are worked. At Vesuvius it is not
common, but occurs in the ejected lavas of Monte
Somma.
Etymology : The original name vvpirw, full of fire,
was used by Pliny, the mineral giving forth sparks or
fire when struck with steel, but the name now
adopted (Pyrite) is from *$/, fire, and the usual
mineralogical termination ite. Pierre d'Arquebuse
is from the mineral having been used instead of
flint in early times for firearms.
PYROXENE, Haliy (Pirossene), Augite, Volcanite.
Pyroxene, like Amphibole, is the name for a large
number of sub-species of minerals all agreeing in
being Silicates of Lime and Magnesia with Iron,
or (CaO, MgO) SiO 2 +FeO. It thus has three
of the essential constituents of Amphibole, but in
Pyroxene the amount of Lime is greater than
that of the Magnesia, while in Amphibole the
reverse is the case. Like Amphibole, pyroxenous
316 MOUNT VESUVIUS.
minerals may be divided into two groups, one con-
taining little or no Alumina, and the other being
decidedly aluminous. The Vesuvian Pyroxene is
an aluminous mineral, as shown by the following
analysis by Kudermatsch : Silica 50.90, lime 22.96
magnesia 14.43, protoxide of iron 6.25, and alumina
5-37=99-9i-
Crystallisation, Monoclinic, usually in short thick
crystals, often twinned. It also occurs amorphous,
roughly lamellar, granular and fibrous, the fibres
being sometimes long and fine. Hardness 5 6,
Specific Gravity 3.23 3.5. The colour, similar to
that of Amphibole also, is usually very dark, either
a dark green or black, but sometimes it passes
through shades of green to white. It is opaque to
transparent, with a vitreous lustre, in some cases
pearly, a white or grey streak, and a conchoidal
uneven fracture. Brittle. Pyroxene is only slightly
acted upon by acids, but fuses with effervescence
before the blowpipe and yields a light or dark
coloured glass.
The dark or black Pyroxene, more properly that
called Augite, is one of the chief constituents of the
basic volcanic rocks or lavas, and hence the term
Augitic as applied to such rocks.
Pyroxene is a widely distributed mineral occur-
ring in igneous rocks in many localities. At
Vesuvius it is abundant in the crystalline blocks
and the metamorphic conglomerates of Somma, and
from its variable character it has been mistakenly
THE MINERALS OF VESUVIUS. 317
named Topaz, Epidote, and Tourmaline. Small
crystals of Augite are common in the crater and are
often the product of eruptions.
Etymology : From wp, fire, and &QS, a guest, from
its igneous origin. Varieties of Pyroxene : Mala-
colite, Mussite, Sahlite, Diallage, Fassaite, Schiller
Spar, Epidote, Uralite, Jeffersonite.
PYRRHOTITE, Brithaupt (Pirrotina), Pyrrhotine,
Magnetic Pyrites.
Sulphide of Iron, Fe 7 S 8 = iron 60.5, sulphur
39.5-100.
Crystallisation, Hexagonal, in irregular six-sided
prisms, with a perfect cleavage parallel to the base.
It is, however, rare in crystals, and usually occurs
massive and amorphous. Hardness 3.5 4.5,
Specific Gravity 4.4 4.7. The colour is darker
than that of Pyrite, being between bronze-
yellow and copper colour, and its surface speedily
tarnishes on exposure to the air. It has a metallic
lustre and greyish-black streak, is brittle, with an
imperfect conchoidal fracture, and is to some extent
magnetic. Pyrrhotite is soluble in hydrochloric
acid, giving off sulphuretted hydrogen, and fuses
before the blowpipe into a greyish-black globule,
also magnetic. It is distinguished from Pyrite both
by its colour and its much less hardness.
This mineral occurs in mining localities in Eng-
land, Wales, Scotland, and Ireland; and at Vesuvius
it is found, but not common, in the crystalline masses
of Monte Somma.
318 MOUNT VESUVIUS.
Etymology : From vvppvrw, reddish, from its
colour.
QUARTZ (Quarzo), Rock Crystal.
Pure Silica, or Silicic Acid, Si O 2 =zsilicon 46.67,
oxygen 53.33.
Crystallisation, Hexagonal, in six-sided prisms
terminated by six-sided pyramids. Also massive,
granular to cryptocrystalline, or flint-like. Fre-
quently in veins (vein quartz), often containing
particles of gold. Hardness 7, Specific Gravity
2.52.8. Colourless (Rock Crystal, " Pebbles"),
white (Milky Quartz), grey to black (Smoky Quartz),
golden yellow (Cairngorm), violet (Amethyst), and
rose coloured (Rose Quartz), &c. It has a vitreous
lustre and a good conchoidal fracture. Transparent
to opaque. Quartz is insoluble in every acid except
hydrofluoric, and is infusible before the blowpipe
when alone, but with soda fuses with efflorescence
to a glass.
Varieties of Quartz : Agate, Chalcedony, Flint,
Chert, Opal, Jasper, Carnelian, Cat's Eye, Onyx,
Sard, Sardonyx, Chrysoprase, Heliotrope, Lydian
Stone, Siliceous Sinter, Wood Opal, Silicified
Wood, &c.
Quartz often contains small cavities filled or partly
filled with a liquid of unknown composition, but
called by Dana Brewsterlinite, which expands 25
per cent, with an increase of 30 Fahr., being
twenty-one times more expansible than water. On
exposure to the air, dries to separate particles, which,
THE MINERALS OF VESUVIUS. 319
however, even by the moisture of the hand, become
again liquid, when the fluid resumes its rapid move-
ments.
The finest crystals of pure colourless transparent
Quartz (Rock Crystal) are found in the Alps of
Switzerland and Savoy, the neighbourhood of An-
dermatt on the St. Gothard being a well-known
locality. In the British Islands, Cornwall, Devon,
Derbyshire, Cumberland, and North Lancashire
furnish good crystals. At Clifton, in Gloucester-
shire, the crystals are known as " Bristol diamonds,"
and from Wales, Scotland, and many localities in
Ireland, Rock Crystal is obtained. As a rock-
forming mineral, Quartz forms enormous masses of
sands and sandstones, quartzites and conglome-
rates, as well as the sands of the sea-shore. At
Vesuvius it is in the ejected lavas of Monte
Somma and in the fragments enveloped in the lava
of 1631.
REALGAR (Risagallo), Red Arsenic, Red Sulphuret
of Arsenic.
Sulphide or Sulphuret of Arsenic, As S
arsenic 70.07, sulphur 29.93.
Crystallisation, Monoclinic, in prismatic crystals,
and also granular and compact. Hardness 1.5 2,
Specific Gravity 3.4 3.6. Colour, orange-red of
various shades, with a resinous lustre and a yellow
streak. It is sectile and may be scratched with the
finger-nail. Its fracture is conchoidal to uneven,
and it becomes negatively electrical by friction.
320 MOUNT VESUVIUS.
Realgar is soluble in caustic alkalies, while before
the blowpipe it fuses readily in the closed tube, and
exposed to the air burns with a blue flame, giving
off sulphurous and arsenical fumes.
Realgar is obtained from several localities in
Central Europe, and at Vesuvius it was found by
Monticelli and Covelli in the crater after the great
eruption of 1822.
Etymology : The name used by the alchemists.
SAL AMMONIAC (Glorammonio), Muriate of Am-
monia, Salmiac.
Chloride of Ammonium, N H 4 Cl =n ammonium 33.7,
chlorine 66.3=100. A Vesuvian specimen gave
Klaproth : Chloride of ammonium 99.5, sulphate of
ammonia 0.5.
Crystallisation, Cubic, in small octahedrons, but
generally stalactitic, or in crusts, or as an efflor-
escence. Hardness 1.5 2, Specific Gravity 1.528.
Colour white, but sometimes tinged greyish or
yellowish by impurities. It is transparent to opaque,
with a dull external and vitreous internal lustre,
a conchoidal fracture, and a saline pungent taste.
It is soluble in water, but only sparingly so in
alcohol, and sublimes before the blowpipe at a great
heat, but does not fuse.
In England, Sal Ammoniac is found near ignited
beds of coal, but it is most common as a sublimation
near volcanoes. At Vesuvius it is abundantly crys-
tallised upon crusts of lava some time after consoli-
dation, and is stated to be found in the crater.
THE MINERALS OF VESUVIUS. 321
There is a beautiful yellow variety coloured by
chloride of iron.
Etymology : Ammonia from/tama nijak (Arabic),
dung of camels which was burnt to produce the salt.
SARCOLITE, Thomson (Sarcolite).
Silicate of Alumina and Lime with Soda, 3A1 2 O 3 ,
Ca O, 3Si O 2 +Na O, or according to Dana, (^ (- L % Ca
Q+ij Na O) 3 +1A1 2 O 3 ) 2 3Si O 2 = silica 39.7, alu-
mina 22.8, lime 33.4, soda 4.1 = 100. An analysis
of a specimen from Somma by Prof. Scacchi gave :
Silica 42.11, alumina 24.50, lime 32.43, soda 2.93 =
101.97. Prof. Dana says that Sarcolite has a
nearly corresponding composition to that of Idocrase
or Vesuvianite (which see), but it appears to me
to be considerably different.
Crystallisation, Square Prismatic, in small flesh-
coloured or brownish-white crystals, semi-transparent,
with a vitreous lustre. It is very brittle, and gene-
rally so filled with incipient cracks that the mineral
easily falls to pieces. Sarcolite gelatinises with acids
and fuses to a white enamel.
At Vesuvius it is found in the crystalline ejected
blocks of Monte Somma associated with Wollastonite
and Hornblende, but its occurrence is rare.
Etymology : From ^i, flesh, and */&>?, stone, from
its prevailing colour.
SASSOLITE (Sassolino), Boric Acid, Boracic Acid,
Native Sedative Salt.
Hydrated Boracic Acid, BO 3 + 3H 2 O = boracic
acid 56.4, water 43.6=100.
Y
322 MOUNT VESUVIUS.
Crystallisation, Triclinic, usually in small scales,
probably six-sided tables, and sometimes it occurs
in stalactitic forms which are also made up of small
scales. Hardness i, Specific Gravity 1.48. The
true colour is white, but it is sometimes yellowish
from the presence of sulphur. Transparent to trans-
lucent, with a pearly lustre and a smooth and
unctuous feel. Taste acid, but slightly bitter and
saline. Sassolite is both very easily soluble and easily
fusible. It is soluble in water and alcohol, the flame
of which it colours green, and it fuses in the flame
of a candle, to which it also gives a green colour
until the water of crystallisation is driven off.
The mineral is especially abundant in the crater
of Vulcano in the Lipari Islands. The Tuscan
lagoons, where it was first found by Hoefer, yield
7,000 to 8,000 pounds troy a day. At Vesuvius it
was discovered by Monticelli and Covelli in the
crater in 1817.
Etymology : Named from Sasso, near Sienna,
where it was first discovered.
SCACCHITE, Adam (Scacchite).
Chloride of Manganese, Mn Cl.
After the eruption of 1855 the saline incrustations
on the lava were dissolved in distilled water, and the
solution was tested with ferrocyanide of potassium,
with the result that a white precipitate was formed
which in a little time acquired a roseate tint, and
thus the existence of the Chloride of Manganese
was ascertained. In " Lo Spettatore " Prof. Scacchi
THE MINERALS OF VESUVIUS. 323
says it is common among the deliquescent salts of
the crater.
SCOLECITE, Fuchs (Scolezite), Skolezit.
Hydrous Silicate of Alumina and Lime (A1 2 O 3
CaO) 3Si O 2 -f- 3 H 2 O = silica 45.8, alumina 26.2, lime
14.3, water 13.7=100.
Crystallisation, Monoclinic, in prismatic and aci-
cular crystals, often twinned ; but it occurs massive
and also in nodules, with a fibrous and radiating
structure. Hardness 5 5.5, Specific Gravity 2.2
2.7. Colourless and white, and also of pale grey,
yellow, and red tints, with a vitreous lustre, or
silky when fibrous. It is translucent towards the
edges, is brittle, having an uneven fracture, and is
pyro-electric. Scolecite gelatinises with hydro-
chloric acid, and with oxalic acid dissolves with
separation of Oxalate of Lime. Before the blow-
pipe its action is peculiar, twisting and curling like
a worm previous to fusion, when it forms a blistered
glass.
This mineral was obtained from the igneous rocks
of Staffa and other islands in the Hebrides as well
as from Iceland, the Faroes, and other localities.
At Vesuvius certain globules with a radiate struc-
ture in the ejected lavas of Somma are considered
by Prof. Scacchi to be Scolecite.
Etymology : o*Aji, a worm, from its action be-
fore the blowpipe.
SODALITE (Sodalite).
Silicate of Alumina and Soda with Chloride of
324 MOUNT VESUVIUS.
Sodium, 3A1 2 3 Si0 2 +Na O 3 Si O 2 + Na Cl, or
3 [(A1 2 3 ) 2 (Si 2 ) 3 ] + 3Na O 3 Si O 2 + 2 Na Cl=
silica 37.1, alumina 31.7, soda 19.2, sodium 4.7,
chlorine 7.3=1100.
Crystallisation, Cubic, in rhombic dodecahe-
drons; and massive. Hardness 5.5 6, Specific Gra-
vity 2.136 2.37. Colour various, as white, grey,
yellowish, greenish, lavender, blue, and light red,
with a vitreous lustre. It is translucent, and has a con-
choidal fracture. With hydrochloric acid, Sodalite
yields gelatinous Silica, and before the blowpipe it
fuses, and forms, like Scolecite, a blistered glass,
sometimes intumescing.
This mineral is found in many northern localities
in both Europe and America, and at Vesuvius it is
in large white dodecahedral crystals, occurring
in the crystalline masses of Monte Somma, the
chinks of the lava of 1631, and in the metamor-
phic conglomerates ejected by the eruption of
1872.
Etymology : From soda and *ffa s , a stone.
SOMMITE, Delametherie (Sommite), Nepheline,
Nephelite, Davyne, Cavolinite, Elaeolite, Beau-
dantite.
Silicate of Alumina, Soda, and Potash, 5 A1 2 O 3
Si O 2 + 4NaO Si O 2 +KO Si O 2 2 (Scheerer), or
Al 2 3 Si0 2 3 + (Na O 3 , KO 3 ) Si O 2 3 +3Si O 2 =
silica 44.2, alumina 33.7, soda 16.9, potash, 5.2 =
100. Three analyses of, Vesuvian specimens
gave :
THE MINERALS OF VESUVIUS. 325
By Silica. Alumina. Soda. Potash. Lime, i* Water.
Arfved ... 44.11 33-73 20.46 0.62= 98.92
Scheerer... 44.03 33.28 15.44 4.94 1.77 0.65 0.21=100.32
Scheerer... 44.29 33.04 14.93 4-7 2 I -% 2 -39 0.21= 99.40
Crystallisation, Hexagonal, in six-sided (the pri-
mary form) and twelve-sided prisms, with the sum-
mits either plane or having the edges replaced,
some terminated by the faces of many pyramids.
The faces of the pyramidal terminations are some
(Nepheline) at 135 10', and some (Davyne) at an
angle of 154 9' to the plane of the base. It occurs
also compact and columnar. Hardness 5.5 6,
Specific Gravity 2.5 2.65. Colourless and greyish
and yellowish white, but when massive it is of
various tints, as green, bluish and reddish, with a
vitreous, or a shining or silky lustre, and varies
from transparent to opaque. The variety Davyne
has a feeble lustre, and Rammelsberg states con-
tains Carbonate of Lime, while Cavolinite is
marked by a silky lustre. It is brittle with a sub-
conchoidal fracture, and possesses, though weakly,
double refraction. Sommite gelatinises with acids,
and before the blowpipe fuses to a colourless
blistered glass,
This mineral is in both Plutonic and Volcanic
rocks, and has been found at Capo di Bove, and in
several localities in Central Europe. The variety
Elaeolite occurs in Northern Europe and Asia, and
in North America. At Vesuvius, Sommite was first
found in crystals in the ejected crystalline blocks of
326 MOUNT VESUVIUS.
Monte Somma, some associated with glassy felspar,
and some associated with Pyroxene and Biotite.
Etymology : Although this mineral is usually
called Nephelite by mineralogists, who have gene-
rally adopted Hauy's name of 1801, I prefer the
name Sommite, as used by Professor Scacchi, both
from its indicating the original locality and from
priority, it having been given by Delametherie to
the species in 1797. Nepheline is from ve<p*q, a
cloud, from strong acids producing cloudiness.
Elaeolite, from &/&*, oil, from its greasy lustre.
SPINELLE (Spinello), Pleonaste, Rubicelle, Alman-
dine.
Anhydrous Aluminate of Magnesia, but usually
with Silica and Oxide of Iron, when pure Mg O
A1 2 O 3 = alumina 71.99 and magnesia 28.01 100.
Two analyses of Vesuvian specimens by Abich
gave :
Alumina. Magnesia. Silica. Iron Protoxide, Iron Peroxide.
67.46 25.94 2.38 5.06 ... = 100.85
62.84 24.87 1.83 3.87 6.5= 99.56
Part of the magnesia is sometimes replaced by lime
and the protoxides of zinc and manganese.
Crystallisation, Cubic, in octahedrons and rhombic
dodecahedrons and sometimes in macles. Hard-
ness 8, Specific Gravity 3.54.9. The colour
varies much, and determines the names of the
varieties, the fine red Spinelle being the Spinelle
Ruby, and the rose-red the Balas Ruby of jewellery,
while the orange-red is Rubicelle, and the violet
THE MINERALS OF VESUVIUS. 327
Almandine. The dark-coloured or black is named
Pleonaste, which is the usual Vesuvian variety ;
Almandine, the other Spinelle of this area, occurring
very rarely. Spinelle is transparent to almost
opaque, with a vitreous lustre or white streak,
and a flat-conchoidal fracture. It is soluble only
with difficulty in hydrochloric and strong sulphuric
acids, and is infusible before the blowpipe, but red
Spinelle when cooling becomes green, and then nearly
colourless, but subsequently again becomes red as at
first. Spinelle is distinguished from Oriental Ruby
by being only 8 instead of 9 in the Scale of Hard-
ness, by having less specific gravity, and by its
crystallisation.
In the British Islands, Spinelle occurs in small
rounded grains in the beds of the mountain streams
of Wicklow, but the Spinelle Rubies are chiefly from
Burma, Ceylon,, and Cashmere. At Vesuvius the
mineral is found in the crystalline ejected blocks of
Monte Somma, and usually associated with Peridote
and Humite.
SULPHATE OF MANGANESE (Solfato Manganoso).
Found by Monticelli and Covelli in the " red sand"
of the 24th October, 1872, which was one of the
products of the great eruption of that year.
SULPHATITE, Dana (Solfatite), Oil of Vitriol.
Hydrous Sulphuric Acid, SO 3 + H 2 O~ sulphuric
acid 81.6, water 18.4=1100.
Liquid, Specific Gravity 1.85, colourless. Dilute
sulphuric acid is found occasionally near volcanoes.
328 MOUNT VESUVIUS.
In cavernous hollows in an old volcano in Tuscany,
near Sienna, and in a cavern at Aix-les-Bains, as
well as in several American localities, it is also
present. Its formation is due to the oxidation of
sulphuretted hydrogen.
SULPHURETTED HYDROGEN GAS (Idrogeno Solfo-
rato).
Sulphur and Hydrogen, HS.
This gas is evolved from the fumaroles of the
crater, but does not appear to be abundant or
indeed common.
SULPHUROUS ACID GAS (Anidride Solforosa).
Anhydrous Sulphurous Acid, SO 2 .
Prof. Scacchi reports this gas as being a common
emanation from the fumaroles of the craters.
TENORITE, Semmola (Tenorite), Melaconite.
Protoxide of Copper, Cu O zz copper 79.85,
oxygen 20.15.
Crystallisation, Hexagonal, in laminae sometimes
triangular, and it also occurs earthy and pulverulent.
It is doubtful whether the same species is not
trimorphous, if not quadrimorphous, since a similar
oxide of copper, melaconite, is Cubic, some crystals
of which from Cornwall have been found to be
Monoclinic, while Kalkowsky says Tenorite is
Triclinic. Hardness 3, Specific Gravity 5.952 6.25.
Colour, dark iron-grey to black, opaque with a
metallic lustre, or dull and earthy, and black streak.
Folia elastic. It is soluble in hydrochloric and
nitric acids, and before the blowpipe on charcoal
THE MINERALS OF VESUVIUS. 329
fuses and gives a red globule which in nitric acid
dissolves with effervescence. Tenorite was found
by Prof. Maskelyne to possess double refraction.
This mineral occurs at Vesuvius as a sublimation
often with chloride of sodium on the lavas and
about the bocche and fumaroles of the crater.
Etymology : Tenorite is so named in compliment
to Signor Tenore, President of the Neapolitan
Academy of Sciences.
THENARDITE, Casaseca (Pirotecnite).
Anhydrous Sulphate of Soda, Na O SO 3 = soda
56.18, sulphuric acid 43.82=1100.
Crystallisation, Rhombic, in rhombic octahedrons
giving acute pyramids, aggregated in crusts and in
drusic cavities. Hardness 2 3, Specific Gravity
2.55 2.73. Colour white to brown, translucent,
with a vitreous lustre ; possesses double refraction ;
has a saline taste, and effloresces with a white
powder on the surface on exposure to the atmo-
sphere. It is quite soluble in water, and the crystals
of the Vesuvian mineral were obtained from a solu-
tion of the sublimations of the crater.
Thenardite is deposited from the waters of a
spring at Les Salines d'Espartines, near Aranjuez,
in Spain, and it occurs at Tarapaca, in Peru. At
Vesuvius it was on the scoriae of the eruption of
1855-
The name is in compliment to Thenard, the
French chemist.
THOMSONITE, Brooke (Comptonite).
330 MOUNT VESUVIUS.
Silicate of Alumina, Lime, and Soda with water
(one of the Zeolites) = (Ca Na) O, A1 2 O 3 , 2Si O 2 ,
2 H 2 O, (Scacchi) (Ca O, NaO) 3 Si O 3 + 3A1 2 O 3 +
;H 2 O = silica 37.4, alumina 31.8, lime 13.0, soda 4.8,
water 13=100.
Crystallisation, Rhombic, but it generally occurs
in masses with a columnar or radiated structure.
Hardness 5 5.5, Specific Gravity 2.35 2.4. Snow
white, or colourless. Transparent to translucent.
Brittle, with an uneven fracture and vitreous lustre.
Pyro-electric. Before the blowpipe exhibits the
zeolitic intumescence, and gelatinises with acids.
Occurs in basalt in various localities in Scotland
and Ireland, in the Faroe Islands, Sicily, Bohemia,
&c. At Vesuvius it is in the ejected lavas of Monte
Somma frequently associated with Phillipsite, but
rather rare in the conglomerates.
, Etymology : The Vesuvian mineral was named
Comptonite by Brewster after Lord Compton, by
whom it was first distinguished, but the name Thom-
sonite, after Prof. Thomson, of Glasgow, was given
to Scotch specimens by Brooke a year previously.
TITANITE, Klaproth (Titanite), Sphene, Semeline,
Ligurite.
Silicate of Titanium and Lime, Ti O 2 Si O 2 + Ca O
Si O 2 = silica 35, titanic acid 33, lime 32 = 100.
Crystallisation, Monoclinic, often in twinned crys-
tals and sometimes in double twins. It also occurs
massive, compact, and, though rarely, lamellar.
Hardness 55-5. Specific Gravity 3.43.56. The
THE MINERALS OF VESUVIUS. 331
colour varies from dark brown to light yellow
(Sphene), with an adamantine to resinous lustre and
a whitish streak. It is transparent to opaque, and
brittle, with an imperfect conchoidal fracture, and
possesses double refractive powers. Decomposed
by hydrochloric, hydrofluoric, and sulphuric acids,
with separation of gelatinous Silica, and before the
blowpipe fuses after intumescence to a yellow or
dark-coloured glass.
In the British Islands, Titanite occurs at Strontian
and other localities in Scotland, and also in Devon-
shire, Wales, and Ireland. At Vesuvius it is in
small crystals (Semeline), but not common, in the
crystalline blocks of Somma rich in orthoclase.
Etymology : Sphene is from ^^, a wedge, from
the shape of its crystals.
VESBINE, A. Scacchi (Vesbina).
Vanadate of Alumina ? (A1 2 O 3 VO 3 ).
This substance forms thin yellow crusts on the
lava of the eruption of Vesuvius in 1631, and was
thought by Prof. Scacchi to contain a new chemical
element which he named "Vesbium" (Att. Accad.
Napoli, Dec. 13, 1879). In " Lo Spettatore" (1887),
however, the Professor describes Vesbine as pro-
bably, but not positively, a vanadate of alumina, or
a compound of alumina with vanadic acid.
VESUVIANITE, Werner (Idocrasia), Idocrase.
Silicate of Lime and Alumina with Iron and
Magnesia = (3Ca O + A1 2 O 3 ) 3Si O 2 + Mg O +
Fe O = silica 37.50, lime 33.75, alumina 18.50,
332
MOUNT VESUVIUS.
magnesia 4.o,"iron oxide 6.25=1100. Three analyses
of Vesuvian specimens gave :
By Silica. Lime. Alumina. Magnesia. Iron Oxide.
Magnus 37.36 29.68 23.53 5- 21 ( witn Mn ) 3-99
Karsten 37.50 33.71 18.50 3.10. +. 10 of Mn O 6.25
Scheerer 37.80 32.11 12.11 7.11 (with trace of MnO) 9.36 with
[1.67 water
Crystallises in the Square Prismatic System, and
occurs also massive. The crystals are usually rec-
tangular prisms, terminated by planes, the angles of
the prism being often replaced. Hardness 6.5,
Specific Gravity 3.349 3-45- Colour brown to
green, sometimes yellow and sometimes blue (the
Vesuvian mineral being hair-brown or olive-green),
with a lustre vitreous, inclining to resinous, and a
white streak. Translucent and sometimes nearly
transparent, and is doubly refractive. Fracture, sub-
conchoidal. This mineral is partly decomposible by
hydrochloric acid, and entirely so after fusion, when
it gelatinises. Fusion is easily produced by the
blowpipe with intumescence, when a glass is pro-
duced, which is with microcosmic salt opalescent.
Stones for jewellery are cut from Vesuvianite in
Italy, and called by various names according to their
colour.
In the British Islands the mineral occurs in
Aberdeenshire and Skye in Scotland, and in
Donegal in Ireland. In Finland it is called Fru~
gardite, Gokumite, and Loboite ; in Norway, Cyprine;
and in Bohemia, Egeran. At its chief locality,
Vesuvius, it is of frequent occurrence in the
THE MINERALS OF VESUVIUS. 333
crystalline masses of Monte Somma, associated
with biotite and garnets.
Named Vesuvian by Werner from its original and
chief locality, and called Idocrase by Haliy, Phillips,
and other mineralogists, from ilia, to seem, and **r/? r
o * *
a mixture, from its crystalline forms being mixed
figures and often mistaken for others.
WAGNERITE (Crifiolite).
Fluophosphate of Magnesia zz Mg O 3 P O 5 +
Mg F zz phosphoric acid 43.8, magnesia 37.1,
fluorine 11.7, magnesium 7.4=100.
Crystallisation, Cubic, occurs in complex crystals
with vertical striae. Hardness 5 5.5, Specific
Gravity 2.985 (untransparent) 3.068 (transparent).
Colour yellow, of various tints, and sometimes
greyish. Translucent, with a vitreous lustre and an
uneven and splintery fracture across the prism. When
powdered it dissolves slowly in warm nitric and sul-
phuric acid, giving off fumes of hydrofluoric acid.
Occurs in quartz veins in clay-slate near Salzburg,
in Austria. At Vesuvius it was found in a mass of
old volcanic rock enveloped in the lava of 1872.
Etymology : Named after Von Wagner, Director
of Mines in Bavaria.
WOLLASTONITE, Stutz (Vollastonite), Tabular Spar.
Silicate of Lime, Ca O Si O 2 =silica 51.7, lime
48.3 zz 100. An analysis of Wollastonite from
Vesuvius by Wiehagen gave: Silica 51.90, lime
46.44, magnesia 0.65, protoxide of iron with man-
ganese 0.96 = 99.95.
334 MOUNT VESUVIUS.
Crystallisation, Monoclinic, but rarely in distinct
tabular crystals. It occurs usually in lamellar,
granular, or columnar masses. Hardness 4.5 5,
Specific Gravity 2.785 2.895. Colour white or
tinged with grey, yellow, or red. Sub-transparent to
translucent, with a vitreous lustre. It is sometimes
very tough and sometimes rather brittle, with an
uneven fracture, and becomes phosphorescent by
heat or when scratched with a knife. Wollastonite
is decomposed by hydrochloric acid, with the pro-
duction of gelatinous Silica, but fuses with difficulty
to a semi-transparent glass.
It occurs in Aberdeenshire with Vesuvianite, and
in the north of Ireland, where it has a somewhat
fibrous structure. At Vesuvius, the lamellar Wol-
lastonite is common in the crystalline masses of
Somma.
Named after Dr. Wollaston.
ZIRCON, Werner (Zircone), Jargon.
Silicate of Zirconia, Zr O 2 Si O 2 =: silica 33,
zirconia 67=100.
Crystallisation, Square Prismatic in quadrangular
crystals, terminated by pyramids, resembling those
of Cassiterite, and also in rounded grains. Hardness
7.5, Specific Gravity 4 4.75. Colourless, grey, and
various shades of yellow and brown, sometimes, but
rarely, white. It is transparent to opaque, with
double refraction and variable adamantine lustre.
The streak is white, and the fracture conchoidal.
Zircon is only with difficulty soluble in concentrated
THE MINERALS OF VESUVIUS. 335
sulphuric acid, and in other acids it is not acted
upon, It is also infusible when alone before the
blowpipe, but with a large quantity of borax it fuses
with difficulty.
In the British Islands, Zircon occurs at Strontian,
Argyleshire, in the Island of Harris, and in Ireland
at Croghan, Kinshela Mountain. At Vesuvius it is
rare in the glassy felspar of the crystalline ejections
of Somma.
Etymology : From the Arabic zerk, meaning a
precious stone.
INDEX OF SYNONYMS AND INCLUDED
VARIETIES.
Acido cloridico
see Hydrochloric acid gas.
Actinolite
Amphibole.
Adularia
Orthoclase.
Aftalosa
,, Aphthitalite.
Agate
Quartz.
Alabaster
Gypsum.
Alite
Halite.
Almandine
Spinelle.
Alume
,, Alum.
Amazon stone
,, Orthoclase.
Amethyst
Quartz.
Amianthus
Amphibole.
Amphigene
Leucite.
Andridite
Garnet.
Anfibolo
Amphibole.
Anglesine
Anglesite.
Anhydrous sulphate
of copper ,, Dolerophanite.
Anidride carbonica
,, Carbonic acid gas.
Anidride solforosa
Sulphurous acid gas.
Anidrite
Anhydrite.
Anortite
Anorthite.
136
MOUNT VESUVIUS.
Aragon spath
Arcanite
Asbestos
Asparagus stone
Atelina
Augite
Auina
Auripigmentum
Ausmannite
Azoturo di ferro
Azurite
Azzurrite
Beaudantite
Belonesia
Bischofite
Bitter spar
Black Jack
Black lead
Blue carbonate of copper
Blue copper
Blue John
Blue vitriol
Boracic acid
Bristol diamonds
Cairngorm
Calcantite
Calcareous spar
Calce
Capillary pyrites
Carbonate of lime
Carbuncle
Carnelian
Cavolinite
Chalcanthite
Chalcedony
Chert
Chloride of calcium
Chloride of iron
Chloride of lead
see Aragonite.
Aphthitalite.
Amphibole.
Apatite.
Atelite.
Pyroxene.
Haiiynite.
,, Orpiment.
Hausmannite.
Ferric nitrate.
Chessylite.
,, Chessylite.
Sommite.
Belonesite.
Chloromagnesite.
Dolomite.
Blende.
Graphite.
,, Chessylite.
,, Chessylite.
Fluorite.
Cyanosite.
Sassolite
Quartz.
Quartz.
Cyanosite.
Calcite.
Calcite.
Millerite.
Calcite.
,, Garnet.
Quartz.
,, Sommite.
Cyanosite.
Quartz.
,, Quartz.
,, Chlorocalcite.
,, Molysite.
Cotunnite.
THE MINERALS OF VESUVIUS.
337
Chloride of magnesia
Chloride of sodium
Chondrodite
Christianite
Chrysoprase
Cianocroma
Cianosa
Clinohumite
Cloralluminio
Clorammonio
Clorocalcite
Cloromagnesite
Clorotionite
Common felspar
Common salt
Comptonite
Copper vitriol
Cotunnia
Covellina
Covelline
Covellinite
Crifiolite
Criptoalite
Cubic zeolite
Cupreous sulphate of lead
Cuspidina
Davyne
Derbyshire spar
Diallage
Dolerofano
Dolomie
Edenite
Elseolite
Ematite
Epidote
Epsom salts
Eriocalco
Eritrosidero
Euclorina
see Scacchite.
Halite.
Humite and Chondrotite.
Anorthite.
,, Quartz.
,, Cyanochroite.
Cyanosite.
Humite and Clinohumite.
Chloralluminite.
,, Sal ammoniac.
,, Chlorocalcite.
Chloromagnesite.
Chlorotionite.
,, Orthoclase.
Halite.
Thomsonite
Cyanosite.
Cotunnite.
Covellite.
Covellite.
, Covellite.
Wagnerite.
Cryptohalite.
,, Analcime.
Linarite.
Cuspidine.
Sommite.
Fluorite.
Pyroxene.
Dolerophanite.
Dolomite.
Amphibole.
Sommite.
Haematite.
Pyroxene.
Epsomite.
Eriochalcite.
Erithrosiderite.
Euchlorinite.
338
Exantalosa
Fassaite
Felspar
Fillipsite
Flint
Flos ferri
Fluor spar
Fluoride of calcium
Galena
Gelenite
Gesso
Glaserite
Glauber salt
Grafite
Grammatite
Granato
Grossularite
Halleflinta
Haiiyna
Haiiyne
Heliotrope
Hornblende
Humboldtilite
Hydrofluoric acid
Iceland spar
Idocrase
Idocrasia
Idrociano
Idrodolomite
Idrofluore
Idrogeno solforato
Idrogiobertite
Indigo copper
Iron glance
Iron pyrites
Jade
Jargon
Jasper
Jeffersonite
MOUNT VESUVIUS.
see Exanthalose and Mirabilite.
,, Pyroxene.
Orthoclase.
Phillipsite.
Quartz.
Aragonite.
Fluorite.
Fluorite.
Galenite.
Melilite.
Gypsum.
Ophthitalite.
Mirabilite.
Graphite.
Amphibole.
Garnet.
Garnet.
Orthoclase.
Haiiynite.
,, Haiiynite.
Quartz.
Amphibole.
Melilite.
Hydrofluorite.
Calcite.
Vesuvianite.
Vesuvianite.
Hydrocyanite.
Hydrodolomite.
Hydrofluorite.
Sulphuretted hydrogen gas.
,, Hydromagnesite.
Covellite.
Haematite.
Pyrite.
Amphibole.
Zircon.
Quartz.
Pyroxene.
THE MINERALS OF VESUVIUS.
339
Kalinite
Kupferlasur
Labrador felspar
Lapislazuli
Latialite
Ligurite
Lime felspar
Litidionite
Lode stone
Loxoclase
Lydian stone
Magnesia mica
Magnesian carbonate of lime
Magnetic iron ore
Magnetic pyrites
Magnoferrite
Marcasite
Melacolite
Melaconite
Melanotallo
Mellilite
Meroxene
Mica
Microlin
Molibdenite
Molisite
Molybdena
Molybdate of magnesia ?
Moonstone
Moroxite
Mountain leather
Mundic
Murchisonite
Muriate of ammonia
Muriate of copper
Mussite
Native alum
Native sedative salt
Native ultramarine
see Alum.
Chessylite.
Labradorite.
Lapis Lazuli.
,, Haiiynite.
Titanite.
Labradorite.
Lithidionite.
Magnetite.
Orthoclase.
Quartz.
Biotite.
Dolomite.
Magnetite.
Pyrrhotite.
Magnesioferrite.
Pyrite.
Pyroxene.
Tenorite.
Melanothallite.
Melilite.
Biotite.
Biotite.
Orthoclase.
Molybdenite.
Molysite.
Molybdenite.
Belonesite.
Orthoclase.
Apatite.
Amphibole.
Pyrite.
Orthoclase.
Sal ammoniac.
Atacamite and Eriochalcite.
,, Pyroxene.
Alum.
Sassolite.
Lapis Lazuli.
340
Necronite
Necrociano
Neocrisolite
Nepheline
Nephelite
Nephrite
Oil of vitriol
Olivine
Onyx
Opal
Orpimento
Orthoclase felspar
Ortoclasia
Pearlspar
Pebble
Periclasia
Peridote
Peridoto
Peroxide of iron
Perthite
Phosphorite
Picromeride
Pierre d'Arquebuse
Pirite
Pirossene
Pirotecnite
Pirrotina
Plagioclasia
Pleonaste
Plumbago
Potash alum
Potash felspar
Proidonina
Protoxide of copper
Pseudocotunnia
Pyrites
Pyrope
Pyrrhotine
Quarzo
MOUNT VESUVIUS.
see Orthoclase.
,, Necrocyanite.
,, Neochrysolite.
Sornmite.
,, Sommite.
Amphibole.
Sulphatite.
Chrysolite.
,, Quartz.
Quartz.
Orpiment.
,, Orthoclase.
Orthoclase.
Dolomite.
Quartz.
Periclasite.
Chrysolite.
Chrysolite.
Haematite and Limonite.
,, Orthoclase.
Apatite.
Picromerite.
Pyrite.
Pyrite.
,, Pyroxene.
Thenardite.
Pyrrhotite
Labradorite.
Spinel.
Graphite.
Alum.
Orthoclase.
Proidonite.
Tenorite.
Pseudocotunnite.
Pyrite.
Garnet.
Pyrrhotite,
Quartz.
THE MINERALS OF VESUVIUS.
341
Raucierite
Rautenspath
Red arsenic
Red copper
Red iron ore
Red oxide of iron
Red sulphuret of arsenic
Risagallo
Rock cork
Rock crystal
Rock salt
Ruberite
Rubicelle
Sahlite
Salmiac
Sanidine
Sapphairos
Sard
Sardonyx
Sassolino
Satin spar
Schiller spar
Scolezite
Silica
Selenite
Semolina
Siliceous sinter
Silicified wood
Skolezit
Smaragdus
Solfatite
Solfato manganoso
Somervillite
Sphalerite
Sphene
Spinello
Sulphate of copper
Sulphate of lead
Sulphate of lime
see Hausmannite.
Dolomite.
Realgar.
Cuprite.
Haematite.
Haematite,
Realgar.
Realgar.
Amphibole.
Quartz.
Halite.
Cuprite.
Spinel.
Pyroxene.
j, Sal ammoniac.
Orthoclase.
Lapis Lazuli.
Quartz.
Quartz.
Sassolite.
Aragonite and Gypsum.
Pyroxene.
Scolecite
Quartz.
Gypsum.
Titanite.
Quartz.
Quartz.
Scollecite.
Chrysolite.
Sulphatite.
Sulphate of manganese.
Melilite.
Blende.
Titanite.
Spinel.
Cyanosite.
Anglesite.
Gypsum.
342
MOUNT VESUVIUS.
Sulphate of magnesia
Sulphate of soda
Sulphuret of arsenic
Sulphuret of iron
Sulphuret of lead
Sulphuret of nickel
Sulphuret of zinc
Sulphuric acid
Tabular spar
Tile ore
Tremenhurite
Tremolite
Triclinic felspar
Umite
Uniaxial mica
Uralite
Vesuvian salt
Vesbina
Volcanite
Vollastonite
White copperas
White garnet
Wood opal
Ziguelina
Zigueline
Zircone
Zurlite
see Epsomite.
Exanthalose*and Thenardite.
Orpiment.
Pyrite.
Galenite.
Millerite.
Blende.
Sulphatite.
Wollastonite.
Cuprite.
Graphite.
,, Amphibole.
Labradorite.
Humite.
Biotite.
Pyroxene.
Aphthitalite.
Vesbine.
Pyroxene.
Wollastonite.
Coquimbite.
Leucite.
Quartz.
Cuprite.
Cuprite.
Zircon.
, Melilite.
343
CHAPTER XL
THE FLORA OF VESUVIUS.
The Floras of Vesuvius and Capri compared Cause of difference
Vesuvian Flora very varied List of Families and Summary of
Species List of Medicinal Plants Genera of Graminaceae,
Musci, Hepaticae, and Lichens List of Species with Habitats, of
Ferns and Fungi.
As might be expected from the fertility of the soil
and the favourable character of the climate, the
Flora of Vesuvius is exceedingly varied and
interesting. A very valuable work by Senor
Giuseppe Antonio Pasquale was published in Naples
in 1869,* for the purpose of demonstrating the
effects of difference of soil on vegetation, and with
that object the Flora of Vesuvius, produced on
volcanic soils, was compared with the Flora of the
neighbouring island of Capri, produced by cal-
careous soils, that island being composed of lime-
stone, and not at all volcanic. From this comparison
it appears that no less than twenty-six Vesuvian
genera are unknown at Capri. These are the
following :
* " Flora Vesuviana o Catalogo Ragionato delle Piante del Vesuvio
confrontate con quelle dell' Isola di Capri e di altri luoghi
circonstanti."
344
MOUNT VESUVIUS.
GENERA OF PLANTS ON OR ABOUT VESUVIUS
NOT ON THE ISLAND OF CAPRI.
(VESUVIUS, VOLCANIC SOIL; CAPRI, CALCAREOUS.)
Aristolochia.
Cephalanthera.
Cheilanthes.
Coscinodon.
Cystopteris.
Daphne.
Enthostadon.
Ehrharta.
Epipactis.
Fabronia.
Genista.
Glechoma.
Habrodon.
Humulus.
Imperata.
Lilium.
Limodorum.
Lycium.
Pleuridium.
Pogonatum.
Saccharum.
Senebiera.
Stereocaulon.
Tilia.
Webera.
Zygodon.
Altogether, no less than 934 species and 326
varieties of plants are enumerated as growing on
the slopes and flanks and immediate surroundings
of the volcano. These range from the noble oak
and chestnut to the lowly lichen, the Stereocaulon
Vesuvianum, that is found on recent lavas, and is the
first plant to grow on the products of Vesuvius.
The grape vine, the Vitis vinifera, may be said
to be the chief Vesuvian plant, for it clothes the
great proportion of the Vesuvian cultivated area.
Of the fruit of the Vitis vinifera, as many as 97
sorts of grapes are produced in the vineyards
around Vesuvius, of which 32 are white, 57 black,
and 8 are of shades of red and violet.
About twenty varieties of pears, and more than
that number of apples are cultivated, and there are
THE FLORA OF VESUVIUS, 345
all the ordinary south-temperate as well as sub-
tropical fruits : Almonds, figs, olives, peaches,
apricots, cherries, plums, mulberries, and the fol-
lowing species of orange and lemon : Citrus
bigardia, C. aurantium, C. medica, C. limonum,
C. limetta, and C. deliciosa.
Of ordinary timber trees there are growing luxu-
riantly the oak (both Quercus robur and Q. Ilex) y
the elm, the lime, the poplar (P. alba, P. nigra, and
P. tremuld), the acacia, the willow, the birch, the
chestnut (which, with the broom, the Genista
tinctoria, clothes elevated tracts on Monte Somma),
the walnut, the maple, the alder, the hornbean, with
the flowering thorn (the Celtis australis), the hazel,
three species of Pinus, and the Cupressus semper-
virens. The cactus also flourishes with the myrtle,
laurel, &c. Seven species of rose are found, and
many varieties are cultivated. Culinary vegetables
are grown in abundance, and Signor Pasquale
enumerates 75 species of Graminaceae. The date
palm grows, and produces fruit, but not eatable.
The following is a summary of the results arrived
at by the investigations of Signor Pasquale :
DICOTYLEDONES.
Thalamiflora.
Ranunculaceae 12
Papaveracese ... ... 3
Fumariaceae 4
Cruciferse ... ... ... 26
Capparideae i
Resedaceae i
Cistineae 4
Violariae ... ... ... ,4
Caryophyllese 23
Lineae ... ... ... 2
Malvaceae 5
346
MOUNT VESUVIUS.
Aurantiaceae
6
Valerianeae...
Tiliaceae
i
Dipsaceae
Hypericineae
4
Compositae
Ocerineae ...
2
Campanulaceae
Ampelideae
I
Ebenaceae
Geraniaceae
7
Ericaceae
Oxalideae
2
Zygophylleae
I
Corolliflora.
Rutaceae ...
I
Primulacese
Calyciflora polypetalcz.
Oleaceae
Apocynaceae
Rhamneae
2
Asclepiadeae
Celastrineae
I
Gentianeae...
Terebinthaceae
I
Convolvulaceae
Zanthoxyleae
I
Boragineae
Leguminosae
8 4
Solanaceae ...
Amygdaleae
12
Scrophularineae . . .
Rosaceae ...
16
Orobancheae
Pomaceae
9
Acanthaceae
Onagrariae
i
Verbenaceae
Myrtaceae ...
i
Labiatae
Granateae
i
Plantagineae
Cucurbitaceae
4
Portulaceae
i
Monochlamydece.
Paronychieae
Crassulaceae
7
Phytolaccaceae
Ficoideae
/
I
Amarantaceae
Cactaceae
I
Chenopodiaceae ...
Saxifragaceae
4
Nyctagineae
Umbelliferae
21
Polygoneae
Loranthaceae
I
Laurineae ...
Araliaceae
I
Aristolochieae
Santalaceae
Calyciflora gamopitalce.
Cy tineae
Euphorbiaceae
Corneae
I
Urticaceae ...
Caprifoliaceae
3
Moreas
Rubiacese
IO
Cannabineae
2
8 9
6
2
2
5
4
3
i
3
3
12
17
23
7
i
2
31
7
4
8
i
9
i
i
i
i
7
6
ii
2
THE FLORA OF VESUVIUS,
73
Celtideae ...
Ulmaceae . . .
Juglandeae . . .
Cupuliferae...
Aroideae . .
Lemnaceae
Palmae
Orchidaceae
Irideae
Amaryllidae
Betulaceae ...
Salicineae . . .
Coniferae
MONOCOTYLEDONES.
2 Dioscoreae
i Smilaceae ..,
i Liliaceae ...
13 Juncaceae
Cyperaceae
Graminaceae
i
... 6
... TI
5
... 6
75
Vasculares.
Ophioglosseae
Lycopodiaceae
Polypodiaceae
i
i
ii
ACOTYLEDONES.
Cellulares.
Musci 69
Hepaticae 25
Lichenes 33
Fungi 56
In " Lo Spettatore del Vesuvio" there is a
highly interesting contribution from Signor Orazio
Comes, of the Botanical Laboratory of the Royal
School of Agriculture at Portici, " Le Lave il
Terreno Vesuviano e la loro Vegetazione," in which
it is stated that the following medicinal plants may
be gathered on Vesuvius. In giving this list Signor
Comes remarks that it strikingly corroborates a
statement by Bracini, that in his time the Atrio del
Cavallo was a veritable garden of simples.
LIST OF MEDICINAL PLANTS GROWING ON
VESUVIUS.
Androsaemum officinale.
Asparagus acutifolius.
Artemisia arborescens.
Campanula Rapunculus.
Chelidonium majus.
Clematis vitalba.
348
MOUNT VESUVIUS.
Cornus sanguinea.
Cistus saloifolius.
Datura stramonium.
Delphinium cardiopetalum.
Erythraea centaurium.
Genista tinctoria.
Geranium Robertianum.
Helleborus foetidus.
Helianthemum vulgare.
Hypericum perforatum.
Hyoscyamus albus.
Inula viscosa.
Melissa officinalis.
Mercurialis annua.
Origanum vulgare.
Orchis maculata.
Phytolacca decandra.
Plantago major.
Pistacia Lentiscus.
Psoralea bituminosa.
Rosa canina.
Ranunculus lanuginosus.
Reseda fruticulosa.
Ruscus aculeatus.
Saponaria officinalis.
Sambucus nigra.
Scabiosa columbaria.
Smilax aspera.
Thymus acynos.
Tamus communis.
Teucrium chamaedrys.
Tussilago farfara.
Urtica dioica.
Verbascum thapsus.
Viola odorata.
Vinca major.
The large number of forms of the lower orders of
plants is also remarkable, since it appears from the
"Flora Vesuviana" that there are 75 species of
Graminaceae, 69 of Mosses, 25 of Hepaticae, 33 of
Lichens, and 56 species of Fungi.
The following are the genera of the Grami-
naceae :
^Egylops.
Alopecurus.
Ampelodesmos.
Andropogon.
Anthoxanthum.
Arundo.
Avena.
Brachypodium.
Briza.
Bromus.
Calamagrostis.
Catapodium.
Chrysurus.
Corynephorus.
Cynodon.
Cynosurus.
Dactylis.
Digitaria.
Echinochloa.
Ehrharta.
Eragrostis,
Festuca.
THE FLORA OF VESUVIUS.
349
Gaudinia.
Holcus.
Hordeum.
Imperata.
Koeleria.
Lolium.
Melica.
Phleum.
Poa.
Psilurus.
The genera of the
Anacalypta.
Bartramia.
Bryum.
Coscinodon.
Cryphaea.
Dicranum.
Eucalypta.
Fabronia.
Fissideus.
Funaria.
Grimmia.
Gymnosternum.
Habrodon.
Hypnum.
Leptodon.
The genera of the
Anthoceros.
Corsinia,
Jungermannia.
Lunularia.
The genera of the
Cladonia.
Collema.
Lecidia.
Lepra.
Opegrapha.
Rottboelia,
Saccharum.
Sclerochloa.
Secale.
Sesleria.
Setaria.
Sorghum.
Trisetum.
Triticum.
Zea.
Musci are
Leskea.
Leucodon.
Muium.
Orthotrichum.
Phascum.
Philonotis.
Physcomitrium.
Pleuridium.
Pogonatum.
Pterigynandrum.
Pterogonium.
Trichostomum.
Webera.
Weisia.
Zygodon.
Hepaticae are
Marchantia.
Riccia.
Sphaerocarpus.
Targionia.
Lichens are
Parmelia.
Peltigera.
Ramalina.
Stereocaulon.
350
MOUNT VESUVIUS.
Ferns and Fungi are now so frequently sought
for and collected that the following lists of Vesuvian
species of these interesting and beautiful though
lowly plants, with their habitats and localities, may
prove useful to visitors to Naples who have time
and opportunity to explore the lower slopes and
immediate neighbourhood of the mountain. The
lists are compiled from the information given by
Signor Pasquale in the " Flora Vesuviana."
FERNS.
Adiantum capillus Veneris, Lin. In grottos, hollows, and steep
paths.
Aspidium aculeatum, Sw. Hedges, borders of woods, and most
commonly in hollows. Camaldoli, Canteroni, Somma, &c.
A. pallidum, Bory. Very rare in the Vesuvian district, once
found on the lavas near the Chapel of S. Vito, and in
shady valley bottoms, where it is very large. Somma,
S. Anastasia.
Asplenium Adiantum nigrum, Lin. Rocks and walls in shady
places, and also common in plantations.
,, var. acutum, Ten.
A. trichomanes, Lin. Stones, walls, and lavas in low-lying
places.
Ceterach officinarum, D.C. Stones and walls of vineyards, most
commonly attached to stones.
Cheilanthes odora, Sw. In the middle zone of Vesuvius, on
walls and rocks. Strada vecchia del Salvatore, S. Vito,
Tironi, and abundant in the Vallone di Tironcelli di
Torre del Greco.
Cystopteris fragilis, Guss. Once found on the moist northern face
of a rock on the summit of Monte Somma, near to the
Punta Nasione, not elsewhere, therefore very rare a
Vesuvius.
Grammitis leptophylla, Sw. Wayside mounds and shady fields,
and also common in cavities.
THE FLORA OF VESUVIUS. 351
Ophioglossum lusitanicum, Lin. In open seaside meadows at
Granatello di Portici, not elsewhere.
Polypodium vulgare, Lin. Most commonly on exposed walls.
Pteris aquilina, Lin. More abundant on the northern than on
the southern side of the mountain. Somma, Monticello a
Torre del Greco, &c.
FUNGI.
Agaricus segirita, Brig. Old Poplars and the Celtis Australis.
amethystseus, Bull. Chinks of rocks filled with earth,
Somma.
androsaceus, Lin. Withered leaves of the Olive after
autumnal rains, Portici, Resina, Somma.
auricolor, Brig. Grove by a villa at Portici.
Caesareus, Scop. Plantations, S. Anastasia.
campestris, var. edulis. Rich Olive groves, Tironcelli
di Torre del Greco.
., var. pratensis.
var. sylvicola. Open cultivated land.
fascicularis, Pers. Rich gardens, Royal Park of Portici.
fucatus, Fr. Cultivated land and meadows.
,, medusa, Brig. Orange groves.
melleus, Vahl. Common at the base of neglected and
uprooted trees.
var. vitis, Brig. Vines after the autumn rains.
var. citra, Pas. Trunks of Orange trees.
,, mucida, Brig. Almond husks, Portici.
oreades, Bolt. Common in grassy places.
ovoideus, Bull. Plantations, Somma, S. Anastasia.
,, var. leucosarcos, Brig.
,, ruber, Schceff. Chestnut woods.
rotula, Scop. Stalks of Nepeta, mint.
solitarius, Bull.
strobiloides, Brig. Trunks of trees and cultivated land.
Vesuvianus, Brig. Dry and open land, Portici.
Boletus edulis, Bull. Plantations, Somma, Ottajano, &c.
luridus, Schceff. Accompanies B. edulis, Somma.
352 MOUNT VESUVIUS.
Cantharellus cibarius, Fries. Plentiful in oak and chestnut
woods on Monte Somma, and also still more abundant in
groves at Barra, Royal Park of Portici, Parco di Bisig-
nano, &c.
Capuodium citri, Bakl. Foliage of Orange trees.
Clathrus cancellatus, Lin. Rich soils, Royal Parks of Portici
and La Favorita.
Clavaria flava, Pers. Groves with moisture, Royal Parks of
Portici and La Favorita, and the Parco Bisignano at Barra.
Cyathus olla, Pers. Cultivated land on dry litter.
Daedalea quercina, Pers. Base of tree trunks, wood yards of
Torre del Greco.
sepiaria, Fries. Ilex trees, Royal Park of Portici.
Exidia auricula, Judae. Dead trees.
Geastrum hygrometricum, Pers. Gravelly or sandy exposed
plantations, Bosco di Mauro, Camaldoli della Torre.
Graphiola Phoenicis, Poit. Portici.
Helvella esculenta, Pers. Common in vineyards, most abun-
dant about the vines, Somma, Resina, &c.
Hydnum repandum, Lin. Groves, Royal Park of Portici, Parco
di Bisignano.
Lycoperdon bovista, Lin. Sandy damp plantations, Mauro,
Torre del Greco.
Morchella esculenta, Pers. Cultivated ground.
conica, Pers. Cultivated ground.
semilibera, D.C. Vineyards, S. Anastasia.
Mcemaspora aurea, Fr. Dry trunks of Poplars, sunny spots of
Vesuvius, Portici, Bagnoli.
Oidium Tuckeri, Berckel. A pest of the vine, appeared first in
1851.
,, leuconium, Desm. Indian rose.
var. cucurbita, Gaspar
}, var. ranunculi, Gaspar.
erisyphoides, Fr.
Peziza aurantia, Pers. Both on the ground and on the trees,
Royal parks.
cerea, Sow.
hemisphaerica, Fl.
THE FLORA OF VESUVIUS. 353
Peziza vesiculosa, Grev. Decayed leaves of the ilex, Royal
Park of Portici.
Phallus impudicus, Lin. Richly cultivated lands.
Polyporus conchatus, Fries. Ilex trees in shady places, Royal
Park of Portici.
frondosus, Fries. Somma, S. Anastasia.
perennis, Fr. Very common, and always on the
ground in unproductive plantations.
ribis, D.C. Base of the Crataegi Azarolli (thorn),
common at the bottom of the Indian Rose trees,
Royal Parks of Portici.
squamosus, Fr. On the oldest Paper Mulberry trees
in groves.
versicolor, Fr. Common on dry trees.
Polysaccum pisocarpum, Fr. Sandy, sunny places amongst
underwood, Mauro, Torre del Greco.
Scleroderma corium, Graves. In sandy, exposed plantations
Mauro, Torre del Greco.
Sphseria typhina, Pers. On the end of the Dactylis hispanicse in
plantations, Camaldoli.
Uredo Candida, Pers. Shoots of Bursa pastoris.
leguminosarum. On several sorts of vegetables.
rosae, Pers. On the foliage of the Dog Rose.
symphyti, D.C. Borders of woods in dells.
2 A
APPENDIX.
LETTERS OF PLINY THE YOUNGER,
CONTAINING AN ACCOUNT OF THE ERUPTION OF A.D. 79. FROM "THE
LETTERS OF PLINY THE YOUNGER." BY JOHN EARL OF ORRERY.
PLINIUS C^ECILIUS SECUNDUS (CAIUS) to CORNELIUS TACITUS.
(Book VI., Epistle XVI.)
You are desirous that I should give you an account of the death
of my uncle, that you may be enabled to transmit it to posterity
with the greater truth. I return you thanks. I foresee that
his death when celebrated by you must procure eternal honour
to his name ; for although his fall was attended by the destruc-
tion of most beautiful territories, seeming, as it were, destined
to be remembered equally with those nations and cities who
perish by some memorable event ; although he had compiled
works both numerous and lasting, yet the immortality of your
writings will lengthen out the character which he has established
to himself. I consider it as a blessing to be possessed of endow-
ments which either qualify us for actions worthy of public record,
or inspire us to write anything worthy of public attention. But
I think those persons peculiarly favoured from heaven who obtain
both these qualifications. My uncle by his own works and by
yours may be numbered among these last, for which reason I
more readily undertake, and even wish for, the employment that
you enjoin.
356 APPENDIX.
He was at Misenum, where he had the command of a fleet
which was stationed there. On the ninth of the calends of Sept-
ember, about the seventh hour, my mother informed him that a
cloud appeared of unusual size and shape. After having reposed
himself in the sun, and used the cold bath he had tasted a slight
repast, and was returned to his studies he immediately called
for his sandals, and repaired to a higher point of view, from
whence he might more plainly discern this prodigy. The cloud
(the spectators could not distinguish at a distance from what
mountain it arose, but it was afterwards found to be Vesuvius)
advanced in height; nor can I give you a more just representa-
tion of it than the form of a pine-tree, for springing up in a
direct line, like a tall trunk, the branches were widely distended.
I believe, while the vapour was fresh, it more easily ascended ;
but when that vapour was wasted the cloud became loose, or,
perhaps oppressed by its own gravity, dilated itself into a
greater breadth. It sometimes appeared bright, and sometimes
black, or spotted, according to the quantity of earth and ashes
mixed with it. This was a surprising circumstance, and it de-
served, in the opinion of that learned man, to be inquired into
more exactly. He commanded a Liburnian galley to be pre-
pared for him, and made me an offer of accompanying him if I
pleased. I replied it was more agreeable to me to pursue my
studies ; and, as it happened, he had allotted me something at
that time to write. He went out of the house with his tablets
in his hand. The mariners at Retina being under consternation
at the approaching danger (for that village was situated under
the mountain, nor were there any means of escaping but by sea),
entreated him not to venture upon so hazardous an enterprise.
He continued firm to his resolution, and performed, with great
fortitude of mind, what he had at first undertaken from a thirst
of knowledge.
He commanded the galleys to put off from land, and em-
barked with a design not only to relieve the people of Retinse
but many others in distress, as the shore was interspersed with
a variety of pleasant villages. He sailed immediately to places
which were abandoned by other people, and boldly held his
course in the face of danger, so composed as to remark distinctly
LETTERS OF PLINY THE YOUNGER. 357
the appearance and progress of this dreadful calamity and to
digest and dictate those remarks.
He now found that the ashes beat into the ships much hotter
and in greater quantities ; and as he drew nearer, pumice-stones,
with black flints, burnt and torn up by the flames, broke in upon
them. And now the hasty ebb of the sea, and ruins tumbling
from the mountain, hindered their nearer approach to the shore.
Pausing a little upon this, whether he should not return back,
and instigated to it by the pilot, he cries out, " Fortune assists
the brave : let us make the best of our way to POMPONIANUS," who
was then at Stabiae, and lay opposite to a bay into which the sea,
creeping gently along that winding coast, insinuates itself.
Pomponianus, although not in immediate peril, yet seeing it
plainly and finding it approaching fast, was putting his baggage
on board some vessels, with a design of making his escape by
sea whenever the contrary wind should abate. My uncle,
arriving with a fair wind at this place, embraced, comforted, and
encouraged his trembling friend ; and to effect this, seemed him-
self to be under no kind of apprehension, but ordering his
servants to carry him to the bath, when he had bathed, went to
supper, either with a real cheerfulness, or, what is equally the
sign of a great mind, the appearance of it.
In the meantime flames issued from various parts of Mount
Vesuvius, and spreading wide and towering to a great height, made
a vast blaze, the glare and horror of which were still increased by
the gloominess of the night.
My uncle, to move the general fear, said that the blaze was
occasioned by the villages being on fire which were now deserted
by the country people. Then retiring to take his rest, he enjoyed
a sound sleep ; for being of a gross and corpulent habit of body,
he was heard to snore by those who waited upon him. The
court beyond which was his apartment by this time was so filled
with cinders and pumice-stones that had he continued any longer
in his room his passage from it would have been stopped up.
Being awakened therefore, he quitted his chamber and returned
to Pomponianus and the rest, whose fears had hindered them
from sleeping, and who had been upon the watch. They con-
sulted together whether it would be more advisable to keep
358 APPENDIX.
under the shelter of that roof or retire into the fields ; for the
house tottered to and fro, as if it had been shaken from the
foundation, by the frequent earthquakes. On the other hand,
they dreaded the stones, which, by being burnt into cinders,
although they fell with no great weight, yet fell in large quantities.
But after considering the different hazards which they run, the
advice of going out prevailed. In others, one kind of fear con-
quered another; in my uncle, one prudential reason only
succeeded to another.
They covered their heads with pillows bound with napkins :
this was their only defence against the shower of stones. And
now, when it was day everywhere else, they were surrounded
with darkness blacker and more dismal than night, which how-
ever was sometimes dispersed by several flashes and eruptions
from the mountain. They agreed to go farther in upon the
shore, and to look out from the neighbouring land if they might
venture to sea ; but the sea continued raging and tempestuous.
Then my uncle, laying himself down upon a cloth spread on the
ground, called twice for some water, and drank it ; but the flames
and a stench of sulphur which preceded them obliged others to
immediate flight and roused him. He raised himself upon his
feet, supported by two servants; but his respiration being
stopped, he immediately dropped down, stifled, as I imagine, by
the sulphur and grossness of the air. His lungs, as he was
narrow chested, were naturally weak and subject to inflam-
mations. When the light returned, which was not till the third
day after his death, his body was discovered, untouched by the
fire, without any visible hurt, in the dress in which he fell,
appearing rather like a person sleeping than like one who was
dead.
My mother and I still continued at Misenum. But this has
no relation to the history, nor did you desire any particulars
except those of my uncle's death. I shall therefore finish my
letter, adding only that I have sent you all the circumstances
which I either saw myself or were communicated to meat a time
when the truth of every single incident could be easily recol-
lected. From hence you will select such passages as you shall
think proper ; for it is one thing to write a letter, another to
LETTERS OF PLINY THE YOUNGER. 359
compile a history : nor is the difference less between writing to a
friend in particular than to the world in general. Farewell.
PLINIUS C.ECILIUS SECUNDUS (CAIUS) to CORNELIUS TACITUS.
(Book VI., Epistle XX.)
You tell me that my former letter, which at your own desire I
wrote to you concerning my uncle's death, has tempted you to
inquire not only into the terrors, but the distress I suffered
while I was left at Misenum, for with that particular my letter
concluded.
"I will restrain my tears, and briefly tell." When my uncle
was gone from us I employed my time (having stayed behind for
that purpose) at my studies. I bathed, went to supper, and had
a very imperfect and restless sleep. We had for several preceding
days together felt an earthquake, which, being common in
Campania, did not much alarm us ; but the shocks were so
violent this particular night that all things around us were not
only moved, but seemed upon the brink of destruction. My
mother hastened into my bed-chamber, at the moment of time
when I was rising with an intention to awaken her if I had found
her sleeping. We retired into a little court which lay between
the house and the sea. I am in doubt whether my conduct
ought to be called fortitude or thoughtlessness upon this occa-
sion, for I was then but eighteen years of age. I called for a
" Livy" and read it as if I had been quite at ease : and, in the
manner I had begun, went so far as to select passages from that
author.
A friend of my uncle's, who was lately come from Spain on
purpose to see him, finding my mother and me sitting thus
together, and taking notice that I was reading, reproved the
patience of her temper and the indifference of mine. However,
I still continued intent upon my book. It was now six o'clock
in the morning, yet there was but a faint and glimmering light.
The house shook violently j and though we were in an open
court, yet, as it was very narrow and built almost all round, we
were certainly in great danger. We then thought it expedient
360 APPENDIX.
to eave the town : the people, distracted with fears, followed us,
and (such is the nature of fear which embraces, as most
prudential any other dictate in preference to its own) they
pressed upon us and drove us forward. When we were out of
reach of the buildings we stopped ; our astonishment was great,
nor were our apprehensions less, for the carriages which we had
ordered out of the town were so violently shaken from side to
side, although upon plain ground, that they could not be kept in
their places even when propped by heavy stones. The sea, too,
seemed to be forced back upon itself, repelled as it were by the
strong concussions of the earth. It is certain that the shore was
greatly widened, and many sea-animals were left upon the strand.
On the land side a dark and horrible cloud, charged with
combustible matter, suddenly broke and shot forth a long trail
of fire, in the nature of lightning, but in larger flashes. Then
my uncle's friend, the same who came out of Spain, said to us,
with great vehemence and eagerness, " If your brother and your
uncle be still living, his wishes are employed for your safety. If
he has lost his life, he was desirous yours might be saved. Why
then will you not immediately leave this place ? " We answered
that we were not so solicitous for our own as for my uncle's
preservation. He then hastily withdrew, running with the utmost
expedition from danger. Not long after, the cloud descending
covered the whole bay, and we could no longer see the island of
Caprea or the promontory of Misenum. My mother now began
to beseech, advise, and command me to make my escape in
any manner I could. ' She observed that as I was young I might
easily take my flight ; but that she, who was in years and less
active, could patiently resign herself to death, in case she was
not the occasion of my destruction. My answer was, " I will
never attempt at safety if we are not together." And then,
leading her by the hand, I assisted her to go faster ; she yielded
with regret, still angry at herself for delaying me.
The ashes now fell upon us ; however, in no great quantities.
I looked back. A thick dark vapour just behind us rolled along
the ground like a torrent, and followed us. I then said, " Let us
turn out of this road, whilst we can see our way, lest the people
who crowd after us trample us to death." We had scarce
LETTERS OF PLINY THE YOUNGER. 361
considered what was to be done, when we were surrounded with
darkness, not like the darkness of a cloudy night or when the
moon disappears, but such as is in a close room when all light
is excluded. You might have heard the shrieks of women,
the moans of infants, and the outcries of men. Some were
calling for their parents, some for their children, some for their
wives : their voices only made them known to each other. Some
bewailed their own fate ; others the fate of their relations.
There were some who, even from a fear of death, prayed to
die. Many paid their adorations to the gods ; but the greater
number were of opinion that the gods no longer existed,
and that this night was the final and eternal period of the
world. There were others who magnified the real dangers by
imaginary and false terrors. Some affirmed that Misenum was
burnt to the ground. The report, although not true, gained credit.
A little gleam of light now appeared. It was not daylight,
but a forewarning of the approach of some fiery vapour which,
however, discharged itself at a distance from us. Darkness
immediately succeeded. Then ashes poured down upon us in
large quantities, and heavy, which obliged us frequently to rise
and brush them off, otherwise we had been smothered or pressed
to death by their weight.
I might boast that not one sigh or timorous word broke from
me through all this distress, had I not fortified myself with one
great consolation a miserable one indeed that all nature was
perishing with me.
At last this darkness, which now was drawn into the thinness
of a cloud or of smoke, went off; true day appeared. The sun
shone forth, but pale, as at the time of an eclipse. All objects
that offered themselves to our sight (which was yet so weak that
we could scarce bear the return of light) were changed, and
covered with ashes as thick as snow. At our return to Misenum,
after having refreshed ourselves, we remained in that suspense
and doubt of mind which hope and fear inspire : fear indeed was
most prevalent ; for the earthquake still continued, and several
enthusiasts, by dreadful prophecies, increased their own fears
and the fears of others. But although we had undergone many
dangers, and dreaded still more, yet we could not be persuaded to
362 APPENDIX.
quit the town till we had received some intelligence concerning
my uncle.
You will read this account without any intention of making
it a part of your history, of which it is by no means worthy ;
and you must blame yourself for requiring it from me, if you
think it not worthy of a letter. Farewell.
THE FORMATION OF MONTE NUOVO
IN 1538.
FOUR CONTEMPORARY NARRATIVES.
I.
BY MARCO ANTONIO DELLI FALCONI.*
DeV Incendio di Puzzuolo^ Marco Antonio delli Falconi alV Illns-
trissima Signora Marchessa della Padula ml MDXXXVIII.
FIRST, then, will I relate simply and exactly the operations of
nature, of which I was either myself an eye-witness, or as they
were related to me by those who had been witnesses of them.
It is now two years that there have been frequent earthquakes at
Puzzuolo, at Naples, and the neighbouring parts ; on the day and
in the night before the appearance of this eruption, above twenty
shocks, great and small, were felt at the above-mentioned places.
The eruption made its appearance the 2Qth September, 1538, the
feast of St. Michael the Angel ; it was on a Sunday, about an
hour in the night ; and as I have been informed, they began to
see on that spot, between the hot baths or sweating-rooms and
Tripergoli, flames of fire, which first made their appearance at
the baths, then extended towards Tripergoli, and fixing in the
little valley that lies between the Monte Barbaro and the hillock
called del Pericolo (which was the road to the lake of Avernus
and the baths), in a short time the fire increased to such a
degree, that it burst open the earth in this place, and threw up
so great a quantity of ashes and pumice-stones mixed with water,
as covered the whole country ; and in Naples a shower of these
* From the " Campi Phlegrsei," by Sir William Hamilton, K.B., F.R.S. Page 70.
FORMATION OF MONTE NUOVO. 363
ashes and water fell great part of the night. The next morning,
which was Monday, and the last of the month, the poor
inhabitants of Puzzuolo, struck with so horrible a sight, quitted
their habitations, covered with that muddy and black shower,
which continued in that country the whole day, flying death, but
with faces painted with its colours ; some with their children
in their arms, some with sacks full of their goods ; others leading
an ass, loaded with their frightened family, towards Naples ;
others carrying quantities of birds of various sorts that had fallen
dead at the time the eruption began ; others again with fish
which they had found, and were to be met with in plenty upon
the shore, the sea having been at that time considerably dried up.
Don Petro di Toledo, Viceroy of the kingdom, with many
gentlemen, went to see so wonderful an appearance ; I also,
having met with the most honourable and incomparable gentle-
man, Signer Fabrizio Moramaldo, on the road, went and saw the
eruption and the many wonderful effects of it. The sea towards
Baia had retired a considerable way ; though, from the quantity
of ashes and broken pumice-stones thrown up by the eruption,
it appeared almost totally dry. I saw likewise two springs in
those lately discovered ruins, one before the house that was the
Queen's, of hot and salt water ; the other of fresh and cold
water, on the shore, about 250 paces nearer to the eruption :
some say that, still nearer to the spot where the eruption
happened, a stream of fresh water issued forth like a little river.
Turning towards the place of the eruption, you saw mountains of
smoke, part of which was very black and part very white, rise up
to a great height ; and in the midst of the smoke at times, deep-
coloured flames burst forth with huge stones and ashes, and you
heard a noise like the discharge of a number of great artillery.
It appeared to me as if Typheus and Enceladus from Ischia and
Etna with innumerable giants, or those from the Campi Phlaegrei
(which, according to the opinions of some, were situated in this
neighbourhood) were come to wage war again with Jupiter, The
natural historians may perhaps reasonably say that the wise poets
meant no more by giants than exhalations shut up in the bowels
of the earth, which, not finding a free passage, open one by their
own force and impulse, and form mountains, as those which
364 APPENDIX.
occasioned this eruption have been seen to do ; and methought
I saw those torrents of burning smoke that Pindar describes in
an eruption of Etna, now called Mon Gibello, in Sicily; in
imitation of which, as some say, Virgil wrote these lines :
" Ipse sed horrificis juxta tonat JEtna. minis," &c.
After the stones and ashes with clouds of thick smoke had
been sent up, by the impulse of the fire and windy exhalation
(as you see in a great cauldron that boils) into the middle region
of the air, overcome by their own natural weight, when from
distance the strength they had received from impulse was spent,
rejected likewise by the cold and unfriendly region, you saw them
fall thick, and by degrees the condensed smoke clear away,
raining ashes with water and stones of different sizes, according
to the distance from the place ; then by degrees, with the same
noise and smoke, it threw out stones and ashes again, and so on by
fits. This continued two days and nights, when the smoke and
force of the fire began to abate. The fourth day, which was Thursday,
at 2 2 o'clock, there was so great an eruption, that as I was in the
Gulf of Puzzoli, coming from Ischia, and not far from Misenum,
I saw in a short time many columns of smoke shoot up, with
the most terrible noise I ever heard, and bending over the sea,
came near our boat, which was four miles or more from the
place of their birth ; and the quantity of ashes, stones, and smoke
seemed as if it would cover the whole earth and sea. Stones
great and small, and ashes more or less, according to the impulse
of the fire and exhalations, began to fall, so that a great part of
this country was covered with ashes ; and many that have seen it
say they reached the vale of Diana, and some parts of Calabria,
which are more than 150 miles from Puzzoli. The Friday and
Sunday nothing but a little smoke appeared ; so that many taking
courage went upon the spot, and say that with the stones and
ashes thrown up a mountain has been formed in that valley, not
less than three miles in circumference, and almost as high as the
Monte Barbaro, which is near it, covering the Canettaria, the
castle of Tripergoli, all those buildings and the greatest part of
the baths that were about them ; extending south towards the
sea, north as far the lake of Avernus, west to the Sudatory, and
FORMATION OF MONTE NUOVO. 365
joining east to the foot of the Monte Barbaro ; so that this place
has changed its form and face in such a manner as not to be
known again : a thing almost incredible to those that have not
seen it, that in so short a time so considerable a mountain could
have been formed.
On its summit there is a mouth in the form of a cup, which may
be a quarter of a mile in circumference, though some say it is as
large as our market-place at Naples, from which there issues a
constant smoke ; and though I have seen it only at a distance, it
appears very great. The Sunday following, which was the
6th of October, many people going to see this phenomenon,
and some having ascended half the mountain, others more,
about 22 o'clock there happened so sudden and horrid
an eruption, with so great a smoke, that many of these
people were stifled, some of which could never be found.
I have been told that the number of the dead or lost
amounted to twenty-four. From that time to this, nothing
remarkable happened ; it seems as if the eruption returned
periodically like the ague or gout. I believe henceforward it will
not have such force, though the eruption of the Sunday was
accompanied with showers of ashes and water which fell at
Naples, and were seen to extend as far as the mountain of
Somma, called Vesuvius by the ancients ; and as I have often
remarked the clouds of smoke proceeding from the eruption,
moved in a direct line towards that mountain, as if these places
had a correspondence and connection one with the other. In
the night many beams and columns of fire were seen to proceed
from this eruption, and some like flashes of lightning.
We have, then, many circumstances for our observation the
earthquakes, the eruption, the drying up of the sea, the quantity
of dead fish and birds, the birth of springs, the showers of ashes
with water and without water, the innumerable trees in that whole
country, as far as the grotto of Lucullus, torn from their roots,
thrown down, and covered with ashes, that it gave one pain to
see them ; and as all these effects were produced by the same
cause that produces earthquakes, let us first inquire how earth-
quakes are produced, and from thence we may easily comprehend
the cause of the above-mentioned events.
366 APPENDIX.
II.
BY PIETRO GIACOMO DI TOLEDO.*
THE account of the formation of the Monte Nuovo, by
Pietro Giacomo di Toledo, is given in a dialogue between the
feigned personages of Peregrino and Secessano, the former of
which says :
" It is now two years that this province of Campagna has been
afflicted with earthquakes, the country about Puzzuoli much more
so than any other parts; but the 2yth and 28th of the month of
September last, the earthquakes did not cease day or night in the
above-mentioned city of Puzzuoli ; that plain which lies between
the lake of Averno, the Monte Barbaro, and the sea was raised a
little, and many cracks were made in it, from some of which
issued water ; and at the same time the sea, which was very near
the plain, dried up about two hundred paces, so that the fish
were left on the sand, a prey to the inhabitants of Puzzuoli. At
last, on the 2 9th of the said month, about two hours in the night,
the earth opened near the lake, and discovered a horrid mouth,
from which were vomited furiously smoke, fire, stones, and mud
composed of ashes ; making at the time of its opening a noise
like very loud thunder : the fire that issued from this mouth went
towards the walls of the unfortunate city j the smoke was partly
black and partly white ; the black was darker than darkness
itself, and the white was like the whitest cotton : these smokes
rising in the air seemed as if they would touch the vault of
heaven ; the stones that followed were, by the devouring flames,
converted to pumice, the size of which (of some I say ?) were
much larger than an ox.
" The flames went about as high as a cross-bow can carry, and
then fell down, sometimes on the edge, and sometimes into the
mouth itself. It is very true that many in going up could not be
seen on account of the dark smoke ; but when they returned
from the smoky heat, they showed plainly where they had been
by their strong smell of fetid sulphur, just like stones that have
* From the " Campi Phlegnei," p. 75.
FORMATION OF MONTE NUOVO. 367
been thrown out of a mortar, and have passed through the smoke
of inflamed gunpowder. The mud was of the colour of ashes,
and at first very liquid, then by degrees less so ; and in such
quantities that in less than twelve hours, with the help of the
above-mentioned stones, a mountain was raised of a thousand
paces in height. Not only Puzzuoli and the neighbouring
country was full of this mud, but the city of Naples also, the
beauty of whose palaces was, in a great measure, spoiled by it.
" The ashes were carried as far as Calabria by the force of the
winds, burning up in their passage the grass and high trees,
many of which were borne down by the weight of them. An
infinity of birds also, and numberless animals of various kinds,
covered with this sulphurous mud, gave themselves up a prey to
man.
" Now, this eruption lasted two nights and two days without
intermission, though it is true, not always with the same force,
but more or less : when it was at its greatest height, even at
Naples you heard a noise or thundering like heavy artillery when
two armies are engaged. The third day the eruption ceased, so
that the mountain made its appearance uncovered, to the no
small astonishment of every one who saw it. On this day, when
I went up with many people to the top of this mountain, I saw
down into its mouth, which was a round concavity of about a
quarter of a mile in circumference, in the middle of which the
stones that had fallen were boiling up, just as in a great cauldron
of water that boils on the fire.
" The fourth day it began to throw up again, and the seventh
much more, but still with less violence than the first night ; it
was at this time that many people who were, unfortunately, on the
mountain were either suddenly covered with ashes, smothered
with smoke, or knocked down with stones, burnt by the flame,
and left dead on the spot. The smoke continues to this day,*
and you often see in the night-time fire in the midst of it.
* The cup or crater on the top of the new mountain is now (1776) covered
with shrubs, but I discovered at the bottom of it in the year 1 770, amidst the
bushes, a small hole, which exhales a constant hot and damp vapour, just
such as proceeds from boiling water, and with as little smell : the drops of
this steam hang upon the neighbouring bushes. Sir W. Hamilton.
APPENDIX.
Finally, to complete the history of this unforeseen event, in
many parts of the new-made mountain, sulphur begins to be
generated."
Giacomo di Toledo, towards the end of his dissertation, says
that the Lake of Avernus had a communication with the sea
before the time of the eruption.
III.
BY FRANCESCO DEL NERO.*
A Letter to Niccolo del Benino on the Earthquake at Pozzuoli, by
which the Monte Nuovo was formed in 1538.
I AM not aware whether you have ever been at Pozzolo. Six bow-
shots from the town, there commences a plain about half a mile
broad, directly before Monte Barbaro, which enclosed a part of
this bay ; but now the plain extends over the whole of it, a cir-
cumstance which, although a natural event, nevertheless is very
remarkable, and worthy of being accurately inquired into.
Aristotle, in his 2 Meteor, mentions two similar events as
worthy of record the one in Pontus, the other in the island of
Sagre.
On the 28th of September, at mid-day, the sea-bottom near
Pozzolo became dry over an extent of 600 braccie (1,300 yards),
so that the inhabitants of the town carried off waggon-loads of
fish left on the dry land. About eight o'clock in the morning of
the 29th, the earth sank down about two canne (13^ feet) in that
part where there is now the volcanic orifice, and there issued
* From a communication by Leonard Horner in the Quarterly Journal of
the Geological Society, vol. iii., part ii., page 19, and previously published in
German in the Neues Jahrbuch fur Geologic, of Leonhard and Brown, of
1846. The original MS., in Italian, was discovered in a volume in the
library of the Marquis Capponi, but formerly belonged, Francesco Palermo
says, to the family of Roffia di Samminiato.
FORMATION OF MONTE NUOVO. 369
forth a small stream of very cold water, as we were told by some
persons we interrogated, but others stated that it was tepid, and
somewhat sulphurous. As all the people whom we spoke to
were persons worthy of credit, I am of opinion that they all spoke
the truth, and that the water was at first cold and afterwards
tepid. At noon on the same day, the earth began to swell up, so
that the ground in the same place where it had sunk down
13 J feet, by eight o'clock, or thereabouts, was as high as Monte
Ruosi that is, it was as high as that hill is where the little tower
stands upon it ; and about this time fire issued forth and formed
the great gulf with such a force, noise, and shining light, that I,
who was standing in my garden, was seized with great terror.
Forty minutes afterwards, although unwell, I got upon a neigh-
bouring height, from which I saw all that took place, and, by my
troth, it was a splendid fire, that threw up for a long time much
earth and many stones. They fell back again all round the gulf,
so that towards the sea they formed a heap in the form of a
crossbow, the bow being a mile and a half, the arrow two-thirds
of a mile in dimension. Towards Pozzolo, it has formed a hill
nearly of the height of Monte Morello, and for a distance of
seventy miles round, the earth and the trees are covered with
ashes. On my own estate I have neither a leaf on the trees nor a
blade of grass. In the neighbourhood of Pozzolo, to a distance
of six miles, there is not a tree standing which has not its
branches broken, and frequently it is not possible to say that there
has been a tree on the spot. The ashes that fell here were
also soft, sulphurous, and heavy. They not only threw down the
trees, but an immense number of birds, hares, and smaller
animals were killed. I was yesterday obliged to return by sea to
Pozzolo, my companion being Messer Cacco de Loffredo, the
agent of Messer Pavolo Antonio.
Many men were looking on, and with amazement. Nothing
was to be seen there but the hill itself. When I say nothing, I
mean in comparison with what took place the preceding night,
when the earth swelled up that is, at the time I came to the
place. And as there was no one from Naples, and few capable of
describing it who saw the fire on that night, there is no one but
myself who can make a report upon it. Since the night when the
2 B
APPENDIX.
troops left the place, nothing remarkable has occurred, or that
can in the least be compared with that which happened before. I
will make the event clear to you by an example.
Imagine the fiery gulf to be the Castle of St. Angelo, filled with
lighted rockets. There can be no doubt that these rockets,
although they would shoot right up into the air, would, in coming
down, change their direction, and in place of falling back into the
castle from which they were sent up, would fall into the Tiber
and on the neighbouring meadows. Imagine, further, that the
cases of the rockets fell in such numbers into the Tiber as to fill
up its channel, that they lay 27! feet thick, and that they fell in
such quantities on the meadows as to form a hill, extending from
Messer Bindo's vineyard as far as Monte Mori, and with a
height little less than that of Santo Silvestro, near Tusculum ;
towards St. Peter's we shall suppose that few fell, because the
wind blowing from the west carried them in another direction.
Just so was it with the fiery gulf, from which there was shot up
into the air, to a height which I estimate at a mile and a half,
masses of earth and stones as large as an ox. They fell down
near the gulf in a semicircle of from one to three bow-shots in
diameter, and in this way they filled up this part of the v sea, and
formed the above-mentioned hill. When the earth and stones
fell, they were quite dry. The same fire, however, threw out at
the same time a light earth and smaller stones to a much greater
height, and these fell down in a soft muddy state an evident
proof that they had reached the higher regions, and that the
vapours, like other vapours which rise to the same height, were
converted into water. This was the cause that the ashes fell in
a softened state, mixed with a small quantity of water, although
the sky was clear.
I could now state the natural causes of the drying up of the
sea-bottom, and the mode by which that drying-up by means of
the little stream, first of cold and afterwards of tepid water, was
brought about ; I could also state the causes of the sinking of
the ground and the elevation of it that followed, and finally the
causes of the outburst of the fire, and of the earthquakes which
were felt here ten days before, and so frequent as ten in one hour,
which unceasingly shook the earth at Pozzolo, but entirely ceased
FORMATION OF MONTE NUOVO. 371
both here and there as soon as the eruption took place. But as
I know that Messer Simone Porzio, who possesses a thorough
knowledge of the subject, has written to the Viceroy and to the
highly distinguished Farnese, I will not seem to be decking my-
self with the merits of others. Pozzolo is quite deserted by the
inhabitants, and you would not know the place of the sea here,
for it would appear like a ploughed field, and it has a covering of
what is here called rapillo^ about half a palm thick (i \ inch),
which is so light as to swim on water. But what is to me incon-
ceivable is the mass of stones and ashes that was poured forth
from this gulf; and when we take into account the quantity that
must have fallen into the sea, and upon the newly formed hill,
and think of the ashes which, as you know, were scattered in all
directions, and are the remains of burnt materials, and if we
imagine all these brought together in one place, what an immense
mountain they would form ! I spoke this morning with a man
from Eboli, a town forty-five miles distant from the fire. He told
me that the ashes had fallen in that place, that the fire had
extended ten miles underground, and that this was the cause of
the extraordinary quantity of earth that had been thrown into the
air. Had this eruption not happened, the fire must have extended
much further underground ; and God grant that the vault may
not spread out under Naples ! Only yesterday, as we returned to
Pozzolo by land, we saw two fire-gulfs just opened in the ground
three miles from Naples. Many opinions have been expressed
by very able men, and some think that Naples is in great danger.
There have been some processions, and innumerable very deep
wells have been sunk between Naples and Pozzolo, " as it were
to bleed the fire." Viewed as an omen, the event is thought to
forebode, as the rockets were driven from west to east, that the
Emperor is going to attack the Turks.
372 APPENDIX.
IV.
BY SIMONE PORZIO.*
De Conflagratione Agri Puteolani Simoni Portii Neapolitam
Epistola
To the Most Illustrious Don Pedro de Toledo, Prince of Villafranca,
Viceroy of the Kingdom of Naples, Generalissimo of the
Army.
THERE are many things which, although proceeding from
natural causes, nevertheless because they occur rarely, appear to
be portentous marvels, and especially so to those who only hear
of the events without having actually witnessed the phenomena.
Wherefore, since nothing untrue may be related to you concerning
that which not long ago (A.D. 1538) happened in the plain of
Pozzuoli, and feeling under an obligation to state to you my
* This letter of the eminent Neapolitan " philosofo " of the sixteenth
century, in its first printed form, is exceedingly rare, but a copy is preserved
in the Biblioteca Nazionale di Napoli. The epistle was, however, with
thirty-four corrections by its author, included in his works (Simoni Portii
Opera, Flor. 1548-1553), and so published in the year 1551.
An edition, also in Latin, was published in Naples in 1817. [I Tre
Rarissimi Opuscoli di Simone Porzio, di Girolano Borgia, e di
Marcantonio delli Falconi, scritti in occasione della Celebre Eruzione
awenuta in Pozzuoli nell'[anno 1538, colle Memorie Storiche de' suddetti
autore, Raccotte da Lorenzo Giustiniani, Bibliotecario della Real Biblioteca
Borbonica, e Regio Revisore. Napoli, MDCCCXVILJ
The letter was translated into Italian by Giuseppe Amanduni, and
published in Naples in 1878, with some interesting prefatory remarks.
[Dell' Incendio dell' Agro Puteolano Epistola di Simone Porzio al Vicere
d. Pietro di Toledo, Traduzione critica di Giuseppe Amenduni, Napoli, Tipo-
grafia dell' Accademia Reale delle Scienza, Diretta da Michele de Rubertis,
1878.]
Simone Porzio's letter is now for b the first time printed in English. To
make this version reliable, a translation of Amanduni's edition by myself
has been compared with two independent translations by accomplished Latin
scholars, the Rev. F. A. Walker, D.D., and Prof. Langhorne Orchard, M.A.,
who very kindly at my request separately translated the edition of 1551, and
improvements so suggested have been adopted. J. L. L.
FORMATION OF MONTE NUOVO. 373
experiences, and especially those which relate to our studies, I
have resolved to narrate with brevity the whole matter, and to
state to you its causes, as is properly the part of a philosopher,
under the impression that I shall not be doing what is distasteful
to you.
You indeed witnessed the conflagration, and had in your view
the whole plain of Pozzuoli. This district is near the sea, and
abounds with warm waters and sulphurous mud, and has moun-
tains on its northern and on its southern side, which extend quite
down to the sea, and which have at their termination many large
caverns in which there is a great force of heat. The region was
disturbed for about two years by violent earthquakes, so that no
house remained uninjured, and there was no building which was
not threatened with sure and speedy destruction. And truly, on
the 26th and 2yth of September, the earth was continually, both
by day and by night, thoroughly agitated ; the sea receded for
about 200 paces, and on its bed not only did the inhabitants take
an immense quantity of fish, but springs of fresh-water were also
seen to gush forth. At length, on the 28th, the large tract of
land which lay between the foot of the mountain, called by the
inhabitants of the vicinity Barbaro, and the sea in the neighbour-
hood of Avernus, was seen to rise and take the form of a newly
produced mountain. And on the same day, at the second hour
of the night, this mound of earth opened like a mouth, with a
great roaring, vomiting much fire and pumice and stones, with
such a great abundance of offensive ashes as covered the buildings
still remaining standing in Pozzuoli, quite covering over the
herbage, breaking the trees, and reducing to ashes the hanging
vintage as far as the sixth milestone, and killing birds and some
quadrupeds, while the inhabitants of Pozzuoli, flying amidst the
gloom along with their children and wives, and made their way to
Naples with groans, and cries and tears.
The ashes, by the force of the explosion, were ejected to a
distance of about sixty thousand paces; and what may seem more
marvellous, those that fell near the centre of disturbance were
dry, while those falling at a distance were muddy and wet. But
what was most wonderful of all, the hill at the centre of disturb-
ance was seen to have been piled up in a single night with
374
APPENDIX.
pumice and cinders to a height of more than a thousand paces;
in which indeed were many vents, of which now only two remain,
one near the shore going on to Avernus, the other in the middle
of the mount itself. As to Avernus, a large portion is covered
with ashes. Those baths, celebrated through so many centuries,
and which used to give health to so many invalids, lie buried in
ashes. And this conflagration continues, though with some inter-
ruptions, to this day, of which, in accordance with my promise, I
will endeavour to explain the proper natural causes.
Some things that happen in nature rarely do not proceed from
a single cause, since some are without a definite origin, as those
that arise haphazard and by chance ; but there are others which,
although of rare occurrence, are not without a particular cause.
Of this kind are eclipses, fiery exhalations, and earthquakes.
But this eruption of which we are treating having occurred after
violent earthquakes, something ought to be first said respecting
these earthquakes, after which the conclusions concerning the
opening of the earth may be more conveniently explained.
The sun acting on the damp earth draws out a certain sort of
fume which, if very dense and moist, is called vapour, that pro-
duces watery things, as clouds, the rains, and perennial waters ;
but if drier or that which Aristotle called exhalations, it produces
things which are dry and arid. This fume generated in the caves
and caverns of the earth is either all discharged, or all confined,
or it is partly emitted and partly retained. If it all escapes it
impels the air with its force and produces winds ; if it is alto-
gether retained, either by the passages and fissures of the earth,
or because of the solidity of the dry land, or from frequent rains
which obstruct the earth's pores, or from the neighbouring sea, which
as much by its cold as by its waves drives it back again into the
interior of the earth, then being fiery and restrained by force,
and seeking a vent with swiftest motion, it shakes the earth and
causes violent earthquakes. But if part only escapes and part is
retained under the earth, there are less violent earthquakes, since
the force is diminished; the portion which is released moves
the air, and that which is retained agitates the earth.
Neither should those higher causes be omitted which Astro-
logers adduce, namely, the conjunction of stars and the eclipses
FORMATION OF MONTE NUOVO. 375
of the sun and moon. All these have occurred during these
times of which we speak. In the first place, there was the con-
junction of Mars with Saturn in Virgo, in the last solstice, which
usually causes exhalations and excites earthquakes. There were,
moreover, not only in this, but also in the previous year an eclipse
of the moon and appearances of comets.
There are also to be taken into consideration the seasons
most favourable for the production of earthquakes, and which are
the spring and the autumn, in which occur an increase of moisture
and heat, whence the sun generates vapours and exhalations the
production of which is impeded in the winter by much cold, and
in the summer by much heat.
Such are some of the causes that are considered by philoso-
phers capable of producing earthquakes and determining the
seasons of their occurrence. To them should be added the fact
that during last summer there were copious rains, giving the
season more the character of autumn than of summer ; whence it is
not to be wondered at that our district has suffered from frequent
earthquakes, since the season furnished more plentiful and suitable
material wherewith the sun could produce exhalations.
The dawn is, moreover, the time favourable for earthquakes
because the sun returning to us drives away the cold from the
earth, and this obstructs the outlets of the exhalations, which
then moving with great force and rapidity, shake the earth.
But still more favourable is noonday, when the sun dissipates
the upper exhalations, and draws up those below which shake
the earth j and thus the surface may be undisturbed, while the
interior is moved.
But the locality that is especially liable to be shaken by
earthquakes is one that has the following natural conditions :
proximity to the sea, and a soil, like a sponge, that has many
Openings and caverns ; and these conditions characterising the
Plain of Pozzuoli, frequent earthquakes are here occasioned.
Numerous exhalations are therefore gathered together in the deep
places of the earth, and this accumulation seeking an outlet,
approaches the place whence it can escape, and disturbs the
more those places adjoining the vent. This was the cause of
the earthquakes being continuous in those days. Finally, these
376 APPENDIX.
exhalations with the most rapid motion inflamed the bitumenous
and fire-affected matter in the caverns of the earth, which, with a
great explosion, was completely ejected. These are, therefore,
the causes which have produced the opening. But many
phenomena having preceded the formation of this gulf and
opening of the earth, and accompanied it, it will not be foreign
to my purpose to particularly examine into their causes.
Firstly, the sea retreated, truly, from no other reason than
because the exhalations, seeking a vent, rarified the ground,
which, as though thirsty, absorbed the water through its pores,
whence it happened that the part first washed by the sea became
dry, and the shore was raised in height by the ashes and
lapilli.
Again, there had been previously a spring of cold water. This
was because the water was compressed by the exhalations rising
out of the earth, so poured out more abundantly, from the earth
yielding to the outrush of the water, and the water falling to the
bottom was quickly raised again by the force of the exhalations
seeking escape.
Some persons are in doubt as to whether the fire pre-existed
in the bitumen, or whether it was not rather kindled by the
action of the exhalations. Our reply is that the matters were
previously burning, since the waters that were forced from them
and issued at the surface were hot, but that the fire was much
increased from the impetus and the force of the ejections making
their escape.
Others wonder why it is that smoke is not constantly issuing,
and the roaring is not constantly heard, since during certain
intervals of time all seems to be quiet. The cause of this is that
at first the mouth of the opening was small, and the flames issuing
from the deep interior of the earth, being ready and near the
mouth of the gulf, were ejected with great roaring, then afterwards,
while the other part of the exhalations was moving from the
depths of the earth towards the mouth of the gulf, the noise could
not be heard by persons at a distance. It is true that the ashes,
after having ascended, fell drier in neighbouring places, and were
moist at a distance. Of this phenomenon I believe the cause to
be that the ashes ascending are made drier by the burning heat,
FORMATION OF MONTE NUOVO. 377
but when not being able to fall for a long distance, not before
reaching the middle region of the atmosphere, they are there
made denser and more humid, and then they fall.
But the less educated inquire how long this eruption will con-
tinue. To such persons my reply is that I am not able to tell,
nor can it be told until the matter on which the fire is fed is
weighed. Certainly, whoever compares the fire of Vesuvius with
this of Pozzuoli will easily understand that this one will not have a
less duration, since it is a large area, indeed the whole district of
Pozzuoli, full of sulphurous bitumen, the material specially
adapted for fire, and such as does not quickly become exhausted.
Some anxiously inquire what these things prognosticate. I
say truly, along with the Peripatetics, that there is no certainty in
any foreboding, although Cicero gives great heed to, and also
draws much from, portents. Nevertheless I affirm what I have
contended elsewhere, that nothing certain is to be expected from
these events except dryness, usually followed by dearth, and also
pestilence, from learning what happened many centuries ago.
The astrologers say that intestine wars are to follow, since even
as bodies burn from former defilements, so is the soul of man
more subject to anger. But all these things are consequent upon
dryness, as has been shown in my books on Meteorology. If
there are those who think differently, I will not refuse at any time
to be taught by their arguments.
Aristotle has left it on record that similar things happened in
Heraclea, a city of Pontus, and in an island sacred to ^Eolus.
In the second year of the reign of the Emperor Titus, Mount
Vesuvius from another vortex ejected a great quantity of fire.
Similarly in the reigns of the Emperors Caesar Augustus, Titus,
and Antoninus Quartus, and Diocletian, and also in the consulates
of L. Marzio and Sextus Julius, it has been recorded that such a
gulf opened and such conflagrations occurred in the Island of
Ischia, the place where so many fires were burning in the year
of our salvation 1300, that almost the whole island was on fire.
The cause of this will, however, be explained on another
occasion.
What I have here stated, I have thought it my duty to
write, O my Msecenas [patron], lest the soothsayers and
378 APPENDIX.
interpreters of dreams and the common astrologers explain
otherwise those phenomena that take place under the guidance
of Nature.
CATALOGUE OF RECORDED
ERUPTIONS.
FROM the renewal of the activity of Vesuvius in A.D. 79 to the
present time, upwards of eighty eruptions have been recorded, of
which thirteen have been accounted great or paroxysmal eruptions.
The following table gives the dates of the various historic
eruptions. But the word " eruption " requires explanation, since it
is now seen to have rather a relative than a specific meaning.
Judging from the observations of modern times, as previously
stated, the volcano has often, and sometimes for long periods^
been in a state of little developed eruption. Who shall say that
this has not been the case in long-back times, when there were
no such careful recorders as recent days have furnished ?
ERUPTIONS OF MOUNT VESUVIUS.
A.D.
A.D.
*79- Pompeii, Herculaneum, and
1660.
Stabia destroyed.
1676. Perpendicular column of lava.
*20 3 .
1682.
*472.
1685.
* 5 I2.
1689.
*68 5 .
1694. March 12, with feeble recur-
983-
rences till
*993-
1698.
*IO36. First recorded fluid lava.
1701.
1049.
1704. May 20, with feeble recur-
*i 138 or 9. 6 Kal. Jan.
rences till August, 1707.
1306.
1707.
1500.
1712. With recurrences in 1713,
1568.
1714, 1716.
*i63i. Great flow of lava 18,000
,1717 and 1718.
persons perished.
1720. With recurrences in 1723,
1 I6 49-
1724, 1725.
t A MS. account of this eruption has recently been 'discovered, and is
printed in " Lo Spettatore "
THE STRATA UNDERLYING VESUVIUS.
379
A.D.
1726.
1730.
1733.
1737.
1751-
1754.
1759-
*i76o.
1766.
1767.
1771.
1776.
1779.
1783-
1784.
1786.
1787.
1788.
1790.
*i794-
1804.
1805.
1806.
July 26.
February 27.
May 14, great flow of lava.
October 25.
December 2.
December 23, new crater on
mountain side opened.
March 25.
October 23.
September 22.
August 3, perpendicular
column of lava.
August 1 8.
October 12 and December.
October 31.
December 21.
July 19.
September 6.
June 15, great flow of lava,
Torre del Greco suffered
great injury.
August 12 and November 22.
July.
May.
A.D.
1810.
1812.
1813.
1816.
1817.
1818.
1819.
1819.
1820.
1828.
I8 3 I.
1833.
I8 34 .
l8 3 8.
1845.
1850.
1854.
1855.
1858.
1861.
1868.
*i872.
1881.
December 10.
May to December.
December 22 to 26.
April 17.
November 25.
800 feet of the cone blown
away; great discharge of
ash and vapour.
August 1 8.
August.
Minor eruptions of scoria.
Ditto.
Lava very fluid.
Long continued.
Exterior eruptions.
THE STRATA UNDERLYING VESUVIUS-
ARTESIAN WELL SECTION (Pozzo DELL' ARENACCIA).
THE construction of an artesian well at Arenaccia, near the
Ponte della Maddalena, on the Vesuvian side of Naples, in the
year 1880, has furnished a very interesting section, showing the
precise character of the strata underlying the plain from which
Vesuvius rises, to a depth of about 400 feet below the level of the
sea. The section is compared with that furnished by the
artesian well of the Royal Palace at Naples, with detailed descrip-
tion and analyses by Dr. Paride Palmieri, in " Lo Spettatore del
3 8o
APPENDIX.
Vesuvio," from which the following particulars of the
well of Arenaccia have been obtained.
IL Pozzo ARTESIANO DELL' ARENACCIA,
Below sea level.
Feet. Ins.
40 10
57
73
78
85
95
102
380
383
400
120
121 8
138 I
193 10
226
246
249
262
272
324 II
361 o
364 3
8
Character of Beds.
Arable soil .
Sea level.
Sand..,
Pozzuolana, lapilli .
Volcanic " delsito " .
Sand
Coarse sand ...
Stones, lava ...
larger ,
Pozzuolana ...
Stones, tufa ...
Sand with water
Tufa, yellow ...
Tufa, greenish
Tufa, vesicular
Marly clay
Stones, lava ...
Ashes
Clay
Stones, lava, lapilli
Sand ...
Pumice
Sand ...
Tufa
Gravel (water)
beds at the
Thickness
of Beds.
Feet. Ins.
40 10
52
36
3
16
3
16
16 5
16 5
4 ii
6 7
9 10
7 6
6 7
ii 6
i i
16 *
55 9
32 9
19 8
2 II
13 5
Q 10
PROFESSOR PALMIERI'S SEISMO-
GRAPH.
THE author is greatly indebted to the Proprietors of the
Engineer for permission to reproduce their illustration of
Professor Palmieri's Vesuvian Seismograph, which, together with
PROFESSOR PALMIERI'S SEISMOGRAPH. 383
the following description, appeared in the Engineer of June 7th,
1872 : *
E is a helix of brass wire (gauge about one millimetre) ; the
helix consists of fourteen or fifteen turns, and has a diameter of
from twenty to twenty-five millimetres ; it hangs from a fine
metal spring, and can be raised or lowered by a thumb-screw.
From the lower end of the helix hangs a copper cone with a
platinum point ; the latter is kept close to the surface of mercury
in the iron basin,/, which rests on an insulating column of wood
or marble, G. The distance of the point from the surface of the
mercury remains constant, as the metal pillar, T, is of such a
length that its expansion or contraction by change of temperature
compensates that of the helix ; the latter is in connection (by T)
with one pole of a DanielPs battery of two cells, and the basin,/,
is connected with the other pole. Any vertical movement, how-
ever slight, makes the platinum point dip into the mercury, and
thus completes the circuit. In this circuit are included two
electro- magnets, C and D ; these, during the circulation of a
current, attract their armatures, which are connected with levers.
The action of C's lever is to stop the clock, A, which thus records
.to a half-second the time of the occurrence of the shock, at the
same instant that the clock strikes an alarm bell, which attracts
the attention of an observer. The lever attached to the
armature of D, at the first instant of the current frees the
pendulum of the clock, B, which was before kept from swinging,
in a position out of the vertical ; the clock then acts as a time-
piece, and its motion unrolls a band of paper, k k k, at a rate
of three metres an hour. At the same time the armature of D,
while attracted, presses a pencil-point against the band of paper
which passes over the roller, m, marking on it, while the earth-
quake lasts, a series of points or strokes which occupy a length of
paper corresponding to its duration, and which record the work
of the shock. After it is over, the paper continues to unroll from
the drum, /, and passing round the clock, rolls on to the drum, /.
If a fresh shock occur the pencil indicates it, as before, on the
* The description was originally contained in Mr. Mallet's " Notes " to his
translation of Palmieri's "Eruption of Vesuvius in 1872," and the illustration
is from Plate VIII. of that volume.
384 APPENDIX.
paper, and the length of blank paper between the two sets of
marks is a measure of the interval of time between the shocks.
By way of additional check, several helices, h h /i, are hung from
a stand, with small permanent magnets suspended from their
ends ; below and close to these latter are small basins, holding
iron filings ; into these the points of the magnets dip, when their
helices oscillate vertically, and some filings remain sticking to the
magnets as a record of the shock. One of the magnets has a
shoulder on it which moves an index hand along a graduated
arc, thus again registering the amount of the vertical movement.
Such are the arrangements intended for the record of the
undulatory or horizontal elements of the wave of shock.
The following are the arrangements proposed for recording the
horizontal motions : On the stand, to the right of the clock, A,
are set four U-shaped glass tubes, open at their ends. One of
each pair of vertical branches must have a diameter at least
double that of the other. These pairs, with their supporting
columns, are shown in plan, where one pair lies N. and S.,
another E. and W., a third N.E. and S.W., and the other N.W.
and S.E. It will be observed that metallic bars pass from the
pillar, P, over the ends of all the long branches, and similar bars
pass from R, over the ends of the short branches ; the pillars
themselves, as in the case of the other instruments, are each
connected with one pole of a DanielPs battery, the connections
including the electro-magnets, C and D. The description of one
U tube, , will apply to all the others ; n is partly filled with
mercury, and an iron or platinum wire, 0, suspended from the
bar above the short branch, dips into the mercury therein, while
another platinum wire hung from the bar over the mouth of the
longer branch has its end very close to the surface of the mercury
in that branch. Any shock which is not perpendicular in direc-
tion to the plane of the branches of the U will cause the mercury
to oscillate in the tubes, and more sensibly in that with the
smaller diameter ; when it rises up in the latter, so as to touch
the platinum point, the connection between P and R is made and
the circuit completed, starting the action of the electro-magnets
C and D, which record the shock, as already described. By
having the planes of the tubes set in the different azimuths,
PROFESSOR PALMIERl's SEISMOGRAPH. 385
already mentioned, one or more of the pairs is sure to be acted
upon, and by observing in which the oscillation takes place the
direction of the shock is supposed to be ascertained. Besides
this, each long branch of the U, viz., that of the smaller diameter,
has a small ivory pulley, ^, fixed above it, over which passes a
single fibre of silk, with an iron float at one end, resting on the
surface of the mercury ; at the other end of the fibre hangs a
counterpoise ; fixed to the pulley is a fine index hand, capable of
moving along a graduated arc. When the shock takes place the
mercury, rising in the long branch, raises the float on its surface,
the silk fibre at the same time makes the pulley revolve with its
index hand, which afterwards remains stationary, as the counter-
poise prevents the float from sinking again with the mercury.
The reading on the graduated arc is thus a measure of the
movements produced in the instrument by the horizontal element
of the shock, and is supposed to measure that shock. It is
assumed that in all these instruments shocks, however small, can
be recorded with certainty by adjusting the distance between the
platinum points and the mercury.
IN DEX.
Abich, 227, 244, 310, 326
Abrazite, 312
Abyssinia, 209
Aci Reale, 167
Acotyledones of Vesuvius, 347
Acqua Capona, 42
,, Termo Minerale Nunzianta, 59
Activity of Vesuvius long continued,
1 60
^Enaria, 44
JEneid, the, quoted, 28, 29
Agrippa, 28, 30, 36, 37
,, canal of, 32
Agnano, 27, 39, 41
Alban hills, 206
Albite, 294
Allogovite, 218
Almandine, 327
Alps, upheaval of, 207
Alum, 41, 256
Alumina, 73
Amalfi, in
Amanduni, G., 372
Ammonia, 320, 321
Amphibole, 240, 257, 315, 316
Amphiginite, 219
Amygdaloidal dolerite, 219
Analcime, 220, 258, 295
Analcymite, 220
Anamesite, 220, 223, 225, 229
Andernach, 245, 247, 289
Andes, the, 220
Andesine, 220, 294
Andesite, 216, 220, 245
Anglesite, 259
Anhydrite, 260
Anorthite, 260, 294
Antrim, basalt of, 207, 209
Apatite, 179, 261, 307
Apennine limestone, 19, 182, 249
Apennines, the, 18, 19, 22, 61
Aphthitalite, 262
Aragonite, 179, 262
Arco d' Aricia, 1 8
Arenaccia, Pozzo dell', 379
Argillaceous perlite, 237
Argilo-trachyte-porphyry, 245
Artesian well borings at Naples, 182,
379
Ascension, Island of, 210
Ascent of Vesuvius, 121, 122, 123
Asphaltum and volcanic action, 189
Astroni, 26, 1 80
Atacamite, 263, 279
Atelite, 264
Atrio del Cavallo, 82, 83, 107, 114,
125, 136, 137, 138, 139, 147, 149,
150, 151, 172, 180, 225
Augite, 25, 170, 171, 179, 223, 228,
229, 266, 315, 316
Augite andesite, 220
Auvergne, volcanoes of, 45, 207, 208,
226
Avernus, 20, 27, 28, 29, 30, 40, 42, 43,
232, 373, 374
Babbage, Mr., 34, 112
Bagni di Tritoli, 42
Bagnoli, 41
Baiffi, 20, 23, 41, 42, 43
bay of, 21, 30, 35, 41,204
Barra, 54, 55, 6 1
Basalt, 58, 1 68, 170, 177, 206,218,
220, 222, 223, 225, 229, 293, 330
388
INDEX.
Base of Vesuvius, 163, 179, 186
Bath, volcanic action at, 207
Bath of the Sibyl, 29
Baths of Nero, 40
Battle of Vesuvius, 23
Bauli, baths of, 42
Belisarius, capture of Naples by, 50
Belonesite, 264
Beoti, 118
Bergmann, 243, 309
Beudant, 237
Bianca, village of, 73
Biotite, 265, 333
Bitumen and volcanic action, 189
Blende, 266
Blight on foliage, 222
Bocche, 45, 59, 75, 76, 92, 106, no,
"5, 157
Bohemia, lavas of, 207
Boracic acid, 148, 321
Bosco di Cupaccia, 78
,, Reale, 60, 113, 142
tre Case, 60, 76, 106, 141
Bourbon, isle of, volcano in, 175, 232
Bournon, Count, 267, 290
Bracini, 103
Breislak, 34, 38, 103, in, 189, 191
Breislakite, 171, 266
Breithaupt, 243
Brewster, Sir D., 330
Brewsterlinite, 318
Bridge of Caligula, 35
Bristow, quoted, 282
British Association, Vesuvian Com-
mittee of, 161
Brocchi, 235, 247
Brohl, valley of, 245
Brydone, 75
Calcite, 267
Calderas, 69
Caligula, 35, 42
Camaldoli della Torre, 59, 75, 139
157
Camaldoli di Napoli, 37, 38, 183
Cambrian rocks, 2OO
Campagna di Roma, the, 18, 22, 208,
219, 247
Campania, 22, 23, 47, 59, 66
,, fertility of, 22
Campanus Ager, 22, 23
Campi Phlegraei, 20, 176, 363
Canale del Inferno, 82
Canary Islands, 69, 175, 184, 206,
220
Capillary transmission of water, 192,
208
Capitoline hill, tufa of, 247
Capo di Bove, 219, 267, 302, 312, 325
,, Miseno, 62
Posillipo, 41
Caposecchi, 60, 76, 112
Cappella del Tesoro, 50
Capri, island of, 19, 56, 63, 66, 118,
249
flora of, 343
Capua, 23
plain of, 22, 43, 61
Casa del Vescovo, 167
Casamicciola, 45, 145
earthquake of, 154
Carbonic acid gas, 39, 115, 145, 228,
268
Cascades of fire, 118, 120
Castagno di Cento Cavalli, 75
Castel del Carmine, 54
dell' Ovo, 49, 64
,, Nuovo, 54
S. Elmo, 38, 49
Castellamare, 19, 51, 59, 249
Cava Grande, 167
Secca, 167
Cavolinite, 325
Cercola, 61, 76, 114
Chalcidians, 45
Changes of level, 34, 35, 36
Chemical action, subterranean, 212,
213
Chemical hypothesis of volcanic
action, 189, 190, 191
INDEX.
389
Chessylite, 268
Chloralluminite, 269
Chlorides, 191, 208, 209
Chlorine, 228
Chlorocalcite, 269
Chloromagnesite, 269, 270
Chlorotionite, 270
Chondrodite, 270, 273, 289, 290
Chrysolite, 271, 308
Cicero, 43, 377
Cimini Mountains, 235
Cimmerides, the, 29
Cisterna, 181
Clifton, volcanic action at, 207
Clinkstone, 237
Clinohumite, 271, 272, 289, 290
Club Alpino, 51
Coccineus, M., 37
Columnar structure of basalt, 58
Comes, Orazio, 347
Compendium of volcanic phenomena,
204
Cone of Vesuvius, 61, 70, 71, 78, 85,
100, 125, 128, 159, 163, 164, 165,
1 66, 1 68, 179
Cone of Vesuvius, ascent of, 129, 130
,, ,, inclination of, 85,
86
,, ,, increase of, 178
,, ,, lava beds of, 166,
1 68, 177
new, 1867-8, 89,
117, 132
,, ,, sinking of, 106
,, ,, summit of, 87, 131
Cones, new, 106, 157
Copper, 120, 131, 135, 159, 172, 242,
268, 274, 275, 277, 280, 291, 301,
308, 328
Coquimbite, 273
Cordier, M., 194, 201, 219
Costa, G. O., 250
Cotunnite, 126, 171, 231, 243, 273,
313
Covelli, 274, 275, 320, 322, 327
Covellite, 274
Cremate, the, 45
Crater of Vesuvius, 71, 90, 91, 103,
m, 133, 144, 145, 148, 151,
1 5 2 , J 53> i57i i59, 1 60, 165, 1 68,
169, 170, 171, 172, 176, 273, 277,
280, 288, 290, 309, 313, 329
Crater of Vesuvius, effects of erup-
tions on, 87, 88, 90, 91
Crater of Vesuvius, interior of, 92
i, ,, pre-historic, 174
Crocella, the, 80, 81, 82, S$, 115, 117,
128, 129, 174
Cryptohalite, 275
Cultivated zone of Vesuvius, 123
Cumae, 21, 22, 23, 43
Cupa di Sabataniello, 308
Cuprite, 275
Cupromagnesite, 276
Cuspidine, 276
Cyanochroite, 276
Cyanosite, 277
Cyclades, 220
Cyclophyre, 22O
Dacite, 220, 225
D'Arso, Lava, 45
Damour, 302
Dana, Prof. J. D., 202, 255, 270, 284,
298, 299, 306, 318, 321
Darwin, Charles, 189
Daubeny, Dr., 25, 31, 34, 39, 40, 74,
94, 191, 245,246
Daubree, M., 192, 208
Davy, Sir Humphrey, 190, 191, 227
Davyne, 325
Delametharie, 326
Des Cloiseaux, 272, 290
Desert platform of Vesuvius, 71, 78,
124
Deville, 296
Diatomaceae in volcanic ejecta, 208,
210
Diccearchia, 25
Dicotyledons of Vesuvius, 345
390
INDEX.
Diodorus Siculus, 94, 97, 9 8 , IO1
Dion Cassius, 101
Dolerite, 170, 178, 219, 220, 223, 225,
228
Dolerophanite, 277
Dolomite, 278
Domite, 225, 229, 232, 245
Dufresnoy, 167
Earth, contraction of radius of, 194,
209, 213
,, interior condition of, 193, 196
rigid, 195, 204
crust of, 195, 201
Earthquakes, 32, 45, 60, 98, 103, 104,
145, 153, 210, 211, 359, 360, 362,
365, 366, 368, 373, 374, 375
Earthquake at Bologna, 155
,, in Ischia, 154
of 1857, 57
Egypt, 25
Ehrenberg, 210
Eifel, the, 90, 247, 295
,, volcanic products of, 289
Ejected blocks, 248, 249, 286, 290,
296, 301, 306, 308, 311, 312, 319,
321, 323, 33, 33 1 , 333
Electrical action, subterraneous, 212
Electrometer, bifilar, 233
Elevation of Central Europe, 207
Elie de Beaumont, 167
Elyssian Fields, the, 43
Eustatite-andesite, 220
dolerite, 225
Eocene beds, 182
Epidote, 316
Epomeo, 44, 45, 209
,, eruption of, 45, 74
Epsomite, 279
Erhebungs Cratere theory, 44, 184
Eriochalcite, 280
Eruptions of Vesuvius
A-D. 79, 55, 60, 98, 99, 101, 169,
J 74> i75 208, 210,
235, 355, 359
Eruptions of Vesuvius (continued)
A.D. 203, 101
472, 101
512, 102
685, 102
i 993, I02
1036, 102
1049, 102
1138, 102
"39, I02
M 1631, 56 57, 58, 74, 77, 103,
104, 169, 225, 264,
267, 268, 308, 331
1676, 104
M ^94, 105
1696, 105
I, 1707, 105
1737, 57, 105
1751, 1 06
M 1754, 106
1760, 1 06
,, 1766, 106
1767, 1 06, 107
1770, 106
1776, 1 10
1779, 1 10, 241
M 1794, 57, 76, 92, no, 169
1804, 76
1805, 76
1806, 76
1822, 57, in, 165, 169,
171, 241, 274, 310,
320
1828, 112
1833, 227
1834, 76, 112
1839, 274
1850, 76, 141, 273
1855, 61, 141, 171,231, 274,
299, 322, 329
1858, 115, 141
1861, 57, 59, 76, 92, 115,
234
1867-8, 89, 1 16, 227, 231,
280, 291
INDEX.
391
Eruptions of Vesuvius (continued)
A.D. 1872, 81, 137, 138, 141, 142,
222, 234, 241, 258,
269, 270, 276, 280,
303, 313, 324, 327
1880, 150
Eruptions of Vesuvius, Catalogue of,
378
Eruptions, prehistoric, 95, 97
,, appearance by day and
by night, 64
,, external, 140
moderate, 88, 91
,, paroxysmal, 88, 95, 101,
143, 165, 175, 249, 378
unobserved, IOI
Eruptive action, 81, 133, 183,209,216
,, axis of Vesuvius, 172
,, position changed, 173,
207
,, energy, periodicity of, 2IO
mouths, 75, 76, 133
Erythrseans, 45
Erythrosiderite, 280
Esquiline Hill, tufa of, 247
Etna, 19, 75, 92, 97, 102, 108, 143,
158, 167, 173, 174, 177, 185, 1 88,
207, 226, 243, 363
Etna, observatory on, 21 1
Euchlorinite, 264, 279
Euganian Hills, 18, 234
Exanthalose, 280, 305
Expansion by fusion, 214, 215
Falconi, M. Antonio delli, letter of,
32, 362
Faraday, Michael, 189
Fatality of 1872, 138
Felspar, 25, 73, 179, 229, 230, 286,
293> 2 94, 3 10
Ferdinand and Isabella, charter of,
35
Ferns of Vesuvius, 350
Ferric Nitrate, 282
Ferroligiste, 243
Fishes in volcanic ejecta, 210
Fisher, Rev. Osmond, 192, 193, 200,
201
Flora of Vesuvius, 343
Fluorite, 282
Fontes Leucogaei, 41
Forbes, Prof. James, 34, 40, 89
Forest of Carpinetto, 75
Forsterite, 312
Fosse of Vesuvius, 77
Fossils cf Vesuvius, 250
Fosso Bianco, 77
Corvo, 77
Cancheroni, 252, 299
,, Faraone, 77, 81, 114, 142
Grande, 77, 80, 81, 115, 250
Vetrana, 81, 114, 136, 142, 174
Fouque, M., 214
France, Central, volcanoes of, 225, 232
Francesco del Nero, letter of, 32,
368
Freada, Prof., 298, 304
Fulgori, 227, 233, 234
Fumaroles, 24,92, 115, 119, 120, 137,
150, 242, 273, 275, 277, 281, 288,
290, 292, 309, 328, 329
Fumaroles, eruptive, 141
Fungi of Vesuvius, 351
Funicular railway, 86, 129, 150, 158
Fusi Jama, Japan, 184
Fusion, cause of rock, 193
,, intermediate region of, 201
Gaeta, Gulf of, 22, 43, 12 1
Galena, 266, 283
Galenite, 283
Garnet, 179,284,333
Geikie, Dr., 209
Gelenite, 303
Geology of Vesuvius, 162
Geological structure, importance of, 23
Germany, volcanic rocks of, 207,245,
295
Giacomo di Toledo's account of Monte
Nuovo, 32, 366
392
INDEX.
Giant's Causeway, basalt of, 223
Giardino del Popolo, Naples, 48, 54
Gismondine, 312
Giuamicola, 167
Giuscardi, 227
Gladstone, Mr., on volcanic flame,
226
Glauber salts, 280, 304
Goethe on the Serapeum, 34
Goths in Italy, 43, 50
Granatello, 55, 80, 104
Granitic rocks, 73
Granular shelly perlite, 237
Grapes of Vesuvius, 344
Graphite, 285
Grasses of Vesuvius, 348
Greece, 25
Grotto del Cane, 39
,, of Posillipo, 36
of Sejanus, 37
Guarinite, 286
Guides of Vesuvius, 56, 123
Guiscardi, 36, 274
Gurgitello, baths of, 46
Gypsum, 286
Hadrian, 42, 49
Haematite, 281
Halite, 287
Hamilton, Sir William, 102, 107, 241,
250, 367
Hannibal, 22
Hardness of minerals, scale of, 257
Hausmann, 307
Hausmannite, 288
Haiiy, 326, 333
Haiiyne, 228
Haiiynite, 288
Haiiynophyry, 228
Hawaii, craters of, 92, 231, 236
Heat, increase of, with descent, 193,
205
internal, 195, 212
Hebrides, 206
Helkusometer, 215
Herculaneum, 23, 50, 51, 54, 55, 98,
100, 101, 104, 235, 247
Hermitage, the, 61, 80, 122, 129, 174
History of Vesuvius, 94, IOI, 114,
135
Hoefer, 322
Hopkins, Mr., on earth's crust, 194
Hornblende, 171, 179, 257, 286, 321
andesite, 220
dolerite, 225
Horner, Leonard, 368
Hot springs, 41, 207
Humboldt, 176, 185, 189
Humboldtilite, 303
Humite, 179, 271, 272, 273, 289, 290
327
Hungary, volcanic rocks of, 207, 208
237
Hydrochloric acid, 39, 131, 145, 150,
228, 242, 290
Hydrocyanite, 290
Hydrodolomite, 291
Hydrofluoric acid, 228
Hydrofluorite, 292
Hydrogen, 214, 227, 228
Hydromagnesite, 292
Hypotheses of volcanic action, 189
203, 212216
Idaho, lava rock of, 209
Idocrase, 179, 285,301, 321, 331,332,
333
Idrociano, 302
I Granili, 54
Inarime, 44
Insects on volcanoes, 143
lona, lava rock of, 207
Iron, 73, 131, 147, 171, 229, 242, 243,
282,307,311,313,317
Ischia, 19,43, 44, 45> 46, 63, 66, 74,
102, 1 88
,, earthquake in, 154
Isola del Salvatore, 49
Italy, 22, 50
,, mountain axis of, 19
INDEX.
393
Java, eruptions of, 175, 238
Jorio Canonico on Serapeum, 34
Jorullo, 185, 207, 210
Judd, Prof., 209, 2ii
Jupiter Serapis, 42
Juvenal quoted, 22
Kaolin, 73, 310
Kilauea, crater of, 92, 207, 209, 236
Klaprotte, 296
Krakatoa, eruption of, 175, 208, 221,
2 3 8
Kremersite, 280
Labradorite, 223, 228, 229, 292, 294
Lachryma Christi, 57
La Favorita, 56
Lagne of Vesuvius, 77
Lago Albano, 18, 295
,, Bolsenna, 18
Bracciano, 1 8
,, Fusaro, 43
Nemi, 18
Lapilli, 58, 74, 99, 100, 136, 140, 224,
228
Lapis Lazuli, 294
Laplace on density at earth Vcentre,
205
LaPlaine, 78, 80, 117, 124
La Starza, 35
Lava, 104, 152, 209, 229, 232, 281,
288, 296
Lava of A. D. 1036, 102
1631, 55, 104, 230, 266,
269, 288, 296, 308,
311, 319, 324, 3751
1694, 1707, & 1737, 105
I75i 1754, & 1760, 1 06
1767, 107
1793-4, 57, 76, in
1804, 1805, & 1806, 76
1813, 281
,, 1822, in
1834,76,112
1844 & ^46, 296
Lavaof A.D. 1850, 76, 113,292
1855, 76, 114, 126, 142,
231
1858 & 1861, 115
1867-8, 116, 117, 118,
119,230,231,262
1870, 292
1871, 137
1872, 76, 137, 138, 139,
141/142,262,275,
292, 3!3, 333
1878, 147
1880, 150
1883, 153, 154
1884-5, 158, 282
1886, 158, 159
Lava, composition of, 170, 206, 230
d'Acqua, 233
decomposition of, 73, 74, 75
,, de fuoco, 232, 233
emission of, 128, 139, 165, 203,
214, 215, 216
false, 233, 249
,, filamentose, 154, 231, 236
,, flows, 24, 52, 57, 61, 64, 75, 76,
77, 81, 125
fluid, 114, 126, 127, 152, 231,
232, 274
heat of, 127, 193, 231, 232
rocks, 25, 55, 56, 58, 73, 76, 77,
104, 106, 112, 113, 124, 126,
136, 148, 149, 170, 177, 178,
209, 219, 222, 223, 225, 229,
230, 232, 235, 286, 295
solidification of, 126, 136, 166,
167, 170, 171, 185, 206, 231
source of, 192, 193, 197, 203,
205, 212, 213, 214
tunnels, 120, 128, 151, 160, 232
Lavis, Dr. Johnston, 151, 152, 155,
157, 159, 161, 183, 211, 249, 252
Lead, 120, 126, 131, 171, 242, 297,
313
Leeward Islands, eruption in, 175
Lemery's hypothesis, 189, 191
394
INDEX.
Leucite, 112, 113, 136, 154, 170, 171,
178, 179, 219, 222, 230,295, 296,
3"
Leucitophyre, 219
Lichens of Vesuvius, 349
Lime in volcanic rocks, 73
Limonite, 297
Linarite, 297
Lipari Islands, 19, 173
Liparite, 234, 245
Liscanera, 243
Liternum, 23
Lithia in volcanic rocks, 296
Lithidionite, 298
Lithium, 148, 150
Lithodomus lithophaga, 33
Liverworts of Vesuvius, 349
Lucan quoted, 40
Lucrine lake, 20, 29, 30, 35, 40, 42
Lyell, Sir Charles, 34, 94, 105, 1 66,
167, 185, 213
Macigno, 182, 250
Madeira, 175, 206
Magnesia in volcanic rocks, 73, 242,
292
Magnesioferrite, 298
Magnetite, 299
Magnus, 332
Mallet, Mr., 138, 141, 143, 195, 207,
383
,, hypothesis by, 198
Malpais, the, 185
Mammelons, 232
Manganese, sulphate of, 327
Mare Morto, the, 43
Marinella, the, 54
Martial quoted, 40, 43, 50
Masaniello's insurrection, 54
Masenga, 234
Massa di Somma, 61, 76, 114, 117,
142, 144
Mauna Loa, crater of, 92, 207, 208,
209, 236
Mauritius, 175
Medicinal plants of Vesuvius, 347
waters, 28, 41, 42, 59
Mediterranean, 18, 19, 56, 66, 247
Meerfeld, crater of, 90
Meionite, 300, 305
Melanite, 286
Melanothallite, 301
Melilite, 302
Mesozoic crust of the earth, 201
Mica, 138, 171, 228, 265
,, andesite, 220
,, dolerite, 225
Microcosmite, 303
Millerite, 303
Millstone porphyry, 245
Milne, Prof., 211
Mineral waters of Baiae, 41
Minerals of Vesuvius, 50, 171, 179,
253
Minerals of Vesuvius Catalogue, 256
Mirabilite, 280, 304
Misenum, 23, 43, 47, 62, 66
Mizzonite, 305
Molara di Massa, 252
Mollucas, eruptions in, 175
Molybdenite, 306
Molysite, 269, 307
Mongibello, 173
Monocotyledones of Vesuvius, 347
Montagnone, 45
Monte, meaning of term, 67, 68
Albano, 1 8, 24, 289
,, Artemesia, 18
Barbaro, 26, 180, 366, 373
,, Campana, 27
,, Campignano,*45
,, Cigliano, 27
Corvo, 45
Grille, 30
Nuovo, 30, 31, 32, 35, 90, 103,
1 80, 207, 208, 210, 362, 366,
368, 372
,, Ottajano, 84
,, Procida, 22
Rotaro, 45
INDEX.
395
Monte S. Angelo, 63, 78
,, Sicco, 41
Spina, 27
Tabore, 45
,, Trocchia, 84
,, Vico, 45
,, Vulture, 1 8, 228, 289
Monticelli, 94, 250, 274, 303, 308,
310, 320, 322, 327
Monticellite, 307
Moon, crater-rings of, 24, 175
influence of, 149, 150, 2IO, 215
Mosses of Vesuvius, 349
Mount Ararat, 221
Mountain chains, origin of, 199
Mull, lavas of, 207
Museums of Naples, 5
Muscovite, 265
Myrtaetae, 42
Naples, 21, 36, 37, 38, 43, 47, 48, 49,
5, 53- 6 3> 98, 105, 107, 1 08, 109,
1 10, 115, 120, 140, 142, 246, 367
Naples, Bay of, 19, 47, 58, 62, 63, 66
,, site of, 49, 182
Neapolitan volcanic region, 17, 1 8, 19,
30, 249
Nebular hypothesis, 195
Nekrolite, 235
Nenfro, 235
Neochrysojiite, 308
Neocyanite, 308
Nepheline, 179, 302, 303, 325, 326
,, dolerite, 220, 235
Nero, 40, 42, 49, 98
Nicolini, Sig., 36
Niedermendig, 228
Nisida, 19, 40, 44
Nitrogen, 73, 208, 228
Nola, 23, 6 1
Novelle, the, 76, 142, 260
Observatory of Vesuvius, 80, 81, IOI-,
1 1 8, 129, 138, 174, 233, 234,380
Observatory Hill, 82, 136
Obsidian, 235, 238, 239, 243
Oligoclase, 220, 294
trachyte, 226, 245
Olivine, 170, 179, 228, 229, 271, 272
dolerite, 225
Oplontum, 51, 58
Orchard, Prof. H. L., 372
Organic matter in volcanic ejecta, 222-
Orpiment, 309
Orthoclase, 73, 230, 244, 310, 331
Oranges of Vesuvius, 345
Ottajano, 61, 78, 113, 117
Pacific Ocean and volcanoes, 207
Palseopolis, 49
Palaeozoic, earth's crust, 201
,, volcanic action, 204
,, climatal conditions, 204
Palazzo Reale, 53
Palma, 61, 184
Palmieri, Prof., 80, 8 1, 89, 115, 117
119, 136, 138, 140, 141, 142, 144,
147, 148, 149, 152, 161, 166, 170,.
171, 211, 222, 233, 243, 380
Palmieri, Dr. P., 379
Palus Acherusa, 43
Papandayang, 175
Pasquale, G. A., 343, 345
Patagonia, tufa of, 208
Pausilypus, 49
Pearlstone, 237
Pedamentina, the, 70, 80, 101, 174
Pele's hair, 231, 236
Peperino, 236
Periclasite, 311
Peridote, 271, 308, 327
Perlite, 237, 239
porphyry, 237
Peru, 235
Phases of Vesuvius, 183
Phillips, Prof. John, 30, 95, 132
William, 312, 333
Phillipsite, 312, 330
Phlegrasan Fields, 19, 20, 21, 24, 26 r
30, 32, 36, 38, 67, 90, 180, 216
396
INDEX,
Phonolite, 237
Photography, use of, in vulcanology,
139, 140, 141
Physio-chemical hypothesis, 212, 253
Piano, the, 78, 115, 124, 127, 128, 225
del Genestre, 80, 117, 119
de Quatro, 37
Pianura, 37
Picentia, 23
Picromerite, 312
Pilla, Prof., 113, 227
Pincian Hill, tufa of, 247
Pisciarelli, thermae of, 41
Pitchstone, 238
Pithecusa, 44
Pizzofalcone, 49
Plagioclase, 220, 293
Pleonaste, 302
Pliny, 41, 43, 51, 55, 224, 315, 355,
359
Pliny the Younger, letters of, 99, 355,
359
Pluto and volcanoes, 188
Plutonic rocks, 209
Policastro, bay of, 22
Pollena, 61
Pompeii, 20, 23, 43, 45, 50, 51, 52,
58, 59, 60, 74, 98, 99, 100, 101, 112,
228, 295
Ponte Maddalena, 54, 109, 379
Ponticelli, 61, 142
Ponza Islands, 18, 238
Portici, 54, 55, 56, 80, 104, 108, 115,
148
Port of Naples, 54
Porzio, Simone, letter of, 32, 371, 372
Posillipo, 49, 120
ridge of, 36, 37, 183
Post-pliocene beds, 182
Potash in volcanic rocks, 73, 135, 230
Potassium chloride, 288
M oxidation of, 190
Pozzuolana, 37, 238
Pozzuoli, 25, 26, 32, 33, 34 , 3S| ^
4i, 182, 368, 369, 371, 373, 375
Pre-historic Vesuvius, the, 95
Pressure, effects of, 196, 210, 213
,, central, 205
lateral, 212, 213
,, tangential, 198, 209, 212
vertical, 196, 209, 212
Prestwich, Prof., hypothesis by, 2O2
Prevost, C., on pressure, 198
Primo Monte, 84
Primogenial water substance, 2O2, 203
Primrose Hill, comparison of cone
with, 87
Procida, 19, 43, 44, 66
Procidionite, 313
Procopius, 102
Promontorium Minervse, 62
Propylite, 206
Pseudocotunnite, 313
Pumice, 74, 238, 239
Pumiceous perlite, 237
,, trachyte-porphyry, 245
Punta della Campanella, 62
di Coraglio, 35, 37
,, del Nasione, 84
del Paolo, 89, 132
Puteoli, 23, 24, 25, 49
Puy de Dome, 45, 225
Puys La Vache, Noir, and Solas, 1 73
Pyrite, 313
Pyroxene, 73, 154, 170, 222, 229, 240,
315,316
Pyrrhotite, 3 1 7
Quartz, 318, 319
Quaternary beds, 182
Quirinal Hill, 247
Rammelsberg, 290, 299, 325
Realgar, 319
Recent shells in tufa, 37
Recupero on decomposition of volcanic
rocks, 75
Region of undecomposed lava, 78, 124
Resina, 51, 54, 55, 80, 104, in, 115,
119, 120, 123
INDEX.
397
Retina, 51, 55
Rhine, volcanic rocks of, 2io, 228,
245, 247, 289
Rhyolite, 206, 239, 240
Richter, 296
Richthofen, 206
Ring terrace of 1868, 89, 131, 132
Riviera di Chiaja, 48
Rivo di Quaglia, 252
Rocca Monfina, 18, 244
Rod well, Mr., 145, 147, 149
Romagna, earthquake in, 155
Roman cement, 238
,, volcanic region, 1 8, 19, 73,
178,235
Romans, the, and Campania, 23, 25,
37, 49
Rome, 1 8, 20, 21, 23, 25, 58, 247, 295,
312
ports of, 25, 43
,, tufa of the seven hills, 247
Roth, 250
Rowley rag, 236, 243
Rubies, Balas and Spinelle, 326, 327
St. Helena, volcanic structure of, 175
St. Paul at Puteoli, 25
Sal-ammoniac, 243, 275, 320
Salernum, 23
Salt, common, 131, 144, 191, 287
sea, 144, 147, 208, 222, 242
,, effects on vegetation, 143
Salto della Giumenta, Etna, 167
San Anastasia, 61
Giorgio a Cremano, 55, 62, 105
Giovanni a Teduccio, 54
,, Januarius, 50, 105, 109, no
Jorio, 114
,, Nicolo, 44
,, Salvatore, 81, 82, 129
Sebastiano, 61, 76, 114, 142, 144
Sandwich Islands, 236
Sanidine, 244, 311
,, trachyte, 245
Santa Lucia, 49, 64
Santa Lucia, landslip at, 38, 119
Sarcolite, 321
Sarno, river, 60
Sassolite, 321
Scacchi, Prof. Archangelo, 51, 149,
179, 250, 254, 264, 266, 268, 270,
273, 274, 276, 277, 280, 282, 284,
290, 35, 307, 311, 3!3 323, 326,
328, 331
Scacchi, Eugenic, 292
Scacchite, 322
Scale of hardness of minerals, 257
,, Vesuvian activity, 155
Scolecite, 323, 324
Scoriae, 126, 128, 132, 133, 140, 149,
231, 240
Schemnitz, Hungary, 237
Schiuma, 117, 240
Scrope, Poulett, 31, 176, 185
Sea, association with volcanoes, 191,
208, 216
ebb of, at eruptions, 210, 357,
360, 363, 365, 373> 376
Sebeto, river, 54
Secular, cooling of the earth, 195,
213
Seismic action, 45
Seismograph, Palmieri's, 80, 116, 146,
Seismology, advance in, 2H
Selenite, 286
Semeline, 331
Seneca on earthquake of A.D. 63, 98
Serapeum, 33, 41
Sibyl, cave of the, 29
Sicilian volcanic region, 18, 19
Sicily, 50, 121, 1 88
Silica, 73, 318
Silurian rocks, 200
Silvestri, Prof., 282
Sinuessa, 23
Sinus Cumanus, 62
Siren, the, 49
Slaty trachyte porphyry, 245
Slopes, lower, of Vesuvius, 65, 71, 72
398
INDEX.
Sodalite, 171, 179, 288, 323
Sodium chloride, 119, 131, 274,287,
329
Solfatara, the, 24, 25, 26, 39, 41, 102,
209, 310
,, eruption of, 24, 35
Somervillite, 303
Somma, Monte, 52, 60, 67, 69, 70, 71,
77, 81, 83, 84, 105, 163, 172, 174,
177, 179, 185, 252, 272, 286, 296,
311,326.
Somma, Monte, escarpment of, 130,
174, 1 80
dykes of, 130, 296
lavas of, 1 78, 179, 296
ridge of, 83, 125, 130,
137, 172, 174, 1 80
town of, 61, 67, 78,
172
Sommanus, the god, 67, 82
Sommite, 179/303, 324
Sorrento, 66, 112
peninsula, 19, 51
Spartacus and Vesuvius, 95
Sphserutitic perlite, 237
Sphene, 286, 330
Specific gravity of globe, 205
Spinelle, 290, 326
Springs, medicinal, 28, 41, 42
mineral, 42, 59
,, warm, 40, 41, 42
Stabiae, 51, 55
Staffa, basalt of, 207, 223
Stalactites, volcanic, 151
Steininger, 243
Stereocaulon Vesuvianum, 344
Sterry Hunt, Dr., hypothesis by, 201
Strabo quoted, 21, 24, 37, 44, 47, 49|
67, 97, 98
Stradadi Toledo, 48
Strombolean activity, 146, 156, 157,
209
Stromboli, 19, 92, 209, 210, 244
Stufie di Germane, 39
de Nerone, 40
Sublimations, 92, 119, 131, 145, 147.
150, 242, 280, 322
Subsidence of Central Europe, 207
Sulphatite, 327
Sulphur, 24, 39, 41, 189, 191, 243, 328,
368
Sulphuretted hydrogen, 39, 328
Sulphuric acid, 228, 242, 327
Sulphurous acid, 145, 150, 228, 243
328
Sumbawa, eruption of, 175
Sunset glows of 1883-5, 221
Surrentum, 23
Sylvine, 313
Synonyms and included varieties list
of, 335
Tachylite, 236, 243
Teall, Mr. Harris, 220, 225
Teanum, 23
Temple of Apollo, 28, 42
Serapis, 33, 34, 35, 41
Teneriffe, Peak of, 1 74, 244
Tenorite, 171, 243, 264, 328
Tertiary lava outpouring, 207
Thallium, 150
1 heophrastus quoted, 281, 287
Thenardite, 329
Theories of volcanic action, 189, 190,
194, 196, 198, 201, 202, 212
Thermae, 28, 39, 41, 374
Tholeite, 243
Thomson, Sir William, 194
Thomsonite, 329
Tiberias at Baiae, 42
Titanite, 286, 330
Titus at Neapolis, 49, 98
Torre del Annunziata, 58, 59, 75, 104,
106, in, 153
Greco, 56, 58, 59, 61, 75, 76,
77, 80, 104, 105, 106, 108
in, 115, 118, 157, 234
,, Scassata, 58, 104
Topaz, 272
Tourmaline, 316
INDEX.
399
Trachyte, 73, 74, 206, 220, 225, 226,
229, 235, 244
dolorite, 243, 245
porphyry, 234, 239, 245
Prachytic volcanic rocks, 25, 26, 206,
229, 232, 237, 239, 243, 244, 246
Trass, 245, 247
Trees of Vesuvius, 345
Tripergoli, 32, 362
Trocchia, 6 1
Tschermak, Prof., 2O2
Tufa, 19, 27, 37, 38, 43, 182, 208, 236,
238, 245, 246, 247
,, deposits, 38
granular, 247
lithoide, 58, 247
Two Sicilies, Kingdom of, 5
Typhon, the, 44, 1 88, 363
Tyrrhenian Sea, 22
Ulysses at Avernus, 29
Val del Bove, 92, 173, 177
,, Inferno, 82, 83, 152, 159, 160
Vallone, 77, 78, 252
Vegetable remains in Vesuvian ejecta,
210
Venafrum, 23
Vesbine, 149, 331
Vesbium, 149, 331
Vesicular porphyry, 245
Vesuvian area, fertility of, 47, 48, 72
, , populousness of, 47, 48
,, minerals of, 253
Vesuvianite, 301, 321, 331
Vesuvius, activity of, 46, 51, 64, 95,
183
age of, 182
,, ascent of, 56, 12 1
changes of form, 95, 96, IOO,
112
,, dormancy of, 95, 102, 103
,, etymology of, 67
,, focus of, 207
form of, 68, 69, 70, 80
Vesuvius, gardens of, 123, 124
,, guides of, 56
height of, 88, 89, 90
illustrative, 68, 93, 162
injury by, 48, 50, 51, 57,
no, in, 112, 115, 140,
141, 142
,, origin of, 180, 181
,, pre-historic, 95, 172
,, phases of, 183
,, road around, 52, 60, 72
,, surface of, 71
substructure, 182, 379
,, summit of, 87, 131, 132
,, surroundings of, 47
,, towns of, 52, 62, 72
,, views of, 63, 70
Via Appia, 23
,, Domitiana, 23
,, Puteolana, 24
,, Roma, 48
Vicenian hills, 1 8
Villa Nazionale, 48
,, of Lucullus, 37
Vinchieta, 153
Virgil, 28, 29, 43, 49
Viterbo, 235
Vitreous perlite, 237
Vitruvius, 37, 97
Voccole, 92
Volcanic action, 19, 32, 45, 81, 187,
1 88, 200, 205, 206, 207,
208, 209
,, action, hypothesis of, 189,
190, 194, 196, 198, 201,
202, 2IO, 211, 212
ash, 32, 50, loo, 1 08, 109,
III, 115, 120, 128, 129,
139, 140, 143, 146, 159,
221, 240, 356, 360, 361,
362, 363, 364, 367, 369,
37i, 373
,, bombs, 128, 133, 224
cinders, 109, 132, 133, 224,
357, 358
400
INDEX.
Volcanic darkness, 140, 358, 360, 361
earthquakes, 32, 45
ejections, 133, 134
eruptions, 45, 65, 81, 102, 140
explosive, 107,
1 08, 130, 131, 134, 147,
208, 209, 215, 216, 241
eruptions, external, 140, 143
,, non-explosive, 208,
209, 216
flame, 133, 146, 148, 226, 227,
357. 362, 363. 366, 369
foci, 207, 212, 213
fumes, 39, 40, 92, no, 132,
133,141,143, 145,227,242
floods, 104, 108, in, 235,
247
,, islands, 184, 185
lightning, no, 143, 227, 233,
234
mud, 32, 100, 210, 233, 235,
247, 367
products, 195, 206, 217, 218
,, catalogue of, 218
rain, 104, in, 143
rocks, acidic, 25, 26, 206,
229, 232, 237, 239, 243,
244, 246
rocks, basic, 73, 206, 229,
243. 293
rocks, sequence of, 206
sand, 140, 222, 327
smoke, 128, 138, 139, 143,
144, 145, 146, 147, 221,
233, 234, 240, 363, 364,
3 6 5376
soils, 45, 72, 73, 74, 75
steam, 32, 39, 64, 65, 92, 100,
104, in, 125, 127, 133,
141, 147, 149, 191, 196,
208, 214, 215, 216, 221,
240, 241, 242, 247
,, thunderings, 107, 1 08, 109,
118,139,140,144,367,376
vents, cause of, 216
Volcanic water, 108, 191, 192, 193,
196, 202, 203, 208, 210,
213,214,215,216,234,369
Volcanoes, distribution of, 191, 207,
208, 215, 216
,, conduits of, 209, 214, 215
cones of, 27, 45, 164, 165,
184, 185, 209
dormant, 209
extinct, 208
craters of, 24, 26, 27, 30,
38, 43, 44, 45, 69, 83,
90,91,96,138, 172, 173,
174, I75> J 76, 184
dykes of, 158, 168, 177,
178, 184, 209
,, form of, 184
fissures of, 115, 120, 137,
139, 158, 159
,, structure of, 43, 165
,, sympathy between, 2IO
Von Buch, 44, 184, 219
Von Cotta, 220, 240, 243, 244
Von Kobell, 302
Von Leonhard, 235
Vulcanello, 19, 207
Vulcano, 19, 173, 207
Vulcanology, 211
Vulturno, 22
Vulturnum, 23
Wacht, 284
Wagnerite, 333
Walker, Rev. Dr., 372
Waltershausen, 205
Well borings at Naples, 182, 379
Wells, falling of water in, 111,210
Wollastonite, 321, 333
Weathering of volcanoes, 184
Werner, 333
Wine of Vesuvius, 123
Zeolites, 258
Zircon, 334
Zurlite, 303
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