of the fame nature with the former ides. T a m a has;oji itscfhores
coral rocks and madrepores): the beaches, are covered with a blackilh
land, conlifting o f minute pieces of hierhahd.pumice-hdrie, which are
formed by the allies conhantly thrown up'by avolctadj and fcattered
over the whole furfacoof the lfland. ■ (f'tlm 'ex’cinerarias, "Linn.')) .The
furface of the whole ille. conlihs therefore o f this pumiffe-fand
mixed .with a black mould formed - by the i pu trifled vegetables.
T h e pumice-land is very abundant:;, for- there ijt a t■ certain times,:
feveral .leagues diftant from the volcano,: .not a leaf :of any tree:or
plant, nor any grafs, which is not entirely covered with alhes,
which' I examined, jindJound to be this very pumice-land : however,:
this forms, a: mod: admirable alhy, fertile, foil, in which all vegetables
thrive with the .-greateft luxuriance. . We found a few tingle detached
rock-hones; being a mixture o f quartz and black dazfoor
m ica; nay, one o f thefe pieces was a coarfe.dilfolved granite,-covered
with black button-ore, which is a fort o f iron-ore.
T h e chief ftrata o f the ille, as far as . I could form-a judgment o f
them, foom, the various cliffs: furrounding the harbour, are o f a clay
mixed, with aluminous earth, interlperfed with lumps o f pure chalk:
T h e flrata o f th e clay are about £x inches more or lefs, deviating
very little from the horizontal line. In a few places I found a foft,
blackilh fand-hone,' compofed o f the alhes fpread by the volcano1,
andfome parts o f clay.1:; 'Here and there I obferved a fubhance commonly
monly called, rotten-ftonei which. & • a .brown clayey, tripoli ; and, s t r a t a .
between the. rotten-hone and the: above-mentioned fand-hone, is a
hfatum containing both mixed together. High on the fides o f the
hills, towards the volcano, I found à whitilh, argillaceous fubhance,
through : which aqueous: and, Mphufèous; : beams): 1 ftom thd-very
neighbourhood o f the volcano, werebontinually rifing, and ■ made
the place intenfely hot.: its tahe is hyptic,:and I believe.aluminous
Some nativç.;hdpbup;y!«$;toqbe-feen in this earth, : together with
Icyeral green fpecks or marks o f copper. Under thefe folfataras,
(which, , at each eruption from the volcano, emitted greater quantities?,
o f hot beams) are lèverai hot wells, elofe to the'high-water
mark, which, however, feem not to be in the leah fulphureous. I
K ■ found
. the neighbourhood of the .folfataras: infTanpa contains volcanic productions. The
floitles hear it<are îaÿàs ; .thé' fand cohfifts 'of Vôlcàfric ifhesX and' the''foil is clay mixed' witli
this fand. j It:is therefore beyond any doubt, that .the., clayey, white, fubftance, found in the
very îpiràculum^ is‘ nothing but a new modification of the Volcanic productions. The “firil
who ever had this idea, that clays are produced by an operation of the vitriolic acid upon vi-
trefeent or vitrified fuhitanc.es, is the ingenious Mr. Beaurne, who founded it on a feries of
experiments. , But thd,very firft,iwhoapplied, this idea .tp, the great operations o f -nature in
the folfataras, is Mr. Berber, the molt intelligent, and moft accurate mineralogipal writer of
this age, -which may be feen more at largeEïn'hià xith létter-, dâtcd Fehfuàl,y-i ÿ, -iy72; pub-î
lifhed in his Travels through Italy, tranflated b y Mr. Rafpe. Sir William Hamilton, that indefatigable
,obfervef’b f volcanos, had already examined -the ToMateira' h r iÿ y r ; “ but heTe'ems,
at .that.time, not to have had, the leaft intimation ofr this remarkable process ; fince,. in his
letter to Dr. Maty,'dated March 5, 1771; he calls thè'öpëration going forward i t the fofia-'
tara frcakinatitm :: ,$nd he mentions to bave,feen half o f a large piece-of Iftya, pcffêih calcined,
vjlnlfl the' other half oufo f the reach 'óf the vapours,' has been üntouchef; anfin fomfpicces, thccen-
tre ferns to be already .converted into true marble.,* Xh^Gj whifilh gl&ys-rmig/f even by their
appearance, fays Mr. Ferber, p. 165, be mifaken fo r limc-flone ; no wonder, therefore, that
they fhould fuggeft the idea of calcination and of true marble*.