the moifture of weather, improper ftqnes, and broken cement, but
by firft imbibing ftrbngly, then'^efting.pd detaining the damps,
and dtaining the cement jpas that’^ capnot tranfmit its dampnéfs
through the walls: thié^bnck^w^l dó.ÜÜ it is faturated with , redundant
nioifture, arid thenitqb^atesdamps no longer ; and it follows,
that the tnoré our .granites partake of the nature of bricks, the
dryer they .are for walling; dn thè other hand, the more they admit
and condenfe, and the f jeafier vtheyf qu.i,t anjl vdifperfe the moifture
they receive, thè greater damps they, Accafion,^keeping the body of
the cement, and every thing contiguous, .in a continual unwhole-
Ibme ftate of moifture. _
.C H A P . X.
O f Stones o f Ornament and Curiofity^ viz. Pebbles, Flfhts, Porphyry,
Haky Stala&ites, AJbefios, and fmall Gems found iit Cornwall.
TH E R E are no gravel pits where pebbles rand Hints ; lie tin
heaps, and Jlrata at prefent difcovered in Cornwall, which
have reached my knowledge, but nature has made Sufficient amends
by heftrewing the beach o f our bays abd creeks with aminfeute
number of pebbles, flints, and nodules. Here therefore;the curious
Naturalift will find, Ipread as it were for his betterbbjeiyatibia,
a large colle&ion, wherein, though tKbre' are many duplicates,;.yet
is there a greater diverfity of curious ftones on^a beach^qf aa few
furlongs, than are to be found in fome^hundreds of'miles.^travelled
over in the inland country. When the. learned-travel, theyr;8nly
take notice of, and colled; what; is rare to them, or not yet de-
fcribed; whence it happens oftentimes, that thole things. yhich
are reckoned among the moft entertaining produds of nature in
other countries, lie on our own fhores negleded, ; merely becaufe
they are well known to the Literati, and Found in other places , by
the occasional vifitors of this, and other particular counties.
I fhall range the pebbles by the colour of their grounds as I have
done before by the granites.
x. N ’. i . O f the white pebbles lome are veined like marble, fome
clouded with a lively flefli-colour, lome variegated with purple and
other fpots, as well as veined, others charged with black pebbles,
fome rough and gritty to the touch, others fmooth, fome tranfoa-
rent as rock cryftal. O f this laft fort I have feen a feal cut out of
(what the lapidaries call) Pebble Cryftal, extreamly bright and clear:
the pebble was found, as I am informed, on the top of Routor,
the
the .higheft hill in Cornwall according to my eftimate'. It is alio
found in our mines,- but feldom; the only one. I have feen was
taken out o f a mine, called Huel-toyal, in Camborn; it was quite
ovular, half uncovered and half fixed in a focket o f angular and
puculated cryftal; one inch and half long, and one inch and one-
fifth wide : hut our white pebbles are moftly of an opake white
quartz; ;
,< N°. 2v O f the yellow kind oUr pebbles are ufoally of a high
polifli and amber-like fubftance,.'differently clouded, veined, or
zlpotted;- with| other colours.
'5 N°. 3. Pebbles of,a green ground are rare wjth us, none which I
have met with tranfparent; in fome.the willow-grccn is charged with
pale-yellow cryftalline granules, th& charge prominent, fhewing that
it is o f a harder firm® confidence than the ground.
N'°. 4.; O f the ruddy ground 'Some o i a faint lake-colour have
large irregular granules of opake white quartz funk in them,
thereby* approving themfelves fofter than the ground.
i O f . the,. brown-red fome are of a high polifh, fine texture,
clouded | with red interfered by a blackifli vein, plainly of the
agate kind.:,.;
• 5• Pebbles ..of the blue ground are very differently charged;
ofie o f a- blue killas is leeded with innumerable little micaceous
IpotSj .of-fo' faint ateaftas lcafce diftinguilhable from the ground;
faencfamgeM thin Iprinkling of opake white quartz; the ftone is
porous, and to the touch feels rough, as any granite pebble.
Another o f blue killas- is charged with pale, flefh-colourcd,
toothy, grains, from an inch diameter and under, and differs only
from the Bolworlas granites (beforementioned page, 101) in this,
that its ground is blue inftead o f black.
O f a blue-black, fome are of a very high polifli, and dole
texture« >
||M k 6. -Of the black ground, lome pebbles are lb equal a mixture
of ftriated glofly eockle and white quartz, that were not the latter
in diftind granules from the fourth of an inch and under; it would
be difficult to dedde which is the ground and which the charge;
it is a pretty motded ftone, but rough and Icabrous to the touch.
A black flattilh pebble, finooth, but of no great polilh ;
its fibres parallel and longitudinal ; it has the properties o f a true
touch-ftone. It was brought me from the lea-fliore in the parilh
of St. Kevran, and feems to owe* its pebbly figure to the attrition of
the waters ; lb that it is not unlikely that there Ihould be thereabouts
fome courle of black marble of the nature o f the lapis Lydius,
1 Xn Oxfordmfre they fometimes find fuch pebbles wholly pellucid, about the bignefs of a wallnut.
Woodward’s Cat. Vol. I, page 32. '
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