terribly, that a man there at work ran out.jof it, concluding it to
be falling» Several perfons then in the mine,-working fixty fathom
deep* thought they found the earth about them to move, ’and heard
an uncommon noile : fotae heard the noife, and felt nb-themor;
others, working in a'mine adjoining, tailed I&efoBflfog, were fo
frightened, that they called to theirdompaniohs above to tbe draWri
Up from the bottoms: their mobrhoufe was fhaken, and the padlock
of their candte-cheft was heard to ftrike againft the ftapfes.-—
To<fhew that this noife proceeded from below^ and not from any
concuflion in the atmofphere above, this very intelligent cdpt-am of
the mine • obferves from his own experience, that thunder was nevef
known to afffedt the air at fixty fathoms deep, even in a fingle lhaft
pierced into the hardeft ftone; much Ids could it continue the
found through fuch workings as there are in this mine, impeded in
ail parts with deads, great quantities of timber, various noifes, fuch
as the rattling of chains, friftion of wheels and ropes, and dafhing
o f waters; all which muft contribute to break the vibrations of. the
air as they defcend: and I entirely agfee with this’ gentleman’s
conclufion, that thunder, or any other noife from above in the a©
moiphere, could not be heard at half the depth of this mine.
This therefore could be no other than a real tremor q$|th<x- earth,
attended with a noife owing to a current of air and vapotif proceeding
upwards from the earth.
I do not hear of any perfcn fouthofe parts who was fo fortunate•
as to be near any pool or lake, and had recolleiftion enough to
attend to the motion of die waters; but it may be taken for granted,
that, during the tremors o f thefeaffh,* the , fluids muft bef>teoi#'af-
fedted than the folids; nay the Watters will apparently bd agitated
when there is no motion of the earth perceptibly IS was the Pafe
of our ponds and lake-waters in moft parts of Britain, on the ift of
November 1755 f : whence this comes is difficult to fe y ; whether
the earth’s bofom undergoes at fuch times a kind of refpiration, and
alternately emits and withdraws a vapour through its more porous
parts fefficient to agitate the Waters, yet not foffieient to fbake the
earth; or whether the earth, during the agitation of the waters,
does rock and vacillate, though not fo as to be fenfible to man, is
what I fhall leave to future enquiry.
Earthquakes are very rare in Cornwall; this was but of fhort duration,
and did no harm any-where, as far as I can learn; and it is
to be hoped not the fooner forgotten for that reafon, but rather remembered
with all the impreffions of gratitude fuitable to an incident
fo alarming and dangerous, and yet fo fparing and inoffenfive.
If Philofophical Tranfaftions, 1756.
C H A P ,
c Mr. John Nancarrow.
0ÜG H A P.
O f thé fü r ihfy^ _ th&JSouM t and fteatites. ó f ■ Óórnwall.
T HE vegetable Soils may be diftinguifhed into three forts, the sect.r.
black and gritty, the fhelfy flatty Soil, and the ftiff redifofh
Soil, .approaching more to the nature of Qlay. •.
The higheft1’grounds are covered' with the'black Sqil, ,and oln the sbct.ii.
Jtops andftdes of hills, 'iewfoilax-.and cold,^iritl'.faltsrfadifperfe^
by the rain and.fhow, that wheredt is.dry atbottom it bears nothing
but,four graft, tm©fe?iJafoi heath, which is^duttup fo thin,turfs for •<
firing, or at beft, fhort, dwarf, conjm’oply palled Qoffofh Fur^e; where
the tains have not liberty to run off, bogs (though in Cqm^alJ none
.dangerous or extenfive) and marfhes are formed: here the^ojl- fo Ipfs
gravelly and deeper, but'to be rang’d among tfo black .Sojfo, and of
little othef ufc than that it yields a thick brick turf, full o f the matted
roots of fedge-graft, the juncus, and ,other mafoh-plants, which,
when thoroughly dryed, make a ftrong fuel. On the banks of the
riverH^l^fo the parifh ófSt.Erth, there is .a ftrqngf'gfofe-grafoed
.turf, which.I have feen cut'intb ^Wbs^-ten,inches fquare, and fix
deep: they were ranged in the {foe of a moorhouEc *-as regularly,
and alraoft as clofe, as i f they had been fquarod ftongSj jand' made,
inftcad of a hedge, a-moft neat wall, if I may, fay.fo, the corneas o f
the ends, doors, and windows, were fo welfoamed. This- turf has a
ftiff, white, compafi: clay under the fpine, whfoh gfofo it ’frs con-
fiftence. In crofts, farther dqwn from the fofos, this foaok^oil ferves
as wintering for horned cattle, bears good potatoes, ryefoiand pjlfas,
the avena nuda of Ray j in field-s, barley and oats, and ffoves as paf-
.ture for dairy and fheep, especially rearing young hfofocks; ..but fel-
foom turns to any account when fown with wheat, It -fo more or
left charged with gravel* and therefore called by thf iffornifli i^ouwi
.(or gravelly), foe earthy parts exceeding light, fo in a dry
fommer, the fun quickly exhales its moifture.; and, fo a m fe'
fummer or winter, the tilled grounds of this fort have much of the
vegetable Soil wafhed away from the grain.
A great part of the Cornifh ^oil, efoeciftlly about the -middle f©f sect.'iii.
the County, is of a -fhel-fy, flatty earth. , This, is reckoned to bear ,She®
better corn, efoeciahy wheat; as alfo a ftronger fofo e pf graft than
the
A hutt, belonging to a mine, for \6lie-feelter o f the.-workmen, -andjbëepkg feii- ijjp|ements.