SECT. IV.
Damps.
the Toffee' of »gunpowder *;by the proportion at leaft. of two-to one.
Rarefied vapour if^of great ufe :in- Cornwall,tand enables tneigniners'
to get rid ofHhe Water, of their deepeft works,by. meam of the fire-
engine (as" will be more particularly fet, forth in the:fequd)^-.an
engine which adts more forcibly and coriftantly than any pthef
Hydraulic machine hitherto invented.
-Water having been now confidered in. its moft minute ftate;(that of
rarefied vapour^ it rnuft next be obferved; that damps rifing- in ,our
mines oftentimes fb affedt the miner that he.caniiot work, neither
will candles bum; This generally happens when the workings-are
got to any-great diftance from the communication with the" open air.;
and the reafon is this: Vapours are thrown up-by the heat of .that fire
which all bodies more or* lefs- contain in Ithemfelves or receive from
other bodies; but in a deep mine,they cannot rife much, above,the
furface of the ground, becaufe there is not .air -enough. m the- pafles
of the mine to buoy them up, confequehtly, they- are-,too..mpift,foir
refpiration, becaufe they want a foflicient mixture of air; neither can
they yield that inflammable -nourifhment tortfie..candle. which< coipj
mon air by its own elafticity, larid its mixtures-of>pik§'earthjt and
folphur, ■ at all times does afford; fp- that the flame ispftifleck ifeifig
equally unable to throw off the parts which.arejburn^^j^-Xq^promote
a fi^fh .fiicceffi<m ;of . cily: parts requ^Sftbf re^^®§^ fir^
Thefe fluggifh damps are" greater ’ or lefs obftrudtions to -tfie \yqrk-
ifien, according to the moiflure or drought of] ;thft ground -biihey
have nothing pernicious,* generally fpeaking,;, in th^r- own-jna^^ ;
they reft near the bottom,, and incommode ,mer©ly forj,want;i9t -,an
a&ive air to difpell and raife them higher.
damps are infeded with mundic, and are then'}Very finy^ipTome,
creating naufeatings in the ftomach,
vifage fickly and wan; but I never yetheard of any damp§3in our
Comifh mines fb venomous as to be immediately.-fatal; the;? reafon
of which may be this, that moft of-our mines,'yiel^iaji|B^Rti;lif
Water in the bottom; this ftirs and carries off the damps, and prevents
their ftagnating into a thicknefs which clogs and flops all vital
motion. In order to admit the air,- a pipe or . funnel qf.ffomed
timber, about nine inches fquare, is ufoally fixed, and reaches from
the top to the bottom of the mine ; and when the damps are thick
and ftubborn, the air is aflifted in its defcent by a bellows applied, to
the pipe. But this is a very flow and infofficient remedy where
any dangerous damps are apprehended. Much more effedual it is,
according to a modern author11, to throw from; you as far as poffible
1 Muflchenbr. p. 429. Se£t. 873. k Letter to Mr. Hoofon, author of the Miner’s
Didtionary.
into
into the fufpeded or tainted pit, two quarts of fpiritus Urinofus
?y®ktilis, Whiehl will: ‘ qecafion feasgreat a rarefa<Sfof$as 'to overpower
the- "pckfonous t vjtppursj asd fofpa Sp^etime'* fojpply&fihe-' -want of
airk "the mfffierl taking; care nofe^^'^nahedtintb the. pit t#L twelve
hours aftent-he infufion. ;Dr. Plbt5^rd p ofa l1 k more ehfilylexecuted.
He advifesp that one peck of unpacked iktfet may be thrown into
fuch’ fiipe&ed pktee^iiwhich flak^iarijEthei^ater, 'and-'fiiming' out’
a^tHeftbp,, willffd,ueff©t9iually' difpdialL poifon'ouS vapours arra little
ti&e, j^hat' there will homo furth«ianger. ' Thefe,. may! ferve for
temporary expedients, .,but, the moft |eff©(ftua^i’> though-’experifivb
remedy is by'a frefh fhafk“, to open ;a mommtiniGation -betwixt the.
drift»».and the ^common t air.
u The Dews in.vGorhwall are.’ nofejBrematkablyivrimiouS dither
herbs .or animals, which TattriHute to^huEskavklg jno .long: calms/
nor laftjng fogs.
^Springs may be divided into fimple'iand riiineral. SimplI^Spring^
|VaJer 'may ahe--.,confidered either kaS-' foperficial or ‘fdbtdrraneOus.;
By, the Superficial, ;I.mean thofe.‘•Springs1’, which’--'-rife-routrof,- or1
iflue* frqm, the furface.1 of the .'.earth by. the tfefetetaaneotis,(i-fch'oie
which have their 'dianels1i deeper}? ‘ and1 rWifiCbUfIc^l'drfgbrrrinder-
- ground. oThat .fuperficial Springs tarelthe iqffq^aoferainfi^dtdewslf
cannot well be difputed, when we$fee their-, etfereafe. »and Vdetereafe,
according as the jj feafonrproves wet, lor-MPthejrWifeq-i but-Whence ?the
ptbtfrraneous, and. thofe which -feel .no, a^emtionxfrom < the* fcafe>n$
fleriyed^k-bfigm,has - employed the enquiries •ofikhe.'.driifious, and
hitherto .divided their ientiments.? fobterraneous
heat; .and no .one. labours; more ftrenuoufly.for this opi-
niofi;,' than the learned.Morton, in'-his NaturaHHiftory \o%Nbrth-
amptonfhire,l who has not only adopted,whatsidthers^hav©-produced
for,’ the. better-*; cnnfirmatinn of this hypothefis^tfbuf diadhpEoduced'
foveral thermomett^^gteriments of his;, own, 'ini orders to »eftablilh-
t i™ He derives Springs ^ conftahts'Springs Lm.OT.e.' .'efpecially*): ' ham
Vapours thrown up by fo|Oterraneotis heatr, and thinks hisrob&rva-;
tSons pianifeftly^ew hc®t, the Water:of fueh- Springs isfjflft^ppBed.'
His arguments are drawn from.-the heat people .feel at their firfb
entering ,the. pit or well, 'Whicfoheatj.encrsafes^manifeftfy.affithey
defeend h That .wells in ifencHare hotter than: any* other-» afi^hke
depth ; and that the qext degree.tofv heat* m/>vefiaj]fiav,in:ithofe. cut
..into a .rock: That the i .fainting« vwhieh feize.-Sthe .workmen, are
t< page’163... " NorthumptonflliiT, page 296. ‘ ,
■ bSt'Bhe pit by which we defeeud into mines wc 0 lb. 207.
call a,fliaft. ' .
p tta r.v .
ip'Bi^and
[heirOrigine.
H owing