the answer I received from a very ingenious Gentleman who lives among mines and is not a little concern'd in some of them For having inquired of him What he had observed about the lying or not lying of the Snow on the minerall Soils near the place of his Residence he replyed that in some of them he did not take notice of any peculiar Indisposition to let the Ice and Snow continue on them which I conceive may proceed either from the want of such mineralls in the Subjacent parts as were then in the state of Incalescence or else from this that according to what we have elsewhere observed about the Snows on Aetna the direct ascension of the hot Steams was hindered by some Layers of Rocks or other Stone through which the Steams could not penetrate or could doe it but so slowly as to loose their actuall warmth by the way But this Gentleman added that in other places near that of his abode and such as he knew to have minerall-Veins beneath them he observed that the Snow nor the Ice would scarce continue at all upon the Surface of the Ground even in an extraordinarily cold winter It will be a considerable Instance to our purpose if it be indeed true which some learned men have written that near the Gold-mines in Hungary the leaves of the trees especially those that respct the Ground are oftentimes found ennobled with a golden-colour from the metalline Exhalations of the Gold-mines which one would think must by reason of their ponderousnesse need a considerable heat to elevate them especially into the open Air. But though doubting of this Relation as not made by mineralists or accurate Observers I inquired about it of a person whose Curiosity carried him purposely to visit those mines I was answerd that he could not be a witnesse to the truth of the Observation yet he told me an observation which I else where mention that doth not discountenance that Tradition If it be objected that what has hitherto been said about Latent Fires and heats in the Bowells of the Earth will give an account of the warmth only of those places that are within teach of the action of such Magazines of heat which probably may be wanting in many places of the Earth I shall readily confesse that as I first made this Objection to my selfe so I do not yet discern it to be unreasonable and that for ought I know if men had occasion to digg as deep and be as far conversant in many other low places of the Earth where there are no signs of Mineralls as they have done where the hopes of actuall discovery of veins of metalls and other mineralls worth working have invited them divers places in the Third Region of the Earth would be met with that would bedestitute of the warmth that has hitherto been generally found in places of the same Region that either abound with mineralls themselves or are near some of the deep and latent Aestuaries above-mentioned And as for those parts of the Third Region of the Earth which men feel not only warm but troublesomly hot that incommodious degree of heat seems not at least in some places to be derivable from the two above mentioned causes which must to produce so considerable an effect be assisted by a third cause more potent then themselves which seems to be the incalescence there is produced in many mines and other Places by the mutuall action of the component parts promoted by water of immature and more loosely contexted mineralls especially such as are of a Marchasiticall nature That such an Incalescence may by such a way be produced in the Bowells of the Earth I have elsewhere shewn in my discourse of Subterraneall Fires heats by the examples of such incalescences producible in minerall Bodies here above ground That Marchasites which for the most part abound in Vitrioll are bodies very fit to procure this Subterraneall heat may be consirm'd not only by the Sulphureous and Saline parts they abound with and by this that many of them may be wrought on as we have tryed both by simple water and even by moist Air which argues the resolublenesse of their Constitution but also by this that having purposely inquired of a Gentleman that went out of Curiosity to visit one of the deeper Hungarian mines he confirmed to me what I had otherwise been informed of by answering me that in the lower parts of the mâ—ne he had gathered Vitrioll that appâ—ared above ground to be of a golden nature and that in a Cave that is on one side of the Groove in the deep Gold-mine near Cremnitzo the corrosive smell is so strong and noxious that men have not dared to dig out the native Gold it richly abounds with being deterr'd by the ill fate of livers that ventured to work in it Adding that though he passed by it in great hast yet he could not avoid the being offended by the noysome Exhalations And on this occasion 't will not be I presume disliked if I illustrate what I was saving of Immature mineralls by subjoining That having asked this Chymist whether the Vitrioll he found very deep underground were all solid or some of it soft he affirm'd that as he gathered it he found some of it soft And to satisfy my curiosity to know whether it continued that yeilding consistence he further told me that it was soft in the deeper part of the mine but when he had brought it into the Superterrestriall Air it hardened there and appeared to have 9 divers golden streakes in it CHAP. X. ONe thing there is which must not be here omitted though it will probably be great news to those that philosophize only in their studies and have not received information from any that visited the deeper parts of the Earth The Phaenomenon is this That the Diggers in mines having found by unwelcom experience that in deep Grooves the Air unless ventilated and renewed dos in a short time become unfit for respiration have been put upon this expedient to sinke at some convenient distance from the Groove where the miners worke another pit by some called a vent pitt that usually tends directly downwards though sometimes it make Angels to which our English-minemen do in severall parts of this Kingdom give differing names whereof the most signisicant seems to be that given it in the Leadmines of Darbyshire where they call it an Air-shaft and are wont to make it 40 50 and sometimes 80 or 100 paces off and as one of the cheife and skillfull Miners there informed me as deep as the Groove or Well Though I find that the best German and some English Miners think a less depth will often suffice From this Air-shaft to the Groove the men work in there passes a Channell or if I may so call it Ventiduct to convey the Air from the former to the latter which is that that Agricola sometimes for he employs not the Terme alwaies in the same sense denotes
The Tract here pointed at is a Discourse of Subterraneall Fires and Heats that many of them will conceive a very considerable degree of heat will it not be very probable that the Temperature of the Earth in the place that abounds with these Marchasiticall mineralls will be very warm in comparison of the Temperature of the other place where the Soil dos plentifully produce nitrous and other refrigerating Bodies though both the places be supposed to be at the same distance from the surface of the Earth and consequently in the same Subterraneous Region Upon the like grounds it may also be suspected that in the same places the Temperature may not be alwaies the same even upon the account of the Soil For I elsewhere shew that some Saline Earths especially nitrous and some mineralls that partake of the nature of marchasites admit a kind of graduall maturation and perhaps other Changes that seem to be spontaneous And that such changes happen the more notably in those parts of such Bodies that are exposed to the Air as those are that chance to be placed at the sides of the deep Wells we are talking of Which things being presupposed 't will not be absurd to conceive that the minerall to which either heat or cold is to be referr'd may be more copious ripe and operative at one time then at another or that at length all the Earth capable of being as it were Assimilated by the minerall rudiments harbour'd in it may be consumed or the minerall it selfe may arrive at a perfection of maturity which will make its texture so close as to be unfit to be penetrated and wrought upon as before by the water or other Liquor that occasioned its incalescence CHAP VII I Omit to speak of the transient changes that may be occasion'd in the temperature of the second Region of the Earth by severall Accidents and especially by the Subterraneall Exhalations that in some places and times copiously ascend out of the lower Regions of the Earth Nor shall I insist upon any of the other causes of a more durable difference of temper in some parts of the second Region such as may be the Vicinity of Subterraneall Fires in the third Region that heat the incumbent Soil because I would hasten to the Third and last part of this Discourse which yet I must not do without premising this advertisement that I think my selfe oblig'd to speak the more hesitantly and diffidently about the Temperature of Subterraneall Air because mineralists have not had the Curiosity to examine it by Weather-glasses which would give us much more trusty Informations then our sense of feeling powerfully preaffected by the cold or heat of the externall Air. I did indeed send fitt Instruments to some daies journey from this place to examine the Air at the bottom of some of our deep mines but through some unlucky casualties upon the place the attempt miscarried But when I shall God assisting recover an opportunity that I have since wanted I hope an accurate seal'd Weather-glasse join'd with a portable Baroscope will give me better Information then mineralists have yet done I say a seal'd Weather-glasse because though common Thermoscopes had been employed by miners I durst not rely upon them being perswaded by tryalls purposely made as well as by the Reason of the thing of the Fallaciousnesse of such Thermoscopes for in them the included Air is liable to be wrought upon not only by the Heat and coldnesse but by the weight or Pressure of the externall Air. So that if a Thermoscope be let down from a very considerable height at the top of which the station of the pendulous Liquor be well markt that Liquor will be found to have risen when the Instrument rests at the bottom as if the included Air were manifestly refrigerated though the temper of the externall Air may be in both places alike the cause of the pendulous Liquors rising being indeed that the Aereall pillar incumbent on the stagnant Liquor is higher and heavier at the bottom where the Instrument rests then that which lean'd upon it at its first or upper station nearer the top of the Atmospher From whence 't will be easy to conclude that at the bottom of a deep Groove where the Atmosphericall pillar that presses the stagnant water will be much longer and heavier then at the top the Air may appear by the Instrument to be colder in places where 't is really much hotter the increased weight of the incumbent Air being more forcible to impell up the pendulous Liquor then the indeavour of expansion procur'd in the included Air by the warmth of the place is to depresse it CHAP. VIII THat which challenges the third and last part of my discourse is the lowermost Region of the Earth about whose temperature I shall comprize what I have to say in the following Proposition Proposition the 4. The third Region of the Earth has been observed to be constantly and sensibly warm but not uniformly so being in some places considerably hot I mention that the recited temperature has been observed in the Lower Region because I would intimate that I wovld have the proposition understood with this Limitation as far as has been yet that I know of observed For allmost all the deep Grooves that mineralists have given us accounts of and wherein men have wrought long enough to take sufficient notice of the Temperature of the Air have been made in Soils furnished with metalline Oars or other mineralls without which men would not be invited to be at so great a charge as that of sinking so very deep pits and maintaining work-men in them So that experience has yet but slenderly or at least not sufficiently informed us of the Temperature of those parts of the third Region of the Earth that are not furnished with ponderous mineralls and consequently has not informed us of the Temperature of the Lowermost Region in generall as will better appear by what I shall ere long represent Having premised this Advertisement about our proposition we may proceed to the distinct proofe of the two parts or members it consists of And to begin with the first whatever the Peripateticks teach of the innate Coldnesse of the Earth especially where 't is remotest from the mixture of the other Elements yet having purposely inquired of severall persons that visited and also frequented the Third Region in differing Countries Soils and at differing depths under ground and Seasons of the year I did not perceive that any of them had ever found it sensibly and troublesome cold in the Third Region of the Earth And on this occasion I remember I had some light suspition that at least in some Cases the narrowness of the Cavities wherein the Diggers were in divers places reduc'd to worke might make the warmth they felt proceed in great part from the Steams of their own Bodies and perhaps of the mineralls and from the Difficulty of cooling or ventilating the Blood in an
Air clogg'd with steams And I was the rather induced to thinke this possible because I had even in metalline mines that were but shallow and very freely accessible to the Air observed a strong smell of the metall abounding there I have likewise found by severall tryalls that the exhalations that proceed from the Bodies of Animalls doe so vitiate the Air they abound in as to make it much less fit for their Respiration and to be apt to make them sick and faint Wherefore I thought it not altogether unfit to inquire whether the heat of the Subterraneall air in such places as have been newly mentioned might not be referr'd to these Causes But I was answered in the negative especially by an inquisitive person that had been in the deepest and hottest mines that have been visited by any Acquaintances of mine This way of accounting for the Subterraneall Warmth being laid aside it seem'd I confesse somewhat difficult to conceive how it should be produced yet two principall Causes there are to which I thinke we may probably refer the Temperature of those places where the air is but moderately warm To which a Third is to be added when we come to give an account why some places are troublesomly hot And first why the Coldnesse of Winter should not be felt in the Lowermost Region of the Earth may be that the air there is too remote from the Superterrestriall air to be much affected with those adventitious Causes of Cold that make that Quality intense in the air above ground But because this Reason shews rather why it should not be in the Earths Lower Region much Colder in Winter then in Summer but not why it should be in all seasons warm there I shall add as a Conjecture that the positive cause of the actuall warmth may proceed from those deeper parts of the Subterraneall Region which ly beneath those places which men have yet had occasion and ability to dig For it seems probable to me that in these yet inpenetrated Bowells of the Earth there are great store-houses of either actuall Fires or places considerably Hot or in some Regions of both from which Reconditories if I may so call them or magazines of hypogeall heat that quality is communicated especially by Subterraneall Channells Clefts Fibres or other Conveyances to the less deep parts of the Earth either by a propagation of heat through the substance of the interposed part of the Soil as when the upper part of an Oven is remissly heated by the same Agents that produce an intense heat in the Cavity or by a more easy diffusion of the Fire or heat through the above mentioned Conveyances as may be exemplified by the pipes that convey heat in some Chymicall structures Or else which is perhaps the most usuall way by sending upwards hot minerall Exhalations and Steams which by reason of the comparatively heavy materialls they consist of and by reason of their being lesse dispersed nearer the places whence they proceed are usually more plentifull in the deeper parts of the Earth and somewhat affect them with the Quality that they brought from the workhouses where they were form'd and that they retain for some time after CHAP. IX THat manifest Steams oftentimes are found in Grooves especially in deep ones is evident by the damps that infest most of them and that in distant Regions as in severall provinces of Germany Bohemia Hungary c. as also in severall parts of England in Grooves some of which I have received Relations from the mine-men themselves By which it appears that severall of these Exhalations ascending from the entralls of the Earth are sulphureous Bituminous in smell and in some Grooves one whereof I elsewhere mention my selfe to have visited these Steams are apt actually to take fire The warmth of many Subterraneall Exhations I thinke may be made further probable by some other Observations For though these newly mentioned are not to be rejected and may be employed for want of better yet I have severall times questioned whether I ought to acquiesce in them alone For I do not thinke the easy inflammableness of Bodies to be alwaies a sure proofe of the actuall sensible warmth of the minute parts it consists of or may be reduced into For though Salt-peter be very inflammable yet being by a solution in fair water reduced to invisible Corpuscles it highly refrigerates that Liquor Nor have I observed its fumes when far from the Fire to have any heat sensible to our Touch. And the like may be said of the Exhalations of highly rectifi'd spirit of Wine which yet we know is itselfe totally inflammable Nay I know not whether for a Reason elsewhere declared copious Exhalations may not ascend from the lower parts of the Earth and yet be rather Cold then Hot. For in another Paper I mention a way by which I made a mixture that plentifully enough enitted Steams of whose being rather of a Cold then hot nature there was this probability that the mixture whence they ascended even whilsts its component Ingredients were briskly acting upon one another was not only sensibly but considerably Cold. One main thing therefore that induces me to assent to the Opinion whereto the former Instances do but incline me is That having purposely inquired of an observing man that frequented deep mines wherein he had a considerable share he answered me that he plainly observed the fumes that came out of the mouths of the deep pits to be actually and sensibly warm and that in a warm season of the year And Morinus above cited speaking of the deep Hungarian-mines makes it the first Epithite of the copious Exhalation that ascended from the bottom that it was hot And a few pages after he says that at the mouth of the Well the ascending Fumes were sensibly hot in Summer it selfe And the same Arguments that I have elsewhere given to shew that there are very hot places and as it were Aestuary in the Bowells of the Earth may serve to make it probable that the steams ascending thence may be actually warm That also in many places of the Earth where no Grooves are dugg and no visible Exhalations are taken notice of they may yet pervade the Soil and exercise some operations of warmth may be probable by this that the experienced Agricola himselfe reckons it among the signs of a latent minerall vein that the hoar-frost does not ly upon that tract of the Surface of the Earth under which a vein though perhaps very deep runs The like Directions I have known given by the skillfull in England for the Discovery of places that contain Coal-mines And I remember a near relation of mine shewed me a great scope of Land of his which though in an outward appearance likely to be as cold as any place thereabouts he affirm'd would not suffer Snow to ly upon it above a day or two in the midst of Winter The probability of which Relation was confirmed to me by