M R Boyles HISTORY OF PARTICULAR QUALITIES.   

THREE TRACTS WRITTEN By the Honourable ROBERT boil.  
Of the 

Temperature of the Subterraneal Regions.  
Temperature of the Submarine Regions.  
Bottom of the Sea.    
OXFORD, Printed by W.H. for Ric. Davis.  
1671.   

ADVERTISEMENT.  
THe two following Tracts were designed to have been accompanied by three or four Others, whereof the First, Treated about the Temperature of the Regions of the Air, as to Heat and Cold, and had been premised to the Two that now come forth, had it not been judged more proper to reserve them to accompany some other Papers concerning the Air. To the following Tract about the Submarine Regions, it is thought fit to adjoin some Relations about the Bottom of the Sea, to which was to have been added some Observations, concerning the Saltness of the Sea; but in that Treatise, some Blanks having been left for Particulars, which the Author could not seasonably find among his Loose Papers to fill them up with, these that now appear, having no dependence on them, it was not thought sit they should stay any longer for them.  
But about these several Tracts, this General advertisement is to be here given, That being Historical Pieces, consisting chief, (though not only,) of such Particulars, as the Author must owe to the Informations of Others, he would not stake his Reputation for the Truth of every one of them; contenting himself, to have performed what can be reasonably expected of him; which is, that he should carefully make his Inquiries from credible Persons, who for the most part, deliver their Answer upon their own knowledge, and that he should faithfully set down the accounts he procured from such Relators.   

Of the TEMPERATURE Of the SUBTERRANEAL REGIONS, As to HEAT and COLD.  

OF THE TEMPERATURE, Of the SUBTERRANEAL REGIONS. As to Heat and Cold. CHAP. I  
IF when I used to visit mines, I had thought of writing on the subject I am now about to treat of, and had designed to satisfy myself about the Temperature of the Subterraneal Air, as much as I did about the other Subjects I was then concerned to be informed of, I think I should have enabled myself to deliver much more upon my own observation, than I shall now pretend to do. But though for the reason newly intimated, and because of my being particularly subject to be offended by any thing that hinders a full freedom of Respiration, I was not solicitous to go down into the deep mines; yet after having discoursed of the Temperature of the Air above Ground, I presume it may not be improper or unwellcome to say something of the Temperature of the Subterraneal Regions and of the Air reaching thither. For deep mines being places which very few have had the opportunity, and fewer have had the curiosity to visit, and of which I have scarce found any thing at all observable by Classic Authors, and by other writers, but very little, especially that I think probable enough to make use of, I presume it will not be unacceptable to you, if of Regions so little frequented, and less known, I report what I have been able to learn (by diligent enquiry purposely made) from the credible Relations of several Eye-witnesses differing in nation, and for the most part unacquainted with each other.  
Though I do not think it absurd to suspect that in some places of the Earth, the peculiar constitution of the Soil, and other circumstances, may make it reasonable to assign those places fewer or more Regions than three; yet speaking in the General, the Ternary number seems not inconvenient to be assigned to the Subterraneal Regions, not so much upon the score of the Analogy, that by this Division will be established between the Regions of the Earth and of the Air, as because there seems to be a reason of the Division included in the Division itself. And indeed Experience appears to favour it in the Subterraneal Cavity, that I have hitherto been able to procure an account of, from any Ocular witness, and (very few excepted) one of the deepest that we yet know of, in the world. And since it has been received for a Rule among Philosophers, that which is perfectest or compleatest in its kind, aught to be the Standard whereby the rest are to be measured, or estimated, I shall begin the remaining part of this Essay by a Relation that I obtained from a Chemist, that had purposely traveled into Hungary, and other places to visit the mines those parts are justly famous for, and who bringing me the honour of a Compliment from a Prince, to whom he belonged gave me the opportunity of ask him divers Questions, his Answers whereunto (which I presently after put into writing,) afforded me the ensuing account.   

CHAP. II.  
THat very near the Orifice of the Groove, he felt the Air yet warm; but afterwards descending towards the lower parts of the Groove, he felt it cold, till he came to such a depth, as he had scarce attained by a quarter of an hours descent, and that the Cold he felt during this time seemed to him considerable, especially when in descending he had reached to a good depth.  
That after he had passed that Cold Region, he began by degrees to come into a warmer one which increased in heat, as he went deeper and deeper. So that in the deeper veins he found the Workmen digging with only a slight garment over them; and the Subterraneal heat was much greater, then that of the free Air on the top of the Groove, though it were then Summer.  
[What is here mentioned of a cold region in the Earth, has been since confirmed to me by an ingenious Physician, upon an observation made in another Hungarian mine (near a Town whose name I remember not) that was not of Gold, but Copper; and of much lesser deepness than that newly spoken of. For this Relator answered me that in going down, he felt a considerable degree of Cold. And when I asked whether he found the like in his Return upwards, he told me, he observed it then too. And when I further inquired after the extent of this cold Region, he replied, that not expecting to be asked about such Circumstances, he had not taken particular notice of them: but thus much Information my Questions procured me, that he began to feel the above mentioned coldness when he could receive no more light at all by the mouth of the Groove, and that this cold Region lasted till he came somewhat near the bottom, which was estimated to be about an 100 fathom or more distant (in a straight Line) from the Top.]  
This Relation agrees well enough for the main, with that short, but considerable one of Morinus, (which I elsewhere cite) who above forty five years ago, visited the deep Hungarian-mines in the month of July, and takes notice, that when he came down to the burrows, as he calls them, he did not find any heat, as at the mouth of the Well; but the beginning of a very Cold, as well as considerably thick Region: though I easily believe him, when he confesses, that he felt it much the Colder, because he had left of his own Clothes, and put on the slight Garments used there by the Diggers. He further informs his Reader, that when they had descended about 80 fathoms beneath the surface of the Earth, he began to feel a breath of an almost lukewarm air; which warmth increased upon him, as he descended lower, pleasing him not a little, because it freed him from the troublesome scents of his former coldness. Adding that the Overseer of the mine who conducted him, affirmed to him, as also the Officers of other Hungarian mines unanimously did, that in all their mines, at least all the deep ones, after a thick tract of Cold Earth, there succeeds a Lower Region, that is always hot. And that after they arrived at such a depth, they felt not any more Cold, but always Heat, how deep soever they dig. And to add upon the by, though this Learned Man lay much weight upon Antiperistasis; yet in the next page to those that contain what I have been just now relating, he either very candidly or inconsiderately takes notice, that they informed him, that their mines, whether more or less deep, they observed that at some times in the year, a somewhat intenser heat was felt, and the two Times that he expressly names, are those oppositely qualified Seasons of Summer and Winter.  
Having laid down these general narratives, I now proceed to consider the Earth's Regions in particular, about which the Sum of what I yet have to propound, may be conveniently enough comprised in the 4 following Propositions.   

CHAP. III. Proposition the 1.  
THe First Region of the Earth is very variable, both as to Bounds, and as to Temperature.  
The former part of this observation will not be difficult to prove, since 'twill be easily granted, that the manifest operation of the Sunbeams is (caeteris paribus) greater, and reaches further in hot Climates then in Cold ones; in the midst of Summer, then in the depth of Winter.  
The Second part of the Observation may be proved by the same Arguments as the First; to which may be added, as to some places, the Solidity or porousness of the Earth, as also the nature of some Salts, Marchasites, and other Bodies contained in it, which by their natural Temperature may dispose the Soil to Coldness or Heat. As I shall have occasion to show, when I come to speak of the second Region.  
In the mean time I have this to observe further, That in this First Region, the Air is usually more temperate, as to Cold and Heat, then that above the surface of the Earth, and that this Region is not wont to be considerably deep: Both parts of which Observation are capable of being made good by the same Reasons, and therefore I shall endeavour to prove them jointly.  
That in the uppermost Region of the Earth, it should be less cold than above the surface, seems reasonable to be allowed upon this Consideration, That the Subterraneal Cavities of the Earth are sheltered by the thickness of the sides, from the direct action of the Sunbeams, the Winds, etc. and is also kept from an immediate, or at least from so full a contact of the external Air, when that is vehemently, either heated or refrigerated.  
And first as to the heat of the Sun, that That does much less powerfully affect such places as are sheltered from its action by solid Bodies, may appear by the Conservatories of Ice and Snow, wherein frozen water is kept in that State during all the Heat of Summer, and that oftentimes in Cavities that are at no considerable depth beneath the Superficies of the Earth. Nay I remember that having had occasion, (for the perfecting of some Conclusions I was trying) to keep Ice many weeks after the frosty Wether was gone, and a milder Season was come in, I was able to do it, (contrary to the expectation of some Curious men,) without either digging to a notable depth in the ground, or building any substantial Structure over the Cavity. For wanting conveniencies, I contented myself (though 'twere in a champain place) with a pit somewhat broad at the bottom, of about four foot deep or less, whose mouth was sheltered only by a little low thatched hovel, that was wide open to the North, and only screened the mouth or vent of the little pit from the direct Beams of the Sun. And though I will not deny, that in deep Conservatories of Snow, the natural Coldness of the Earth, especially in some places, may contribute to the effect; yet I remember, that discoursing once with a Traveller and Scholar that was born in hot Countries, of a conjecture of mine that in an arched building, whose walls were sufficiently thick, and whose Air were carefully kept from all avoidable intercourse with the external Air, one may without digging so much as a man's depth into the Ground, make a sufficient Conservatory for Ice in very open and unsheltered places, and even such as Salisbury plain itself; discoursing (as I began to say) with this Traveller about this Conjecture, he told me, that at a place he named to me, in the Southern part of France, whose heat seemed to me to exceed that of divers parts of Italy, some Curious persons that were resolved at any rate, to have Ice in Summer, though the Soil were such, that they could not dig 4 foot without meeting with water, were yet able to make use of Conservatories by covering the Brick-Building they made over their pits, with Clay and Sand to a very considerable thickness, and taking care that the only place that should permit access to the outward Air, should be a small Northern Door to go in and out at, fitted to shut exactly close, and fenced with a little porch furnished with another Door. And by this means he affirms these Gentlemen to reserve the included Ice not only all the Summer long, but sometimes for two or three years together, the heat of that Region making many of their Winters too mild to recruit them with Ice.  
To all these things I shall add, that even where the intercourse is not quite debarred, but left free enough betwixt the Subterraneal and the superior Air, the operation of the Sunbeams may be very much less in a Cavity though but shallow, beneath the Surface of the Ground then above it. For besides that Trials have informed me, that Liquors that differ in little else then in consistence, will not so easily pervade each other, as a man would surmise; unless some external motion hasten their intimate mingling with one another. I remember that one morning pretty late, having had the Curiosity to descend into a pit where they were digging out Iron Oar; though this Cavity had not very narrow Orifice, and was dug directly downwards, and exceeded not ten or twelve foot in depth: yet I found not the heat at all troublesome whilst I stayed there, Though the pit were in an open field unshaded by Trees, and though the Air abroad were much heated at that time of the year, which was in that season (or at least very near it) that is wont to be called the Dogg-days.   

CHAP. FOUR  
ANd as we have shown, that the Subterraneal Air, even in the first Region is usually much less heated, than the Superterrestriall Air; so we may also easily observe, that That Inferior Air is (Caeteris paribus) wont to be much less refrigerated by the grand Efficients of intense Cold, than the Superior Air.  
I will not urge on this occasion what I have observed by a surer way, then for aught I know has been before practised, about the smoking of some Springs in Frosty Wether; because I do not know but that those Springs may have come from, or passed a good way through, some place very deep beneath the Surface of the directly incumbent ground, and perhaps from a Soil peculiarly fitted to warm them: whence the water may have derived a warmth considerable enough not to be quite lost, till it began to spring out of the ground, where it needed only not to be quite Cold to appear to smoke; the intense Coldness of the Air making those exhalations visible in Frosty Wether, which would not be so in milder: As is evident in a man's Breath, which appears like a smoke in such weather, though it be not visible in Summer.  
That therefore, which I shall propose in favour of our observation, is first taken from the nature of the thing, which may persuade us, that the Subterraneal Air being though comparatively cool, yet indeed moderately warm in Summer, ought not to be affected with Winter's Cold, so much as that contiguous to the Surface of the Earth, from whose immediate Contact, it is by a thick arch of Earth (if I may so call it) defended; and that the Cold reigns most in the free Air; and the Superficial parts of the Terrestrial Globe, may appear by Water's beginning to freeze at the Top, not at the Bottom. To which Reason from the nature of the thing, I shall add only this from experience, that we see that in Cellars that are arched and carefully kept close from the Communication of the outward Air, Beer, and other Liquors may be kept from freezing in frosty, and snowy Wether. As I have observed in a cellar that was but shallow, but well arched in a Winter that was sharp to a wonder, and froze stronger Liquors than Beer in another Cellar very near it, that differed not much from it in depth, but had not so thick and solid a roof. And that not only here in England, where the Cold is less violent, but even in Russia itself, where it is wont to be so extreme, it reaches not near so deep as one would think, I learned by Inquiry purposely made of an ingenious Physician that lived at Moscow, who answered me, that others and he himself, did in that City keep all the Winter long, not only their Wine but their Beer from freezing in Cellars that were not above 12 or 14 foot deep, but well covered above, and carefully Lined with planks of Fir, without any entrance, but a small trap-Door (commonly at the top,) which was fitted so exactly to the Orifice it was to close, as to exclude (as much as was possible) all communication between the internal and external Air, that the latter might not affect the former with its Coldness.  
I have indeed suspected that in some Cellars, the comparative warmth we find there, may be partly due to Subterraneal Exhalations that are penned up in them: and perhaps too in some measure from the Steams of the fermenting, or fermented Liquors lodged in those places. And I was somewhat confirmed in this Suspicion, by an Information my Inquiries obtained from the newly mentioned Doctor, who told me upon his own observation, that in one of the Cellars he made use of at Moscow, having occasion to open the above mentioned trap-door, after the Cellar had for a good while been kept very close shut, there came out at the vent that was thereby given, a copious Steam in the form of smoke, which to them, who had their Bodies affected with the external Air, was very sensibly warm, and was almost unfit for Respiration. Which Circumstance increased my suspicion that there might be among these steames, some of the nature of those, that have been observed to come from fermenting Liquors, especially Wine, and so abound in some Cellars, as almost to stifle those that ventured into those Vaults, And to kill some of them outright. Which effects the long abode of Subterraneal Steams in stagnating Air, even in many places, where no metalline Oars at all, not other noxious minerals have been found, has enabled that Air to produce. Of which divers sad Instances have been given within less than a mile of this place, upon men's first going down into pits or Wells, that had not in a long time been opened or made use of: (but this is here mentioned only upon the By) nor have we any necessity to fly to Subterraneal Exhalations, for the Comparative warmth that good Cellars in general afford in frosty weather; since that Phaenomenon may be accounted for, by the reason formerly given, That the closeness of the Cavity, and the thickness of the sides and Roof, keep it from being vehemently affected with the Cold of the Ambient Air.  
I know 'tis pretended that the warmth we speak of, proceeds from an Antiperistasis, but not now to engage in a controversy that would take up too much time, it may here suffice to represent, that in our case there appears no necessity of recurring to it, the Phaenomenon being solvable by the Region newly cited, which may be confirmed by this Experiment, that in the Vaulted Cellar above mentioned, wherein Beer was kept from freezing, in an almost prodigiously sharp Winter, the included Air, though sensibly warm, to those that came out of the free Air, had not so intended its native heat, as the Assertors of Antiperistasis would have expected; being Colder than the free Air commonly is in that place, not only in the heat of Summer, but in other seasons, when the weather is Temperate; As I was assured by comparing my own observations made at other times, with the account brought me by a skilful person, whom I employed into that Cellar at late hours, in one or two of the sharpest nights of the forementioned cruel winter with the same excellent sealed weatherglass that I had long kept suspended within a stones cast of that place.   

CHAP. V.  
HAving said thus much about the Earth's uppermost Region, I now proceed to that which lies next beneath it; whose Temperature I cannot so conveniently give an account of, in less than two Propositions, whereof the First is this;  

Proposition the first.  
The Second Region of the Earth seems to be for the most part cold in comparison of the other two.  
This proposition may be confirmed partly by Reason, and partly by experience.  
And first it seems consonant to Reason, that since the Earth is naturally a Body consisting of gross and heavy parts, that are usually much less agitated, than those of our Organs of Feeling, it should as to sense be cold; and that therefore that quality may be justly ascribed to it, in that Region where by virtue of its situation, it is kept from being considerably affected, either by the heat of the Superior Air, or by that of the deep parts of the Earth: which upper, and lower heat are the two Agents, that seem of all others the most likely to put its parts into an unusual motion, and thereby change its natural Temper.  
That our proposition is also confirmable by Experience, may be gathered from the Relations set down in the former part of this discourse,  
And here it will be proper to take notice of the Advertisement intimated in the close of our above delivered proposition, That this Coldness ascribed to the second Region of the Earth, is to be understood comparatively to the other two. For otherwise that even this Earth is not (as many naturalists would have it) the Summum Frigidum I gather from this, That I could never hear of any Ice met with there, at any time of the year though Snow or Hail may be produced in the middle Region at differing, and sometimes quite opposite seasons of the year; nay, I have not found by the Answers that were made me by those that have descended far enough into this Region, that they found the cold any where very great, or that in some places they have found it at all considerable. As we shall see in the explication of the next proposition. I know not whether it will much strengthen what has been said, if I add, that I learned by inquiry of such persons as I lately mentioned, that at the mouth of deep Grooves, in mines, the steams that ascend, do often feel warm; though the outward Air where the Observation is made, be affected with the heat of Summer. But though this probably argue, that if the middle Region of the Earth, through which these Steams must ascend, were very intensely cold, they would be so refrigerated in their passage, as to feel rather Cold than hot at their appearing above ground, especially in Summer: yet I shall not lay much weight (for some may perhaps be allowed it) upon this Argument; because I have not yet tried, how far a warm Steam may be altered in its passage, thorough a Cold Conduit: not to mention that in the Earth, the passage by being directly upwards may be much the nimblier traversed.    

CHAP. 6.  
THe second proposition relating to the Temperature of the second Region of the Earth, may be delivered in these Terms.  

Proposition the 3  
In several places, which by reason of their distance from the surface of the Earth, one would refer to the middle Region of it, The Temperature of the Air is very differing at the same times of the year  
I chose to express myself thus, to prevent some ambiguities and objections which I foresaw, that shorter, but less dear and full expressions, might give occasion to.  
In the proof of our proposition, both Experience and Reason may distinctly be employed. And to begin with experience,  
Whereas in the above recited descent into the Hungarian-Mines, there was observed a notably Cold Region of a considerable thickness, I have purposely procured accounts from divers persons that have here in England had occasion, some of them frequently to descend into deep pits or Grooves of differing minerals, without finding by the narratives they made me, that they took notice of any notably cold part that they passed thorough; unless I particularly asked a question about such a thing. But for aught I could gather from their Spontaneous Relations, they felt in Summertime a remission of the heat of the external Air, assoon as ever they began to descend; which warmth did not so far decrease, as to terminate in any notable Coldness, before they came into a deeper part of the Earth, where they are never troubled with that quality. And some of these Relations I had from professed Miners, and was curious that the Relations I procured should be of Subterraneal parts seated in very differing parts of England, as well as of places not all, or most of them having Veins of one and the same mineral. And I learned by particlar inquiry from a practical Mathematician that was often employed about Lead-mines that at such depths as, (according to Morinus) the second Region of the Earth reaches to, he himself observed it to be sensibly warm at all seasons of the year (for about that Circumstance I was peculiarly solicitous to be satisfied.)  
Nor is it unconsonant to Reason, that the middle Region of the Earth, in the sense meant in the proposition, should not be of the same temperature in all places; not only because of the differences, which the Climate may produce, by reason of its being very much hotter, or very much colder in one place then in another: but from the peculiar constitution of the Soil; to the Consideration whereof I shall here confine myself.  
Now this Temperament of the Soil itself may be divertified, not only by its greater or lesser compactness (upon which account some Soils are Rocky or stony and others Light and spongy) but from the nature of the springs or Subterraneous Liquors, that may abound in it, or strain through it into the Groove or pit, we suppose the Observer to be in; and that especially by the minerals, particularly Salts, and Marchasites that grow near the sides of the Well, or are brought thither by the waters.  
To illustrate this, give me leave to consider, that nature does not regulate herself under ground by our imaginary Divisions: but, without taking notice of them, produceth marchasites, Salts, and other minerals, most frequently (perhaps) in what we call the lower Region of the Earth; but yet sometimes to, in our upper Region and oftentimes in our middlemost Region. Let us then suppose, that in some places of this last named Region, there be a mine of that Earth that naturally abounds with embryonated nitre, or with some other salt that is apt, especially being dissolved or moistened with water, (a thing very familiarly to be met within in mines; to send out a refrigerating Effluvium, or by its contact to cool the Air. Let us also suppose that by the sides of another Well of the same depth, there are store of unripe minerals that are in the process of generation, or rather a great quantity of marchasiticall Earth, if I may so call it, that is such a substance, as I have met with, in more than one place, copiously impregnated and as it were blended with minerals of a marchasiticall nature; and yet of so open and lose a Texture, as not only water would in a few hours, but Air also would in not very many, evidently work upon it. And since during the time that marchasites are slowly dissolving, it has been observed according to what we have elsewhere delivered 
* The Tract here pointed at is a Discourse of Subterraneal 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 minerals will be very warm in comparison of the Temperature of the other place, where the Soil does 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 always the same, even upon the account of the Soil. For I elsewhere show, that some Saline Earth's, especially nitrous, and some minerals that partake of the nature of marchasites, admit a kind of gradual 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, 'twill not be absurd to conceive, that the mineral, to which either heat or cold is to be referred, 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 mineral rudiments harboured in it, may be consumed, or the mineral itself 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 occasioned in the temperature of the second Region of the Earth by several Accidents, and especially by the Subterraneal 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 Subterraneal 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 myself obliged to speak the more hesitantly and diffidently about the Temperature of Subterraneal Air; because mineralists have not had the Curiosity to examine it by Weather-glasses, which would give us much more trusty Informations than our sense of feeling powerfully preaffected by the cold or heat of the external Air. I did indeed send fit Instruments to some day's 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 sealed Weatherglass, joined with a portable Baroscope will give me better Information than mineralists have yet done. I say a sealed Weatherglass because though common Thermoscopes had been employed by miners, I durst not rely upon them; being persuaded by trials purposely made, as well as by the Reason of the thing, of the fallaciousness of such Thermoscopes: for in them the included Air is liable to be wrought upon, not only by the Heat and coldness, but by the weight or Pressure of the external 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 marked, 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 external Air may be in both places alike, the cause of the pendulous Liquors rising being indeed that the aereal pillar incumbent on the stagnant Liquor, is higher and heavier at the bottom, where the Instrument rests, then that which leaned upon it, at its first or upper station nearer the top of the Atmosphere. From whence 'twill 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 than at the top, the Air may appear by the Instrument to be colder in places, where 'tis really much hotter, the increased weight of the incumbent Air being more forcible to impel up the pendulous Liquor than the endeavour of expansion procured in the included Air by the warmth of the place is to depress 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 comprise, 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 would have the proposition understood with this Limitation, as far as has been yet (that I know of,) observed. For almost 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 minerals, without which, men would not be invited to be at so great a charge, as that of sinking so very deep pits, and maintaining workmen 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 minerals, and consequently has not informed us of the Temperature of the Lowermost Region in general; as will better appear by what I shall ere long represent.  
Having premised this Advertisement about our proposition, we may proceed to the distinct proof of the two parts or members it consists of.  
And to begin with the first, whatever the Peripatetics teach of the innate Coldness of the Earth, especially where 'tis remotest from the mixture of the other Elements; yet having purposely inquired of several 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 suspicion, that (at least in some Cases) the narrowness of the Cavities wherein the Diggers were in divers places reduced to work, might make the warmth they felt, proceed in great part from the Steams of their own Bodies, and perhaps of the minerals, and from the Difficulty of cooling or ventilating the Blood in an Air clogged with steams. And I was the rather induced to think 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 metal abounding there.  
I have likewise found by several trials, that the exhalations that proceed from the Bodies of Animals, do 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 Subterraneal air, in such places as have been newly mentioned, might not be referred 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 Subterraneal Warmth being laid aside, it seemed I confess somewhat difficult to conceive how it should be produced; yet two principal Causes there are to which I think 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 Coldness 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 shows rather, why it should not be in the Earth's 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 actual warmth may proceed from those deeper parts of the Subterraneal Region, which lie beneath those places which men have yet had occasion and ability to dig. For it seems probable to me, that in these yet inpenetrated Bowels of the Earth, there are great storehouses of either actual 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 Subterraneal Channels, 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 Chemical structures:) Or else, (which is perhaps the most usual way,) by sending upwards hot mineral Exhalations and Steams, which by reason of the comparatively heavy materials they consist of, and by reason of their being less dispersed nearer the places whence they proceed, are usually more plentiful in the deeper parts of the Earth, and somewhat affect them with the Quality that they brought from the workhouses where they were formed 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 several provinces of Germany, Bohemia, Hungary, etc. as also in several parts of England in Grooves, some of which I have received Relations from the mine-men themselves. By which it appears, that several of these Exhalations ascending from the entrails of the Earth are sulphureous & Bituminous in smell and in some Grooves (one whereof I elsewhere mention myself to have visited) these Steams are apt, actually to take fire.  
The warmth of many Subterraneal Exhations I think 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 several times questioned, whether I ought to acquiesce in them alone. For I do not think the easy inflammableness of Bodies to be always a sure proof of the actual sensible warmth of the minute parts it consists of, or may be reduced into. For though Saltpetre 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 rectified spirit of Wine; which yet we know is itself 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 than 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 Epithet 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 itself. And the same Arguments that I have elsewhere given to show that there are very hot places, and as it were Aestuary in the Bowels 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 dug, 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 himself reckons it among the signs of a latent mineral vein, that the hoar-frost does not lie 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 skilful in England, for the Discovery of places that contain Coal-mines. And I remember a near relation of mine shown me a great scope of Land of his, which (though in an outward appearance, likely to be as cold as any place thereabouts,) he affirmed would not suffer Snow to lie upon it above a day or two in the midst of Winter.  
The probability of which Relation was confirmed to me by the answer I received from a very ingenious Gentleman who lives among mines, and is not a little concerned in some of them. For having inquired of him, What he had observed about the lying, or not lying of the Snow on the mineral Soils near the place of his Residence; he replied, 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 minerals 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 do it but so slowly, as to lose their actual 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 ponderousness 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 answered that he could not be a witness 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 Bowels 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 confess, that as I first made this Objection to myself, so I do not yet discern it to be unreasonable, and that for aught I know if men had occasion to dig as deep and be as far conversant in many other low places of the Earth, where there are no signs of Minerals, as they have done where the hopes of actual discovery of veins of metals, and other minerals 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 minerals themselves, or are near some of the deep and latent Aestuaries .  
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 than themselves: which seems to be the incalescence there is produced in many mines, and other Places, by the mutual action of the component parts promoted by water of immature and more loosely contexted minerals, especially such as are of a Marchasiticall nature. That such an Incalescence may by such a way be produced in the Bowels of the Earth, I have elsewhere shown (in my discourse of Subterraneal Fires & heats) by the examples of such incalescences producible in mineral Bodies here above ground. That Marchasites which for the most part abound in Vitriol, are bodies very fit to procure this Subterraneal heat, may be confirm'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 tried, 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 mine's, he confirmed to me what I had otherwise been informed of, by answering me, that in the lower parts of the m●ne, he had gathered Vitriol that appeared 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 deterred by the ill fate of livers that ventured to work in it. Adding that though he passed by it, in great haste; yet he could not avoid the being offended by the noisome Exhalations. And on this occasion, 'twill not be (I presume) disliked, if I illustrate what I was saving of Immature minerals, by subjoining, That having, asked this Chemist whether the Vitriol he found very deep underground were all solid, or some of it soft? he affirmed that as he gathered it, he found some of it soft. And to satisfy my curiosity to know whether it continued that yielding 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 streaks in it.   

CHAP. X.  
ONe thing there is, which must not be here omitted, though it will probably be great news to those that philosophise 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  experience that in deep Grooves, the Air (unless ventilated and renewed) does in a short time become unfit for respiration, have been put upon this expedient, to sink at some convenient distance from the Groove where the miners' work, another pit (by some called a vent pit) that usually tends directly downwards (though sometimes it make Angels) to which our English-minemen do in several 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 chief and skilful 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 Channel 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 Term always in the same sense) denotes by his Cuniculu; 
Lib. V 〈◊〉 VI De re metal.  and which though differingly named by our Miners in several parts of England is in the above mentioned Lead-mines called a Drift, because the Air does usually in the form of Wind drive thorough it: and thereby enables the Workmen to breath freely and conveniently enough at the very bottom of the Well. On this occasion I remember that a very observingrman who much frequented these Mines told me, that at the depth of no less than about 200 yards, be found that by the help of the Air-shaft, the Air was not only very commodious for Respiration, but temperate as to heat and Cold. And when I further asked, what time of the year it then was? he told me 'twas about the latter end of August and the beginning of September.  
Now that which seems to me to deserve a farther and accurate observation about the motion and Temperature of the Air in these Artificial under ground Cavities, is a Relation of Agricolas which, (though he be the most Classic Author we have about m●nes,) has not (that I know of) been taken notice of, in him. For this experienced Writter, though in his Treatise 
* Idcirco f●robes, putei cuniculi eff●ssi complentur exteriore Aere. Atque ipsum in eos influere imprimis hyema li tempore evidens est in duobus puteis, ad quorum utrumque ex modico intervalh cuniculus aliquis pertinet. Nam Aer in unum continuo influit rectâque per cunicul●m permeat & transit ad alterum; atque ex eo rursus evolat foras.  de Ortu & causis Subterraneorum, he only says indefinitely, that by means of the Cuniculus or Drist, which connects the Air-shaft & the well, that Air which comes in at one of those two, passes out at the other; yet in his Fifth Book de re metallicâ he gives a more particular and odd account of the course of the Air in these not over clear Terms, Aer autem exterior se suâ sponte sundit in cava terra, atque cum per ea penetrare potest, rursus evolat soras. Sed diversâ ratione hoc sieri solet; etenim vernis & aestivis diebus in altiorem puteum influit, & per cuniculum vel fossam latentem permeat, ac ex humiliori effluit similiter iisdem diebus in altiorem cuniculum infunditur, & interjecto puteo defluit in humiliorem cuniculum atque ex eo emanat. Autumnali verò & hyberno tempore, contra in cuniculum vel puteum humiliorem intrat, & ex altiori exit: verum ea fluxionum Aeris mutatio in temperatis Regionibus fit in initio veris, & in fine Antumni: in frigidis autem, in fine veris & in in initio Autumni. To which he adds that which is more remarkable; That the Air in both the mentioned times, 
Sed Aer utroque tempore anteaquam cursum suum illum cons●etum co●st 〈◊〉 teneat plerum 〈…〉 dierum spacio 〈◊〉 habet mutationes, 〈…〉 ●ltiorem 〈◊〉 ●●el cuniculum ins●aens, modo in humiliorem.  before its wont course come to be durably settled, uses to be for the space of a fortnight liable to frequent changes, sometimes flowing into the upper or higher groove or Drift, and sometimes into the lower, (and passing out at the other.) If this Observation constantly hold, though but in some deep Mines, it may hint some odd inquiries, about considerable and 〈◊〉 changes in the Subterraneal parts of the Earth, or in the Air, or in Both, which though they have not yet been considered, deserve be so. I have endeavoured to learn whether any such thing has been observed in some deep Lead-mines, whence I have procured divers informations about other particulars. But a very observing Person, that had the chief hand in contriving the Subterraneal structures there, assured me that both Winter and Summer, the current of Air, went constantly the same way: the Air entering in at the Mouth of the Air-shaft, and coming out at the Perpendicular Groove, which takes its denomination from a Cave, (or Casa Pu●ealas) usually built over the Orifice of it, to shelter the Workmen from rain, and other inconveniences.  
And since the writing of this, I found in Morinus (his Relation already mentioned) a passage that may somewhat illustrate the darkly expressed Observation of Agricola. For the lately mentioned Author writes, that in the deep Hungarian-Mines he visited, the outward Air passed (first) through the Burrows, and so through By ways, (if I may so call them) that tended not directly downwards, reached at length to the bottom of the Well, or perpendicular Groove, whence, together with the Steams proceeding from the Mine) is ascended straight upwards. But Morinus taking no notice at all of Agricola's Observation about the differing course of the Subterraneal Air at differing Seasons of the year: though (as I find by what he writes elsewhere,) 'twas Summer when he visited the Mines, and so what he reports, agrees well with one part of what Agricola seems to say; yet, as to the other, and principal part of his Observation, he says not any thing. And the sensible heat he ascribes to the steams ascending out of the perpendicular Well, leaves it somewhat dubious, what interest the Rarefaction of the Air, by the Subterraneous Heat may have in the Phaenomena we have been discoursing of.  
But to return to what I was saying before I had occasion to mention Morinus. Which perhaps it will not be impertinent to add, that I loarned by inquiry, that the Air-shafts, and the Wells, were in these Mines much of a depth. But I hope ere long to have accounts of what happens in other mines, in other parts of England, as to the course of the Subterraneal Air especially when it's issuing out of the Well, or the Air-shaft depend not on the changes of the Winds that blow above ground: And I wish the curious would employ the like endeavours in other Countries.  
For indeed what I have hitherto discoursed in this Treatise, is accommodated but to the scant Information I have hitherto received; and therefore aught to be rectified or Confirmed by farther Informations if they can be procured.  
In the mean time, I think I may probably enough, gather from the pased Discourse, that though in some Mines, three Subterraneal Regions, and their distinguishing Attributes, may be not inconveniently assigned; yet generally speaking of the whole Body of the Terrestrial Globe (as far as we know it) both the Bounds and the Temperature of the Regions of the Earth, as well as those of the Air, are various and uncertain enough.  
And much less have we any certain knowledge of the Temperature of the more inward, and (if I may so speak) the more central parts of the Earth; in which, whether there be not a continued solidity, or great Tracts of Fluid matter, and whether or no, differing Regions are to be distinguished, and what their number, Order, thickness, and qualifications may be, we are as yet ignorant, and shall I fear long continue so, For it is to be noted (with which observation I shall conclude) that what has been hitherto discoursed, belongs only to the Temper of those Subterraneal parts, to which men have been enabled to reach by Diging. 'Tis true indeed that some Mines especially in Germany, and Hungary are of a Stupendious depth, in comparison of the generality of ours, and of the more obvious Cavities of the Earth; yet I find it boasted in a Discourse written purposely of the Various Mines, in the World, that the rich Mine at Sueberg is 400 yards deep: And they are scarce believed, that relate one Hungarian-Mine which they visited to be 400 sathom; which though double the depth of the former, reaches not to half a mile. But the deepest of all the mines that I have as yet read or heard of, from any credible Relator, is that which the experienced Agricola in the Tract he calls Bermannus, Cap. 12. mentions to be at Cotteberg. But this itself though it reach to above 500 fathom, that is, 3000 foot, yet this prodigious depth does not much exceed half a mile & falls short of three quarters, 
Licet variae de ambitu tervae opiniones sint, nobis tamen propemodum constet, esse ipsam milliarum Italiarum 26255, quoth in maximo ad Terrae superficiem circulo respondeant uni gradui milliaria proximè 73. etc. Gassend. Instit. Astronom. Lib: 2. Cap. 13.  and how small a part is that of the whole depth of the Terrestrial Globe? whose semidiameter, if we admit the recent account of the Learned Gassendus, reckoned at 4177. Italian miles: in comparison of which, (as I was saying), how small a thing is a depth that falls very short of a single mile?  
FINIS.    

Of the TEMPERATURE Of the SUBMARINE REGIONS As to HEAT and COLD.  

OF THE TEMPERATURE, Of the SUBMARINE REGIONS. As to Heat and Cold. CHAP. I  
THough the Aristotelians who believe water and Air to be reciprocally transmutable, do thereby fancy an Affinity between them, that I am not yet convinced of: yet I readily allow of so much Affinity betwixt those two fluid Bodies, as invites me (after having treated of the Temperature of the Aerial Regions) to say something of that of the Submarine Regions: which name of Submarine, though I know it may seem Improper, I therefore Scruple not to make use of, because even among the Generality of Learned Men use has Authorized the name of Subterraneous Places. For as these are not by this name, and indeed cannot in Reason be supposed to be beneath the whole Body of the Earth, but only the Superficial parts of it: so by the Appellation of Submarine Regions 'tis not to be supposed that the places so called are below the Bottom of the Sea, but only below the surface of it.  
But to come from words to things, I presume it will not be expected that I that never pretended to be a Diver should give of the Regions I am to treat of, an Account build on my own Observations; and I hope it may gratify a Reasonable Curiosity about a subject, of which Classic Authors are so very silent, and about which Philosophers seem not so much as to have attempted any Experiments (for want of Opportunities and mean to make them.) I offer the best Information I could supply myself what by purposely conversing with Persons that have dived some without, and some by the help of Engines. To which I have added some reports that I judge fit to be allowed, made me by Persons that had conversed with the Divers upon those African and Indian-Coasts, where the most famous and expert are thought to be found.  
And I the rather report the Answers and Relationsmy Inquiries procured because the Informations they give us concern a subject considerable as well as vast, about which nevertheless I among many others am not in a condition to satisfy at all my Curiosity by Trials of my own making, and because also what I shall say will probably spoil the credit of the Vulgar Error that in all deep water of which the Sea is the Chiefest, the lowermost are still the warmest parts, unless in case that in some very hot Climates or seasons, the superficial ones happen to be a little warmed by the Extraordinary or Violent heat of the Sun.   

CHAP. TWO  
THough the Air and the Earth have been discriminated as to Temperature into three Regions; yet the Informations I have hitherto met with, invite me not to assign to the Sea any more than two. The former of which may be supposed to reach from the superficies of it, as far downwards as the manifest operation of the variously reflected and refracted Beams of the Sun, or other Causes of warmth penetrates: from which to the Bottom of the Sea, the other Region may be supposed to extend.  
According to this Division the Limits of this upper Region will not be always constant; for in the Torrid Zone and other hotter Climates, it will, Caeteris paribus, be greater than in the Frigid Zone or in the Temperate Zones: and so it will be in Summer then in Winter: and in hot weather then in Cold; supposing in these Cases the Heat to come from the Sun and Air; and not, as sometimes it may do, from the Subterraneal Exhalations.  
The same causes are likewise proper as 'tis manifest to alter the Temperature as well as the Bounds of this Region, But this Temperature may also be changed in some few places by at least two other Causes; The one is the differing constitution of the Soil that composes the Shore, which may affect the neighbouring water if it do extraordinarily abound with Nitre, loosely contexed marchasites, or other substances capable considerably to increase or lessen the Coldness of the water. Another though unfrequent Cause, may be the figure and situation of the less deep parts of the Shore, which may in some sort reverberate the Heat that proceeds from the Sun; and upon such an account may either add to the warmth, or allay the Coldness that would else be found in the neighbouring water. For whatever the Schools are wont to teach about the Interest of the Attrition of Air in the heat produced by the Sun Beams, I have elsewhere shown by Experiments, that those Beams may considerably operate upon Bodies placed quite under water.  
Besides these two Cases that may occasion Exceptions to the general Observation; I intimated by the words, at least, that there might be others. Because, to mention now but one Example, though it seem probable from what I have elsewhere delivered concerning the Subterraneal Fires and Heats, that may in some places be met with, even beneath the bottom of the Sea, that the Phaenomenon I am going to recite may be reduced to the causes newly intimated; yet I am not absolutely certain but that in this case, whereto some others may perhaps be found resebling, some other cause, than those hitherto mentioned, may produce or concur to the effect. The Relation here meant is afforded us by the following Passage, taken out of the Voyage of Monsieur de Monts into New-France, (whereof he went to be Governor) where the Relator thus recites his observation. About the eighteenth day of June we found the Sea-water during three day's space very warm, and by the same warmth, our wine also was warm in the bottom of our ship; yet the Air was no hotter than before. And the 21 of the said month, quite contrary, we were 2 or 3 days so much compassed with mists and cold, that we thought ourselves to be in the month of January, and the water of the Sea was extreme cold: which continued with us until we came upon the Bank by reason of the said mists, which outwardly did procure this cold unto us. This effect he attributes to a kind of Antiperistasis in the following part of his narrative; which I shall not now either transcribe or examine.   

CHAP. 3  
And thus much being briefly noted touching the upper Region of the Sea, and the requisite Cautions (that may perhaps extend further than it) being premised; it remains that I take notice of the Temperature of the Lower Region, which, in one word, is Cold (unless in some few places to be presently mentioned.) For water being in its natural or most ordinary state, a liquor whose parts are more slowly agitated then those of men's Organs of Feeling, must be upon that account Cold as to sense: and consequently it need not be strange that those parts of the Sea, which are too remote to be sensibly agitated by the Sunbeams, or wrought upon by the warmth which the Air and upper parts of the Earth may from other Causes receive, should be felt Cold by those that descend into it; unless in those few places where the Coldness may be either expelled or allayed by hot Springs or Subterrestrial Exhalations, flowing or ascending from the subjacent Earth, or the lower parts of the shore into the incumbent or adjacent parts of the water.  
To justify my ascribing of this Coldness to the second, or lower Region of the Sea, I shall now subjoin some Relations I procured from persons that had occasion to go down into it, or otherways take notice of its Temperature in very differing Regions of the World, and at very unequal depths.  
And first as to the Temperature of the lower Region in the Northern Sea, I had the opportunity to converse often, and sometimes to oblige a man bold and curious enough, who for some years got the best part of his subsistence by descending to the bottom of the Sea in an Engine, whose structure I elsewhere describe, to seek for, and recover Goods lost in Shipwrackt Vessels. This person I diligently examined about divers Submarine Phaenomena, about which his answers may be elsewhere met with. And as to the Temperature of the lower parts of the Sea (the knowledge of which is that alone that concerns us in this place) he several times complained to me of the Coldness of the deep water, which kept him from being able to stay in it so long as he might have been put into a condition of doing by the goodness of his Engine; for I remember that he related to me that he stayed once betwixt an hour or two, at a depth that was no greater than 14 foot and a half upon the coast of Sweden, in a place that was near the shore; and I afterwards learnt that he stayed much longer in a deeper place; (use having probably made the Cold more supportable to him) He told me then, that about two years before he was engaged by a good reward to go down with his Engine to the bottom of the Sea to fetch up some Goods of value out of a Ship that had been cast away there within about a miles distance from a very little Island, and if I mistake not about 6 miles from the Shore. He farther answered me that though he felt it not at all Cold on the Surface of the Water (his attempt being made in June) yet about the depth of the Ship, it was so very Cold, that he felt it not so Cold in England Winter and Frosty . And he told me that an excessive Cold was there felt not only by him but by very sturdy men, who invited by his example, would needs also go down themselves to participate and promote the hoped for Discovery. He told me also, that the upper water did but cool and refresh him; but the deeper he went the Colder he felt it, which is the more considerable, because he had some times occasion to stay at 10 fathoms or even 80 foot under water. And I since found that he informed divers Virtuosos, that purposely consulted him, that he found the Coldness of the Water increase with its depth: and gave that for the reason why he could not stay so many hours as otherwise he might, at the bottom of the Sea. Adding that before his Engine was well fitted, he was once so covered over with it, that he was forced to touch the ground with his hands and feet, and the neighbouring parts, to which he found a Coldness communicated by the Fundus he leaned upon; though the closeness of his disordered Engine made the other, and (whilst he was in that posture) upper parts of his Body, of a very differing Temper.  
An inquisitive person of my acquaintance that made a long stay in the Northern America (at about two or three and forty degrees of Latitude) and diverted himself often with swimming under water, answered me, that though he scarce remembered himself to have dived above two fathoms beneath the surface of the Sea; yet even at that small depth, he observed the water to increase in coldness, the lower he descended into it. Which argues, that though the Sunbeams do often penetrate plentifully enough to carry light to a great depth under water; yet they do not always carry with them a sensible heat: and that at least in some places, the upper Region of the Sea reaches but a little way.  
The coldness of the Climate in these western parts of Europe, and the want of considerable inducements to invite men to dive often to any great depth into our Seas, has kept me from being able to procure many observations about the temperature of their lower Region, but upon the hotter Coasts of afric, and the East-Indies, the frequent Invitations men have to dive for Coral, pearls, and other Submarine Productions, has made it possible for me to get more numerous observations: some of which I shall now annex.   

CHAP. 4.  
MEeting with a Person of Quality who had been present at the sishing of Coral upon the shore of Africa, and Who was himself practised in diving, I inquired of him whether he found the Sea upon the African Coast to be much colder at a good depth, then nearer the surface; whereto he answered me, that though he had seldom dived above three or four fathoms deep, yet at that depth he found it so much colder than nearer the Top of the water, that he could not well endure the coldness of it.  
And when I farther asked him whether when he was let down to the bottom of the Sea in a great diving Bell (as he told me he had been) he felt it very cold, though the water could not come immediately to touch him, he replied that when the bell came first to the ground, he found the Air in it very cold, though after he had stayed a while there, his breath and the steams of his Body made him very hot.  
That also at a greater depth in those hotter Climates the Sea-water is sensibly Cold may be thus made probable, Enquiring of a famous Sea-Commander who had been upon the African Coast, to what depth he was wont to sink his Bottles to preserve his Wine any thing cool in that excessive hot Climate, he Answered me that in the day time he kept it in a tolerable temper so as to be drinkable, by keeping it in the Bottom of the ship, and in sand, but in the morning he had it cool enough by sinking his Bottles over night into the Sea, and letting them hang all night at 20 or 30 fathom deep under water.  
Enquiring also of an intelligent Gentleman that was employed to the river of Gambra, & sailed up 700 miles in it, in a small frigate, whether he had observed that in the Sea, even of those hot climates, wine may be preserved cool, he told me that it might, and that by the means I hinted to him, which was to let down when the ship came to an Anchor in the Evening several Bottles full of wine (they used that of Madera) exactly stopped to ten, 12, or 14 fathoms deep, whence being the next morning drawn up, they found the wine cool and fresh (as if the vessels had been in these parts drawn up out of a well) provided it were presently drink, for if that Circumstance were omitted, the heat of the Air on the upper part of the water would quickly warm the Liquor.  
I remember too, that having met with a man of Letters that sailed to the East-Indies in a Portugal-Caraet, I learned by enquiry of him, that 'twas the practice in that great Vessel for the Captain and other Persons of note, whilst they pass through the Torrid Zone, to keep their Drink, whether Wine or Water, cool, by letting it down in bottles to the depth of 80, 90, anc sometimes an hundred Fathom or better, and letting it stay there a competent time; after which he told me he found it to be exceeding cool and refreshing.  
Lastly, to satisfy myself as far as I could, to how great a depth the Coldness of the Sea reached; meeting an observing Traveller whose affairs or Curiosity had carried him to divers parts both of the East and West-indieses, I enquired of him whether he had taken notice of any extraordinary deep soundings in the vaster seas, To which being answered, that some years ago sailing to the East Indies in a very great ship, over a place on the other side the Line that was suspected to be very deep, they had the Curiosity to let down 400 Fathom of Line, and found they needed no less. Whereupon I enquired of him, whether he had taken notice of the Temperature of the sounding Lead assoon as 'twas drawn up: To which he told me, that he, and some others did; and that the Led which was of the weight of about 30, or 35 l, had received so intense a degree of coldness as was very remarkable; insomuch that he thought that if it had been a mass of Ice, it could not have more vehemently refrigerated his hands: and when I asked in what Climate this observation was made, he told me 'twas in the Antarctick Hemisphere, but at a great distance from the Line. As indeed I concluded by some Circumstances he mentioned to me, that 'twas about the 35th degree of Southern Latitude.   

CHAP. 5.  
These are the chief Relations I have hitherto been able to procure about the Temperature of the Sea; which if they be so confirmed by others, as that we may conclude they will generally hold; it will not be irrational to conceive that in reference to Temperature, those two Fluids, Air and Water, may have this in common, that where their Surfaces are contiguous, and in the neighbouring parts, they happen to be sometimes cold, and sometimes hot, as the particles they consist of, chance to be more or less agitated by the variously reflected Sunbeams, or more or less affected by ●ther causes of Heat. But that part of the Air which they call the second, & is superior to the first, as also the lower Region of the Sea, being more remote from the operation of those causes, do retain their natural or more undisturbed Temperature, which, as to us men, is a considerable degree of coldness, the Agitation of their small parts being usually in those Regions much inferior to that of the Spirits, Blood, & other parts of our Organs of Feeling. So that the Regions of the water and Air seem to answer one another; but in an inverted order of situation, and the Analogy might perhaps be carried further, if I had time and opportunity to do it in this place. And here I shall not dissemble that I was somewhat perplexed by meeting with a traveller that had visited the East- Indian Coast, near the famous Cape of Comory: for ask him some questions touching the neighbouring Sea, I gathered from his discourse, that he concluded from that of some Divers, that the Sea near Ceylom was warmer at the bottom then at the top. And when I thereupon asked him whether this happened not in their Winter, he replied that it was indeed Winter, though not with us, yet with them; it occurred indeed to my thoughts on this occasion, that perhaps in a part of the Torrid Zone so near the Line as about 80 degrees, if the Sea were not of a considerable depth, the heat of the two not far distant shores of Coromandell and Ceylom might have no small influence upon the Tempetature of the water. I considered also (which did not a little weigh with me) that in divers parts of the East-Indies, and even in a Region bordering upon Coromandell, where an ingenious Acquaintance of mine lived some years, it has been observed, that Winter and Summer are not so much discriminated by Cold weather & Hot, as by very Rainy weather and very dry. Nay in some places the sultry heat of the Climate is more complained of, in what they call their Winter then their Summer. So that there will be no necessity to recur to an Antiperistasis occasioned by the coldness of the Winter. I thought too, that it may perhaps be without absurdity suspected, that as the bottom of the Sea in this place had a peculiar Constitution that fitted it more than others for the copious production of pearls: so there might be some peculiarity in the nature of the subjacent Soil, or there may be some Subterraneali Fire or heat beneath it, which may occasion an unusual warmth in that part of the Sea, by which cherishing warmth, perhaps such abundance of shell Fishes teeming with pearls, may be invited to settle there rather than in any of the neighbouring places. But with all these conjectures, I should not have been so well satisfied, as with the answer I afterwards obtained by a Gentleman whose Curiosity had carried him to be an assiduous Spectator of the famous pearl-fishing near the Island of Manar; between that and the Coast of Coromandell, which reaches near, if not fully to the Cape of Comoris. For this Person having had much Conversation with the Divers for Pearls, not only learned from them, that they found the water very sensibly Cold at the bottom which in some places he estimated to be 80 or 100 fathom deep; but observed divers of them at their return to the Boats, to be ready to shake with Cold, and hasten to the fires that were kept ready for them in little Cabins upon the shore: Which Relation being accompanied with divers Circumstances of credibility and arguing the person that made it to have been acquainted with the report above mentioned, and had met with some that had dived in the place whereto it had relation, made me conclude that as to that report hither something extraordinary had happened in that place, or that there was some mistake of him to whom 'twas made, or that divers did not descend to a sufficiently considerable Depth  
If I had been furnished with opportunity, I would have engaged some ingenious Navigators to examine the Temperature of the Submarine-Regions, both of differing seasons of the year (especially the hottest part of Summer and Coldness of Winter, & with Hermetically sealed Weatherglasses in order to the Discovery of such Particulars as these, Whether there be in some Seas any such varying Differences of Temperature, as may invite us at least in some places, to make more than two Submarine Regions. Whether the Submarine Coldness do at the bottom of the Sea, or elsewhere either Equal or surpass that degree which we here find sufficient to freez● common water. Whether the parts of the Sea-water are still the Colder, as they are the deeper, And Whether or no this increase of Coldness be regular enough to be reducible to any settled proportion. But for the resolving of these and the like Questions, I did not causelessely intimate that a sealed Weatherglass was to be employed; for I take a common one to be altogether unfit for such purposes, not only because the Sea-water would mingle with such Liquors as are wont to be employed in it, for that Inconveniency I could easily remedy, by substituting, as I have several times done in other cases, Mercury instead of ordinary Liquors: but chiefly because the incumbent Sea-water would gravitate upon the restagnant Liquor of the Weatherglass, and thereby render its Informations false or uncertain. According to what I have had occasion to observe in another Tract.  
Whereto, that there may not in this place be any need to recur, I shall add a slight experiment that I made for the satisfaction of some Ingenious men not w●ll acquainted with hydrostatics, or not rightly principled in them. And this Trial I shall the rather mention, because many will not allow Water to press upon Me●cury immersd therein, t●●s being a far more ponderous Liquor then that; and others will expect, that the included Air, having no place to escape out at, should resist the ascension of the subjacent Mercury, more than indeed it will. We made then a small Weatherglass differing from common ones, (besides the bigness,) in that it was turnished with Mercury instead of Water; and in that we employed to contain the stagnant Mercury, a Glass Vial with a narrow neck, wherein (by a piece of Cork or two) the Stem of the Glass ball was well fastened that this globula put of the Instrument might not be lifted up when it was under water. Then having by applying cold water to the outside of the Ball endeavoured to reduce the Air to the same Temper with the Water, or at least to an approaching degree of Coldness; and having taken notice of the Station of the Mercury in the shanck or stem above mentioned; we did, (by strings tied about the neck of the small Vial) let the Instrument gently down into a large tall glass Body filled with fair water that the Liquor and Vessel being both transparent, we might easily perceive the motions of the Mercury in the slender pipe. By which means it appeared, that as the Thermometer descended deeper and deeper into the Water, the Mercury was pressed up higher and higher in the Stem. And that it may not be suspected, that this ascension proceeded only, or chiefly, from the refrigeration of the Air by the Water, I shall add to what I have just now noted, that though the Coldness of the Water may well be supposed uniform as at least to sense; yet the whole instrument being leisurely removed sometimes to the upper surface of the Water. (The like Experiment we might have tried with a Thermoscope furnished with Water and let into Oil; or with deliquated Salt of Tartar and pure Spirit of Wine instead of Mercury and Water: if we had been furnished with sufficient quantities of those Liquors and had judged it to be requisite.) But this Circumstance, I thought fit to admonish the spectators of, that 'tis not to be expected, that the Mercury should rise as much in proportion when it is (for example) a foot under water, as when it is but two or three Inches; because according as the Instrument is let down deeper and the Air crowded into a less room, the Spring of that compressed Air becomes the stronger and makes the more resistance. Which Advertisement agreed well with the Experiment, whose other Phaenomena I pass over as not pertinent to this place, where I would only justify what I said of the unfitness of Weather-glasses made (though with other Liquors) after the Common ways for making the Submarine Trials I proposed.  
But till such Artificial Observations can be obtained we may from what has been above delivered, probably gather that though the lowermost of the Submarine Regions be very sensibly Cold, yet Water, at least that of the Sea, does not by these Phaenomena appear to be the Summum Frigidum. Though I have been several times able to produce Ice in Salt-water, yet I find not by any Observation, that there has been Ice met with and generated at the bottom of the Sea, under which the Earth has been found unfrozen by our Divers; and appears to be soft at depths exceedingly surpassing the greatest they have reached; as is evident by the Mudd, Gravel, etc. fetched from the bottom of the Sea by sounding plummets, let down to 80 or 100 fathom, or even a depth, whereof examples may be met with in the Journals of Navigators; n●y, my curiosity procured me this account, from the sober Commander of a ship, that came this year from the remoter parts of the great Ocean, that at about 35 degrees of Southern Latitude, the tallow with which his sounding Lead was anointed brought him up grey Sand from the immense depth of no less than two hundred & twenty Fathom. But to this Observation 'tis just to annex this Caution, That we cannot safely conclude from men's finding no Ice at the bottom of the Sea, that the Cold there cannot be very intense; for as I have found by more than one Relation (
* Notes aboat the Saltness of the Sea.  elsewhere recited) that, whatever the Schools surmise, the Sea is at least as Salt at the bottom, as at the top: so I have more than once tried, that Salt water will without freezing admit a much greater degree of Cold, then is necessary to turn fresh Water into Ice.  
FINIS.    

RELATIONS About the BOTTOM OF THE SEA.  

RELATIONS about the Bottom of the Sea.  
The First SECTION.  
I Do not pretend to have visited the Bottom of the Sea, but since none of the Naturalists whose writings I have yet met with, have been there any more than I, and 'tis great rarity in these cold parts of Europe to meet with any men at all that have had at once the Boldness, the occasion, the Opportunity and the Skill to penetrate into those concealed and dangerous Recesses of Nature, much less to make any stay there, I presume it will not be unpleasant, if about a subject, of which, though none of those very few Naturalists that writ any thing at all, writ otherwise then by hear-say, I recite in this place, what I have learned by Enquity from those Persons that among the many Navigators and Travelers I have had opportunity to converse with, were the likeliest to give me good Information about these Matters.  
It would be needless here to take notice, that the Sea is usually Cold and Salt at the bottom, nor to repeat those other Things that I have already delivered in other Discourses. I shall therefore begin what I have to say in this, by relating that one of the chief things that I was solicitous to inquire after about the Bottom of the Sea, was, the inequality I supposed to 〈◊〉 in the Soil. For though the surface of th● Sea when 'tis not agitated by the winds, appears very plain and level, and though it be indeed, at least i● this or that particular Sea, Spherical and (Physically speaking) concentrical to the earth; yet I could not think it probable, for Reasons not necessary to be here discoursed of, that the Bottom, the Superficies of the Ground, or of the Vess ll that contained it, should be either flat or level, or regularly concave.  
To satisfy myself about this matter, I enquired of a Person that had visited the famous Pearl fishing at the little Island of Manar (near the rich Isle of Ceylon) in the East Indies, and had by his stay there much opportunity to see Divers at their Work and converse with them. By the Answers of this man who was a Scholar, I learned, that the Divers had assured him, That they found the Floor of the Sea, if I may so call it, in divers places exceedingly unequal, in some places being flat, in others asperated with crabby Rocks a considerable height, and elsewhere sinking into precipitous depths in which they found it very cold.  
Besides the recited Testimonies of the Divers, I enquired of several pilate's and other Navigators, that had made long Voyages, what gradual or abrupt inequality they had observed at their Soundings in very neighbouring places; it being easy to be gathered from thence, whether the Sea were there uniformly deep, or did at least with some regularity alter its depth by degrees, or whether as I suspected, there were not at the bottom of the Se●, ●illy places, and steep Praecipices, and perhaps deep Valleys or Wells, as we observe in the discovered part of the Terrestrial Globe.  
By these inquiries I obtained several Observations, whereof the most material are those that follow.  
First, An ancient Sea-Commander, that had many years frequented Africa and the Indies, told me as others had done before, that when they sailed in the Ocean very far from sight of Land, they did not often put themselves to the trouble of Sounding, but that as far as they had Sounded, he had usually found the depth of the Sea, to increase or decrease gradually, without very great irregularities, excepting some places, instancing particularly in the Excavation that makes the Bottom of the Sea, within sight of the Cape of good Hope, where though for the most part, he found the water to deepen more and more as he sailed farther from the shore, yet in one place, he and others had met with a Bank (as he conceived it to be) at a considerable distance from the surface of the Water. So that though when they were as they imagined near the edge of that bank, they found but a moderate number of fathoms, yet when sailing a very little way farther, they had gone beyond it, they found the Sea of an immense depth. In short, I gathered from his Answers, that in the greater Seas, he had found for the most part, the ground at the bottom, to fall away by degrees; but nearer the shores, that is, within a moderate number of Leagues, he observed in divers places that the Submarine Ground was very unequal, and had as it were, Hills and Praecipices.  
A man of Letters, that had sailed both to the East and West Indies, and in divers other Regions besides, and had made some of his Voyages in ships of such great burden, as obliged the Mariners to be very frequent and careful in sounding, informed me, that some times at considerable distances from shore, he had observed the Sea to be 20, 30, or perhaps 40 fathom deeper when they cast the sounding Lead from one side of the ship, than it had been just before, when they had sounded from the other, and from other Things that he told me, I found myself much confirmed in the above proposed Opinion.  
Hearing of a Sea-Captain of extraordinary skill in Maritine Affairs, that was come home this year from East-India, his reputation made me endeavour to have a little conference with him, about the subject of this discourse; but his occasions hastening him to another place before I could send to him, I procured from the chief Persons that employed him, a sight of some Notes, touching his last Voyage, which he had left with them; hoping to sinned there something at least, about the Soundings of so accurate a Seaman, and accordingly I met with a Passage, very pertinent to my purpose, and worthy to be here transcribed.  
Febr. 12. After our Observation, (he means a former one very agreeable to this) seeing the ground under us, we heaved the Lead, and had but 19 fathom rocky ground, then haled by N.N. Et. the Wind at N.W. and found our water to shoal from 19 to 10 and 8 Fathom hard Coral Ground, then suddenly deepned again from 8 to 20 and 22 fathom Sandy Ground, and then suddenly saw Rocks under us, where we had but 7 fathom, and the next cast 14 fathom again. And so having run N. N. Et. from 6 in the morning till 12 at noon about 19 mile, we deepened our Water, from 16 to 25, and the next cast, no ground with 35 fathom of Line.  
Lastly, having opportunely met with an Ancient Navigator, who passes for the most experienced Pilate in our Nation for an East Indian voyage; I asked him about his own Observations concerning these unequal Soundings, I was answered, that he had not only met with them elsewhere, but that not far from the mouth of out Channel, he had sometimes found the bottom of the Sea so abrupt, that in sailing twice the Length of the ship, he had found the Water deepen from 30 fathom to a hundred, if not also much more.  
Since I received these Relations, having the honour to discourse with a Noble Person, who has divers times deservedly had the command of English Fleets, and is no less curious than intelligent in Maritine affairs, I took the opportunity to inquire of his Lordship, whether he had not observed the bottom of the Sea to be very unequal in neighbouring places? To which he replied, that he had found it exceedingly so. And to satisfy me that he spoke not upon mere conjecture, he told me that sailing once with his Fleet even in our Channel, he perceived the Water to make a rippling noise (as the Seamen call it) as the Thames does under London Bridge. So that he was afraid they were falling upon some shoal, the Water being 12 or 14 fathom deep, and going on a little farther, he cast out the Plummet again, and found it about 30 fathom. He added that he made divers such Observations, but took notice of such rippling Waters only when the Tide was ebbing: and yet in a deep Sea meeting with the like appearance in the upper part of the water, and thinking it improbable that there should be any shoal there, he ordered the depth to be sounded, and found it to exceed 30 fathoms; and after he had passed on a very little farther, he found the Sea so deep, that he could not fathom it with his ordinary Line.   

The Second SECTION.  
ANother thing observed at the Bottom of the Sea, is the great pressure of the water there against other Bodies. For what ever men may Philosophise in their studies, and may conclude from the Principles that are generally received about the Non-gravitation of Water in its proper place, yet experience seems very little to favour that General Doctrine.  
For first, I remember that having caused a pretty large Cylinder of Glass, that was open only at one end, to be so depressed into a large Glass vessel full of water with a conveniently applied weight of Lead, that none of the air could get out, I could easily discern through the Liquor and Vessels, which were all transparent, that as the inverted Cylinder descended deeper and deeper, the external Water compressed the imprisoned air, and ascended higher and higher in the Cavity of the Cylinder, against whose side we had before hand placed a row of Marks, whereby to take notice of the gradual ascent and descent of the Internal Water.  
Secondly having inquired of two several observing Persons, whereof one had with a Diving Engine visited the bottom of the Sea in a Cold Northern Region; and the other had done the like in an Engine much of the same sort, upon the coast of afric, I found their Relations to agree in this, that the deeper they descended into the Sea, the more the air they carried down with them was compassed, and the higher the Water ascended above the Lip, or Brim of the Engine into the Cavity of it.  
But I shall now add a more considerable experiment or two, to the same purpose. For discoursing one day with an Engineer of my Acquaintance, that had been often at Sea, and loved to try Conclusions, of a way I had thought of, to make some estimate of the pressure of the water at a considerable depth beneath the surface, and show that the pressure is great there, he told me he could save me the labour of some Trials, by those he had made already, and assured me that having divers times opportunity to sail near the straits Mouth, over a place where the Sea was observed to be of a notable depth, he had found, that if he had let down with a weight into the Sea, not a strong round Glass-bottle, but a Viol, such as the Seamen use to carry their Brandy and strong waters in, such a Vessel which might contain a Pint or a Quart of water, would when it came to be sunk 40 fathom under water, if not sooner, be so oppressed, by the Pressure of the incumbent, and lateral Water, as to be thereby broken to pieces.  
He also averred to me, that having exactly closed an Aeolipille of Metal, and with a competent weight, sunk it to a great depth in the Sea, as to forty, fifty, or sixty fathom deep, when he pulled it up again, he found to his wonder, that the great pressure of the water, had in divers places crushed it inwards. And though I had some suspicion, that the coldness of the Sea at such a depth, might by weakening the spring of the included Air, something contribute to the effect, yet I did not admire the event, having divers years before had a thin Aeolipile of Copper crushed inwards by the pressure of a much lighter Fluid than Sea-water.   

The Third SECTION.  
ANother thing observed in the Bottom of the Sea is, the Tranquillity of the Water there, if it be considerably distant from the surface. For though the Winds have power to produce vast waves in that upper part of the Sea that is exposed to their violence, yet the vehement agitation diminishes by degrees, as the Parts of the Sea, by being deeper and deeper, lie more and more remote from the superficies of the water. So that the Calm being less and less disturbed towards the Bottom of the water, if that lie considerably deep, the water is there either calm, or scarce sensibly disturbed.  
But that is for the most part to be understood, of places at some distance from the shore; for oftentimes in those that are too near it, the progress of the waters being rudely checked, and other circumstances concurring, the Commotion of the water is so great, that it reaches to the very bottom, as may appear by the heaps of Sand, the Amber, and in some places, the stones that are wont to be thrown up by the Sea, in, and after storms.  
The above mentioned Calmness of the Sea at the Bottom (will I doubt not) appear strange to many, who admiring the force of stormy Winds, and the vastness of the Waves they raise, do not at the same time, consider the almost incomparably greater Quantity, and weight of Water that must be moved, to make any great commotion at the bottom of the Sea, upon which so great a Mass of Salt-water, which is heavier than fresh, is constantly incumbent. Wherhfore for the Proof of the proposed Paradox, I will here set down a memorable Relation, which my inquiries got me from the Diver elsewhere mentioned, who by the help of an Engine could stay some hours under Water.  
This Person then being asked, whether he observed any operation of the Winds at the bottom of the Sea, where it was of any considerable depth? Answered me to this purpose, That the Wind being stiff, so that the waves were manifestly six or seven foot high above the surface of the Water, he found no sign of it at 15 fathom deep; but if the Blasts continued long, than it moved the Mudd at the Bottom, and made the water thick and dark. And I remember he told me, which was the Circumstance I chief designed, that staying once at the bottom of the Sea very long, where it was considerably deep, he was amazed at his return to the upper parts of the water, to find a Storm there which he dreamt not of, and which was raised in his absence, having taken no notice of it below, and having left the Sea calm enough when he descended into it.  
For farther Confirmation, I shall add, that having inquired of a great Traveller, who had assisted at a rich Pearl-fishing in East Indies, whether he had not learned by his Conversation with the Divers, that storms reach not to the bottom of the Sea, if it be of any considerable depth, he answered, that he had seen the Divers take the Water, when the Sea was so very rough, that scarce any Vessels, would hazard themselves out of Ports, that those returning Divers told him, that at the Bottom, they had found no disturbance of the Water at all. Which is the more considerable, because of the situation of that place where they dive for Pearls; for this is near the shore of Manar, and that itself is sealed between the great Island of Ceylon, and the vast Cape of Comori: and though it may be much nearer the former, is not yet far distant from the latter. Which situation and the Neighbourhood of the vast Indian Ocean, on the one side of Ceylon, and the great Gulf of Bengala, (anciently Sinus Gangeticus) on the other, makes the place where the Pearls are fished for, exceeding likely to be subject to very troubled Seas.  
It will perhaps be thought no slight addition to the foregoing Arguments, if I here add, that meeting one day with an ancient and expert Seaman, whom his merit had advanced to considerable Employments in his Profession, I was confirmed by the Inquiries I made of him, not only in the Opinion I had about the Calmness of the Bottom of the Sea, but also that the operation of good Gales of Wind, does oftentimes not reach to near so considerable depths into the Sea, as hath been hitherto supposed, even by Navigators themselves. For he assured me, that having sometimes sailed in great Ships that drew much water, as about 12 or 15 foot, he had Dived to the Keel of the ships, when they are under Sail, and observed the Agitations of the Water, to be exceedingly diminished, and grown very languid, even at that small distance, from the upper part of the Waves. And he farther answered, that when in America he learned to Dive of the Indians, they taught him by their Examples, to creep along by the Rocks and great stones, that lay near the shore at the Bottom of the Water, to shelter themselves from the strokes, and other ill effects of the Billows, which near the shore, and where the Sea was so shallow, as it was there, did oftenhurt and endanger Swimmers and unskilful Divers. But when they were by this means got further from Shore and into deeper Water, they would securely leave the shelter they had till then made use of, and swim within a few yards of the Surface of the Sea, as fearing there no danger from the To sings and Commotions of the upper parts of the Water.  
But lastly, for further satisfaction, I had the opportunity to make inquiry about this matter of a great Sea Commander who has both an extraordinary curiosity to make marine Observations, & an unusual Care in making of them accurately, I found the Opinion countenanced by his Answer, which was in short; That he had lately been at a place where the Sea was often tempestuous enough, and that they found by a sure mark that the Storm did not reach with any efficacy four fathom beneath the Surface of the Water.  
About the Tranquillity of the Lower Parts of very deep waters I had a suspicion, which though I fear it might seem somewhat extravagant, because I have not met with it in Authors; yet I thought it worth examining for the use it might be of, if resolved in reference to the Ebbing and Flowing of the Sea.  
I made therefore a Solicitous Inquiry whether the Tides did reach to, or near the Bottom of the deeper Seas, but found it exceeding difficult by reason of men's want of Curiosity to obtain any satissaction about a Problem that most Navigators I have conversed with did not seem to have so much as dreamt of. But thus much I found indeed by enquiring of an Engineer who was curious of Marine Observations, that a famous Sea Commander of his Acquaintance being also a great Mathematician, had affirmed to this Relator, that he had divers times observed, that when he let down his Plumber to a great depth but yet not to reach ground, it would be quickly carried by a motion quite contrary to that of the Shallop whence they sounded and very much qu●cker than it; but I had this only at second hand. Also, if I mis-remember not, I was informed by a skilful Observer that commanded many of our English men of War, that he had near the sound observed the upper and Lower parts of the Water to move with a considerable swiftness quite different ways; but not having committed this Relation to writing, I dare not build much upon it. And among the Answers I had received and written down concerning those matters, all that I can yet find among my Adversaria, is a Relation which though single, will not be unworthy to be transcribed in this Place, because the Person who gave it me, is one of the ancientest and most experien'st Pilots of our Nation.  
This Person therefore assured me, that sailing beyond the Cape of Good Hope into the South Seas, made Trials of the motion of the upper part of the Water above the lower, where sometimes casting out a large and heavy Plummet, he let it down to several depths short of 50 fathom, without any sensible Operation upon the motion of the Boat, or Shallop he stood in to make the Trial; but when he let down the Plummet lower, to about an hundred fathom or more, than he found that though the Plummet reached not to the Bottom of the Water, yet upon the score of the standing water beneath, the Superior Water would make the Bo●t turn towards the Tide or Current, as if it lay at Anchor, and the water would run by the side of the Boat at the rate of about three mile an hour, Thus far this diligent Observer. But how far the inequality of the Soil at the bottom of the Sea, and how far the various depth of the Water, and some other circumstances, may alter the case, and make it hard to determine, what ought to be ascribed to Tides and what to Currents, and are things which I will by no means be positive in; till I can meet with further Information.  
[Since the writing of this, happening to meet with one that spent some time at a famous Eastern Pearle-fishing, and asked him whether he had inquired of the Divers about the Problem lately proposed, and whether the Sea were there deep enough to make observations of that kind: To the latter part of which Question he replied, that in some places it was of a very considerable depth, and fit to make the observation in; And to the former he answered, That he had inquired of the Divers, who affirmed to him that sometimes at the Bottom of the Deep waters there seemed to be a stagnation of the Sea for a great depth, so that till such a height they could rise directly upwards, but that at other heights they would be carried away by the less deep-waters; so as to be found when they came to emerge a great way off from that point of the surface which was perpendicular to that place at the Bottom, whence they began to ascend.]  
FINIS.