far as divers Earthquakes have done but that the fire passes through some little subterraneal clefts or channels or hidden conveyances from one great Cavity or Mine to another yet 't is not improbable but that the vehemently tremulous motion does oftentimes reach a very great way beyond the places where the explosions were made Since though Seneca would confine the extent of Earthquakes to two hundred miles yet observations made in this and the last Century warrant us to allow them a far greater spread The Learned Josephus Acosta affirms that in the Kingdom of Peru in the year 1586 an Earthquake reached along the shoar of the Pacifick sea 160 Leagues and adds that sometimes it has in those parts run on from South to North 300 Leagues And in the beginning of this our age Anno Dom. 1601 good writers relate a much larger Earthquake to have happened since it reached from Asia to that Sea that washes the French Shoars and besides some Asiatick Regions shook Hungary Germany Italy and France and consequently a great part of Europe And if that part of the Narrative be certain which relates that this lasted not much above a quarter of an hour it will be the more likely that this Earthquake shook great Tracts of Land beyond those places to which the fired matter passing from one cavity to another could reach in so short a time As you will the more easily guesse if you try as I have done that in trains of Gunpowder it self the fire does not run on near so swiftly as one would imagine But though I have been in more Earthquakes then one yet since they were too sudden and too short to afford me any considerable observation I shall say no more of them but proceed to take notice that oftentimes the motion of a Coach or Cart that passed at a good distance from the place that I was in has made the buildings so sensibly shake that I could not but wonder that so great a portion of so firm and sluggish a body as the Earth could by a cause that seemed very disproportionate to such an effect be made to tremble it self and manifestly to shake firm buildings that were founded on it And this observation made me the more inclinable to give credit to their Relations who tell us that in a calm night the march of a troup of horse may be felt by attentive Scouts watching at a great distance off by the shake that the ground receives from the trampling of the horses though I formerly suspected much and do yet a little that the impulse of the air conveyed along the resisting surface of the ground might mainly contribute to the effect that is ascribed onely to the motion of the soil Before I advance to the Second Member of this Chapter it may not be impertinent to note that in peculiarly disposed bodies and especially in Organical ones a very languid motion may have a far greater effect than it could produce by a bare propagation of it self For it may so determine the motion of the Spirits or other active parts of the body it works on as to make multitudes of them act as if they conspired to perform the same motions As when a ticklish man by having the pulp of one's finger passed gently along the sole of his foot or the palm of his hand has divers muscles and other parts of his body and face put into preternatural or unusual motions And most men by being lightly tickled with the end of a feather or straw within their Nostrils have their heads and many parts of their bodies put into that violent Commotion wherein Sneezing consists And I remember that having for some time been by a distemper from which God was graciously pleased a while after to free me quite deprived of the use of my hands it more than once hapned to me that sitting alone in a Coach if the wind chanced to blow a single hair upon my face in the Summer-time the tickling or itching that it produced was so uneasy to me 'till by calling out to a footman I could get it removed that though I could well bear it as long as I was wont to do when having the use of my hands I could relieve my self at pleasure yet if I were forced to endure the itching too long before any came to succour me the uneasiness was so great as to make me apprehend falling presently either into Convulsions or a Swoon But 't is time to proceed to the second Member of this Chapter 2. Others there are that cannot believe that Local motion especially if it be languid can be propagated through differing Mediums each of which save that wherein the Motion is begun must they think either repell or check and dead it To these I shall recommend the Consideration of an Experiment I remember I made before some Learned men in our Pneumatick Engine For having caused a large and thick glass Receiver to be so blown that it had a glass button in the inside of that part which upon the Engine was to be placed upwards I caused a Watch to be suspended by a little Silverchain fastned to that button by as slender and soft a body as I thought would be strong enough to support my watch and then the Glass being cemented on close to the Receiver to prevent a Commerce between the Cavity of it and the Air the watch that hung freely near the middle of the Cavity of the Receiver made it self to be heard by those attentive Listners that would hold their ears directly over the suspended watch whose motions were thereby argued to have been propagated either through the included air or along the string to the concave part of the Glass and through the whole thickness of the Glass to the convex part and thence through the interposed air to the Ear. And this mention of watches minds me of what I often observed in a small striking watch that I have worn in my pocket For when it struck the Hours and in some postures when the balance did but move I could plainly feel the brisker motions of the Bell and sensibly the languid ones of the balance through the several linings of my Breeches and some other interposed soft and yielding bodies and this though the watch as I said was small and the balance included in a double case and though the outwardmost were of what they call Chagrine and the innermost of Gold which I therefore mention because that closest of metals is observed more to dead sounds and motions than harder metals as Silver Copper and Iron That Motion may be propagated through differing Mediums may seem the more probable by the shakings that are often felt by men lying on beds that stand in rooms close shut when loud claps of thunder are produced perhaps at a great distance off in the clouds And whether it will be fit to add to this Instance that which you have lately met with in the III. Chapter
in the production of divers difficult Phaenomena of nature that are wont to be referred to less genuine as well as less intelligible Causes FINIS AN Experimental Discourse Of some UNHEEDED CAUSES OF THE Insalubrity and Salubrity OF THE AIR Being a Part of an intended Natural History of AIR LONDON Printed by M. Flesher for Richard Davis Bookseller in Oxford 1685. THE Preface HAving heretofore had occasion to draw together under certain Heads divers unpublish'd Observations and Experiments of my own and some of other men by way of Memorials for a Natural History of the Air I thought fit by more largely treating of two or three of the Subjects distinctly mention'd in my Scheme of Titles to give a Semplar or Specimen of what may be done upon the other Heads of the designed History Vpon this account I treated somewhat largely of the Salubrity and Insalubrity of the Air as a Subject which for the importance of it to Mens healths and lives I thought deserv'd to be attentively consider'd and have its Causes diligently inquir'd into And having observ'd that among the six principal Causes of the healthfulness or insalubrity of the Air namely the Climate the Soil the Situation of the Place the Seasons of the Year the raigning winds and Contingencies whether more or less frequent and especially Subterraneal Steams having I say observ'd that among these Causes there was one viz. the last nam'd about which I thought I could offer something that I had not met with in the Books of Physicians that treat of it I was thereby invited to set down my Thoughts and Observations by way of Conjectures which I was made to believe would appear uncommon and would not prove useless These Observations and Reflexions I referr'd for clearness and distinctions sake to four Propositions But when I had gone thorough the three first and made some progress in the fourth being hinder'd by divers Avocations to make an end of it I laid by the whole Discourse in a place which I thought a safe one but when afterwards I had some opportunity to dispatch what remain'd I found all the diligence I us'd to retrieve the entire Manuscript unsuccessfull At this surprizing Accident I confess I was somewhat troubled because whatever may be thought of the discursive part of those Papers the Historical part contain'd divers matters of Fact that I did not meet with in Books nor can now distinctly remember and will not perhaps be lighted on by even Physicians or such Naturalists as derive their knowledge onely from them 'T is upon this consideration that having afterwards met with many Papers that belong'd to most parts of the unhappy discourse I thought fit to put them together in the best order I could that I might not loose what might give some light to so important a Subject as the Theory of Diseases And this course I the rather pitch'd upon because before the Papers about the Salubrity of the Air I miss'd two other of my Manuscripts whereof the former contain'd a Cellection of Medicinal things and the second a defence of the Mechanical way of Philosophizing about Natural Things as it respects Religion And I remember'd that having formerly lost a Manuscript I was much concern'd for I purposely made a noise of it whence I suppos'd the Plagiary would conclude himself unable to make it pass for his And in effect the Book was in a while after privately brought back so that I found it laid in a By-place where I had before as fruitlesly as carefully sought it AN Experimental Discourse Of some Unheeded CAUSES OF THE Insalubrity and Salubrity OF THE AIR c. THE sixth and last thing upon which the Salubrity and Insalubrity of the Air depends is the impregnation it receives from Subterraneal Effluvia And though this be a cause not wont to be much heeded by Physicians themselves yet I take it to be oftentimes one of the most considerable in its effects The Effluvia that pass into the Air may be distinguish'd into several sorts according to their respective Natures as has been elsewhere shewn wherefore I shall now only take notice of the differences that may be taken from place and time upon which account we may consider that some of them arise from the Crust if I may so call it or more superficial parts of the Earth and others have a deeper Original ascending out of the lower parts and as it were Bowels of the Terraqueous Globe And to this difference taken from place I must add another perhaps no less considerable afforded by Time which difference relates chiefly to the second sort of Steams newly mentioned Of the Subterraneal Effluvia some are almost constantly or daily sent up into the Air and those I therefore call Ordinary Emissions and others ascend into the Air but at times which are not seldom distant enough from one another and those I call Extraordinary Emissions whether they come at stated times and so deserve the title of Periodical or else uncertainly sometimes with far greater sometimes with far smaller intervals and so may be called fortuitous or irregular But though I thought it might render what I am about to say more clear if I made and premised the two foregoing distinctions yet because in many cases Nature does not appear solicitous to observe them but at the same time imbues the Air with Steams referable to divers Members of these distinctions I shall several times though not always take the liberty to imitate her and consider the Effluvia of the Terraqueous Globe in the more general Notion that they are so I know 't is frequently observed and usually granted that Marrish Grounds and wet Soils are wont to be unhealthfull because of the moist and crude vapours that the stagnating waters send up too copiously into the Air. And on the other side dry Soils are because of their being such generally lookt upon as healthy Nor do I deny that these Observations do most commonly hold true but yet I think that besides what can be justly ascribed to the moist vapours or dry Exhalations we have been speaking of in many places the healthfulness and insalubrity of the Air may be ascribed to other sorts of Effluvia from the Soil than those that act merely or perhaps principally as these are either moist or dry PROPOSITION I. TO deliver my Thoughts about this matter somewhat more distinctly I shall lay them down in the four ensuing Observations or Propositions whereof the first shall be this It seems probable that in divers places the Salubrity or Insalubrity of the Air considered in the general may be in good part due to subterraneal Expirations especially to those that I lately call'd Ordinary Emissions For in some places the Air is observ'd to be much more healthy than the manifest qualities of it would make one expect and in divers of these Cases I see no Cause to which such a happy Constitution may more probably be ascrib'd than to friendly Effluvia
breathed in with the Air in Respiration or carried up and down by the Bloud or other Liquors of the Body may pass by other parts of it without doing them any sensible harm and attacking this or that determinate part produce there some Disease such as the fabrick and situation of that part peculiarly dispose it to be affected with And I shall add on this occasion that in our Hypothesis we may render a probable reason why in some Epidemical Diseases some persons may escape much better than other that seem likely to be at best as obnoxious to them without a recourse to the peculiar Constitutions of the Bodies of differing Persons for it may be conjectur'd that the noxious Corpuscles that infest the Air may especially in windy weather be very unequally disperc'd through the Air and many fly in far greater or lesser numbers within equal spaces of Air and consequently the Persons that have the ill luck to be in the way of the more numerous swarms of morbifick Corpuscles may be much more prejudiced by them than others though of weaker constitutions who happen to be attaqu'd but by few of them On which occasion I remember that a great many Trees in some Land that belongs to me having been suddenly much endamag'd by a wind that was not able to doe it by it's bare strength I had the curiosity to view somewhat heedfully a Tree that stood in the Garden and perceiv'd that all the considerable mischief was done to that side of the Tree which respected the corner whence the hurtfull Wind blew the Leaves of the other side continuing fresh and verdant as being by the other part of the same Tree fenc'd from the Wind and it was farther observ'd that even the expos'd side of the Tree was not every-where endamag'd for there were divers parts where the Leaves continued sound and green though neighbouring Leaves were some more some less for all that were prejudic'd were not totally blasted the sound Leaves and the discolour'd being so odly mingled that I conjectur'd the cause of the mischief to have been this that some Arsenical or other corrosive or poisonous Exhalations being suddenly emitted from the Subterraneal parts into the Air were by the Wind they chance to meet with there hurry'd along with it and blown against the Bodies that stood in it's way moving in the Air like Hail-shot discharg'd out of a Gun here in a closer and there in a more scattering order so that as more or fewer of them happend to fall upon the same Branch or Leafe they left more or less marks of their passage by destroying the texture and colour in the Leaves or parts of them they chanc'd to beat upon And this may possibly be the cause of some of those sudden and sometimes fatal Effects that I have known in some places the people talk much of complaining that such a one had his Eyes or his Face or onely one side of it blasted by a malignant Wind of which I thought I saw an Example in a Domestick of my own whilst in such a Wind he was riding after me who thanks be to God had no such mischief done me But the Vulgar have entertain'd such strange Conceits and Stories about these Blastings on which account some of them say that Men are Planet-struck that the fabulous things mingled with those that are possible have made intelligent Persons reject them all One thing more I shall take notice of in favour of our Hypothesis which is that it well agrees with what has been observed not without some wonder of the very short duration of some Epidemical Diseases in certain Times and Places For this may proceed from hence either that all the Morbifick Expirations ascended into the Air almost at once or at least within a short time and so were easily spent that is by diffusion or dispersion so weakned as to be disabled from doing much mischief or else the Subterraneal Commotion that produc'd them may pass on from one place to another and so cease to afford the Air incumbent on the first place the supplies necessary to keep it impregnated with noxious Exhalations And it agrees well with this Conjecture that sometimes we may observe certain Epidemical Diseases to have as it were a progressive Motion and leaving one Town free pass on to another Of which some Observations that I have made encline me to think that if Physicians would heedfully mind it they might take notice of several Instances One thing more may be added as consonant to our Hypothesis namely that sometimes an Epidemical Disease ceases in this or that place almost as sudden as it invaded or at least in a much shorter time than Physicians expected For according to our Hypothesis it may well happen that after one sort of Exhalations whose peculiar Qualities make them Morbifick have deprav'd the Air incumbent on a particular place there may by a new or farther Commotion of Subterraneal Bodies be sent up into the Air store of Expirations of another kind which meeting with those that formerly impregnated it may either precipitate them and so free the Air from them or by other operations on them and sometimes even by Coalitions with them so alter their nature as to disable them from doing any farther mischief This I shall illustrate if not confirm by that very remarkable Phaenomenon that is yearly observ'd at Grand Cairo in Aegypt for though I know not whether or no the Corpuscles that produce it arise from under Ground the affirmative part of the Question being not improbable it appears that by the intermixture of adventitious Corpuscles with the formerly Pestilential Air 't is so alter'd and corrected that within one day or two if not within a lesser compass of time there is a stop put to the progress of the Plagues that in that favourable time of year namely about the middle of Summer scarce ever misses of raging in that populous City and which is more admirable these sanative Corpuscles if I may so call them operate so powerfully that of those that are already seiz'd by that fatallest of Diseases the Plague few or none die of it after once these Antidotal Particles have sufficiently impregnated the Air. I confess so great and sudden a change is very wonderfull and I should scarce think it credible if I had not had the means and curiosity to enquire about it of divers persons some of them very intelligent that either curiously visited or also made some considerable stay in that great City and found them agree in the main about the truth of the matter of fact which is much confirm'd to me by so eminent a Testimony as that of the learned Prosper Alpinus who for several years practis'd Physick in Grand Cairo and as an Eye-witness delivers what he relates more authentically as well as more particularly than any I have met with And though he endeavours to give several reasons of this strange and sudden cessation of the