perhaps other Objects without or beyond the bounds of the Suns Action or Dominion yet being our selves Creatures whose Organs are Fram'd and Tun'd to his Operations to whose unfluence by the Decree of the Almighty we manifestly owe our Life and Being I say that while we inhabit this mortal Tabernacle of Flesh and Blood and have no Motion Animation or Sensation that we cannot by fair Reasoning derive from the Force and Impressions of this Planets Virtue by what Clue of Reason or Deduction when our Reason it self has neither Tools nor Materials whereby to build any Scheme or Notion about natural Knowledge that is not deriv'd from this Fountain can we be thought to have any Radical reflection or sound imagination beyond this Being or in a word by what Method of thinking can we go about Mechanically speaking to inquire into the cause of that Power to whose Action alone we owe the means of thinking at all After this first Necessary Account of some Notions and Opinions about general Causes that have obtain'd with me as I conceive they may somewhere or other relate to my Subject I come now to my Argument namely a Mechanical Solution of the Earths Motion on its Axis by Explaining the causes by which I conceive that Motion is produc'd First By granting the Sun to be the Center of gravity of the Earth and the rest of the Planets I am from thence Taught to conclude that the Tendency or Gravitation of this Globe towards that Center ought to yield the like Effects and produce the same Appearances Mechanicaly discoursing that we find to be brought to pass by any solid Body here with us by means of our Center of Gravity As namely If any solid matter be fram'd or cast into a Sphaerical form whereby it Recieves perhaps a Resemblance of the Earths Globe This Sphear being fitted with Poles nicely plac'd and exactly poiz'd shall by the least Addition of Weight duly apply'd or the Application of any proper degree of Force presently acquire a Motion on its Axis viz. A Verticity or turning on its Poles Secondly Among the many great Effects I have observ'd to be produc'd by the Suns Virtue on this our Globe I have remark'd that the Power of that Planets Influence is hardly any where or on any thing more Conspicuous than by his Action on Fluids on which Bodies it works so suddenly so apparently and with such force that by my frequent Meditation thereupon I came at Length to think it might be no unprofitable attempt to inquire after some yet remoter than the Common and visible Effects of its Power acting on that matter by that Medium Having I thought some Hints from the Ordinary and Familiar Lights his daily Operations afforded that the Sun might also be the cause of manifold other great Productions which seem hitherto to want a clear Solution among which this of the Earth's Motion on its Axis I conceiv'd might possibly be one I observ'd that tho' there might be many other causes of the Production and Variation of Winds yet that the Sun was manifestly the cause of all those we call Periodical Winds as the Trade-Winds Munsons c. as also of the Sea and Land Breezes in warm Countries in the Summer time That the Sun Visibly wrought the like Effects in many parts of the Globe on the Watery Element by Currents in the Ocean Spouts c. That what I had observ'd for many Years together of the production and Force of the Levant-Winds which will be calm in the Morning and by Noon will often blow with such impetuosity as to become a Storm and so die away again as the Sun withdraws and become still and quiet all Night till his return to the Meridian again For thus have I beheld the Scene shift and the Sun Act this part daily in those Countries about the Summer solstice for a Month or six Weeks together From which Observation when I came to turn my Thoughts to this Subject of the Earths Motion and the Causes thereof I gathered such Materials as in the Issue of the question will not I Trust be thought to have been Impertinently apply'd But to hasten to the most prevalent Reasons occurring to my Understanding How the Sun might be the cause of the Earth's Motion on its Axis take them as followeth viz. By my Observation and Calculation as I have been able of the Effects of the Suns force in general acting on different Subjects in divers manners I conciev'd nevertheless that his power by Rarifaction was of all others the most Remarkable and Seem'd to me not Obscurely to intimate that by that Action alone having so Spacious a Field as the Globe of Earth Sea and Air wherein to display his Power I cou'd discern cause enough whereby to determine a good deal towards the Solution of this notable Question And first I consider'd and have no need at all to doubt it that the Hemisphere of this Globe wheresoever the Sun chances to be in the Meridian that is where his Virtue is in greatest Force must needs be the most rarifi'd part thereof whither we consider'd it in the solid and Consistent parts thereof or in the Fluid that surrounds it Which Fluid namely that portion thereof that resides nearest the Earth which we call the Atmosphere being imbu'd with infinite Variety of combustible and inflamable particles Steaming from the Earth is as I may say the Storehouse of those Materials which by the Suns Action thereon produces all that Variety of Appearances which we behold and daily converse with on this our Globe such as Heat and Cold Wind and Rain Storms and Calms Hail Frost and Snow Foggs Vapours Meteors Exhalations Thunder and Lightning c. all which are Legible instances of that Planets power working on matter furnish'd from this Globe Whereof we can have no doubt from our Knowledge of many Situations and Heights that are above all this Hurry and Variety of Action and Motion as namely some part of Mount-Atlas the Peak of Teneriffe Mount Arrarat a long Chain of Mountains in America called the Andes c. which places are known to injoy a perpetual Serenity from whence Men can look down and Contemplate as in a Gallery the whole Action and Shifting of those Scenes that by the Suns Predominancy is produc'd on the Stage of the World below from whence I gather and make two Remarkable Observations thereupon viz. First That the several Species of things that furnish Subject matter for this Action are for the most part of the Earths product Secondly That the Effects reach not beyond a certain Limited distance from its Surface Which Observation of Fact may save us the pains and words of Philosophizing by the Laws of Gravity about Limiting the Action of the Surrounding Fluid which by the Sun's rarifiing Virtue is put is put into Motion Wherefore having noted that the Earth furnishes the Materials for this Motion and that the Action it self is contain'd within Conceivable bounds
it remains That we determine how and which way this Fluid put into Motion may be thought to take its Flight I say then that the Fluid investing that Hemisphere wherein the Sun's Fire chances to be in its Greatest Vigour is directed in its course by Lines drawn or produc'd from the cause that Acts thereon Namely the Sun and this by the same Mechanick Laws by which any body is found to move that is impell'd and driven out of its Place by another Body that has force enough to do it namely by right Angles from the Plane of the cause that Acts Wherefore remarking barely that a Line Conceiv'd to be at any time drawn from the Body of the Sun through the Axis of the Earth any where betwixt the Tropicks will not vary much from East and West this single note may suffice to show that the Course or Tendency of the moving Matter or Fluid must be that way namely by right Angles or thereabouts from the Axis of the Globe or which better Expresses it by Circles parallel a little more or less to the Aequator and not towards the Poles Thus stating the Boundaries and Tendency of the Action or Course by which the Fluid wings it's way that Surrounds this Earth I mean that Portion thereof which we call the Atmosphere I come Lastly to make a short necessary note or two touching the Effects of Rarifaction and Condensation viz. According to common acceptation where I observe that the same Body or Quantity of Matter when it is Rarifi'd becomes bigger or is Extended in all its Dimensions and so comes to require more space wherein to be contain'd than it did before and on the contrary when the same Body comes to be Condens'd or Compress'd it needs Consequently a less Space to contain it by which means any Body so alter'd becomes Lighter or Heavier with Respect to the Fluid or Medium wherein it has its Residence But this Alteration by Extension or Contraction can by no means come to pass but by being the cause of some certain Motion for whatsoever Thing requires a greater Space to contain it than it did the Instant before must needs in the same Moment remove some other thing to obtain such new space and whatsoever Thing becomes on the Sudden lessen'd or contracted must occasion the Motion of something or other at the same time to Replenish the Space it deserted by such contraction or shrinking into narrower bounds Having in some degree clear'd the way and conducted the Reader by those steps and that train of Reflection by which I became Establish'd in my Opinion touching the Certainty and Causes as they seem to me to be of the Earth's Motion on its Axis c. I come now to interpret that Motion as I conceive it to be an Effect of those Causes First Then I take for Granted and hope in due place to give probable Proof thereof that the Sun is the Center of the Earth's Gravity towards which it tends Secondly I have observ'd that the Fluid which Invirons the Earth's Globe by the Concurrence of proper admixtures of Matter furnish'd from thence is dispos'd for Motion and by a Posture of Obedience to proper Causes cannot but be deem'd to be Actually ever in a ready State of Mobillity Thirdly I have noted that Rarifaction and Condensation are causes of Motion and that the same quantity of Matter rarifi'd or condens'd becomes Lighter and Heavier as an Effect of such Causes Fourthly I note that every Action of Fire be it more or less breaks or alters the Aequilibrium of the Neighbouring Fluid which we see verifi'd every Moment by the Fire in our Chimneys which is the cause of that noise and whistling of the Wind through the Crannies and Key-holes of a close shut Room where a good Fire is Kept the Air tending and rushing thitherwards by stronger or weaker impulses ratably to the strength or weakness of the cause Acting thereon Fifthly I am in no great doubt but the Sun is the universal Fountain of Fire by whose Transcendent Masculine Force I conceive all the Seeds or Sparks of that Element existing every where here below is disseminated and propagated through out the World which Planet I conceive Acts in the fame manner on this whole Globe and the Fluid that surrounds it as any part or particle of its Fire is found to do on any Fragment of the same matter We see and know that a very small parcel of his Beams united or contracted by a glass will as certainly burn and therefore as certainly Act in proportion by Rarifaction as any Body of Fire of never so much Greater dimentions can be thought to do Whence we may I think safely conclude from the uniformity We find in the Operations of Nature that the Sun which is an immense Body of Fire whose Magnitude we know to be such as to Imbrace with his Heat and Inlighten with his Beams more than Half the Earth's Globe at once Acts in like manner and Proportion on the universal Mass as a Spark of his Fire shot through a Burning Glass does on a drop of Water or any other visible Fluid which we are sure it will Exhale and cause to disappear in a Moment I say that since we are certain that there can be no very great disparity of Proportion betwixt such drop of Water and the least spark of the Sun's Fire Acting thereon and that of this Globe of the Earth and Fluid compar'd with the Collected force of his Universal Influence on the whole Terrestrial Mass We can hardly withstand the Evidence of this Truth namely that the entire Hemisphere which is at once imbrac'd illumin'd and warm'd by that Planets Virtue cannot chuse but be Affected in the same Degree and be Lyable to all those Motions and Alterations which we behold and know to be the Effect of the like Action on the like Subject in lesser Proportions Sixthly We may determine from a bare Guess by what we see and observe That there is an unspeakable Store or Reserve of combustible and proper Matter contain'd on the Surface and in the Bowels of the Earth prepar'd to obey the Sun's Action and Impression thereon and we shall not I hope be Thought to Resolve too boldly if we conclude that as far as that Planets Force penetrates and warms so far he may be Computed to act by Exhalation or Rarifaction call it what you please on the Universal Mass of matter So that by this Mighty force employ'd on a Sufficient Proportion of Subject matter we may be taught to Expect proportionable Effects Wherefore I believe it will be hard to gainsay but that the enlighten'd Hemisphere or that Face of the Globe which is at any time the Scene of this Action must unquestionably Suffer a manifest dimunition of Matter and consequently of weight by the Transpiration Extension and Motion of the Volatile parts which ever Wing their way from the Light to the Dark side of the Globe where by
the same Laws by which they mov'd they must also cease from Motion and there Subside and be at rest till actuated anew and put on the wing again by the return of the cause by which means namely this Revolution of Action we may conceive a constant course of Diminution and Restitution of Matter or an alternate Gravitation and Alleviation thereof on the Earth's Globe which by plain Mechanick Laws urges a manifest Succession of Change in the Aequilibrium thereof and that in a Double Proportion viz. By borrowing from one Scale to lend to the other Whereby the Preponderancy of the dark Hemisphere or Alteration of the Aequilibrium of the Globe becomes I say so much the Greater And thus I conceive how by the Laws and Action of Gravity we may discern with some Evidence a Proclivity in the Earth's Globe towards a Motion of Verticity or turning round and that from a Cause as Familiar and Intelligible as a Bird 's ringing the Chimes in a Cage Lastly Having produc'd and assign'd the Causes how I imagine the Earth's revolving Motion may by Mechanick Laws be obtain'd I come now to inquire after the Poles of this Motion without which we shall be at a loss and want a Sound Footing of Reason whereon to Build and Govern this Motion which while we consider its Regular and stated Periods it cannot be thought to be fortuitous but founded and stated on Adequate Causes The Earth's Globe being as I have noted immers'd in the Great Fluid or Aether wherein both that and the rest of the Planets are Granted to move This Fluid according to its Nature and Property Claspes and Embraces it universally pressing or Gravitating on the Surface therefore equally every where I say equally because I wou'd not ingage here in any Statical questions but Subject and Obedient still to certain Adventitious Causes which may alter and Diversify such pressure or Gravitation Let it be permitted me then to conceive that this Fluid being simply Consider'd and in its own Native purity namely clean from all whatsoever Admixtures I say this Elemental Aether if I may so call it Nakedly understood viz. stripp'd of all Foreign and Heterogenius Ingredients which by there Inflamable and Explosive Virtue may be conceiv'd to Act thereon is of it self a Passive Lifeless matter destitute of any Intrinsick Force of Action and is no other in short than the Vehicle of those Powers or Ingredients that swim and reside in it which matter or Fluid becomes Lighter and Heavier Slow Swift Rappid and at rest just as it is Impregnated Inspirrited or Deserted by those Forreign Agents or any Heterogenius Body casually Mixing or Floating therein to which I say the Fluid or Aether is nothing else but the meer Vehicle This remark being duly weigh'd we need but recurr to the cause of that Variety of Action and Motion which we have Observ'd to Exist on the Earth's Surface which I observe to be the Sun by whose force Acting on proper Matter all that tumult of Action is rais'd and begotten in proof whereof we need not go further than to note that the greatest Storms and Hurrican's are ever found where that Planets power reigns with greatest force From a reflection on the Power let us go to the Situation or Position of the Agent with respect to the Earth's Globe which furnishes the Materials whereon it works And therein may be considered that the greatest Vigour of the Sun's Action is contain'd betwixt the Tropicks his Beams ever darting somewhere or other within or between those two Circles and no where else at right Angles on the Earth's surface and from or without the Tropicks viz. towards the Poles the Angles of insidence become oblique and ever fall with greatest obliquity at the Poles The use I wou'd make of this observation is That since we can determine where and on what part of the Earth's Globe the Sun's Beams fall with least Obliquity we may resolve also that it is on that part and within those boundaries that his Fire acts with greatest fervour But this force of the Sun's Virtue is found to be greatest betwixt the Tropicks where by his Action on the greater Circles of the Globe the Effect becomes so much the surer by how much we observe a greater Wheel or a longer Lever to Act more forcibly than a lesser which as it fortifies the Reasons already offer'd for the Earth's Verticity by assigning such a position to the Cause as may render the Effect so much the more Probable so it leads us not obscurely to concieve how the Poles of this Motion also are begotton For if there shall appear any Evidence from the Causes we have assign'd for the Fluids pressing or Gravitating less on the Earth's Globe on the greater Circles namely betwixt the Tropicks which cannot fairly be gainsaid the Alleviation thereof being greatest where the Rarifaction and Motion is granted to be Greatest It will not then be hard to allow that every degree of Remission of the Power of the Agent viz. the Sun must produce a proportionable Diminution of the Effect But I have shown or lead the Reader to conceive how it comes to pass that the surrounding Fluid presses Lightest on the Surface of that Region of the Globe that shall be found remotest from the Poles and therefore there will be no difficulty to infer That as the Angles of incidence of the Sun's Beams by whose Action that Alleviation of the Fluids pressure is begotten which we have endeavour'd to explain grow more and more Oblique the Effect becomes more and more diminish'd So that by a Scale as I may say of Diminution or by the Gradual Obliquity of the Angles of incidence which begins at the Tropicks and are ever most Oblique at the Poles we may be taught to discern how the Fluid by this Remission of the Sun's Action thereon comes to press harder or Gravitate more on the Globe at the Poles than elsewhere or rather infer that by this necessary Superiour pressure the Poles of the Earth's Verticity are begotten For in a word the Fluid which I have over and above Endeavour'd to show being heaviest or pressing Hardest when in its native purity must needs abide there above all other parts of the Globe most clean and unmix'd from all such Heterogenius matter those two points of the Earth's Surface being the most absent from that active and Rarifying Force by which by means of such matter it is put into Motion as I have shewn how And I am in no doubt but all those combustible and Inflamable Ingredients which in other Regions of the Globe are the cause cooperating with the Sun of all that Agitation we have observ'd remain here Lazy and Lifeless on the Surface and in the Bowels of the Earth and like a Snake in Winter benum'd and bereft of all Power of Motion through the Absence of that inlivening Virtue to which it owes all its Power of Motion and Action by which means the Fluid or