A Second Letter of Dr Wallis to the Publisher, Relating to Mr Somner's Treatise of Chartham News: And, Some Magnetick Affairs

III. A Second Letter of Dr Wallis to the Publisher, relating to Mr Somner's Treatise of Chartham News: And, some Magnetick Affairs. Oxford, Decemb. 30. 1701. SIR, Since my Letter of Septemb. 20. 1701, (which, with the Post-script, you have thought fit to publish in your Transactions, for October 1701.) relating to the Discourse called Chartham News, in your Transactions for July 1701, (mis-numbered 271, instead of 272,) written by the inquisitive and learned Antiquary Mr William Somner, (to whom, I since find, we are beholden for divers other Pieces, beside those I mentioned in that Letter:) I have seen a Letter of Mr John Luffkin (in your Transactions for Sept. 1701.) which informs us, of divers Bones (of an Extraordinary bigness) found lately (in a Gravel-pit) not far from Harwich in Essex, (much like to those found at Chart-ham in Kent,) at a great Depth under Ground, which Bone, he thinks, rather to have been the Bone of an Elephant, than of an Hippopotamus, or other Marine Animal. But, whether the one, or the other, it matters not much as to the present purpose. For, either way, it will equally prove, those Valleys to have been much Deeper, in former times, than now. If you could obtain from Mr Alderman Gray of Canterbury, a sight of those Pictures (which he hath) of the Bones mentioned by Mr Somner (which, I presume, he would not deny:) or, cause new Draughts of them to be be made, from the Originals, which are said to be now in the Repository of Gref-ham College: It would not be amiss to give us a Copy of them, in your Transactions. Which would help to determine that Point in Question. I observe, that the River in Essex, and that in Kent, (near which the Bones were found,) are (both of them) named the Stowr. Which, whether it be a corruption of the Latin Æstuarium (as Mr Somner conjectures;) or, of the British ys-dwr (that is, the Water,) I will not dispute. And, That the Bones were found (in both places) much at the same Depth, (about 16 or 17 foot, under the surface of the Earth;) which therefore may (probably) have been lodged (in both places) much about the same Time: And, perhaps, when the Emperor Claudius brought his Elephants into Kent and Essex; As Mr Luffkin intimates out of Dio Cassius. I observe also, that those Petrified Bones, in both places, were found in Gravelly grounds, (as are those Petrified Shells, and Bodies of Fishes, in Gravel Pits and Stone Quarries, near Oxford.) How far the Steams, Fumes, or Fluors of the Earth, which contribute to the formation of Stone or Gravel, may conduce to the Petrifying of these Bones, Shells, or other Bodies; I leave to the consideration of inquisitive Naturalists. And, Whether the Impregnation of such Steams, may not Swell such Petrified Bodies, to a larger Proportion than before they had. Like as we observe Wood (and other like Materials) in a Moist Air, to Swell; by the Distention of their Pores, upon the intromission of Moist Particles. For I take all Petrifications to be made, either by Incrustation, or Intromission of Stony Particles. And I well remember, that (many years ago) at Moldash in Kent, (not far from Feversham) on some High Grounds, and very Stony, (which used to be, sometimes Pasture, and sometimes Plowed,) I have observed di- vers Oyster shells (Petrified, or partly so,) much Larger and Thicker, than the ordinary Proportion of Oysters in those Parts, and very Weighty, which Oyster-shells might have been purposely thrown there long before, as being reputed a good Manure for Land; and might have been there Impregnated with like Halitus, Effluvia, as are the Numerous Stones on those Lands. I have known the Inhabitants, heretofore, have used to cause the Stones, in those Lands (because they are very numerous) to be gathered up, and carried off the Lands, by Cart-loads, to make more room for the Grass to grow. But, of later years, they forbear (I have been told) so to do, as thinking the Warmth (or somewhat equivalent) of those Stones, is rather an Help than Hindrance, of the Earth's Fertility. Of which, I shall not adventure to deliver an Opinion; but refer it to further consideration. But (to return to what I was speaking of) I see not why we may not think, the Stowr in Essex, and the Stowr in Kent, to have been (both of them) Æstuaries of the Northern Tyde; before the Rupture of that Isthmus between Dover and Calais: (And the like of the River near Malden, and other small Creeks on the Coast.) Though not so Great as those of Humber and the Thames: (which were then Æstuaries of the same Sea:) as are many others on the Coast of Scotland. I say, Before that Rupture. For, since that Rupture, the case (as to the Thames) is somewhat altered. For the Western Tyde (between Us and France) which was then stopped at this Isthmus; doth now flow-on (through that Fretum) beyond the Mouth of the Thames, (as high as the Dogger-sands;) which doth therefore supply the Æstuarie of the Thames, which was formerly furnished from the Northern Sea. And, these smaller Æstuaries might sooner be swarved-up (by what every Tyde lodgeth there,) while, those Greater Greater Estuaries, are but Shortened, and become Narrower, than they had formerly been. And, as to the Thames in particular; It seems very Evident, (if we consider their Situation, and the Nature of their Soil,) that much of the Low Grounds (in Kent and Essex,) on both sides of the Mouth of the Thames (adjacent to the Sea,) had formerly been Sea, (as well as that of Romney Marsh.) And when the Mouth of the Thames was so much wider, no doubt but it Flowed much further than now it doth. And, how far, who can tell? It may perhaps be objected, that the small Rivers now remaining, in the bottom of these Vallies, which may have been supposed (in former times) to have been Estuaries; do now run more Wriggling (with more Turnings and Windings) than do these Vallies. But this need not at all to seem strange, when as we may daily see the same, in the Bottom of a Muddy Ditch (or Water course) when the Water is almost Drained off, the Mud yet remaining soft: the little Water, yet remaining, will work out of itself (amidst the Mud) a Wriggling passage (according as the Mud will more or less give way) much more Crooked than was such Ditch when full of Water. And the like must needs happen in the (gradual) Draining of such Estuaries, according as the (soft) Earth will permit. Which Crookedness will continue, when the Banks on both sides do (by degrees) grow firmer. These Notions I give ye, as my present Thoughts; upon supposition that there have been such an Isthmus and so broken. If in ought I have mistaken; I am willing to be set right, by those who are better acquainted with these Seas, than I am: with whom (at this distance) I have not the opportunity of discoursing, for better information. As to what I say, concerning the Isle of Oxney; I did then purposely omit many Circumstances, which I did not think much material to the point in hand: Choosing so to do, rather than to be in danger of misrepresenting (on my present Memory) what I had heard long before. That which I thought material to the point in hand, was this, That a low Level, in the Isle of Oxney, (which had for divers years lain under Water,) is now Raised by intromitting the Tyde) to a considerable height above what it had formerly been; And, that the Channel from thence to Rye, is (by the Tydes passing in and out become much Wider and Deeper than heretofore. Both) which are Evident, and not to be denyed. If you would have me speak more particularly to this matter (so far as my Memory serves me) I take it to be thus. If we look in the more Antient Maps of Kent (older than the year 1640) you will find, that (what we call) the Isle of Oxney, was then but a Peninsula; being (by a small Isthmus or neck of Land at the North-East corner of it) continued to the rest of the Country: And the Tyde from Rye to that place (which now flows straight onward on the North side of the Isle) was there stopped by that Isthmus, and did wheel about on the South side of it: Or rather, the River Rother, did (from the North side of the Island) wheel about by the South side (to that Eastern corner,) and thence (by the Chanel) to Rye. While things were in this state; divers Moorish or Marsh-lands, adjoining to the River Rother, were oft in danger (upon great Rains) to be Drowned. But so it once happened (by what accident I know not,) that, this Drowned Land, had unexpectedly (in a nights time, or little more) discharged itself on another Level, somewhat lower than itself. Upon which Indication; it was thought Advisable (by cutting that Isthmus) to allow those Waters (on the North side of the Island) a straighter passage toward Rye; and, to let those Lower Grounds (for some time) to lie under Water (paying the Rent of them,) till such time as (by intromitting the Tyde) they might be somewhat heightened; and, then, timely recovered. In order to which; Commissions of Sewers have ever since (from time to time) been issued out for that purpose; and the work (in good measure) effected, though not quite finished. This I take to be the true state (in brief) of that affair: But, under correction, if (in some circumstances) my Information, or my Memory, may have failed me. But I think it might be Acceptable, if some Gentleman (who is an Inhabitant of those parts, and hath been acquainted with the Proceedings of the Commissioners of Sewers there (for Fifty or Threescore years last) would give us a more particular History of those Proceedings. Which might be of good use for the Direction of others (in like Circumstances) for obtaining like Advantages as these have done; and, avoiding Inconveniences which may have happened. And the like, if Mr de la Pryme (whom you mention, to good purpose, in your Transactions for October 1701) could give us an Account of the Methods used by Sir Cornelius Vermulden in his Draining of Hatfield-Chace. I was about to end here. But (while discoursing of Maritime Affairs) a Friend of mine would have me suggest to you, a Conceit of mine concerning the Mariners Compass, (which being of prodigious Use in Navigation, it is not agreed, Where, or by Whom, it was first Invented.) I have Guesled it to have been an English Invention. Not only for that the English have been long conversant in Navigation: But, even from the Name Compass. Which is used in England (I am sure it was wont to be so used in Kent, when I was a Youth,) for what we otherwise call a Circle. And I take it to be an old English word in that sense; though now (in imitation of the French) the word Circle be more common. I know not whether a Compass (or any word like it) be so used, for a Circle, in any other Language; (but rather Cercle in French; Cerchio in Italian; Circulo in Spanish; or some other word derived from the Latin Circulus.) And from hence, the Circulus Nauticus may come to be called the Mariners Compass, which name, being given it by the first Inventers, might give occasion for like Names in other Languages; (compas, compasso, jzee-kompas, &c.) I do not deny but that the Circinus, or Instrument by which we describe a Circle (called by us a pair of Compasses) may have some like name in other languages. But, how anciently, I do not know; nor that a Circle absolutely consider'd (other than this Circulus nauticus) is so called. How far this conjecture, from the Name, may give us a Title to the Invention, (till a better do appear;) I shall not determine; but only suggest to Consideration. I think it is now agreed on all hands, That (what we call) the Variation of the Variation, is an English Discovery, (of Mr Gellibrand, if I mistake not, one of Sir Thomas Gresham's Professors at Gresham Colledge;) about the year 1635. That is, That the Magnetick Needle (in its Horizontal Position) doth not retain the same Declination or Variation from the true North, (in the same place, at all times, but doth (successively) vary (that Declination) from time to time. Which though it were, about that time, a New Discovery; is Now admitted as an Undoubted Truth. And (what we call) the Dipping Needle; is admitted also to be an English Discovery, somewhat Elder than that former. (I cannot say at present, whether by Mr Blagrave, or some other Greshamite.) That is, That the Magnetick Needle, (besides its Direction toward the North North, in its Horizontal Position, hath also a Direction of Altitude above the Horizon. And (if duly poised about an Horizontal Axis) will point to a determinate degree of Altitude or Elevation above the Horizon, in this or that place respectively. Of which Discovery (though made so long ago,) I do not find that much Use hath hitherto been made: that, of its Horizontal Declination, being more serviceable. 'Tis also an English Observation, That not only a Magnetick Needle, but any Piece of Iron (if kept long in the same Posture,) shall of it self contract a Polarity. As, for instance, an Erect Bar in a Window, (after long continuance in that Position, will (if duly poised) be found, with its upper end, to point toward the North; (and Southward with the other end.) And, if afterwards it be continued long in a contrary Position, it will attain a contrary Polarity. And Mr Gilbert's Notion, (of the Earths whole Body, being but one Great Magnet; and, lesser Magnets being so many Terrella's, sympathizing with the whole,) is English also. It hath been observed also, That a Magnetick Needle, if heated Red-hot, will lose its Polarity: And, if then cooled in a contrary Position, will acquire a contrary Polarity. It hath also been observed (if I have not been mis-informed) by our English Mariners, (and, I think, more than once,) that, upon a great Flash of Lightening (at Sea) their Magnetick Needle hath lost its former Polarity; and contracted the contrary; (pointing the wrong way, and directing the Mariner to a wrong Course.) And (in General) the Doctrine of Magnetism hath been more improved by our English Naturalists, than (for ought I know) by any other Nation. And, if some of our Grec-hamites would take the pains to give us a true History of these (and the like) improvements; it would be be an acceptable service, for the Honour of the Nation, and of that Colledge in particular, and of the Royal Society. But I must beg your Pardon for this long Digression: And subscribe myself, an Humble Servant of the Royal Society; And Yours to serve you, John Wallis. IV. Account of a Book, viz. Aloysi Ferdinandi Comit. Marigli Danubialis operis Prodromus. Ad Regiam Societatem Anglicanam. Fol. 1700. The Author of this Prodromus hath given several proofs of his great Abilities in this part of Learning, as in his Osservazioni entorno al Bosforo Tracio, Printed at Rome in 4to. 1681. In his Dissertazione Epistolare del Fosforo minerale, o Sia della Pietra illuminabile Bolognese, at Leipsick in 4to cum fig. 1698. The Piece now before us is only a Plan or Model of a great Work, which Signor Marigli is carrying on in six large Volumes in Fol. Imperial Paper, which he designs to dedicate to the present Emperor of Germany, by whose Favour he was employed many years in the Turkish Wars, and continues to receive a noble Salary from the same hand. The first Tome is to contain the Geographical Part, illustrated with many Charts and actual Surveys of the Banks of the Danube, from its rise to its exit into the Euxine Sea, describing all along the Channels, Whirlpools,