« PreviousContinue »
Clouds and Rains, to temperate the Cold (c) of the Northern frozen Air, to cool and mitigate the
ascending out of the Water. A small Heatthrowsoff but few Vapours, scarce visible: A greater Heat, and ascending in greater Quantities, carries off grosser, larger, and more numerous VeftcuU, which we call a Steam: And if the Heat breaks through the Water with such a Fury, as to lacerate and lift up great Quantities or Bubble, of Water, too heavy for the Air to carty or buoy up, it causcth what we call Boyling. And the Particles of Water thus mounted up by the Heat, are visible Sphaerules of Water, if viewed with a Microscope, as they swim about in a Ray of the Sun let into a dark Room, with warm Water underneath; where some of the Vapours appear large, some smaller Sphærulcs, according (no doubt) to the larger and lesser Quantities of Heat blowing them up and carrying them off. z. If these Vapours be intercepted in. their Ascent by any Context, especially cold Body, as Glass, Marble, we. they are thereby reduced into Drops, and Masses of Water, like those of Rain, we. 3. These Vapours in their Ascent from the Water, may be observed, in cold frosty Weather, either to rise but a little above the Water, and there to hang, or to glide on a little above its Surface : Or if the Weather be very cold, after a little ascent, they may be seen to fall back again into the Water; in their Ascent and Descent describing a Curve somewhat like that of an Arrow from a Bow. But in a warmer Air, and still, the Vapours ascend more nimbly and copiously, mounting up aloft, till they are out of Sight. But if the Air be warm and windy too, the Vapours are sooner carried out of Sight, and make way forothers. And accordingly I have often observed, that hot Liquors, if not set too thin, and not frequently stirred, ■cool flower in the greatest Frosts, than in temperate Weather, especially if windy. And it is manifest by good Experiments, ..that the Evaporations are less at those times than these; lels by far in the Winter than the warmer Months. '. (c) As our Northern Islands are observed to be more tem-perate than our Continents, (of which we had a notable Instance in the great Frost in 1703, which Ireland and Scotland felt less of, than most Parts of Europe besides ; of which fee Book IV. Chap. 11. Note c.) so this Temperature is owing to the warm Vapours afforded chiefly by the Sea, which by the. preceding Note must necessarily be warm, as they are Vapours, or Water inflated by Heat.
- The Cause of this Heat I take to be partly that of the :Sunf and partly Subterraneous. That it is not wholly that of
- E the
Heats (d) of the Torrid Zone, and to refresh the Earth with fertile Showers j yen, in some measure to minister fresh Waters to the Fountains and Rivers. Nay, so abundant is this great Blessing, which the most indulgent Creator hath afforded us by means of this Distribution of the Waters I am speaking of, that there is more than a scanty, bare Provision, or mere Sufficiency; even a Plenty, a Surplusage of this useful Creature of God, (the fresh Waters) afforded to the World > and they so well ordered, as not to drown the Nations of the Earth, nor to stagnate, stink, and poison, or annoy them > but to be gently carried through convenient Chanels back again
the Sun. is manifest from Vapours, being as, or more copiously raised when the Sun Beams are weakest, as when strongest, there being greater Rains and Winds at the one time than the other. And that there is such a thing as Subterraneous Heat, (whether Central, or from the meeting of Mineral Juices; or such as is Congenial or Connatural to our Globe, 1 have not Time to enquire; but I fay, that such a Thing is,) is evident not only from the Hot-Baths, many fiery Erruptions and Explosions, tyc. but also from the ordinary Warmth of Cellars and Places under Ground, which are not barely comparatively warm, but of sufficient Heat to raise Vapours also: As is manifest from the smoking of perennial Fountains in frosty Weather, and Water drawn out of Pumps and open Wells at such a Time. Yea, even Animals themselves are sensible of it, as particularly Moles, who dig before a Thaw, and against some other Alterations of the Weather; excited, no doubt, thereunto by the fame warm Vapours arising in the Earth, which animate them, as well as produce the succeeding Changes of the Weather.
(d) Besides the Trade-Winds, which serve to mitigate the excessive Heats in the Torrid Zone; the Clouds are a good Screen against the scorching Sun-Beams, especially when the Sun passeth their Zenith; at which Time is their Winter, or coolest Season, by reason they have then most Clouds and Rain. For which Service, that which Varene takes notice of, is a great Providence of God, -viz.. Pleraaue loca Zons. Torrid* vi* cinum habent mare, ut India, InsuU Indict., Lingua Africa, Guinea, Brasilia, Peruvia, Mexicana, Hispania: Pauca loot Zont Torrid*, sunt Mediterranea. Varenii. Geogr. 1. z, c. 26. Prop. 10. §. 7.
to to their grand Fountain (e) the Sea; and many of them through such large Tracts of Land, and to such prodigious Distances, that it is a great Wonder the
(e) That Springs have their Origine from the Sea, and not from Rains and Vapours, among many other strong Reasons, I conclude from the Perennity of divers Springs, which always afford the fame quantity of Water. Of this fort there are many to be found every where. But I shall, for an Instance, single out one in the Parish of Ufminsier, where I live, as being very proper for my purpose, and one that I have had better Opportunities of making Remarks upon above twenty Years. This in the greatest Droughts is little, if at all diminished, that I could perceive by my Eye, although the Ponds all over the Country, and an adjoining Brook have been dry for many Months together; as particularly in the dry Summer Months of the.Year i7oy. And in the wettest Seasons, such as the Summer and other Months were, preceding the violent Storm in November 1703. (Vid. Philos. Trans. N°. 189.) I fay, in such wet Seasons I have not observed any Increment of its Stream, excepting only for violent Rains falling therein, or running down from the higher Land into it; which discoloureth the Waters oftentimes, and makes an increase of only a Day's, or sometimes but a few Hours Continuance. But now, if this Spring had its Origine from Rain and Vapours, there would be an increase and decrease of the one, as there should happen to be of the other: As actually it is in such temporary Springs as have undoubtedly their Source from Rain and Vapours.
But besides this, another considerable Thing in this VpminJ ster Spring (and Thousands of others) is, that it breaks out of so inconsiderable an Hillock, or Eminence of Ground, that can have no more Influence in the Condensation of the Vapours, or stopping the Clouds, which the Maintained of this Hypothesis suppose) than the lower Lands about it have. By some Critical Observations I made with a very nice portable Barometer,.I found that my House stands between 80 and 90 Feet higher than the Low-Water Mark in the River of Thames, nearest me; and that part of the River being scarce thirty Miles from the Sea, I guess, (and am more confirmed from sorrre- later Experiments I made nearer the Sea) that we cannot be much above 100 Feet above the Sea. The Spring I judge nearly level with, or but little higher than where my House stands; and the Lands from whence it immediately issues, I guess about 15 or 20 Feet higher than the Spring; and the Lands above that, of no very remarkable Height.
Fountains should be high enough (/), or the Seas low enough, ever to afford so long a Conveyance. Witness the Danube (g) and Wolga of Europe^ the
And indeed, by actual Measure, one of the highest Hills I have met with in Ejstx, is but 363 Feet high; (yid. Phil. Trans. N°. 313. p. 16.) and I guess by some very late Experiments I made, neither that, nor any other Land in Eflex, to be above 400Feet above the Sea. Now what is so inconsiderable arise of Land to a perennial Condensation of Vapours, fit to maintain even so inconsiderable a Fountain, as what I have mentioned is? Or indeed the High-lands of the whole large County of EJsex, to the maintaining of all its Fountains and Rivulets?
But i shall no farther prosecute this Argument, but refer to the late learned, curious and industrious Dr. Plot's Tentamen Phil.deOrig. Font, in which he hath fully discussed this Matter.
As to the manner how the Waters are raised up into the Mountains and higher Lands, an easy and natural Representation miy be made of it, by putting a little Heap of Sand, Allies, or a little Loaf of Bread, &c. in a Bason of Water; where the Sand will represent the dry Land, or an Island, and the Bason of Water the Sea about it. And as the Water■' in the Bason riseth to, or near the top of the Heap m it, so doth the Waters of the Sea, Lakes, o-c. rife in the Hills. Which cafe I take to be the fame with the ascent of Liquids in capillary Tubes, or between contiguous Planes, or in a Tube filled with A flies: Of which the industrious and compleat Artificer in Air-Pumps, Mr. Hawkfbee, hath given us some, not contemptible Experiments, in his Phys. Mech. Exp. pag. 139.
Among the many Causes assigned for this ascent of Liquors, there are two that bid the fairest for it, -viz.. the Prejsurt $f the Atmosphere, and the Newtonian Attraction. That it is not the former, appears from the Experiments succeeding, as well, or better in Vacuo, than in the open Air, the ascent being rather swifter in Vacuo. This then being not the Cause, 1 shall suppose the other is.; but for the Proof thereof, I shall refer to (bme of our late English Authors, especially some very late Experiments made before our most famous R. S. which will be so well improved by some of that illustrious Body, as to go near to put the Matter out of doubt.
(/) See Book III. Chap. 4.
(g) The Danube in a sober Account, performs a Course os ahove 1500 Miles, (i. e. in a strait Line) from its Rise to its Tall. Bohun'j Geogr.Dict.
Nile (b) and the Niger (/) ofAfrick, the Ganges (k) and Euphrates of A/ia, and the Amazons River (f) and Rio de la Plata of America, and many others which might be named j some of which are said to run above f 000 Miles, and some no less than 6000 from their Fountains to the Sea. And indeed such prodigious Conveyances of the Waters make it manifest, that no accidental Currents and Alterations of the Waters themselves, no Art or Power of Man, nothing less than the Fiat of the Almighty, could ever have made, or found, so long and commodious Declivities, and Chanels for the Paslage of the Waters.
(Jo) Tratlus fe. Longitudo [Nili] est milliarium circiter 630 Germ, five Hal, 1510, pro quibus ponere licet 3000 propter cicr■vaturas. Varen. Geogr. 1. r. c. 16. p. 27.
(») Varene reckons the Course of the Niger, at a middle Computation, 600 German Miles, that is 1400 Italian.
(k) That of the Ganges he computes at 300 German Miles. But if we add the Curvatures to these Rivers, their Chanels are of a prodigious Length.
(/) Oritur, stamen (quod plerumque Aw.az.onum, &c.) haud procitl Quito in montibus —— Cam per leucas Hifpanicas 1356. cursum ab occidente in orientem continudrit, ostio 84 leucas la
to in Oceanum pr&cipitatur. Chr. D'Acugna Relatio de
flumine Amaz. in Act. Erud. Aug. 1683.
The great Variety and Quantity of all Things upon, and in the Terraqueous Globe, provided for theVJes of the fVorld.
THE last Remark I mail make about the Terraqueous Globe in general is, the great Variety of Kinds, or Tribes, as well as prodgious Number of Individuals of each various Tribe, there is of all
E $ Crca