網頁圖片
PDF
ePub 版

Latitude, in the Atlantic, Ethiopic, and PacifOceans : Which proceeds from the Sun's rarifying the Air over those Parts, and the flowing in of the denser Air from the distant Parts of each Hemisphere. (5.) Some Winds blow only one Half or one Quarter of the Year one way, and then the contrary, which are callid Monsoons, or Periodical Trade-Winds; these are found in the Arabian, Indian, and Chinese Seas ; for the Caufe whereof see the Philosophical Grammar. (6.) The Velocity of Wind is at the Rate of 50 or 60 Miles in a great Storm, and a common brisk Wind about 15 Miles an Hour ; and some move not one Mile an Hour. (7.) The Use of the Wind is very great, in cooling and cleansing the Air from all poisonous Contagions, and pestilential Exhalations ; and thereby keeping it pure, and health;ul. The Winds also carry the Clouds, and distribute the Rains to the several Parts of the Earth ; with

many other excellent Uses. Meteorography METEOROG RAPHY is a Description

of the Meteors of the Air ; as Vapours, Clouds,

Rain, Thunder, &c. which here follow in Order. Vapours. VAPOURS, of which most Meteors pro

ceed, are a Body of aqueous Particles fome-how separated from the Surface of the Water, or muist Earth, by the Action of the Sun's Heat, and are so finall as to be specifically lighter than Air, into which therefore they rise and Moat, and form the Clouds.

MISTS and FOGS are a Commixture of Fogs.

Vapours and Exhalations; the latter as they tisibly arise and ascend from particular Places, as Rivers, Lakes, Fens, Marshes, &c. and the former as they descend and fill the Air, and render

it more opake than usual. Clouds. CLOUDS are nothing else but Misty Vapours suspended aloft in the Air, and soaring on

the

Mifts and

the Wings of the Wind : These, when by the Agitation of Winds, the sides of Mountains, or any other Means, they are driven together and condensed into yet thicker and darker Clouds, become specifically heavier than Air, and descend in Drops of Rain.

Rain. SNOW is occasion'd from Particles of Va- Snow. pours frozen into Icicles in the Cold Regions of the higher Air, which being heavier than Air, fall down, and in their Descent several of them striking together, coalesce, and form Fleeces of Snow.

HAIL proceeds from Drops of Rain con- Hail. geald into Ice by Nitrous Particles which they meet with in their Descent through the inferior Air.

ICE and FREEZING are supposed to Ice and Freebe the Effects of Nitrous Particles, which being

zing. sharp and pointed, insinuate themselves into the Pores of Water, Dew, &c. and do thereby fix, crystalize and harden the Superficies thereof into the Substance we call Ice, and Frosts, &c.

THUNDER proceeds from an heteroge- Thunder and nous Commixture of the Effluvia or Exhalations Lightning. of sulphureous, nitrous, and inflammable Bodies in the Air, which ferment, kindle into Flames, and make horrible Explosions (like Gun-powder) which we call Thunder and Lightning.

THE AURORA BOREALIS, or Northern Aurora BoreLights are produced also from Nitro-fulphureous

alis. Vapours, which are thinly spread through the Atmosphere higher than the Clouds, and by Fermentation take Fire, and the Explosion of one Portion kindling the next, the Flashes succeed one another till all the Vapour within their Reach is set on Fire, the Streams whereof will appear to converge towards the Zenith of the Spectator, or the Point over our Heads.

THE

E e 3

Ignis Fatuus.

The IGNIS TATUUS, or Jack with a Lanthorn, is supposed to be nothing but a fat, untuous and sulphureous Vapour, which appears lucid, and is wafted about by the Air, near the Earth's Surface, like a Light in a Lantborn. Such like Vapours kindling in the serene Air in the Night, appear like falling Stars, and are

therefore so call'd. The Rain- THE RAIN-BOW, one of the finest of the Bow.

Phenomena of Nature, exists in falling Rain or Dew, and is produced by Reflection and Refraction of the Sun's Rays in the aqueous Particles; the Manner whereof and the conderful Properties of the Bow, too large and many to be here explain’d, may be seen in my Philofophical

Grammar. Halo's.

HALO'S are those Circles which are seen sometimes to encompass the Sun and Moon, and are often variously colourd ; they always appear in a rimy or frosty Sky, and proceed from the Refraction only of the Light in the Hail-ftones in the Air. Their Diameter is generally about 45 or 46 Degrees.

G E O L O GY. Of Geology, GEOLOGY is a Physiological Description of and its Parts. the Terraquecus Globe, so callid as consiiting of

Land and Water. This Branch of Philojor by is divided into two others, viz. (1.) Geografky, which treats of the dry Land , and (2.) Hydrography, which treats of the watry Parts of the

Globe, and the Properties of Water in general. Geograpiy. GEOGRAPHY is again subdivided into

(1.) Geography especially fo call’d, which treats of the Surface of the Land, and all its ParticuJars. (2.) Mineralogy, which treats of F/?, Minerals, Earths, &c. in the Bowels of the Earth. (3.) Phytology, which treats of the Na

ture

ture of Vegetables ; and (4.) Zoology, which treats of the various kinds of Animals.

HYDROGRAPHY also considers (1.) Hydrography. The Sea, its Figure, Tides, Saltness, Extent, &c. (2.) The Doctrine of Fountains, Rivers, Lakes, &c. Of all which in Order.

SPECIAL GEOGRAPHY has been discoursed of, as a particular Science ; I shall therefore pass to

MINERALOGY, which treats of Sub- Mineralogy'. jects dug up out of the Bowels of the Earth, which may be reduced to these seven Heads. (1.) Earths. (2.) Ores. (3.) Fofils. (4.) Minerals. (5.) Metals. (6.) Stones. (7.) Exuvia, and other extraneous Bodies.

EARTHS include all those softer earthy Sub- Earths. stances, we call Clay, Loam, Marl, Sand; and the Boles or Earths, as the Terra Japonica, Lemnia, Armenia, &c. all which result from the various and different Degree, Mixture, and Modification of the Universal Properties and Specific Qualities of the constituent Particles of the Matter whereof they consist. ·

ORES are those kinds of Earth which are dug Ores.
out of Mines, containing great Quantities of Me-
tallic Particles, and from which Metals are ex-
tracted ; as Gold-Ore, Silver-Ore, &c.

FOSSILS are properly speaking all Bodies Fofils.
dug out of the Earth, concerning which see the
Fossil Kingdom under the Title Chemistry and the
Philofopbical Grammar.

MINERALS are all such Fossil-Bodies as Minerals. are not inflammable, duktile, or fusible ; but are bard; brittle, and may be reduced to Powder, or calcined by Fire. They are sometimes callid Semi-Metals, as being of a middle Nature between Stones and Metals; the principal of these are Marcasite or Bismuth, Antimony, Cinnabar, Chalk,

Coal,

Ee 4

Metals.

Gold.

Silver.

Coal, &c. to which some add Mercury or Quicksilver.

METALS are simple Fossil-Bodies, that fuse or become fluid by Fire ; and by Cold coagulate and harden into a solid Mass; and lastly are malleable or ductile under the Hammer. The Bodies to which this Definition belongs in every Part are but Six, viz. (1.) Gold, which is the beaviet, most ductile, malleable, fixed and pure of all Bodies; it is easier fused than Iron or Copper ; is diffolvable in no Menstruum but Aqua Regia ; and is found sometimes in Glebes of Ore, and sometimes in pire Dust or Grains in the Bottom of some Rivers in Guinea, &c. (2.) Silver is next to Gold in Purity, Fixity, Ductility or Milleability; is more difficult of Fusion than Gold or Lead; is diffolvable in Aqua fortis, but not in Aqua regia ; it is seldom found pure, most often in a kind of stony black Glebe in the Mines of Peru and Chili. (3.) Copper; it is next to Silver in Weight, is very ductile when pure ; its Fixity is greater than that of Lead or Tin; it is diffoluble by all Salt Menstruums yet known : If it be disfolved in an acid one, it turns Green; if in an alcaline, Rod; and in others, Blue. It is the molt Elaflic and Sonorous of all Metals. The richest Copper-Ore is in the Mines of Hungary. (4.) Iron ; this Metal is compounded of a Vitriolic Salt, Sulphur, Earth ill digested together. It is the least duktile, the hardest and most brittle of all Metals. It ignifies long e'er it fuses. It is diffoluble by all Menstruums. It is the only Metal subject to the Magnetic Power, and has a kind of Magnetic Virtue in itself. It is every where found in Mines, in a stony Glebe, like a Loadstone. (5.) Tin ; this is the lightest of all Metals, and the softest except Lead. It has the leaft Fixiły in Fire ; is easily fusible, and that

long

Corper.

Iron,

« 上一頁繼續 »