Of PHYSIOLOGY, or NATURAL
PHILOSOPHY.

HYSIOLOGY, according to its Phyfiology de Derivation, fignifies a Difcourfe fined. concerning Nature, or the Nature of Bodies in general; and hence it is used to denote that Science or Study which enquires into and investigates the Caufes, Properties and Effects of all natural Bodies objected to our Sight, or falling under the Cognizance of any of our Senfes. For this Reafon this Study has long been call'd Phyfics, and Philofophy, or, more commonly, Natural Philofophy; and those who are skill'd therein are call'd Physiologists, Naturalifts, and Natural Philofophers.

THE Subject of this moft excellent Science be- Its Subject. ing no less than the wide and almost boundless Field of Senfible Nature, the Science itfelf must needs be exceeding great, and of the last Importance, of which we shall proceed to give the following short yet comprehenfive Sketch.

NATURAL PHILOSOPHY then may Its Parts. be properly divided into four Parts, viz. (1.) Somatology, which contemplates the Nature of Somatology. Matter in general, and its Properties, Accidents and various Modifications in all Natural Bodies. (2.) Uranology, which difcourfeth of the Conftitu- Uranology. tion of the Heavens, and the great Bodies of the Sun, Moon and Planets therein. (3.) Aerology, Aerology.

Dd

which

Geology.

Of Somatology.

Of Matter.

Its Properties,
Effential or
Accidental.

Effential Properties.

Of Extenfion.

which treats of the Nature of the Atmosphere and the various Meteors thereof. (4.) Geology, which takes a View of the Earth and Sea, with all their various Productions.

Of SOMATOLOGY. SOMATOLOGY is (according to its Etymon) the Doctrine of Natural Bodies, and confiders the Original and Effential Properties of Matter of which they are variously compofed.

MATTER itfelf is that which we generally call the Substance of Things, or that of which all Things do confift, under different Forms and Modes.

THE Properties of Matter or Body are twofold, viz. (1.) Essential and common to all Bodies. (2.) Specific and Accidental, which happen to Bodies not necessarily from the Nature of Matter, but cafually and comparatively only.

THE Effential Properties of all Bodies or Matter are these, (1.) Extenfion, for all Matter is extended. (2.) Solidity, for every Particle of Matter is impenetrable. (3.) Divifibility, for all Matter may be divided into still leffer Parts. (4.) Mobility, for all Bodies are capable of Motion. (5.) Figurability, all Bodies having fome Form or Figure. (6.) Gravity, for all Bodies have fome Weight. (7.) Menfurability, for all Bodies have fome Dimenfions. (8.) Inactivity, for no Matter can act or move of itself. (9.) Ubiety, for all Bodies occupy fome Place. (10.) Durability, for no Part of Matter can be annibilated.

EXTENSION is the Quantity of Bulk or Size into which the Particles of Matter are difpofed, or extended; for there is no Body which has not Length, Breadth and Thickness, which make what we call the Extenfion of Bodies.

SOLIDITY

SOLIDITY is that Property of Body, Solidity. whereby it excludes all others out of the Place which it poffeffeth; for no two Bodies can poffibly be in one and the fame Place at the fame time. Hence the Matter of the fofteft Bodies is equally folid with that of the bardeft: Thus at Cubic Inch of Water will no more than a Cubic Inch of Adamant be comprefs'd into less than a Cubic Inch of Space.

DIVISIBILITY is a Property of Matter Divifibility. which follows from the laft; for fince two Particles of Body cannot exift together or in the fame Place, 'tis neceffary they should exift separately, or in different Places; and fo may be confider'd as diftinct or feparate from each other, which is all that is meant by their being divided. The actual Division of Matter is very furprizing, as is manifeft from the Nature of Odours, Perfumes, Tinatures, Light, and several other Experiments on Bodies. And the Infinite Divifibility of Matter is eafily proved by Geometry.

MOBILITY is a Property which follows Mobility. from the Divifibility of Matter, and its being finite; for fince Matter is divifible into Parts, and does not fill all Space, 'tis poffible for one Part of Matter to be made to change its Place, or be removed from one Part of abfolute Space to another; which is call'd Motion, or local Motion of a Body.

FIGURABILITY is that univerfal Pro- Figurability. perty of Body, whereby it is neceffitated to appear in or put on fomne Shape or Form or other; for fince all Particles of Matter are finite, they must be contain'd within certain Bounds or Extremities, which must have fome kind of Mode or Fashion; which as it refults from mere Contingency, is infinitely various, and is call'd the Formality or Modification of Bodies.

Gravity and
Attraction.

Electricity.

Magnetism.

GRAVITY is that univerfal Difpofition of Matter whereby a lesser Part is carried towards the Center of any greater Part; thus all Parts of Matter, or Bodies on the Earth's huge Surface, have a Tendency to defcend to its Center or Middle Part: And this is call'd their Weight; and Gravitation in the leffer Body, but Attraction in the greater; because it does, as it were, attract and draw that leffer Body to itself. Some diftinguifh Attraction into that of Cohesion and Gravitation. Attraction of Cobefion is that whereby very minute Bodies, or the Particles of the fame Body are mutually drawn towards one another, and made to cobere and flick together. The Sphere of this Attraction is very fmall, for it acts only upon Contact, or at very fmall Distances, and in Proportion to the Surfaces of the attracing Bodies. Attraction of Gravitation is that whereby larger Bodies attract and act upon one another, whofe Sphere of Attraction is very great. This Attration is always proportional to the Quantity of Matter in Bodies, and decreases as the Squares of the Distances between the Centers of attracting Bodies increase.

ELECTRICITY is a kind of Attraction and Repulfion of very light Bodies alternately, by certain polifh'd Surfaces chafed or heated by Rubbing, or Friction: Thus Glass, Sealing-Wax, Amber, and Precious Stones, attract and repel Feathers, Hairs, Straws and other light Bodies at confiderable Distances, as known by common Experiments. Note, if a Glafs Tube be emptied of Air, it lofes its Electrical Quality.

MAGNETISM is another very furprising Species of Attraction, which that Foffil call'd the Ladtone is endow'd with. Every one knows its ftrange Power of attracting and repelling Iron; and the Virtue it communicates to the Mariner's

Compafs,