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Of PHYSIOLOGY, or NATURAL
CHYSIOLOGY, according to its Phyfiology des
Derivation, signifies a Discourse fined.
Study which enquires into and investigates the Causes, Properties and Effects of all natural Bodies objected to our Sight, or falling under the Cognizance of any of our Senses. For this Reason this Study has long been call'd Phyfics, and Philosophy, or, more commonly, Natural Pbilosopby; and those who are skill'd therein are calld Physiologists, Naturalists, and Natural Philosophers.
The Subject of this most excellent Science be- Its Subject. ing no less than the wide and almost boundless Field of Sensible Nature, the Science itself must needs be exceeding great, and of the last Importance, of which we shall proceed to give the following sort yet comprehensive 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 discourseth of the Constitu- Uranology. tion of the Heavens, and the great Bodies of the Sun, Moon and Planets therein. (3.) Aerology, Aerology.
which treats of the Nature of the Atmosphere and Geology. the various Meteors thereof. (4.) Geology, which
takes a View of the Earth and Sea, with all their
Of S O MATOLOGY.
mon) the Do&trine of Natural Bodies, and con-
Matter of which they are variously composed.
call the Substance of Things, or that of which
(2.) Specific and Accidental, which happen to
but casually and comparatively only.
ter are these, (1.) Extension, for all Matter is ex-
bility, for no Part of Matter can be annibilated. Of Extenson.
EXTENSION is the Quantity of Bulk or Size into which the Particles of Matter are difposed, or extended; for there is no Body which has not Length, Breadth and Thickness, which make what we call the Extension of Bodies.
SOLIDITY is that Property of Body, Solidity. whereby it excludes all others out of the Place which it poffeffeth ; for no two Bodies can possibly be in one and the same place at the same time. Hence the Matter of the softest Bodies is equally solid with that of the hardejt: Thus a Cubic Inch of Water will no more than a Cubic Inch of Adamant be compress'd into less than a Cubic Inch of Space.
DIVISIBILITY is a Property of Matter Divisibility. which follows from the last ; for since two Particles of Body cannot exist together or in the same Place, 'tis neceffary they should exist separately, or in different Places; and so may be consider'd as distinct or separate from each other, which is all that is meant by their being divided. The aktual Division of Matter is very surprizing, as is manifest from the Nature of Odours, Perfumes, Tinĉtures, Light, and several other Experiments on Bodies. And the Infinite Divisibility of Matter is easily proved by Geometry.
MOBILITY is a Property which follows Mobility. from the Divisibility of Matter, and its being finite ; for since Matter is divisible into Parts, and does not fill all Space, 'tis possible for one Part of Matter to be made to change its Place, or be removed from one Part of absolute Space to another ; which is callid Motion, or local Motion of a Body.
FIGURABILITY is that universal Pro- Figurability. perty of Body, whereby it is necessitated to appear in or put on soine Shape or Forin or other ; for since all Particles of Matter are finite, they must be contain'd within certain Bounds or Extremities, which must have some kind of Mode or Fashion ; which as it results from mere Contingency, is infinitely various, and is calld the Formality or Modification of Bodies. pd 2
GRAVITY is that universal Disposition 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 descend to its Center or Middle Part: And this is call'd their Weight; and Gravitation in the lesser Body, but Attraction in the greater ; because it does, as it were, attrait and draw that lesser Body to itself. Some distinguish Aitraction into that of Cohesion and Gravitation. Attraction of Cohesion is that whereby very minute Bodies, or the Particles of the same Body are mutually drawn towards one another, and made to cohere and stick together. The Sphere of this Attraction is very small, for it acts only upon Contact, or at very small Distances, and in Proportion to the Surfaces of the attracting Bodies. Attraction of Gravitation is that whereby larger Bodies attract and act upon one another, whose Sphere of Attraction is very great. This Atiraction 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 Attration and Repulsion of very light Bodies alternately, by certain polish'd Surfaces chafed or heated by Rubbing, or Friction : Thus Glass, Sealing-Wix,
Amber, and Precious Stones, attract and repel Feathers, Hairs, Straws and other light Bodies at considerable Distances, as known by common Experiments. Note, if a Glass Tube be emptied of Air, it loses its Electrical Quality.
MÁGNETIS M is another very surprising Species of Attraction, which that Fossil callid the L'adione is endow'd with. Every one knows its strange Power of attrafting and repelling Iron ; and the Virtue it communicates to the Mariner's