B. As having three Dimenfions, viz. Length, Breadth, and Thickness. A. Is this Confideration of Matter the most philosophical? B. No; 'tis too vulgar and defective. A. What is a more accurate Method to acquire the beft Knowledge and Ideas of Matter, or Bodies, that we are capable of? B. By confidering thofe Properties and Affections thereof, which are obvious to us, and best known by us. A. How are the Properties of Bodies distinguished ? B. Into thofe which are common to all alike, and those which are peculiar to each in particular: The firft are called Common and Effential, the latter Specific and Accidental. A. Which are the Properties of the first Sort ? B. They are generally reckoned thefe which follow : I. Extenfion, for all Bodies are extended. II. Divisibility, for all Bodies may be di vided. III. Solidity, for the Particles of all Bodies are hard. IV. Figurability, for all Bodies have fome Form or Figure. Properties, Qualities, of natural Bodies. 35 V. Mobility, for all Bodies are capable of being moved. A. Is this Enumeration of the common Properties of Bodies every way juft, and equal in all Things? B. No, I do not think it is; for firft, they may all be afferted of the whole Body except Solidity, which agrees only to the Particles of Bodies; again, other Properties may as univerfally be afferted of Bodies as fome of thefe, as Durability; for a Pody is no lefs infinitely durable, than it is infinitely divifible. A. Which are thofe other Properties of Bodies, which you call Specific or Acci dental? B. They are generally reckoned the following: I. Light. IV. Gravity and Levity. XII. Humidity and Siccity. XIV. Odours and Sapours. A. What do you call the Elements of natural Bodies? B. Those pure and fimple Substances of which all grofs and mix'd Bodies are said to confift ; and into which they may ultimately be refolv'd, or reduc'd. A. How many are thofe Elements reckoned to be? B. The Ancients counted feven, viz. Fire, Air, Water, Earth, Salt, Sulphur, Mercury. A. How many do the Moderns reckon? B. Some of the modern chymical Philofophers reckon five, viz. Mercury, Phlegm, Sulphur, Salt, and Earth. Others reduce them to three, viz. Mercury, Sulphur, and Salt. Whereas in reality, there are no other Elements of natural Bodies than the primogenial Particles of Matter, or Substance, of which they confift univerfally, and endued with the Properties above mentioned. CHAP. CHA P. II. Of Extenfion, and the Magnitude, and Dimensions of natural BODIES. A. I Remember you faid the first of the univerfal and effential Properties of Matter, or Body, was Extenfion; pray explain what is meant thereby? B. Extenfion of Matter, is the Quantity of Bulk, or Size, into which the primogenial Particles of Matter are distributed, or extended, in any natural Body. A. What ariseth hence? B. The Doctrine of Magnitude, and Dimenfion of Bodies. A. Pray, what do you call the Magnitude of Bodies? B. Their Size, or Bulk, or Quantity of Space, which they take up. A. How do you compute, or estimate, the Magnitude of Bodies? B. By the Quantity of their Dimenfions. A. What do you call the Dimensions of Bodies? B. Their Extenfion in Length, Breadth, and Thickness, or Depth; and these are the common Terms, or Bounds, which limit the Subftance of all Bodies. A. Have all Bodies these three Dimenfions? B. Yes, they have; though one, or two, or all of them, escape our Senfes; yet, they nevertheless exift together in all Bodies. A. How do fome then fay, that a Point hath no Dimenfions? B. They mean by this, a Point, or thefmalleft Part of Space, which, naturally fpeaking, is Nothing, and therefore hath no Properties. A. How are Bodies differenc'd with Refpect to their Dimensions? B. They are by Mathematicians, on that Account, diftinguished into Points, Lines, Superficies, and Solids. A. As how? B. They call that a Point, when all the three Dimenfions are fo very finall, as to be altogether imperceptible, as the Speck A: A Line, is that which appears to have no Breadth, or Thickness, as BC: A Superficies, that which hath Length and Breadth, but no perceiveable Thicknefs, as ABCD: Lastly, they call that a Salid, which hath evidently all the three Dimenfions, as the Solid |