As in _Geometry_, the most natural way of beginning is from a Mathematical _point_; so is the same method in Observations and _Natural history_ the most genuine, simple, and instructive. We must first endevour to make _letters_, and draw _single_ strokes true, before we venture to write whole _Sentences_, or to draw large _Pictures_. And in _Physical_ Enquiries, we must endevour to follow Nature in the more _plain_ and _easie_ ways she treads in the most _simple_ and _uncompounded bodies_, to trace her steps, and be acquainted with her manner of walking there, before we venture our selves into the multitude of _meanders_ she has in _bodies of a more complicated_ nature; lest, being unable to distinguish and judge of our way, we quickly lose both _Nature_ our Guide, and _our selves_ too, and are left to wander in the _labyrinth_ of groundless opinions; wanting both _judgment_, that _light_, and _experience_, that _clew_, which should direct our proceedings. We will begin these our Inquiries therefore with the Observations of Bodies of the most _simple nature_ first, and so gradually proceed to those of a more _compounded_ one. In prosecution of which method, we shall begin with a _Physical point_; of which kind the _Point of a Needle_ is commonly reckon’d for one; and is indeed, for the most part, made so sharp, that the naked eye cannot distinguish any parts of it: It very easily pierces, and makes its way through all kind of bodies softer then it self: But if view’d with a very good _Microscope_, we may find that the _top_ of a Needle (though as to the sense very _sharp_) appears a _broad_, _blunt_, and very _irregular_ end; not resembling a Cone, as is imagin’d, but onely a piece of a tapering body, with a great part of the top remov’d, or deficient. The Points of Pins are yet more blunt, and the Points of the most curious Mathematical Instruments do very seldome arrive at so great a sharpness; how much therefore can be built upon demonstrations made onely by the productions of the Ruler and Compasses, he will be better able to consider that shall but view those _points_ and _lines_ with a _Microscope_.