12. Though there be no body which has not some magnitude, yet if, when any body is moved, the magnitude of it be not at all considered, the way it makes is called a _line_, or one single dimension; and the space, through which it passeth, is called _length_; and the body itself, a _point_; in which sense the earth is called a _point_, and the way of its yearly revolution, the _ecliptic line_. But if a body, which is moved, be considered as _long_, and be supposed to be so moved, as that all the several parts of it be understood to make several lines, then the way of every part of that body is called _breadth_, and the space which is made is called _superficies_, consisting of two dimensions, one whereof to every several part of the other is applied whole. Again, if a body be considered as having _superficies_, and be understood to be so moved, that all the several parts of it describe several lines, then the way of every part of that body is called _thickness_ or _depth_, and the space which is made is called _solid_, consisting of three dimensions, any two whereof are applied whole to every several part of the third. But if a body be considered as _solid_, then it is not possible that all the several parts of it should describe several lines; for what way soever it be moved, the way of the following part will fall into the way of the part before it, so that the same solid will still be made which the foremost superficies would have made by itself. And therefore there can be no other dimension in any body, as it is a body, than the three which I have now described; though, as it shall be shewed hereafter, _velocity_, which is motion according to _length_, may, by being applied to all the parts of a _solid_, make a magnitude of motion, consisting of four dimensions; as the goodness of gold, computed in all the parts of it, makes the price and value thereof. [Sidenote: Equal, great, greater, and less, in bodies and magnitudes, what they are.] 13. _Bodies_, how many soever they be, that can fill every one the place of every one, are said to be _equal_ every one to every other. Now, one body may fill the same place which another body filleth, though it be not of the same figure with that other body, if so be that it may be understood to be reducible to the same figure, either by flexion or transposition of the parts. And _one body is greater than another body, when a part of that is equal to all this; and less, when all that is equal to a part of this_. Also, _magnitudes_ are _equal_, or _greater_, or _lesser_, than one another, for the same consideration, namely, when the bodies, of which they are the magnitudes, are either _equal_, or _greater_, or _less_, &c. [Sidenote: One and the same body has always one and the same magnitude.]