names distinct from those of the things marked by them.  The same reason holds here also.  Visible figures are the marks of tangible figures, and from sect. 59 it is plain that in themselves they are little regarded, or upon any other score than for their connexion with tangible figures, which by nature they are ordained to signify.  And because this language of nature doth not vary in different ages or nations, hence it is that in all times and places visible figures are called by the same names as the respective tangible figures suggested by them, and not because they are alike or of the same sort with them.

141.  But, say you, surely a tangible square is liker to a visible square than to a visible circle:  it has four angles and as many sides:  so also has the visible square:  but the visible circle has no such thing, being bounded by one uniform curve without right lines or angles, which makes it unfit to represent the tangible square but very fit to represent the tangible circle.  Whence it clearly follows that visible figures are patterns of, or of the same species with, the respective tangible figures represented by them:  that they are like unto them, and of their own nature fitted to represent them, as being of the same sort:  and that they are in no respect arbitrary signs, as words.

142.  I answer, it must be acknowledged the visible square is fitter than the visible circle to represent the tangible square, but then it is not because it is liker, or more of a species with it, but because the visible square contains in it several distinct parts, whereby to mark the several distinct corresponding parts of a tangible square, whereas the visible circle doth not.  The square perceived by touch hath four distinct, equal sides, so also hath it four distinct equal angles.  It is therefore necessary that the visible figure which shall be most proper to mark it contain four distinct equal parts corresponding to the four sides of the tangible square, as likewise four other distinct and equal parts whereby to denote the four equal angles of the tangible square.  And accordingly we see the visible figures contain in them distinct visible parts, answering to the distinct tangible parts of the figures signified or suggested by them.

143.  But it will not hence follow that any visible figure is like unto, or of the same species with, its corresponding tangible figure, unless it be also shown that not only the number but also the kind of the parts be the same in both.  To illustrate this, I observe that visible figures represent tangible figures much after the same manner that written words do sounds.  Now, in this respect words are not arbitrary, it not being indifferent what written word stands for any sound:  but it is requisite that each word contain in it so many distinct characters as there are variations in the sound it stands for.  Thus the single letter A is proper to mark one simple uniform sound; and the word adultery is accommodated