all. Wherefore by sect. 21 the OBJECT should
seem to approach the eye gradually as it recedes from the point B, that
is, at O it should (in consequence of the principle I have laid down in
the aforesaid section) seem nearer than it did at B, and at P nearer than
at O, and at Q nearer than at P; and so on, till it quite vanishes at Z.
Which is the very matter of fact, as anyone that pleases may easily
satisfy himself by experiment.

32. This case is much the same as if we should suppose an Englishman to
meet a foreigner who used the same words with the English, but in a
direct contrary signification. The Englishman would not fail to make a
wrong judgment of the IDEAS annexed to those sounds in the mind of him
that used them. Just so, in the present case the OBJECT speaks (if I may
so say) with words that the eye is well acquainted with, that is,
confusions of appearance; but whereas heretofore the greater confusions
were always wont to signify nearer distances, they have in this case a
direct, contrary signification, being connected with the greater
distances. Whence it follows that the eye must unavoidably be mistaken,
since it will take the confusions in the sense it has been used to, which
is directly opposed to the true.

33. This phenomenon as it entirely subverts the opinion of those who will
have us judge of distance by lines and angles, on which supposition it is
altogether inexplicable, so it seems to me no small confirmation of the
truth of that principle whereby it is explained. But in order co a more
full explication of this point, and to show how far the hypothesis of the
mind's judging by the various divergency of rays may be of use in
determining the apparent place of an OBJECT, it will be necessary to
premise some few things, which are already well known to those who have
any skill in dioptrics.

34. FIRST, any radiating point is then distinctly seen when the rays
proceeding from it are, by the refractive power of the crystalline,
accurately reunited in the retina or fund of the eye: but if they are
reunited, either before they arrive at the retina, or after they have
passed it, then there is confused vision.

35. SECONDLY, suppose in the adjacent figures NP represent an eye duly
framed and retaining its natural figure. In Fig. 1 the rays falling
nearly parallel on the eye, are by the crystalline AB refracted, so as
their focus or point of union F falls exactly on the retina: but if the
rays fall