For proof whereof we need go no farther than the case before
us. It having been observed that the most diverging rays brought into the
mind the idea of nearest distance, and that still, as the divergency
decreased, the distance increased: and it being thought the connexion
between the various degrees of divergency and distance was immediate;
this naturally leads one to conclude, from an ill-grounded analogy, that
converging rays shall make an object appear at an immense distance: and
that, as the convergency increases, the distance (if it were possible)
should do so likewise. That this was the cause of Dr. Barrow's mistake is
evident from his own words which we have quoted. Whereas had the learned
doctor observed that diverging and converging rays, how opposite soever
they may seem, do nevertheless agree in producing the same effect, to
wit, confusedness of vision, greater degrees whereof are produced
indifferently, either as the divergency or convergency and the rays
increaseth. And that it is by this effect, which is the same in both,
that either the divergency or convergency is perceived by the eye; I say,
had he but considered this, it is certain he would have made a quite
contrary judgment, and rightly concluded that those rays which fall on
the eye with greater degrees of convergency should make the object from
whence they proceed appear by so much the nearer.
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