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nute Gradations, that the difference of those that are nigher to the Top, from the Superior of all, is very little (and therefore cannot make so considerable a difference in the view of the parts of an-Object), but from those that are further off great enough, and the difference of the highest fibres from the iowest, greatest of all. Besides I would have it observed that 'tis the different tension of the Thalami Optici, and not so much a varying Expansion of them in the Eye, that makes the difference. For as the Eye discerns an Object more by the inward than outward cone of Vision: so the Soul may be well supposed to judg of or discriminate things abroad, not so much by the outward part of the fibres inserted in the Organ, as by the inward that terminate about the common Sensory in the brain and more immediately affect her.
8. Whereas I mention sometimes the parallelisme of the Correspondent fibres, I mean it not in a strict Mathematical Sense (as I partly hinted at the latter end of that Essay,) but only their being as it were in æquilibrio or due poise in respect of their situation; and therefore if those fibres had been straight (and not of a Curv'd figure, as they are) I should have rather chose to have exprest my mind by the phrase of Mathematicians, of their being in eodem plano. But my sense being understood there need not be any exception to the word, since it was not so easy to express my meaning by a better; and therefore I shall pass by this, and proceed to more real objections that have been sent me by Mr. Newton our worthy Prof. of Mathematicks at Cambridge (and other friends,) relating to the Opinion it self.
The i. Objection was made in the R. S. when it was read there, which (as I was told) was this; viz. That it seem'd difficult to conceive how those soft Medullary Fibres of the Nerve could have such a tension. But this is not harder to conceive than in that of a Spiders-Web, whose Mucous substance and Expansion very well answers to that of theRe-
