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Retina (whilst in its due position or Expansion in the Eye;) and as the least breath of Wind moves the one, so the least gale of the Etherial or lucid matter causes a vibration in the other.
Further it was objected, That it was hard to conceive how soft a body as the thalamus Opticus (being only a protuberance of the Medullary part of the Brain) could make such a difference in the Stress or tension of the fibres: But 'tis apparent that upon drawing the Nerve from it forward (according as 'tis situated and runs toward the Eye) the Superior fibres are more upon the Stress than the lateral, and Nature in these cases is finer in her operations (or to speak more properly the great Author of Nature is) then we are in our Conceptions of them. It seems so especially in the formation of this Organ, where the Apparatus of its parts in order to vision is so curiously contrive'd by the great Artist and all is done as it were in so fine Miniature and with so soft Touches of his inimitable hand, that it exceeds as much the other parts of the human body, as that does eminently transcend the remaining frame of the visible World.
2. It has been objected by others, That if the Superior fibres were more tense then the inferior we should see better by raies falling on the top than the bottom of the Eye, or see an object better p1ac't below our Eye (when the raies passing in a straight line from it must terminate in the top fibres) then above it, when vice versâ they must terminate in the lower fibres. To this I answer, that it does accordingly fall out so, and this is a more positive and direct proof of my Opinion; for I appeal to any man's experience whether the Characters in a Book appear not better to him, or he reads not better in it held about half a yard under his Eye than so much above it; or whether he does not more readily discern or find out objects beneath than above him with the same light: and this may be further illustrated by my [1]Ld, Bacons experiment of a mans appearing better on the ground to him that is plac't on a high steeple then vice versâ.
- ↑ Experim (illegible text) Cent. 3. Nat Hist.
3. It
