M.
Species of all sensible things made by the mind. This prov'd either by turning men's eyes into magnifyers or diminishers.
Yr m. v. is, suppose, less than mine. Let a 3rd person have perfect ideas of both our m. vs. His idea of my m. v. contains his idea of yours, & somewhat more. Therefore 'tis made up of parts: therefore his idea of my m. v. is not perfect or just, which diverts the hypothesis.
Qu. Whether a m. v. or t. be extended?
Mem. The strange errours men run into about the pictures. We think them small because should a man be suppos'd to see them their pictures would take up but little room in the fund of his eye.
It seems all lines can't be bisected in 2 equall parts. Mem. To examine how the geometers prove the contrary.
'Tis impossible there should be a m. v. less than mine. If there be, mine may become equal to it (because they are homogeneous) by detraction of some part or parts. But it consists not of parts, ergo &c.
Suppose inverting perspectives bound to ye eyes of a child, & continu'd to the years of manhood—when he looks up, or turns up his head, he shall behold wt we call under. Qu. What would he think of up and down[238]?