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PERSPECTIVE.
Among objects moved from the eye at equal distance, that undergoes
least diminution which at first was most remote.
When various objects are removed at equal distances farther from
their original position, that which was at first the farthest from
the eye will diminish least. And the proportion of the diminution
will be in proportion to the relative distance of the objects from
the eye before they were removed.
That is to say in the object _t_ and the object _e_ the proportion
of their distances from the eye _a_ is quintuple. I remove each from
its place and set it farther from the eye by one of the 5 parts into
which the proposition is divided. Hence it happens that the nearest
to the eye has doubled the distance and according to the last
proposition but one of this, is diminished by the half of its whole
size; and the body _e_, by the same motion, is diminished 1/5 of its
whole size. Therefore, by that same last proposition but one, that
which is said in this last proposition is true; and this I say of
the motions of the celestial bodies which are more distant by 3500
miles when setting than when overhead, and yet do not increase or
diminish in any sensible degree.