[…] But to leave these celestial causes and things done of antiquity long ago, my father by his continual painful practices, assisted with demonstrations Mathematical, was able, and sundry times hath, by proportional glasses duly situate in convenient angles not only discovered things far off, read letters, numbered pieces of money with the very coin and superscription thereof cast by some of his friends of purpose upon downs in open fields, but also seven miles off declared what hath been done at that instant in private places [sig. Aiijv]

[…] You may on this manner from a high hill or mountain, having any plain or level ground on the top, not only measure the distance of any mark that ye can see but also set forth the true plot and proportion of an whole country, with all the towns, coasts, harbors, &c.

[…] But marvelous are the conclusions that may be performed by glasses concave and convex of circular and parabolical forms, using for multiplication of beams sometime the aid of glasses transparent, which by fraction should unite or dissipate the images or figures presented by the reflection of other. By these kind of glasses, or rather frames of them, placed in due angles, ye may not only set out the proportion of a whole region, yea represent before your eye the lively image of every town, village, et cetera, and that in as little or great space or place as ye will prescribe, but also augment and dilate any parcel thereof, so that whereas at the first appearance a whole town shall present itself so small and compact together that ye shall not discern any difference of streets, ye may by application of glasses in due proportion cause any peculiar house or room thereof dilate and show itself in as ample form as the whole town first appeared so that ye shall discern any trifle, or read any letter lying there open, especially if the sun beams may come unto it, as plainly as if you were corporally present, although it be distant from you as far as eye can descry. But if these conclusions I mind not here more to entreat, having at large in a volume by itself opened the miraculous effects of perspective glasses. [sig. Giv-Giir]