Natural v Magick. Doo^ 17.

and there, andinclining, it till it reflect right against the place; which you shall at-tain by locking on it, and coming toward it: and i't it be difficult, you cannot mi-stake, if you ule a quadrant or loose Inch instrument; and let it be let perpendicularupon a line, that cuts the Angle of reflection , and incidence of the lines, and youshall clearly fee what is done in that place. ; So it will happen also in divers places.Hence it is, that if one Glass will not do it well, you may do the fame by more Glas-ses - or if the visible Object be lost by too great a distance, or taken away by walls ormountains coming between * moreover, you (hall fit another Glass just against theformer,upon aright line, which may divide the right Angle, or else it will not bedone, and you (hall fee the place you desire. For one Glass sending the Image tothe other tenfold, and the Image being broken by many things, flies stem the eye,and you (hall fee what you first light upon, until such time as the Image is brought toyou by right lines, and the visible Object is not stopt by the windings of places crwalls: and the placing of it is easie. So oft-times I use to convey Images of things.But if otherwise you desire to fee any high place , or that stands uptight, and yonr eyecannot discern it; fit two Looking-glasses together long-ways, as I said, and fastenone upon the top of a post or wall, that it may stand above it, and the Object maystand right against it; the other to a cord, that you may move it handsomely whenyou please, and that it may make with the first sometimes a blunt, sometimes a sharpAngle, as need requires, until the line of the thing seen, may be refracted by the mid-dle of the second Glass to your sight, and the Angles of reflection and incidence beequal; and if you seek to fee high things, raise it ; if low things, pull it down, till icbeat back upon yonr sight, then (hall you behold it. If you hold one of'themin your hand, and look upon that, it will be mere easily done. I (hew you also

How to make a Glass th st shall jhew nothing hut what you will.

Also a Glass is so framed, that when you look into it, you shall not see your own pi-cture, but some 01 her face, that is not seen any where roundabout. Fasten a plainGlass on a wall upon a plain, set upright perpendicularly, and bow the top of it totheknown proportion of the Angle: right against it cut the wall,according as the pro-portion of some Picture or Tmage may require, and set it by it, according to a fitdistance, and cover it, that the beholder may not fee it (and the matter will be the-more wonderful) nor can come at it: The Glass at a set place will beat back theImage, that there will be a mutual glance of the visible Object and the sight, by theLooking-glasses: there place your eye; you (hall find that place, as I taught you be-fore. Wherefore the spectator going thither , (hall neither fee his own face, nor anything else besides: when he is opposed to it, and comes to the set place, he (hall secthe Image or the Picture,or some such thing, which he can behold nowhere else.You (hall now know

How a Glass may be made of plain Glajfes y whereby you may fee an Image flying in the Air .Nor is that Glass of less importance, or pleasure, that will represent men flying inthe Air. If any man would do it,it is easily done thus: Fit t wo pieces cf wood toge-ther like a square or gnomon of a Dial, aud being well faflned, they may make anAngle as of a tight angled triangle, or Iso'celes. Fasten then at each foot one greatLooking-glass, equally distant, right one against the other, aud equidistant stem theAngle: let one of them lye flat, and let the spectator place himself about the middleof it, being somewhat raised above the ground, that he may the more easily sec theform of the heel going and coming : for presently you shad perceive, if you set yourseisin a right line, that cuts that Angle, audit be equidistant to the horizon. Sothe representing Glass will fend that Image to the other, which > he spectator looksinto, and it will shake and move the bands and feet, as BirdS do when they fly.So (hall he fee his own Image flying in the other, that it will always move, so he de-part not from the place of reflection, for that wculd spoil it.

CHAP.