Of strange Cjlajjes.

or delusions: Swords drawn will glister in at the hole, that they will make peoplealmost afraid. I have often (hewed this kind of Spectacle to my friends, who muchadmired it, and took pleasure to see such a deceit; and I could hardly by naturalreasons, and reasons from the Opticks remove them from their opinion , when I haddiscovered the secret. Hence it may appear to Philosophers, and those that studyOpthks, how vision is made; and the question of intromission is taken away, thatwas antiently so oiscustcd;nor can there be any better way to demonstrate both,thanthis. The Image is let in by the pupil, as by the hole of a window; and t hat part ofthe Sphere, that is set in the middle of the eye, stands in stead ©f afrystal Table.I know ingenious people will be much delighted in this. It is declared more at largein oar Op icks. From hence may one take his priHciples of declaring any thing toone that is confederate with him, that is secret, though the party be far off, (hut up inprison- And no small Arts may be found out. You (hall amend the distance by themagnitude of the Glass. You have sussictent. Others that undertook to teach this,have utter’d nothing but toy es, and I think none before knew it. If you desire toknow

Him you may fee the Sun Eclipsed ,

Now I have determined to (hew how the Suns Eclipse may be seen.When the Sun i§Eclipsed, (hut your Chamber-windows, and put a paper hekoreahole, and yon(hall fee the Sun : let it fall upon the paper opposite from a Concave-glafs, and makea circle of the fame magnitude: do so at the beginning, middle, and end of it. Thusmay you without any hurt to your eyes, observe the points of the diameter of theSuns Eclipse.

Chap. VII.

How you may see in the darls what is light without by reason osTorches,

E may demonstrate the fame without the light of the Sur, not without won-' V der. Torches, or lights lighted on purpose in Chambers , we may fee inanother dark Chamber what is done , by fitting things as I said: but the light mustnot strike upon the hole, for it will hinder the operation ; for it is a second light thatcarries the Images. I will not conceal at last a thing that is still of wonder andmirth, because I am fain upon this discourse,

That by night an Image may seem to hang in a Chamber .

In a tempestuous night the Image of any thing may be represented hanging in themiddle of the Chamber, that will terrific the beholders. Fit the Image before thebole, that you desire to make to seem banging in the Air in another Chamber thatis dark; let there be many Torches lighted round about. In the middle of the darkChamber, place a white (beet, or some solid thing, that may receive the Image sentin: for the spectators that see not the sheet, will see the Image hanging in the mid-dle of the Air, very clear, not without fear and terror, especially if the Artificer beingenious.

Chap. VIII.

How without a Glass or representation os any other things an Image mdy seem to hang

in the Air.

B Efore I part from this Image hanging in the Air, I will (hew how yon may makethe Images of all things seem to bang in the Air, which will be a wonder ofwonders; chiefly being done without the apparition of a Glass, or a visible Object.But first we will examine what the Anticnts writ of this matter. One Vitellta de-scribes the business after his fashion,thus: Fasten the segment of a Cylinder in themiddle of the house, set upon a Table, or 8tvvl, that it may glance perpendicularly