'Natural Maglcr. !Boo\ 17.

teen pillars: Lei one pillar be right against the fight; then raise Looking-glaffesEB-’on tbc lines of ipacebetween , cot exactly, but inclined: place then twoLcokipo.glades at opposition in aright line, but the re 11 about the beginning , .where theyjoyn , and that for no other teaion, but that the beholders face , being not rightly^placed,may not be reflected, as Hard before: lor thus thcGlafl’cs will not reprdentlaces, but pillars, and Spates between, and all ornaments. Hence by the recipro-cal reflection of the Glasses, you shall fee so many pillars, basis, and varieties,keepingthe right order of Architecture, that nothing can be more pleasant, or more wonder-ful to behold.Let the perfective be the Dorick and Corinthian, adorned with GoldSilver, Pearls,sjcwels, Images, Pictures, and such like, that it* may seem the moreMagnificent: the form of it (hall be thus. Let H. G. be the place for the beholder to

iook:t he pillar against him fhal be A,in theGlassA B, or AC, the face of the beholder-shallnot be seen, but A B is reflected into I H,and I H into R D, so by mutual reflectionsthey are so multiplied, thar they ieem to govery far inwardly, ib clearly and apparently,that no spectator that looks into it, unless heknow it, but he will thruki his hands in totouch the orders. If you set a Candle in themiddle, it will seem so to multiply by the I-mages rebounding, that you shall not lee somany Spars in the sJkies, that yon can neverwonder enough at the Order, Symmetry, andthe Prospect. I have raised and made thisAmphitheatre divers ways. spd to shew ether orders, namely two ranks of pillars,io that the one stuck toihcOUffes, the other stood alone in the middle, bound withthe chief Arches, and with divers Ornaments, that it may seem to be a most beautifulPerspective or Architecture. Almost the same way is there made a little chest of ma-ny pjain Glasses, covered round : this they call the Trealury : on the ground,archesand walls, were there Pearls, jewels, Birds, and Monies hanging , and these wereso multiplied by the reflections os the Glasses, that it represented a most rich Trea-sury indeed. Make therefore a Chest of wood , let the bottom be two foot long,and one and half broad ; let it be open in the middle, that you may well thrust inyour head; on the tight and left band, erect the side-boards a foot long, semicircu-lar above, that it may be arched, but not exactly circular, namely, divided into fiveparts, each a hand-breadih. Cover this all about with Glafles ; where the Glassesjoyn, there put Pearls, Pietiom-ssones, specious Flowers, divers colour’d Birds: ahove the bottom set heaps of Gold, aud Silver Meddals ; from the Arches, let therehan° Pearls, fleeces of Gold ;for when the Coffer is moved gently, they will movealsoTand the Images will move in the Glasses, that it will be a pleasant sight.

Chap. IV.

Vtvtrs operations of Concave• Glasts.

B Ut the operations of Concave-glasscs are far more carious and admirable, andwill afford us more commodities. But you can do nothing perfectly with it,until you know first the point of inversion. Therefore that you may do it the better,and more easily

Know the point of Inversion of Images in a Concave-glass ,

Do thus: Hold your Giass against the Son, and where you fee the beams unite,know that to be the point of Inversion. If you cannot well perceive that, breathea thick vapour from your mouth upon it, and you shall apparently fee where thecoincidence is of the reflected beams; or set under it a vessel of boyling water..When you have found the point of Inversion, if you will

'That