EXPLANATION OF THE CONSTRUCTION AND USE.

A quadrant of modest size was constructed by us many years ago in the form shown here. It consists of a solid plate of OrichalcumA golden-colored brass alloy highly prized for its durability and beauty in scientific instruments. of considerable thickness, measuring one cubit from the Center A to the circumference B D C. Every part of it is gilded by means of gold, mercury, and fire original: "Auri hydrargyri & ignis beneficio" — This describes the process of fire-gilding, where a gold-mercury amalgam is applied and heated to create a permanent, lustrous finish., so that it remains more beautiful and clean, and is not subject to the tarnish that brass otherwise gradually collects unless it is frequently cleaned. Its outer limb B D C is subdivided in the common manner into 90 parts degrees, and each of these again into 12, so that this subdivision shows intervals of five minutes each. Within this is another distribution which the most famous Spanish mathematician, Pedro Nunes original: "Petrus Nonnius", described in his learned book On Twilight original: "de Crepusculis", believing it to have been used by Ptolemy in the past. This, however, is hardly worthy of belief. It is designed such that 44 smaller arcs are drawn within the outermost quadrant, following one another in succession. The outermost of these is divided into 89 parts; the following into 88; the third into 87; and so on, until the last and innermost is reached, which has 46 portions. These are represented here in the illustration. Its sighting rule D A has sights original: "pinnacidia" at A and D prepared in the usual way with holes; though at the lower sight at A, parallel slits can sometimes be applied to the upper one, according to our custom, so that the alignment becomes easier and more exact. A plumb line E F G is hung from the back, so that by its help one may know when the quadrant is correctly positioned; so that its lower side A B exactly reflects the equilibrium of the Horizon, and the other side A C the zenith above our heads; and the entire plane of the quadrant matches the plane of some vertical circle. That the quadrant may be so correctly directed is achieved partly by the screws it has near the lower arrangement of the pedestal, marked with the letters S, and partly by the screw at O M, which raises and lowers the quadrant itself until the plumb line shows that it is properly ordered. For it stands on a pedestal N M O P Q R S T, which is made entirely of pure iron along with the other requirements, where it is attached at the back near H. This support is somewhat movable near N, so that the quadrant can be moved up and down by the screw O M. For the iron rules M N and O N can be tightened or widened by means of that same screw O M; thus the quadrant can be raised or lowered slightly as needed. It can also be turned around in a concave channel N P toward any quarter of the sky desired, while the entire lower part of the pedestal, marked by the letters R S Q T, remains firm. This lower portion provides supports in the form you see, so that the quadrant stands firmly on its four screws indicated by the letters S T. These screws, as I said, direct the whole instrument into its proper position. These screws rest on small iron plates placed underneath near T; while these remain stationary on a table V X Y Z, the screws may be turned as desired. Let these general points regarding the quadrant and its pedestal suffice.

However, the picture L K which is somewhat visible within the center and the smallest quadrant, contained in a circular form, was engraved for the sake of ornament and also so that it might teach something through its symbolic meaning original: "Hieroglyphicâ fignificatione", since otherwise that space would be empty. In this illustration (to mention this in passing), next to a tree that is green and leafy on one side sits a young man crowned with laurel upon a square stone. He holds a celestial globe in one hand and a book in the other, extending his feet upon the green grass and herbs covering the roots of the tree. On the other side, namely the left side of the tree, the root is withered and the branches are sterile and lacking leaves. Among these is a table, holding something of almost everything that is held in high price by mortals on this earthly stage, such as: a small chest full of coins, scepters, crowns, family coats of arms, golden necklaces, gems, women's finery, cups, papers, dice, and similar things. All these a certain skeleton, representing death, surrounds with its hands and feet, as if snatching them for itself. Over the whole figure is written a half-verse of poetry which explains the allegorical meaning: WE LIVE BY OUR GENIUS; THE REST SHALL BELONG TO DEATH original: "VIVIMUS INGENIO COETERA MORTIS ERUNT". Thus, the first part of the half-verse hangs from the branches on the right and green side of the tree where that philosophizing youth sits, as if written on a scroll; the other portion follows on the other side. By these we wished to suggest that solid learning—especially the sublime knowledge of heavenly things—grants a perpetuity of life and memory in these lands; all other things are frivolous and fleeting, and perish along with the human body. However, when we look toward the eternity of the Kingdom of Heaven, then these very things which are now on the green side of the tree pass to the back, for there is no proportion between the finite and the infinite. Then the inscribed half-verse is changed differently, namely thus: WE LIVE IN CHRIST; THE REST SHALL BELONG TO DEATH original: "VIVIMUS IN CHRISTO, COETERA MORTIS ERUNT"; so that the first part is adapted to the green tree, the other to the sterile one. Within the green side of the tree, there is also a certain symbolic indication of the life and doctrine of Christ. The rest remains as before, except that human doctrines and inventions also pass to the left and back— The text cuts off mid-sentence, leading to the next page.