THE AUTHOR’S PROPOSITION ON FIGURE V.

A NEW AND UNIVERSAL COMPASS, FOR DELINEATING AN OVAL FIGURE IN A SINGLE STROKE, WHOSE LONG DIAMETER CAN BE SHORT OR LONG, AS MUCH AS ONE WISHES, EXTENDED OR CONTRACTED.

Declaration of the same Fifth Figure.

An ornamental woodcut initial 'Q' containing a depiction of a figure (possibly a deity or mythological character) holding a compass and a globe.This Compass has certain things in common with the others; namely, an immovable Leg and an upper rotating arm, and those two parallel Rulers, which extend from the North to the South; for the rest is particular to it. For it has an arm to the South, parallel and similar to the aforementioned upper one. Then there are two small globes on the fixed Leg, the first of which is distant from the points by 1 measure and 7 parts, the other 1 measure and 2 parts from it, around which two flat orbs of medium thickness rotate freely, so that the interior part of the screw appearing can enter into its solid, and arrange either orb at the agent's discretion. In the middle of each orb is a cavity so elaborated that the lower part is wider than the upper; and it is said to be shaped like a swallow’s tail; in which a Tessella sliding block is adapted, moving freely in a circle around the fixed Leg. From each Tessella sliding block of this and that orb, two similar and parallel arms are produced, in the middle of which is a slot, in which the middle Ruler can be freely pushed and pulled, in which is the mobile point; whose motion toward the center, or the fixed Leg, is restrained by the work of that table, in which there is a screw to retain its motion. The remaining Ruler is for the firmness of the Machine. Now if the rotating parts are led around the immovable one, an Oval will be made; with the orbs so arranged that one part is lower, the other higher. For then the diameters on the plane, in which the fixed Leg is raised at right angles, are smaller in the elevated and depressed part; which a diligent explorer will easily notice.

Addition.

Large ornamental drop cap 'O'.THE Oval Figure is held in such high regard that, because of its beauty, it is very often found in Buildings in many and various ways: for the forming of which very many inventions already exist, partly conceived preposterously, partly of difficult and lengthy labor, and finally, partly detrimental: so that not rarely, indeed, is the work deformed, which we desired to be elaborated in a most beautiful Oval form. This certainly wonderful and illustrious Compass remedies all these inconveniences. It remains therefore to be observed that that screw-like nail, which appears in the Tessella sliding block, has no use there: for the Tessella sliding block itself, with the small arm produced from it, and into whose slot the middle perpendicular Ruler enters, must consist of only a single continuous piece of wood; which is easily recognized from the picture. Furthermore, this Ruler is moved freely in those two small arms into which it is inserted: so that once led, it may easily approach or withdraw from the immovable Leg, for the sake of the Orbs lowered on one side. For if they stood equally; that is, if they were parallel to the surface on which the Oval is to be described, then an Orbicular figure would be delineated. But if they hang lower on one side, and higher on the other, then the diameters will end up being shorter, because the circumference approaches closer to the foot of the fixed Leg, which is the center. The perpendicular Ruler, however, situated to the West, both square and fixed by a screw-like nail from its lower part to the Southern arm, shall finally be as it now appears, annexed to the other Northern Arm from its upper part.