Astronomia Magnetica

PART THREE MAGNETIC ASTRONOMY Planisphaerij Magnetici device, fοινραν, & containing all kinds of οακα νο-α. IIPOOIMATION. AFTERWARDS we have delivered all that can be done in Geometry by the aid of magnets; order now seems to require time, as in the Astronomical business there are miracles and wonders, let us only show that while we are doing it, we trust that we will gain some favor with those who delight in the curious and unseemly spectacles of nature. For this part exhibits many new, rare, and hitherto treated by no one, all of which will be exhibited by the triple method, either in the center of the water, or on the surface of the same, or, in short, outside the water in an isotropic art. Hypothesis I. Imagnetic bodies balanced in the middle of each, obtain a position similar to that of the sup-polar sphere, or very oblique, that is, if the poles of the said bodies, the poles of the horizon, and the axes answered the axis; They will not move at once, nor arrange themselves in a certain direction, but are fixed and immovable. even if they have been established in the orbit of virtue, they will remain; the reason for which was explained above in the magnetic paradoxes. Hypothesis II. The magnetic bodies, balanced in the middle of each other, obtained a position parallel to the horizon, or similar to a straight sphere, that is, if the poles of both magnetic bodies and their axes had a position in the same plane of the horizon; they will move themselves very well in turn, and arrange themselves perfectly; and each circle will complete in one turn. Hypothesis III. The two magnetic bodies having been parallel under the azimuthal plane, arrange themselves the best and most easily of all, and the body they will remain; the reason for which was explained above in the magnetic paradoxes.

When a moving pore moves around, the other movement will complete the circle at the same time; and if both are left to their freedom, both will turn towards the south. Hypothesis IV. If two magnetic bodies, such as needles and magnets, are arranged in this way, the coil is suspended in the air at the other end. That is to be understood. Note that the sections of all cones fall into the 5th species; Indeed, the line on the surface of the cone is either a straight line, or a circle, or a parabola, or a hyperbola, or an ellipse. Between these lines there is an order, the cause of their property, and more analogical than geometrically speaking: that there is a transition from a straight line through infinite hyperbolas into a parabola, and from there through infinite ellipses into a circle; for the straight line is the most obtuse of all hyperbolas, the sharpest parable; thus of all ellipses the most acute is the parabola, the most obtuse circle: supposing this, let the round magnet be ABCD, whose pole CD be the quadrant GEH, let the needle be suspended in G at the ninetieth degree of the quadrant, and let the magnet move above its center in a circle, I mean the needle suspended at G from the pole of the magnet C treat a circle inscribed in a plane normally intersected; for when it has a subpolar position, it is not unlike the Sun's fimen under the pole that describes circles around the gnomon, and she will affect the circle by her motion, when she is equally distant from every side of the pole. Again, the needle is attached somewhere within the 66th degree, and 90, I mean the needle is drawn around the pole of the magnet C, in some interposed plane, describing an ellipse, for when the cone GCT which the needle describes, intersects obliquely with the plane CT, the ellipse follows the necessary birth from there. The needle is actually at 66. degree & 30 min. suspended in the plane CT to the pole, it will describe a parabola. For such is the section of a cone having its base parallel to 1, and the horizontal plane to a latitude of 66 degrees. & 30 min. Finally, if a needle is suspended somewhere within the space HI, it is surrounded by a pole, in a plane intersected by the necessity of a hyperbola

CAPVT I. The Magnetic Sphere. PROBLEM 1. To construct a Magnetic Astrolabe, or Planisphere. Here, Reader, you will have certain things which can be of themselves independently of magnetic motions, but good and just counsels, that I present to you a magnetic apparition, for this is done, not that you may become richer than I; but that the criminal's conviction should not escape from me beyond Rhombus. Let there be a circle in some solid material of any size ABCD divided into 4 quadrants by the ratio you see; and the line AB will refer to the axis of the world DCA the equator, and the circle ABCD to the meridian, to which you will inscribe the parallels of the Sun or of the signs which follow the reasoning. The numbers from the points DC on both sides, both towards A and B, the maximum declination of the Sun, namely 23 degrees and 30 minutes. and by the end, draw straight lines parallel to the Equator, the line of which IS, 69. PN verò W refers to the Tropic; the parallels of the other true signs and the table of the declination of the points of the ecliptic, or describe the degrees of the signs

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