Various Questions and Inventions

A technical diagram of a gunner's quadrant (squadra), an instrument used to measure the elevation of a cannon. It features a right-angled frame with a curved, graduated arc. The vertex is labeled 'H'. The left arm contains the label 'F' and ends at point 'E'. The right arm ends at point 'C'. The arc connecting the arms is marked with several points labeled 'I', 'G', and 'K'. A plumb line (perpendicolo) hangs from the vertex 'H', passing through point 'G' on the arc and ending in a weight or plumb bob labeled 'D'.

Each of these parts, or points, must also be divided into another twelve equal parts in the same order. I have not wished to draw these divisions in this small figure, because they would generate confusion, but in a square of common size, just as I have said, it should be divided, such that the entire said quadrant e. f. i. g. k. will come to be divided into 144 equal parts. These parts we shall call minutes, and these minutes are marked with little lines somewhat shorter than those of the points, because they are then easier to be numbered by means of the points (painted with larger lines), as one already knows that each point contains 12 minutes. Having done this, one must fix a small iron or brass pin precisely at point h. (the center of the quadrant) and attach to that pin a rotatable perpendicolo plumb line, that is, a silk thread (or of other material) with a small lead weight at the end, similar to the plumb line h. g. d. And thus with such an instrument, we have considered all the various positions, or elevations, that can occur in any piece of artillery. And the first position of each piece is understood to be when it is level, that is, so adjusted that by placing the longer leg of our said square into the mouth, extended straight through the bottom of the empty bore of the barrel, the plumb line falls precisely upon the side h. f. k. of the quadrant, as appears below in the first figure. And similarly, a piece is understood to be elevated one point when it is so adjusted that, by placing the said longer leg of our said square into the mouth, extended straight through the bottom of the empty bore of the barrel (as before), the plumb line falls precisely upon the division of the first point, as appears below in the second figure. And thus a piece is understood to be elevated two points when the said plumb line falls precisely upon the division of the said second point, and likewise to the third when it falls upon the division of the third; the same is understood of the fourth, fifth, and sixth. And when a piece is elevated to the sixth point (that is, with...