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A new devise by any staffe, to levell, mount, and imbase any peece.
ALso any peece may with a field Linstock, Rammer, or Spunge, or other staffe be moun∣ted to any degree of the Quadrant, being thus prepared, first mark from one end of that staffe a distance equal unto the height of the pomel or caskabel of the peece, placed levell upon her platform, & then take the distance between the centre of the Tronions, and the po∣mell or caskabell, which make or imagine a semidiametre of a Circle, and divide it by diago∣nals or paralels, or otherwise into a 1000. equal parts. Lastly out of the table of Sines, take the number answering to every degree out of the said 1000. parts, and set that distance from the said mark downwards, and if the totall Syne of the table be 100000. omit the two last figures of each number thereof toward the right hand, and if it be 10000000. then omit 4. figures of each number you find in that Table, and the remaining number will shew how many of those 1000. equall parts are to be set downwards from the mark beneath the said levell for each severall degree: Then drawing also 10. paralels or diagonals from the first degree to the second, and from the second to the third, &c. successively continued from each to his next, no∣ting every degree with Arithmeticall characters, so you may from six minutes to six minutes by those right signes mount the peece, so set forth for any peece which it shalbe prepared for. This may also be described upon such a staffe without the table of synes in a mechanical man∣ner thus, If you describe a Quadrant or quarter of a circle with a semidiametre, equall to the distance from the centre of the trunions, to the centre of the pomel or caskabel, & devide the Arch of that quadrant into 90. equall parts or degrees, and then from each degree letting a line fall perpendicularly upon the base side of the said quadrant, and lastly, each of those right lines being thence transferred from the said first marke downwards upon the said staffe, and marking them with arithmeticall figures for each degree, thereupon making also paralels and Diagonals as aforesaid, you may thereby Geometrically and mechanically marke the same from 6. to 6. minutes as before. The use of them is plain and easie, for if you bring downe the centre of the caskabel or pomel of the peece to any number of the degrees thereon so mark∣ed, for that peece, you setting the lower end of the staffe to the platform being even, although it be rising or descending backwards, I say then the axis of the bore of that peece wilbe found to be elevated to the degree assigned: If you be to imbase the peece, those lines and number also set above the first named mark, will perform the like office there, in the thing required.